From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This is an updated v5 patch series of the v4 series located here: https://lore.kernel.org/qemu-devel/cover.1738171076.git.maciej.szmigiero@oracle.com/ Changes from v3: * Use "unsigned long" for VFIO bytes transferred counter to fixes test issues on 32-bit platforms. * Instead of adding BQL holding around qemu_loadvm_state_main() in postcopy_ram_listen_thread() just add a TODO comment there. * Drop patches for gracefully handling improperly terminated TLS session and rely on recent Fabiano's changes to handle this case instead. * Adapt how MULTIFD_FLAG_DEVICE_STATE value is defined for consistency with neighboring flags. * Return Error type and use migrate_set_error() to set it also for save threads, much like it was previously done for load threads. * Export SaveLiveCompletePrecopyThreadData and make save threads take it directly instead of passing individual parameters stored there to a thread entry point. * Group all multifd device state save variables in multifd_send_device_state variable allocated on demand instead of using multifd-device-state.c globals. * Export save threads abort flag via multifd_device_state_save_thread_should_exit() getter function rather than passing it directly. * Separate VFIO multifd stuff into migration-multifd.{c,h} files. Needed moving VFIO migration channel flags to vfio-common.h header file. * Move x-migration-load-config-after-iter feature to a separate patch near the end of the series. * Move x-migration-max-queued-buffers feature to a yet another separate patch near the end of the series. * Introduce save/load common vfio_multifd_transfer_setup() and a getter function for multifd transfer switch called vfio_multifd_transfer_enabled(). * Move introduction of VFIOMigration->multifd_transfer and VFIODevice->migration_multifd_transfer into the very patch that introduces the x-migration-multifd-transfer property. * Introduce vfio_multifd_cleanup() for clearing migration->multifd. * Split making x-migration-multifd-transfer mutable at runtime into a separate patch. * Rename vfio_switchover_start() to vfio_multifd_switchover_start() and add a new vfio_switchover_start() in migration.c that calls that vfio_multifd_switchover_start(). * Introduce VFIO_DEVICE_STATE_PACKET_VER_CURRENT. * Don't print UINT32_MAX value in vfio_load_state_buffer(). * Introduce a new routine for parsing VFIO_MIG_FLAG_DEV_CONFIG_LOAD_READY. * Add an Error parameter to vfio_save_complete_precopy_thread_config_state() and propagate it from vfio_save_device_config_state() function that it calls. * Update the VFIO developer doc in docs/devel/migration/vfio.rst. * Add comments about how VFIO multifd threads are launched and from where this happens. Also add comments how they are terminated. * Other small changes, like renamed functions, added review tags, code formatting, rebased on top of the latest QEMU git master, etc. ======================================================================== This patch set is targeting QEMU 10.0. ======================================================================== Maciej S. Szmigiero (35): migration: Clarify that {load,save}_cleanup handlers can run without setup thread-pool: Remove thread_pool_submit() function thread-pool: Rename AIO pool functions to *_aio() and data types to *Aio thread-pool: Implement generic (non-AIO) pool support migration: Add MIG_CMD_SWITCHOVER_START and its load handler migration: Add qemu_loadvm_load_state_buffer() and its handler migration: postcopy_ram_listen_thread() should take BQL for some calls error: define g_autoptr() cleanup function for the Error type migration: Add thread pool of optional load threads migration/multifd: Split packet into header and RAM data migration/multifd: Device state transfer support - receive side migration/multifd: Make multifd_send() thread safe migration/multifd: Add an explicit MultiFDSendData destructor migration/multifd: Device state transfer support - send side migration/multifd: Add multifd_device_state_supported() migration: Add save_live_complete_precopy_thread handler vfio/migration: Add load_device_config_state_start trace event vfio/migration: Convert bytes_transferred counter to atomic vfio/migration: Add vfio_add_bytes_transferred() vfio/migration: Move migration channel flags to vfio-common.h header file vfio/migration: Multifd device state transfer support - basic types vfio/migration: Multifd device state transfer support - VFIOStateBuffer(s) vfio/migration: Multifd device state transfer - add support checking function vfio/migration: Multifd device state transfer support - receive init/cleanup vfio/migration: Multifd device state transfer support - received buffers queuing vfio/migration: Multifd device state transfer support - load thread vfio/migration: Multifd device state transfer support - config loading support migration/qemu-file: Define g_autoptr() cleanup function for QEMUFile vfio/migration: Multifd device state transfer support - send side vfio/migration: Add x-migration-multifd-transfer VFIO property vfio/migration: Make x-migration-multifd-transfer VFIO property mutable hw/core/machine: Add compat for x-migration-multifd-transfer VFIO property vfio/migration: Max in-flight VFIO device state buffer count limit vfio/migration: Add x-migration-load-config-after-iter VFIO property vfio/migration: Update VFIO migration documentation Peter Xu (1): migration/multifd: Make MultiFDSendData a struct docs/devel/migration/vfio.rst | 80 ++- hw/core/machine.c | 2 + hw/vfio/meson.build | 1 + hw/vfio/migration-multifd.c | 757 +++++++++++++++++++++++++++++ hw/vfio/migration-multifd.h | 38 ++ hw/vfio/migration.c | 119 +++-- hw/vfio/pci.c | 14 + hw/vfio/trace-events | 11 +- include/block/aio.h | 8 +- include/block/thread-pool.h | 62 ++- include/hw/vfio/vfio-common.h | 36 ++ include/migration/client-options.h | 4 + include/migration/misc.h | 25 + include/migration/register.h | 52 +- include/qapi/error.h | 2 + include/qemu/typedefs.h | 5 + migration/colo.c | 3 + migration/meson.build | 1 + migration/migration-hmp-cmds.c | 2 + migration/migration.c | 4 +- migration/migration.h | 7 + migration/multifd-device-state.c | 202 ++++++++ migration/multifd-nocomp.c | 30 +- migration/multifd.c | 246 ++++++++-- migration/multifd.h | 74 ++- migration/options.c | 9 + migration/qemu-file.h | 2 + migration/savevm.c | 190 +++++++- migration/savevm.h | 6 +- migration/trace-events | 1 + scripts/analyze-migration.py | 11 + tests/unit/test-thread-pool.c | 6 +- util/async.c | 6 +- util/thread-pool.c | 184 +++++-- util/trace-events | 6 +- 35 files changed, 2039 insertions(+), 167 deletions(-) create mode 100644 hw/vfio/migration-multifd.c create mode 100644 hw/vfio/migration-multifd.h create mode 100644 migration/multifd-device-state.c From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> It's possible for {load,save}_cleanup SaveVMHandlers to get called without the corresponding {load,save}_setup handler being called first. One such example is if {load,save}_setup handler of a proceeding device returns error. In this case the migration core cleanup code will call all corresponding cleanup handlers, even for these devices which haven't had its setup handler called. Since this behavior can generate some surprises let's clearly document it in these SaveVMHandlers description. Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Cédric Le Goater <clg@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/migration/register.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/include/migration/register.h b/include/migration/register.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/register.h +++ b/include/migration/register.h @@ -XXX,XX +XXX,XX @@ typedef struct SaveVMHandlers { /** * @save_cleanup * - * Uninitializes the data structures on the source + * Uninitializes the data structures on the source. + * Note that this handler can be called even if save_setup + * wasn't called earlier. * * @opaque: data pointer passed to register_savevm_live() */ @@ -XXX,XX +XXX,XX @@ typedef struct SaveVMHandlers { * @load_cleanup * * Uninitializes the data structures on the destination. + * Note that this handler can be called even if load_setup + * wasn't called earlier. * * @opaque: data pointer passed to register_savevm_live() * From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This function name conflicts with one used by a future generic thread pool function and it was only used by one test anyway. Update the trace event name in thread_pool_submit_aio() accordingly. Acked-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Cédric Le Goater <clg@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/block/thread-pool.h | 3 +-- tests/unit/test-thread-pool.c | 6 +++--- util/thread-pool.c | 7 +------ util/trace-events | 2 +- 4 files changed, 6 insertions(+), 12 deletions(-) diff --git a/include/block/thread-pool.h b/include/block/thread-pool.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/thread-pool.h +++ b/include/block/thread-pool.h @@ -XXX,XX +XXX,XX @@ ThreadPool *thread_pool_new(struct AioContext *ctx); void thread_pool_free(ThreadPool *pool); /* - * thread_pool_submit* API: submit I/O requests in the thread's + * thread_pool_submit_{aio,co} API: submit I/O requests in the thread's * current AioContext. */ BlockAIOCB *thread_pool_submit_aio(ThreadPoolFunc *func, void *arg, BlockCompletionFunc *cb, void *opaque); int coroutine_fn thread_pool_submit_co(ThreadPoolFunc *func, void *arg); -void thread_pool_submit(ThreadPoolFunc *func, void *arg); void thread_pool_update_params(ThreadPool *pool, struct AioContext *ctx); diff --git a/tests/unit/test-thread-pool.c b/tests/unit/test-thread-pool.c index XXXXXXX..XXXXXXX 100644 --- a/tests/unit/test-thread-pool.c +++ b/tests/unit/test-thread-pool.c @@ -XXX,XX +XXX,XX @@ static void done_cb(void *opaque, int ret) active--; } -static void test_submit(void) +static void test_submit_no_complete(void) { WorkerTestData data = { .n = 0 }; - thread_pool_submit(worker_cb, &data); + thread_pool_submit_aio(worker_cb, &data, NULL, NULL); while (data.n == 0) { aio_poll(ctx, true); } @@ -XXX,XX +XXX,XX @@ int main(int argc, char **argv) ctx = qemu_get_current_aio_context(); g_test_init(&argc, &argv, NULL); - g_test_add_func("/thread-pool/submit", test_submit); + g_test_add_func("/thread-pool/submit-no-complete", test_submit_no_complete); g_test_add_func("/thread-pool/submit-aio", test_submit_aio); g_test_add_func("/thread-pool/submit-co", test_submit_co); g_test_add_func("/thread-pool/submit-many", test_submit_many); diff --git a/util/thread-pool.c b/util/thread-pool.c index XXXXXXX..XXXXXXX 100644 --- a/util/thread-pool.c +++ b/util/thread-pool.c @@ -XXX,XX +XXX,XX @@ BlockAIOCB *thread_pool_submit_aio(ThreadPoolFunc *func, void *arg, QLIST_INSERT_HEAD(&pool->head, req, all); - trace_thread_pool_submit(pool, req, arg); + trace_thread_pool_submit_aio(pool, req, arg); qemu_mutex_lock(&pool->lock); if (pool->idle_threads == 0 && pool->cur_threads < pool->max_threads) { @@ -XXX,XX +XXX,XX @@ int coroutine_fn thread_pool_submit_co(ThreadPoolFunc *func, void *arg) return tpc.ret; } -void thread_pool_submit(ThreadPoolFunc *func, void *arg) -{ - thread_pool_submit_aio(func, arg, NULL, NULL); -} - void thread_pool_update_params(ThreadPool *pool, AioContext *ctx) { qemu_mutex_lock(&pool->lock); diff --git a/util/trace-events b/util/trace-events index XXXXXXX..XXXXXXX 100644 --- a/util/trace-events +++ b/util/trace-events @@ -XXX,XX +XXX,XX @@ aio_co_schedule_bh_cb(void *ctx, void *co) "ctx %p co %p" reentrant_aio(void *ctx, const char *name) "ctx %p name %s" # thread-pool.c -thread_pool_submit(void *pool, void *req, void *opaque) "pool %p req %p opaque %p" +thread_pool_submit_aio(void *pool, void *req, void *opaque) "pool %p req %p opaque %p" thread_pool_complete(void *pool, void *req, void *opaque, int ret) "pool %p req %p opaque %p ret %d" thread_pool_cancel(void *req, void *opaque) "req %p opaque %p" From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> These names conflict with ones used by future generic thread pool equivalents. Generic names should belong to the generic pool type, not specific (AIO) type. Acked-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Cédric Le Goater <clg@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/block/aio.h | 8 ++--- include/block/thread-pool.h | 8 ++--- util/async.c | 6 ++-- util/thread-pool.c | 58 ++++++++++++++++++------------------- util/trace-events | 4 +-- 5 files changed, 42 insertions(+), 42 deletions(-) diff --git a/include/block/aio.h b/include/block/aio.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/aio.h +++ b/include/block/aio.h @@ -XXX,XX +XXX,XX @@ typedef void QEMUBHFunc(void *opaque); typedef bool AioPollFn(void *opaque); typedef void IOHandler(void *opaque); -struct ThreadPool; +struct ThreadPoolAio; struct LinuxAioState; typedef struct LuringState LuringState; @@ -XXX,XX +XXX,XX @@ struct AioContext { /* Thread pool for performing work and receiving completion callbacks. * Has its own locking. */ - struct ThreadPool *thread_pool; + struct ThreadPoolAio *thread_pool; #ifdef CONFIG_LINUX_AIO struct LinuxAioState *linux_aio; @@ -XXX,XX +XXX,XX @@ void aio_set_event_notifier_poll(AioContext *ctx, */ GSource *aio_get_g_source(AioContext *ctx); -/* Return the ThreadPool bound to this AioContext */ -struct ThreadPool *aio_get_thread_pool(AioContext *ctx); +/* Return the ThreadPoolAio bound to this AioContext */ +struct ThreadPoolAio *aio_get_thread_pool(AioContext *ctx); /* Setup the LinuxAioState bound to this AioContext */ struct LinuxAioState *aio_setup_linux_aio(AioContext *ctx, Error **errp); diff --git a/include/block/thread-pool.h b/include/block/thread-pool.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/thread-pool.h +++ b/include/block/thread-pool.h @@ -XXX,XX +XXX,XX @@ typedef int ThreadPoolFunc(void *opaque); -typedef struct ThreadPool ThreadPool; +typedef struct ThreadPoolAio ThreadPoolAio; -ThreadPool *thread_pool_new(struct AioContext *ctx); -void thread_pool_free(ThreadPool *pool); +ThreadPoolAio *thread_pool_new_aio(struct AioContext *ctx); +void thread_pool_free_aio(ThreadPoolAio *pool); /* * thread_pool_submit_{aio,co} API: submit I/O requests in the thread's @@ -XXX,XX +XXX,XX @@ void thread_pool_free(ThreadPool *pool); BlockAIOCB *thread_pool_submit_aio(ThreadPoolFunc *func, void *arg, BlockCompletionFunc *cb, void *opaque); int coroutine_fn thread_pool_submit_co(ThreadPoolFunc *func, void *arg); +void thread_pool_update_params(ThreadPoolAio *pool, struct AioContext *ctx); -void thread_pool_update_params(ThreadPool *pool, struct AioContext *ctx); #endif diff --git a/util/async.c b/util/async.c index XXXXXXX..XXXXXXX 100644 --- a/util/async.c +++ b/util/async.c @@ -XXX,XX +XXX,XX @@ aio_ctx_finalize(GSource *source) QEMUBH *bh; unsigned flags; - thread_pool_free(ctx->thread_pool); + thread_pool_free_aio(ctx->thread_pool); #ifdef CONFIG_LINUX_AIO if (ctx->linux_aio) { @@ -XXX,XX +XXX,XX @@ GSource *aio_get_g_source(AioContext *ctx) return &ctx->source; } -ThreadPool *aio_get_thread_pool(AioContext *ctx) +ThreadPoolAio *aio_get_thread_pool(AioContext *ctx) { if (!ctx->thread_pool) { - ctx->thread_pool = thread_pool_new(ctx); + ctx->thread_pool = thread_pool_new_aio(ctx); } return ctx->thread_pool; } diff --git a/util/thread-pool.c b/util/thread-pool.c index XXXXXXX..XXXXXXX 100644 --- a/util/thread-pool.c +++ b/util/thread-pool.c @@ -XXX,XX +XXX,XX @@ #include "block/thread-pool.h" #include "qemu/main-loop.h" -static void do_spawn_thread(ThreadPool *pool); +static void do_spawn_thread(ThreadPoolAio *pool); -typedef struct ThreadPoolElement ThreadPoolElement; +typedef struct ThreadPoolElementAio ThreadPoolElementAio; enum ThreadState { THREAD_QUEUED, @@ -XXX,XX +XXX,XX @@ enum ThreadState { THREAD_DONE, }; -struct ThreadPoolElement { +struct ThreadPoolElementAio { BlockAIOCB common; - ThreadPool *pool; + ThreadPoolAio *pool; ThreadPoolFunc *func; void *arg; @@ -XXX,XX +XXX,XX @@ struct ThreadPoolElement { int ret; /* Access to this list is protected by lock. */ - QTAILQ_ENTRY(ThreadPoolElement) reqs; + QTAILQ_ENTRY(ThreadPoolElementAio) reqs; /* This list is only written by the thread pool's mother thread. */ - QLIST_ENTRY(ThreadPoolElement) all; + QLIST_ENTRY(ThreadPoolElementAio) all; }; -struct ThreadPool { +struct ThreadPoolAio { AioContext *ctx; QEMUBH *completion_bh; QemuMutex lock; @@ -XXX,XX +XXX,XX @@ struct ThreadPool { QEMUBH *new_thread_bh; /* The following variables are only accessed from one AioContext. */ - QLIST_HEAD(, ThreadPoolElement) head; + QLIST_HEAD(, ThreadPoolElementAio) head; /* The following variables are protected by lock. */ - QTAILQ_HEAD(, ThreadPoolElement) request_list; + QTAILQ_HEAD(, ThreadPoolElementAio) request_list; int cur_threads; int idle_threads; int new_threads; /* backlog of threads we need to create */ @@ -XXX,XX +XXX,XX @@ struct ThreadPool { static void *worker_thread(void *opaque) { - ThreadPool *pool = opaque; + ThreadPoolAio *pool = opaque; qemu_mutex_lock(&pool->lock); pool->pending_threads--; do_spawn_thread(pool); while (pool->cur_threads <= pool->max_threads) { - ThreadPoolElement *req; + ThreadPoolElementAio *req; int ret; if (QTAILQ_EMPTY(&pool->request_list)) { @@ -XXX,XX +XXX,XX @@ static void *worker_thread(void *opaque) return NULL; } -static void do_spawn_thread(ThreadPool *pool) +static void do_spawn_thread(ThreadPoolAio *pool) { QemuThread t; @@ -XXX,XX +XXX,XX @@ static void do_spawn_thread(ThreadPool *pool) static void spawn_thread_bh_fn(void *opaque) { - ThreadPool *pool = opaque; + ThreadPoolAio *pool = opaque; qemu_mutex_lock(&pool->lock); do_spawn_thread(pool); qemu_mutex_unlock(&pool->lock); } -static void spawn_thread(ThreadPool *pool) +static void spawn_thread(ThreadPoolAio *pool) { pool->cur_threads++; pool->new_threads++; @@ -XXX,XX +XXX,XX @@ static void spawn_thread(ThreadPool *pool) static void thread_pool_completion_bh(void *opaque) { - ThreadPool *pool = opaque; - ThreadPoolElement *elem, *next; + ThreadPoolAio *pool = opaque; + ThreadPoolElementAio *elem, *next; defer_call_begin(); /* cb() may use defer_call() to coalesce work */ @@ -XXX,XX +XXX,XX @@ restart: continue; } - trace_thread_pool_complete(pool, elem, elem->common.opaque, - elem->ret); + trace_thread_pool_complete_aio(pool, elem, elem->common.opaque, + elem->ret); QLIST_REMOVE(elem, all); if (elem->common.cb) { @@ -XXX,XX +XXX,XX @@ restart: static void thread_pool_cancel(BlockAIOCB *acb) { - ThreadPoolElement *elem = (ThreadPoolElement *)acb; - ThreadPool *pool = elem->pool; + ThreadPoolElementAio *elem = (ThreadPoolElementAio *)acb; + ThreadPoolAio *pool = elem->pool; - trace_thread_pool_cancel(elem, elem->common.opaque); + trace_thread_pool_cancel_aio(elem, elem->common.opaque); QEMU_LOCK_GUARD(&pool->lock); if (elem->state == THREAD_QUEUED) { @@ -XXX,XX +XXX,XX @@ static void thread_pool_cancel(BlockAIOCB *acb) } static const AIOCBInfo thread_pool_aiocb_info = { - .aiocb_size = sizeof(ThreadPoolElement), + .aiocb_size = sizeof(ThreadPoolElementAio), .cancel_async = thread_pool_cancel, }; BlockAIOCB *thread_pool_submit_aio(ThreadPoolFunc *func, void *arg, BlockCompletionFunc *cb, void *opaque) { - ThreadPoolElement *req; + ThreadPoolElementAio *req; AioContext *ctx = qemu_get_current_aio_context(); - ThreadPool *pool = aio_get_thread_pool(ctx); + ThreadPoolAio *pool = aio_get_thread_pool(ctx); /* Assert that the thread submitting work is the same running the pool */ assert(pool->ctx == qemu_get_current_aio_context()); @@ -XXX,XX +XXX,XX @@ int coroutine_fn thread_pool_submit_co(ThreadPoolFunc *func, void *arg) return tpc.ret; } -void thread_pool_update_params(ThreadPool *pool, AioContext *ctx) +void thread_pool_update_params(ThreadPoolAio *pool, AioContext *ctx) { qemu_mutex_lock(&pool->lock); @@ -XXX,XX +XXX,XX @@ void thread_pool_update_params(ThreadPool *pool, AioContext *ctx) qemu_mutex_unlock(&pool->lock); } -static void thread_pool_init_one(ThreadPool *pool, AioContext *ctx) +static void thread_pool_init_one(ThreadPoolAio *pool, AioContext *ctx) { if (!ctx) { ctx = qemu_get_aio_context(); @@ -XXX,XX +XXX,XX @@ static void thread_pool_init_one(ThreadPool *pool, AioContext *ctx) thread_pool_update_params(pool, ctx); } -ThreadPool *thread_pool_new(AioContext *ctx) +ThreadPoolAio *thread_pool_new_aio(AioContext *ctx) { - ThreadPool *pool = g_new(ThreadPool, 1); + ThreadPoolAio *pool = g_new(ThreadPoolAio, 1); thread_pool_init_one(pool, ctx); return pool; } -void thread_pool_free(ThreadPool *pool) +void thread_pool_free_aio(ThreadPoolAio *pool) { if (!pool) { return; diff --git a/util/trace-events b/util/trace-events index XXXXXXX..XXXXXXX 100644 --- a/util/trace-events +++ b/util/trace-events @@ -XXX,XX +XXX,XX @@ reentrant_aio(void *ctx, const char *name) "ctx %p name %s" # thread-pool.c thread_pool_submit_aio(void *pool, void *req, void *opaque) "pool %p req %p opaque %p" -thread_pool_complete(void *pool, void *req, void *opaque, int ret) "pool %p req %p opaque %p ret %d" -thread_pool_cancel(void *req, void *opaque) "req %p opaque %p" +thread_pool_complete_aio(void *pool, void *req, void *opaque, int ret) "pool %p req %p opaque %p ret %d" +thread_pool_cancel_aio(void *req, void *opaque) "req %p opaque %p" # buffer.c buffer_resize(const char *buf, size_t olen, size_t len) "%s: old %zd, new %zd" From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Migration code wants to manage device data sending threads in one place. QEMU has an existing thread pool implementation, however it is limited to queuing AIO operations only and essentially has a 1:1 mapping between the current AioContext and the AIO ThreadPool in use. Implement generic (non-AIO) ThreadPool by essentially wrapping Glib's GThreadPool. This brings a few new operations on a pool: * thread_pool_wait() operation waits until all the submitted work requests have finished. * thread_pool_set_max_threads() explicitly sets the maximum thread count in the pool. * thread_pool_adjust_max_threads_to_work() adjusts the maximum thread count in the pool to equal the number of still waiting in queue or unfinished work. Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/block/thread-pool.h | 51 ++++++++++++++++ util/thread-pool.c | 119 ++++++++++++++++++++++++++++++++++++ 2 files changed, 170 insertions(+) diff --git a/include/block/thread-pool.h b/include/block/thread-pool.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/thread-pool.h +++ b/include/block/thread-pool.h @@ -XXX,XX +XXX,XX @@ BlockAIOCB *thread_pool_submit_aio(ThreadPoolFunc *func, void *arg, int coroutine_fn thread_pool_submit_co(ThreadPoolFunc *func, void *arg); void thread_pool_update_params(ThreadPoolAio *pool, struct AioContext *ctx); +/* ------------------------------------------- */ +/* Generic thread pool types and methods below */ +typedef struct ThreadPool ThreadPool; + +/* Create a new thread pool. Never returns NULL. */ +ThreadPool *thread_pool_new(void); + +/* + * Free the thread pool. + * Waits for all the previously submitted work to complete before performing + * the actual freeing operation. + */ +void thread_pool_free(ThreadPool *pool); + +/* + * Submit a new work (task) for the pool. + * + * @opaque_destroy is an optional GDestroyNotify for the @opaque argument + * to the work function at @func. + */ +void thread_pool_submit(ThreadPool *pool, ThreadPoolFunc *func, + void *opaque, GDestroyNotify opaque_destroy); + +/* + * Submit a new work (task) for the pool, making sure it starts getting + * processed immediately, launching a new thread for it if necessary. + * + * @opaque_destroy is an optional GDestroyNotify for the @opaque argument + * to the work function at @func. + */ +void thread_pool_submit_immediate(ThreadPool *pool, ThreadPoolFunc *func, + void *opaque, GDestroyNotify opaque_destroy); + +/* + * Wait for all previously submitted work to complete before returning. + * + * Can be used as a barrier between two sets of tasks executed on a thread + * pool without destroying it or in a performance sensitive path where the + * caller just wants to wait for all tasks to complete while deferring the + * pool free operation for later, less performance sensitive time. + */ +void thread_pool_wait(ThreadPool *pool); + +/* Set the maximum number of threads in the pool. */ +bool thread_pool_set_max_threads(ThreadPool *pool, int max_threads); + +/* + * Adjust the maximum number of threads in the pool to give each task its + * own thread (exactly one thread per task). + */ +bool thread_pool_adjust_max_threads_to_work(ThreadPool *pool); #endif diff --git a/util/thread-pool.c b/util/thread-pool.c index XXXXXXX..XXXXXXX 100644 --- a/util/thread-pool.c +++ b/util/thread-pool.c @@ -XXX,XX +XXX,XX @@ void thread_pool_free_aio(ThreadPoolAio *pool) qemu_mutex_destroy(&pool->lock); g_free(pool); } + +struct ThreadPool { + GThreadPool *t; + size_t cur_work; + QemuMutex cur_work_lock; + QemuCond all_finished_cond; +}; + +typedef struct { + ThreadPoolFunc *func; + void *opaque; + GDestroyNotify opaque_destroy; +} ThreadPoolElement; + +static void thread_pool_func(gpointer data, gpointer user_data) +{ + ThreadPool *pool = user_data; + g_autofree ThreadPoolElement *el = data; + + el->func(el->opaque); + + if (el->opaque_destroy) { + el->opaque_destroy(el->opaque); + } + + QEMU_LOCK_GUARD(&pool->cur_work_lock); + + assert(pool->cur_work > 0); + pool->cur_work--; + + if (pool->cur_work == 0) { + qemu_cond_signal(&pool->all_finished_cond); + } +} + +ThreadPool *thread_pool_new(void) +{ + ThreadPool *pool = g_new(ThreadPool, 1); + + pool->cur_work = 0; + qemu_mutex_init(&pool->cur_work_lock); + qemu_cond_init(&pool->all_finished_cond); + + pool->t = g_thread_pool_new(thread_pool_func, pool, 0, TRUE, NULL); + /* + * g_thread_pool_new() can only return errors if initial thread(s) + * creation fails but we ask for 0 initial threads above. + */ + assert(pool->t); + + return pool; +} + +void thread_pool_free(ThreadPool *pool) +{ + /* + * With _wait = TRUE this effectively waits for all + * previously submitted work to complete first. + */ + g_thread_pool_free(pool->t, FALSE, TRUE); + + qemu_cond_destroy(&pool->all_finished_cond); + qemu_mutex_destroy(&pool->cur_work_lock); + + g_free(pool); +} + +void thread_pool_submit(ThreadPool *pool, ThreadPoolFunc *func, + void *opaque, GDestroyNotify opaque_destroy) +{ + ThreadPoolElement *el = g_new(ThreadPoolElement, 1); + + el->func = func; + el->opaque = opaque; + el->opaque_destroy = opaque_destroy; + + WITH_QEMU_LOCK_GUARD(&pool->cur_work_lock) { + pool->cur_work++; + } + + /* + * Ignore the return value since this function can only return errors + * if creation of an additional thread fails but even in this case the + * provided work is still getting queued (just for the existing threads). + */ + g_thread_pool_push(pool->t, el, NULL); +} + +void thread_pool_submit_immediate(ThreadPool *pool, ThreadPoolFunc *func, + void *opaque, GDestroyNotify opaque_destroy) +{ + thread_pool_submit(pool, func, opaque, opaque_destroy); + thread_pool_adjust_max_threads_to_work(pool); +} + +void thread_pool_wait(ThreadPool *pool) +{ + QEMU_LOCK_GUARD(&pool->cur_work_lock); + + while (pool->cur_work > 0) { + qemu_cond_wait(&pool->all_finished_cond, + &pool->cur_work_lock); + } +} + +bool thread_pool_set_max_threads(ThreadPool *pool, + int max_threads) +{ + assert(max_threads > 0); + + return g_thread_pool_set_max_threads(pool->t, max_threads, NULL); +} + +bool thread_pool_adjust_max_threads_to_work(ThreadPool *pool) +{ + QEMU_LOCK_GUARD(&pool->cur_work_lock); + + return thread_pool_set_max_threads(pool, pool->cur_work); +} From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This QEMU_VM_COMMAND sub-command and its switchover_start SaveVMHandler is used to mark the switchover point in main migration stream. It can be used to inform the destination that all pre-switchover main migration stream data has been sent/received so it can start to process post-switchover data that it might have received via other migration channels like the multifd ones. Add also the relevant MigrationState bit stream compatibility property and its hw_compat entry. Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Zhang Chen <zhangckid@gmail.com> # for the COLO part Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/core/machine.c | 1 + include/migration/client-options.h | 4 +++ include/migration/register.h | 12 +++++++++ migration/colo.c | 3 +++ migration/migration-hmp-cmds.c | 2 ++ migration/migration.c | 2 ++ migration/migration.h | 2 ++ migration/options.c | 9 +++++++ migration/savevm.c | 39 ++++++++++++++++++++++++++++++ migration/savevm.h | 1 + migration/trace-events | 1 + scripts/analyze-migration.py | 11 +++++++++ 12 files changed, 87 insertions(+) diff --git a/hw/core/machine.c b/hw/core/machine.c index XXXXXXX..XXXXXXX 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -XXX,XX +XXX,XX @@ GlobalProperty hw_compat_9_2[] = { { "virtio-balloon-pci-non-transitional", "vectors", "0" }, { "virtio-mem-pci", "vectors", "0" }, { "migration", "multifd-clean-tls-termination", "false" }, + { "migration", "send-switchover-start", "off"}, }; const size_t hw_compat_9_2_len = G_N_ELEMENTS(hw_compat_9_2); diff --git a/include/migration/client-options.h b/include/migration/client-options.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/client-options.h +++ b/include/migration/client-options.h @@ -XXX,XX +XXX,XX @@ #ifndef QEMU_MIGRATION_CLIENT_OPTIONS_H #define QEMU_MIGRATION_CLIENT_OPTIONS_H + +/* properties */ +bool migrate_send_switchover_start(void); + /* capabilities */ bool migrate_background_snapshot(void); diff --git a/include/migration/register.h b/include/migration/register.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/register.h +++ b/include/migration/register.h @@ -XXX,XX +XXX,XX @@ typedef struct SaveVMHandlers { * otherwise */ bool (*switchover_ack_needed)(void *opaque); + + /** + * @switchover_start + * + * Notifies that the switchover has started. Called only on + * the destination. + * + * @opaque: data pointer passed to register_savevm_live() + * + * Returns zero to indicate success and negative for error + */ + int (*switchover_start)(void *opaque); } SaveVMHandlers; /** diff --git a/migration/colo.c b/migration/colo.c index XXXXXXX..XXXXXXX 100644 --- a/migration/colo.c +++ b/migration/colo.c @@ -XXX,XX +XXX,XX @@ static int colo_do_checkpoint_transaction(MigrationState *s, bql_unlock(); goto out; } + + qemu_savevm_maybe_send_switchover_start(s->to_dst_file); + /* Note: device state is saved into buffer */ ret = qemu_save_device_state(fb); diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c index XXXXXXX..XXXXXXX 100644 --- a/migration/migration-hmp-cmds.c +++ b/migration/migration-hmp-cmds.c @@ -XXX,XX +XXX,XX @@ static void migration_global_dump(Monitor *mon) ms->send_configuration ? "on" : "off"); monitor_printf(mon, "send-section-footer: %s\n", ms->send_section_footer ? "on" : "off"); + monitor_printf(mon, "send-switchover-start: %s\n", + ms->send_switchover_start ? "on" : "off"); monitor_printf(mon, "clear-bitmap-shift: %u\n", ms->clear_bitmap_shift); } diff --git a/migration/migration.c b/migration/migration.c index XXXXXXX..XXXXXXX 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -XXX,XX +XXX,XX @@ static bool migration_switchover_start(MigrationState *s, Error **errp) precopy_notify_complete(); + qemu_savevm_maybe_send_switchover_start(s->to_dst_file); + return true; } diff --git a/migration/migration.h b/migration/migration.h index XXXXXXX..XXXXXXX 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -XXX,XX +XXX,XX @@ struct MigrationState { bool send_configuration; /* Whether we send section footer during migration */ bool send_section_footer; + /* Whether we send switchover start notification during migration */ + bool send_switchover_start; /* Needed by postcopy-pause state */ QemuSemaphore postcopy_pause_sem; diff --git a/migration/options.c b/migration/options.c index XXXXXXX..XXXXXXX 100644 --- a/migration/options.c +++ b/migration/options.c @@ -XXX,XX +XXX,XX @@ const Property migration_properties[] = { send_configuration, true), DEFINE_PROP_BOOL("send-section-footer", MigrationState, send_section_footer, true), + DEFINE_PROP_BOOL("send-switchover-start", MigrationState, + send_switchover_start, true), DEFINE_PROP_BOOL("multifd-flush-after-each-section", MigrationState, multifd_flush_after_each_section, false), DEFINE_PROP_UINT8("x-clear-bitmap-shift", MigrationState, @@ -XXX,XX +XXX,XX @@ bool migrate_auto_converge(void) return s->capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE]; } +bool migrate_send_switchover_start(void) +{ + MigrationState *s = migrate_get_current(); + + return s->send_switchover_start; +} + bool migrate_background_snapshot(void) { MigrationState *s = migrate_get_current(); diff --git a/migration/savevm.c b/migration/savevm.c index XXXXXXX..XXXXXXX 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -XXX,XX +XXX,XX @@ enum qemu_vm_cmd { MIG_CMD_ENABLE_COLO, /* Enable COLO */ MIG_CMD_POSTCOPY_RESUME, /* resume postcopy on dest */ MIG_CMD_RECV_BITMAP, /* Request for recved bitmap on dst */ + MIG_CMD_SWITCHOVER_START, /* Switchover start notification */ MIG_CMD_MAX }; @@ -XXX,XX +XXX,XX @@ static struct mig_cmd_args { [MIG_CMD_POSTCOPY_RESUME] = { .len = 0, .name = "POSTCOPY_RESUME" }, [MIG_CMD_PACKAGED] = { .len = 4, .name = "PACKAGED" }, [MIG_CMD_RECV_BITMAP] = { .len = -1, .name = "RECV_BITMAP" }, + [MIG_CMD_SWITCHOVER_START] = { .len = 0, .name = "SWITCHOVER_START" }, [MIG_CMD_MAX] = { .len = -1, .name = "MAX" }, }; @@ -XXX,XX +XXX,XX @@ void qemu_savevm_send_recv_bitmap(QEMUFile *f, char *block_name) qemu_savevm_command_send(f, MIG_CMD_RECV_BITMAP, len + 1, (uint8_t *)buf); } +static void qemu_savevm_send_switchover_start(QEMUFile *f) +{ + trace_savevm_send_switchover_start(); + qemu_savevm_command_send(f, MIG_CMD_SWITCHOVER_START, 0, NULL); +} + +void qemu_savevm_maybe_send_switchover_start(QEMUFile *f) +{ + if (migrate_send_switchover_start()) { + qemu_savevm_send_switchover_start(f); + } +} + bool qemu_savevm_state_blocked(Error **errp) { SaveStateEntry *se; @@ -XXX,XX +XXX,XX @@ static int qemu_savevm_state(QEMUFile *f, Error **errp) ret = qemu_file_get_error(f); if (ret == 0) { + qemu_savevm_maybe_send_switchover_start(f); qemu_savevm_state_complete_precopy(f, false); ret = qemu_file_get_error(f); } @@ -XXX,XX +XXX,XX @@ static int loadvm_process_enable_colo(MigrationIncomingState *mis) return ret; } +static int loadvm_postcopy_handle_switchover_start(void) +{ + SaveStateEntry *se; + + QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { + int ret; + + if (!se->ops || !se->ops->switchover_start) { + continue; + } + + ret = se->ops->switchover_start(se->opaque); + if (ret < 0) { + return ret; + } + } + + return 0; +} + /* * Process an incoming 'QEMU_VM_COMMAND' * 0 just a normal return @@ -XXX,XX +XXX,XX @@ static int loadvm_process_command(QEMUFile *f) case MIG_CMD_ENABLE_COLO: return loadvm_process_enable_colo(mis); + + case MIG_CMD_SWITCHOVER_START: + return loadvm_postcopy_handle_switchover_start(); } return 0; diff --git a/migration/savevm.h b/migration/savevm.h index XXXXXXX..XXXXXXX 100644 --- a/migration/savevm.h +++ b/migration/savevm.h @@ -XXX,XX +XXX,XX @@ void qemu_savevm_send_postcopy_listen(QEMUFile *f); void qemu_savevm_send_postcopy_run(QEMUFile *f); void qemu_savevm_send_postcopy_resume(QEMUFile *f); void qemu_savevm_send_recv_bitmap(QEMUFile *f, char *block_name); +void qemu_savevm_maybe_send_switchover_start(QEMUFile *f); void qemu_savevm_send_postcopy_ram_discard(QEMUFile *f, const char *name, uint16_t len, diff --git a/migration/trace-events b/migration/trace-events index XXXXXXX..XXXXXXX 100644 --- a/migration/trace-events +++ b/migration/trace-events @@ -XXX,XX +XXX,XX @@ savevm_send_postcopy_run(void) "" savevm_send_postcopy_resume(void) "" savevm_send_colo_enable(void) "" savevm_send_recv_bitmap(char *name) "%s" +savevm_send_switchover_start(void) "" savevm_state_setup(void) "" savevm_state_resume_prepare(void) "" savevm_state_header(void) "" diff --git a/scripts/analyze-migration.py b/scripts/analyze-migration.py index XXXXXXX..XXXXXXX 100755 --- a/scripts/analyze-migration.py +++ b/scripts/analyze-migration.py @@ -XXX,XX +XXX,XX @@ class MigrationDump(object): QEMU_VM_SUBSECTION = 0x05 QEMU_VM_VMDESCRIPTION = 0x06 QEMU_VM_CONFIGURATION = 0x07 + QEMU_VM_COMMAND = 0x08 QEMU_VM_SECTION_FOOTER= 0x7e + QEMU_MIG_CMD_SWITCHOVER_START = 0x0b def __init__(self, filename): self.section_classes = { @@ -XXX,XX +XXX,XX @@ def read(self, desc_only = False, dump_memory = False, elif section_type == self.QEMU_VM_SECTION_PART or section_type == self.QEMU_VM_SECTION_END: section_id = file.read32() self.sections[section_id].read() + elif section_type == self.QEMU_VM_COMMAND: + command_type = file.read16() + command_data_len = file.read16() + if command_type != self.QEMU_MIG_CMD_SWITCHOVER_START: + raise Exception("Unknown QEMU_VM_COMMAND: %x" % + (command_type)) + if command_data_len != 0: + raise Exception("Invalid SWITCHOVER_START length: %x" % + (command_data_len)) elif section_type == self.QEMU_VM_SECTION_FOOTER: read_section_id = file.read32() if read_section_id != section_id: From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> qemu_loadvm_load_state_buffer() and its load_state_buffer SaveVMHandler allow providing device state buffer to explicitly specified device via its idstr and instance id. Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/migration/register.h | 15 +++++++++++++++ migration/savevm.c | 23 +++++++++++++++++++++++ migration/savevm.h | 3 +++ 3 files changed, 41 insertions(+) diff --git a/include/migration/register.h b/include/migration/register.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/register.h +++ b/include/migration/register.h @@ -XXX,XX +XXX,XX @@ typedef struct SaveVMHandlers { */ int (*load_state)(QEMUFile *f, void *opaque, int version_id); + /** + * @load_state_buffer (invoked outside the BQL) + * + * Load device state buffer provided to qemu_loadvm_load_state_buffer(). + * + * @opaque: data pointer passed to register_savevm_live() + * @buf: the data buffer to load + * @len: the data length in buffer + * @errp: pointer to Error*, to store an error if it happens. + * + * Returns true to indicate success and false for errors. + */ + bool (*load_state_buffer)(void *opaque, char *buf, size_t len, + Error **errp); + /** * @load_setup * diff --git a/migration/savevm.c b/migration/savevm.c index XXXXXXX..XXXXXXX 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -XXX,XX +XXX,XX @@ int qemu_loadvm_approve_switchover(void) return migrate_send_rp_switchover_ack(mis); } +bool qemu_loadvm_load_state_buffer(const char *idstr, uint32_t instance_id, + char *buf, size_t len, Error **errp) +{ + SaveStateEntry *se; + + se = find_se(idstr, instance_id); + if (!se) { + error_setg(errp, + "Unknown idstr %s or instance id %u for load state buffer", + idstr, instance_id); + return false; + } + + if (!se->ops || !se->ops->load_state_buffer) { + error_setg(errp, + "idstr %s / instance %u has no load state buffer operation", + idstr, instance_id); + return false; + } + + return se->ops->load_state_buffer(se->opaque, buf, len, errp); +} + bool save_snapshot(const char *name, bool overwrite, const char *vmstate, bool has_devices, strList *devices, Error **errp) { diff --git a/migration/savevm.h b/migration/savevm.h index XXXXXXX..XXXXXXX 100644 --- a/migration/savevm.h +++ b/migration/savevm.h @@ -XXX,XX +XXX,XX @@ int qemu_loadvm_approve_switchover(void); int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f, bool in_postcopy); +bool qemu_loadvm_load_state_buffer(const char *idstr, uint32_t instance_id, + char *buf, size_t len, Error **errp); + #endif From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> All callers to migration_incoming_state_destroy() other than postcopy_ram_listen_thread() do this call with BQL held. Since migration_incoming_state_destroy() ultimately calls "load_cleanup" SaveVMHandlers and it will soon call BQL-sensitive code it makes sense to always call that function under BQL rather than to have it deal with both cases (with BQL and without BQL). Add the necessary bql_lock() and bql_unlock() to postcopy_ram_listen_thread(). qemu_loadvm_state_main() in postcopy_ram_listen_thread() could call "load_state" SaveVMHandlers that are expecting BQL to be held. In principle, the only devices that should be arriving on migration channel serviced by postcopy_ram_listen_thread() are those that are postcopiable and whose load handlers are safe to be called without BQL being held. But nothing currently prevents the source from sending data for "unsafe" devices which would cause trouble there. Add a TODO comment there so it's clear that it would be good to improve handling of such (erroneous) case in the future. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- migration/savevm.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/migration/savevm.c b/migration/savevm.c index XXXXXXX..XXXXXXX 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -XXX,XX +XXX,XX @@ static void *postcopy_ram_listen_thread(void *opaque) * in qemu_file, and thus we must be blocking now. */ qemu_file_set_blocking(f, true); + + /* TODO: sanity check that only postcopiable data will be loaded here */ load_res = qemu_loadvm_state_main(f, mis); /* @@ -XXX,XX +XXX,XX @@ static void *postcopy_ram_listen_thread(void *opaque) * (If something broke then qemu will have to exit anyway since it's * got a bad migration state). */ + bql_lock(); migration_incoming_state_destroy(); + bql_unlock(); rcu_unregister_thread(); mis->have_listen_thread = false; From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Automatic memory management helps avoid memory safety issues. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/qapi/error.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/qapi/error.h b/include/qapi/error.h index XXXXXXX..XXXXXXX 100644 --- a/include/qapi/error.h +++ b/include/qapi/error.h @@ -XXX,XX +XXX,XX @@ Error *error_copy(const Error *err); */ void error_free(Error *err); +G_DEFINE_AUTOPTR_CLEANUP_FUNC(Error, error_free) + /* * Convenience function to assert that *@errp is set, then silently free it. */ From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Some drivers might want to make use of auxiliary helper threads during VM state loading, for example to make sure that their blocking (sync) I/O operations don't block the rest of the migration process. Add a migration core managed thread pool to facilitate this use case. The migration core will wait for these threads to finish before (re)starting the VM at destination. Reviewed-by: Fabiano Rosas <farosas@suse.de> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/migration/misc.h | 3 ++ include/qemu/typedefs.h | 2 + migration/migration.c | 2 +- migration/migration.h | 5 +++ migration/savevm.c | 89 +++++++++++++++++++++++++++++++++++++++- migration/savevm.h | 2 +- 6 files changed, 99 insertions(+), 4 deletions(-) diff --git a/include/migration/misc.h b/include/migration/misc.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/misc.h +++ b/include/migration/misc.h @@ -XXX,XX +XXX,XX @@ bool migrate_ram_is_ignored(RAMBlock *block); /* migration/block.c */ AnnounceParameters *migrate_announce_params(void); + /* migration/savevm.c */ void dump_vmstate_json_to_file(FILE *out_fp); +void qemu_loadvm_start_load_thread(MigrationLoadThread function, + void *opaque); /* migration/migration.c */ void migration_object_init(void); diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h index XXXXXXX..XXXXXXX 100644 --- a/include/qemu/typedefs.h +++ b/include/qemu/typedefs.h @@ -XXX,XX +XXX,XX @@ typedef struct IRQState *qemu_irq; * Function types */ typedef void (*qemu_irq_handler)(void *opaque, int n, int level); +typedef bool (*MigrationLoadThread)(void *opaque, bool *should_quit, + Error **errp); #endif /* QEMU_TYPEDEFS_H */ diff --git a/migration/migration.c b/migration/migration.c index XXXXXXX..XXXXXXX 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -XXX,XX +XXX,XX @@ void migration_incoming_state_destroy(void) * RAM state cleanup needs to happen after multifd cleanup, because * multifd threads can use some of its states (receivedmap). */ - qemu_loadvm_state_cleanup(); + qemu_loadvm_state_cleanup(mis); if (mis->to_src_file) { /* Tell source that we are done */ diff --git a/migration/migration.h b/migration/migration.h index XXXXXXX..XXXXXXX 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -XXX,XX +XXX,XX @@ #define MIGRATION_THREAD_DST_PREEMPT "mig/dst/preempt" struct PostcopyBlocktimeContext; +typedef struct ThreadPool ThreadPool; #define MIGRATION_RESUME_ACK_VALUE (1) @@ -XXX,XX +XXX,XX @@ struct MigrationIncomingState { Coroutine *colo_incoming_co; QemuSemaphore colo_incoming_sem; + /* Optional load threads pool and its thread exit request flag */ + ThreadPool *load_threads; + bool load_threads_abort; + /* * PostcopyBlocktimeContext to keep information for postcopy * live migration, to calculate vCPU block time diff --git a/migration/savevm.c b/migration/savevm.c index XXXXXXX..XXXXXXX 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -XXX,XX +XXX,XX @@ #include "qemu/job.h" #include "qemu/main-loop.h" #include "block/snapshot.h" +#include "block/thread-pool.h" #include "qemu/cutils.h" #include "io/channel-buffer.h" #include "io/channel-file.h" @@ -XXX,XX +XXX,XX @@ static struct mig_cmd_args { * generic extendable format with an exception for two old entities. */ +/***********************************************************/ +/* Optional load threads pool support */ + +static void qemu_loadvm_thread_pool_create(MigrationIncomingState *mis) +{ + assert(!mis->load_threads); + mis->load_threads = thread_pool_new(); + mis->load_threads_abort = false; +} + +static void qemu_loadvm_thread_pool_destroy(MigrationIncomingState *mis) +{ + qatomic_set(&mis->load_threads_abort, true); + + bql_unlock(); /* Load threads might be waiting for BQL */ + g_clear_pointer(&mis->load_threads, thread_pool_free); + bql_lock(); +} + +static bool qemu_loadvm_thread_pool_wait(MigrationState *s, + MigrationIncomingState *mis) +{ + bql_unlock(); /* Let load threads do work requiring BQL */ + thread_pool_wait(mis->load_threads); + bql_lock(); + + return !migrate_has_error(s); +} + /***********************************************************/ /* savevm/loadvm support */ @@ -XXX,XX +XXX,XX @@ static int qemu_loadvm_state_setup(QEMUFile *f, Error **errp) return 0; } -void qemu_loadvm_state_cleanup(void) +struct LoadThreadData { + MigrationLoadThread function; + void *opaque; +}; + +static int qemu_loadvm_load_thread(void *thread_opaque) +{ + struct LoadThreadData *data = thread_opaque; + MigrationIncomingState *mis = migration_incoming_get_current(); + g_autoptr(Error) local_err = NULL; + + if (!data->function(data->opaque, &mis->load_threads_abort, &local_err)) { + MigrationState *s = migrate_get_current(); + + assert(local_err); + + /* + * In case of multiple load threads failing which thread error + * return we end setting is purely arbitrary. + */ + migrate_set_error(s, local_err); + } + + return 0; +} + +void qemu_loadvm_start_load_thread(MigrationLoadThread function, + void *opaque) +{ + MigrationIncomingState *mis = migration_incoming_get_current(); + struct LoadThreadData *data; + + /* We only set it from this thread so it's okay to read it directly */ + assert(!mis->load_threads_abort); + + data = g_new(struct LoadThreadData, 1); + data->function = function; + data->opaque = opaque; + + thread_pool_submit_immediate(mis->load_threads, qemu_loadvm_load_thread, + data, g_free); +} + +void qemu_loadvm_state_cleanup(MigrationIncomingState *mis) { SaveStateEntry *se; trace_loadvm_state_cleanup(); + QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (se->ops && se->ops->load_cleanup) { se->ops->load_cleanup(se->opaque); } } + + qemu_loadvm_thread_pool_destroy(mis); } /* Return true if we should continue the migration, or false. */ @@ -XXX,XX +XXX,XX @@ out: int qemu_loadvm_state(QEMUFile *f) { + MigrationState *s = migrate_get_current(); MigrationIncomingState *mis = migration_incoming_get_current(); Error *local_err = NULL; int ret; @@ -XXX,XX +XXX,XX @@ int qemu_loadvm_state(QEMUFile *f) return -EINVAL; } + qemu_loadvm_thread_pool_create(mis); + ret = qemu_loadvm_state_header(f); if (ret) { return ret; @@ -XXX,XX +XXX,XX @@ int qemu_loadvm_state(QEMUFile *f) /* When reaching here, it must be precopy */ if (ret == 0) { - if (migrate_has_error(migrate_get_current())) { + if (migrate_has_error(migrate_get_current()) || + !qemu_loadvm_thread_pool_wait(s, mis)) { ret = -EINVAL; } else { ret = qemu_file_get_error(f); } } + /* + * Set this flag unconditionally so we'll catch further attempts to + * start additional threads via an appropriate assert() + */ + qatomic_set(&mis->load_threads_abort, true); /* * Try to read in the VMDESC section as well, so that dumping tools that diff --git a/migration/savevm.h b/migration/savevm.h index XXXXXXX..XXXXXXX 100644 --- a/migration/savevm.h +++ b/migration/savevm.h @@ -XXX,XX +XXX,XX @@ void qemu_savevm_live_state(QEMUFile *f); int qemu_save_device_state(QEMUFile *f); int qemu_loadvm_state(QEMUFile *f); -void qemu_loadvm_state_cleanup(void); +void qemu_loadvm_state_cleanup(MigrationIncomingState *mis); int qemu_loadvm_state_main(QEMUFile *f, MigrationIncomingState *mis); int qemu_load_device_state(QEMUFile *f); int qemu_loadvm_approve_switchover(void); From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Read packet header first so in the future we will be able to differentiate between a RAM multifd packet and a device state multifd packet. Since these two are of different size we can't read the packet body until we know which packet type it is. Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- migration/multifd.c | 55 ++++++++++++++++++++++++++++++++++++--------- migration/multifd.h | 5 +++++ 2 files changed, 49 insertions(+), 11 deletions(-) diff --git a/migration/multifd.c b/migration/multifd.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -XXX,XX +XXX,XX @@ void multifd_send_fill_packet(MultiFDSendParams *p) memset(packet, 0, p->packet_len); - packet->magic = cpu_to_be32(MULTIFD_MAGIC); - packet->version = cpu_to_be32(MULTIFD_VERSION); + packet->hdr.magic = cpu_to_be32(MULTIFD_MAGIC); + packet->hdr.version = cpu_to_be32(MULTIFD_VERSION); - packet->flags = cpu_to_be32(p->flags); + packet->hdr.flags = cpu_to_be32(p->flags); packet->next_packet_size = cpu_to_be32(p->next_packet_size); packet_num = qatomic_fetch_inc(&multifd_send_state->packet_num); @@ -XXX,XX +XXX,XX @@ void multifd_send_fill_packet(MultiFDSendParams *p) p->flags, p->next_packet_size); } -static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) +static int multifd_recv_unfill_packet_header(MultiFDRecvParams *p, + const MultiFDPacketHdr_t *hdr, + Error **errp) { - const MultiFDPacket_t *packet = p->packet; - uint32_t magic = be32_to_cpu(packet->magic); - uint32_t version = be32_to_cpu(packet->version); - int ret = 0; + uint32_t magic = be32_to_cpu(hdr->magic); + uint32_t version = be32_to_cpu(hdr->version); if (magic != MULTIFD_MAGIC) { error_setg(errp, "multifd: received packet magic %x, expected %x", @@ -XXX,XX +XXX,XX @@ static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) return -1; } - p->flags = be32_to_cpu(packet->flags); + p->flags = be32_to_cpu(hdr->flags); + + return 0; +} + +static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) +{ + const MultiFDPacket_t *packet = p->packet; + int ret = 0; + p->next_packet_size = be32_to_cpu(packet->next_packet_size); p->packet_num = be64_to_cpu(packet->packet_num); p->packets_recved++; @@ -XXX,XX +XXX,XX @@ static void *multifd_recv_thread(void *opaque) } while (true) { + MultiFDPacketHdr_t hdr; uint32_t flags = 0; bool has_data = false; + uint8_t *pkt_buf; + size_t pkt_len; + p->normal_num = 0; if (use_packets) { struct iovec iov = { - .iov_base = (void *)p->packet, - .iov_len = p->packet_len + .iov_base = (void *)&hdr, + .iov_len = sizeof(hdr) }; if (multifd_recv_should_exit()) { @@ -XXX,XX +XXX,XX @@ static void *multifd_recv_thread(void *opaque) break; } + ret = multifd_recv_unfill_packet_header(p, &hdr, &local_err); + if (ret) { + break; + } + + pkt_buf = (uint8_t *)p->packet + sizeof(hdr); + pkt_len = p->packet_len - sizeof(hdr); + + ret = qio_channel_read_all_eof(p->c, (char *)pkt_buf, pkt_len, + &local_err); + if (!ret) { + /* EOF */ + error_setg(&local_err, "multifd: unexpected EOF after packet header"); + break; + } + + if (ret == -1) { + break; + } + qemu_mutex_lock(&p->mutex); ret = multifd_recv_unfill_packet(p, &local_err); if (ret) { diff --git a/migration/multifd.h b/migration/multifd.h index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -XXX,XX +XXX,XX @@ typedef struct { uint32_t magic; uint32_t version; uint32_t flags; +} __attribute__((packed)) MultiFDPacketHdr_t; + +typedef struct { + MultiFDPacketHdr_t hdr; + /* maximum number of allocated pages */ uint32_t pages_alloc; /* non zero pages */ From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Add a basic support for receiving device state via multifd channels - channels that are shared with RAM transfers. Depending whether MULTIFD_FLAG_DEVICE_STATE flag is present or not in the packet header either device state (MultiFDPacketDeviceState_t) or RAM data (existing MultiFDPacket_t) is read. The received device state data is provided to qemu_loadvm_load_state_buffer() function for processing in the device's load_state_buffer handler. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- migration/multifd.c | 99 ++++++++++++++++++++++++++++++++++++++++----- migration/multifd.h | 26 +++++++++++- 2 files changed, 113 insertions(+), 12 deletions(-) diff --git a/migration/multifd.c b/migration/multifd.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -XXX,XX +XXX,XX @@ #include "file.h" #include "migration.h" #include "migration-stats.h" +#include "savevm.h" #include "socket.h" #include "tls.h" #include "qemu-file.h" @@ -XXX,XX +XXX,XX @@ static int multifd_recv_unfill_packet_header(MultiFDRecvParams *p, return 0; } -static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) +static int multifd_recv_unfill_packet_device_state(MultiFDRecvParams *p, + Error **errp) +{ + MultiFDPacketDeviceState_t *packet = p->packet_dev_state; + + packet->instance_id = be32_to_cpu(packet->instance_id); + p->next_packet_size = be32_to_cpu(packet->next_packet_size); + + return 0; +} + +static int multifd_recv_unfill_packet_ram(MultiFDRecvParams *p, Error **errp) { const MultiFDPacket_t *packet = p->packet; int ret = 0; p->next_packet_size = be32_to_cpu(packet->next_packet_size); p->packet_num = be64_to_cpu(packet->packet_num); - p->packets_recved++; /* Always unfill, old QEMUs (<9.0) send data along with SYNC */ ret = multifd_ram_unfill_packet(p, errp); @@ -XXX,XX +XXX,XX @@ static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) return ret; } +static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) +{ + p->packets_recved++; + + if (p->flags & MULTIFD_FLAG_DEVICE_STATE) { + return multifd_recv_unfill_packet_device_state(p, errp); + } + + return multifd_recv_unfill_packet_ram(p, errp); +} + static bool multifd_send_should_exit(void) { return qatomic_read(&multifd_send_state->exiting); @@ -XXX,XX +XXX,XX @@ static void multifd_recv_cleanup_channel(MultiFDRecvParams *p) p->packet_len = 0; g_free(p->packet); p->packet = NULL; + g_clear_pointer(&p->packet_dev_state, g_free); g_free(p->normal); p->normal = NULL; g_free(p->zero); @@ -XXX,XX +XXX,XX @@ void multifd_recv_sync_main(void) trace_multifd_recv_sync_main(multifd_recv_state->packet_num); } +static int multifd_device_state_recv(MultiFDRecvParams *p, Error **errp) +{ + g_autofree char *idstr = NULL; + g_autofree char *dev_state_buf = NULL; + int ret; + + dev_state_buf = g_malloc(p->next_packet_size); + + ret = qio_channel_read_all(p->c, dev_state_buf, p->next_packet_size, errp); + if (ret != 0) { + return ret; + } + + idstr = g_strndup(p->packet_dev_state->idstr, + sizeof(p->packet_dev_state->idstr)); + + if (!qemu_loadvm_load_state_buffer(idstr, + p->packet_dev_state->instance_id, + dev_state_buf, p->next_packet_size, + errp)) { + ret = -1; + } + + return ret; +} + static void *multifd_recv_thread(void *opaque) { MigrationState *s = migrate_get_current(); @@ -XXX,XX +XXX,XX @@ static void *multifd_recv_thread(void *opaque) while (true) { MultiFDPacketHdr_t hdr; uint32_t flags = 0; + bool is_device_state = false; bool has_data = false; uint8_t *pkt_buf; size_t pkt_len; @@ -XXX,XX +XXX,XX @@ static void *multifd_recv_thread(void *opaque) break; } - pkt_buf = (uint8_t *)p->packet + sizeof(hdr); - pkt_len = p->packet_len - sizeof(hdr); + is_device_state = p->flags & MULTIFD_FLAG_DEVICE_STATE; + if (is_device_state) { + pkt_buf = (uint8_t *)p->packet_dev_state + sizeof(hdr); + pkt_len = sizeof(*p->packet_dev_state) - sizeof(hdr); + } else { + pkt_buf = (uint8_t *)p->packet + sizeof(hdr); + pkt_len = p->packet_len - sizeof(hdr); + } ret = qio_channel_read_all_eof(p->c, (char *)pkt_buf, pkt_len, &local_err); @@ -XXX,XX +XXX,XX @@ static void *multifd_recv_thread(void *opaque) /* recv methods don't know how to handle the SYNC flag */ p->flags &= ~MULTIFD_FLAG_SYNC; - /* - * Even if it's a SYNC packet, this needs to be set - * because older QEMUs (<9.0) still send data along with - * the SYNC packet. - */ - has_data = p->normal_num || p->zero_num; + if (is_device_state) { + has_data = p->next_packet_size > 0; + } else { + /* + * Even if it's a SYNC packet, this needs to be set + * because older QEMUs (<9.0) still send data along with + * the SYNC packet. + */ + has_data = p->normal_num || p->zero_num; + } + qemu_mutex_unlock(&p->mutex); } else { /* @@ -XXX,XX +XXX,XX @@ static void *multifd_recv_thread(void *opaque) } if (has_data) { - ret = multifd_recv_state->ops->recv(p, &local_err); + if (is_device_state) { + assert(use_packets); + ret = multifd_device_state_recv(p, &local_err); + } else { + ret = multifd_recv_state->ops->recv(p, &local_err); + } if (ret != 0) { break; } + } else if (is_device_state) { + error_setg(&local_err, + "multifd: received empty device state packet"); + break; } if (use_packets) { if (flags & MULTIFD_FLAG_SYNC) { + if (is_device_state) { + error_setg(&local_err, + "multifd: received SYNC device state packet"); + break; + } + qemu_sem_post(&multifd_recv_state->sem_sync); qemu_sem_wait(&p->sem_sync); } @@ -XXX,XX +XXX,XX @@ int multifd_recv_setup(Error **errp) p->packet_len = sizeof(MultiFDPacket_t) + sizeof(uint64_t) * page_count; p->packet = g_malloc0(p->packet_len); + p->packet_dev_state = g_malloc0(sizeof(*p->packet_dev_state)); } p->name = g_strdup_printf(MIGRATION_THREAD_DST_MULTIFD, i); p->normal = g_new0(ram_addr_t, page_count); diff --git a/migration/multifd.h b/migration/multifd.h index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -XXX,XX +XXX,XX @@ MultiFDRecvData *multifd_get_recv_data(void); #define MULTIFD_FLAG_UADK (8 << 1) #define MULTIFD_FLAG_QATZIP (16 << 1) +/* + * If set it means that this packet contains device state + * (MultiFDPacketDeviceState_t), not RAM data (MultiFDPacket_t). + */ +#define MULTIFD_FLAG_DEVICE_STATE (32 << 1) + /* This value needs to be a multiple of qemu_target_page_size() */ #define MULTIFD_PACKET_SIZE (512 * 1024) @@ -XXX,XX +XXX,XX @@ typedef struct { uint64_t offset[]; } __attribute__((packed)) MultiFDPacket_t; +typedef struct { + MultiFDPacketHdr_t hdr; + + char idstr[256] QEMU_NONSTRING; + uint32_t instance_id; + + /* size of the next packet that contains the actual data */ + uint32_t next_packet_size; +} __attribute__((packed)) MultiFDPacketDeviceState_t; + typedef struct { /* number of used pages */ uint32_t num; @@ -XXX,XX +XXX,XX @@ struct MultiFDRecvData { off_t file_offset; }; +typedef struct { + char *idstr; + uint32_t instance_id; + char *buf; + size_t buf_len; +} MultiFDDeviceState_t; + typedef enum { MULTIFD_PAYLOAD_NONE, MULTIFD_PAYLOAD_RAM, @@ -XXX,XX +XXX,XX @@ typedef struct { /* thread local variables. No locking required */ - /* pointer to the packet */ + /* pointers to the possible packet types */ MultiFDPacket_t *packet; + MultiFDPacketDeviceState_t *packet_dev_state; /* size of the next packet that contains pages */ uint32_t next_packet_size; /* packets received through this channel */ From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> multifd_send() function is currently not thread safe, make it thread safe by holding a lock during its execution. This way it will be possible to safely call it concurrently from multiple threads. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- migration/multifd.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/migration/multifd.c b/migration/multifd.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -XXX,XX +XXX,XX @@ typedef struct { struct { MultiFDSendParams *params; + + /* multifd_send() body is not thread safe, needs serialization */ + QemuMutex multifd_send_mutex; + /* * Global number of generated multifd packets. * @@ -XXX,XX +XXX,XX @@ bool multifd_send(MultiFDSendData **send_data) return false; } + QEMU_LOCK_GUARD(&multifd_send_state->multifd_send_mutex); + /* We wait here, until at least one channel is ready */ qemu_sem_wait(&multifd_send_state->channels_ready); @@ -XXX,XX +XXX,XX @@ static void multifd_send_cleanup_state(void) socket_cleanup_outgoing_migration(); qemu_sem_destroy(&multifd_send_state->channels_created); qemu_sem_destroy(&multifd_send_state->channels_ready); + qemu_mutex_destroy(&multifd_send_state->multifd_send_mutex); g_free(multifd_send_state->params); multifd_send_state->params = NULL; g_free(multifd_send_state); @@ -XXX,XX +XXX,XX @@ bool multifd_send_setup(void) thread_count = migrate_multifd_channels(); multifd_send_state = g_malloc0(sizeof(*multifd_send_state)); multifd_send_state->params = g_new0(MultiFDSendParams, thread_count); + qemu_mutex_init(&multifd_send_state->multifd_send_mutex); qemu_sem_init(&multifd_send_state->channels_created, 0); qemu_sem_init(&multifd_send_state->channels_ready, 0); qatomic_set(&multifd_send_state->exiting, 0); From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This way if there are fields there that needs explicit disposal (like, for example, some attached buffers) they will be handled appropriately. Add a related assert to multifd_set_payload_type() in order to make sure that this function is only used to fill a previously empty MultiFDSendData with some payload, not the other way around. Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- migration/multifd-nocomp.c | 3 +-- migration/multifd.c | 31 ++++++++++++++++++++++++++++--- migration/multifd.h | 5 +++++ 3 files changed, 34 insertions(+), 5 deletions(-) diff --git a/migration/multifd-nocomp.c b/migration/multifd-nocomp.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd-nocomp.c +++ b/migration/multifd-nocomp.c @@ -XXX,XX +XXX,XX @@ void multifd_ram_save_setup(void) void multifd_ram_save_cleanup(void) { - g_free(multifd_ram_send); - multifd_ram_send = NULL; + g_clear_pointer(&multifd_ram_send, multifd_send_data_free); } static void multifd_set_file_bitmap(MultiFDSendParams *p) diff --git a/migration/multifd.c b/migration/multifd.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -XXX,XX +XXX,XX @@ MultiFDSendData *multifd_send_data_alloc(void) return g_malloc0(size_minus_payload + max_payload_size); } +void multifd_send_data_clear(MultiFDSendData *data) +{ + if (multifd_payload_empty(data)) { + return; + } + + switch (data->type) { + default: + /* Nothing to do */ + break; + } + + data->type = MULTIFD_PAYLOAD_NONE; +} + +void multifd_send_data_free(MultiFDSendData *data) +{ + if (!data) { + return; + } + + multifd_send_data_clear(data); + + g_free(data); +} + static bool multifd_use_packets(void) { return !migrate_mapped_ram(); @@ -XXX,XX +XXX,XX @@ static bool multifd_send_cleanup_channel(MultiFDSendParams *p, Error **errp) qemu_sem_destroy(&p->sem_sync); g_free(p->name); p->name = NULL; - g_free(p->data); - p->data = NULL; + g_clear_pointer(&p->data, multifd_send_data_free); p->packet_len = 0; g_free(p->packet); p->packet = NULL; @@ -XXX,XX +XXX,XX @@ static void *multifd_send_thread(void *opaque) (uint64_t)p->next_packet_size + p->packet_len); p->next_packet_size = 0; - multifd_set_payload_type(p->data, MULTIFD_PAYLOAD_NONE); + multifd_send_data_clear(p->data); /* * Making sure p->data is published before saying "we're diff --git a/migration/multifd.h b/migration/multifd.h index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -XXX,XX +XXX,XX @@ static inline bool multifd_payload_empty(MultiFDSendData *data) static inline void multifd_set_payload_type(MultiFDSendData *data, MultiFDPayloadType type) { + assert(multifd_payload_empty(data)); + assert(type != MULTIFD_PAYLOAD_NONE); + data->type = type; } @@ -XXX,XX +XXX,XX @@ static inline void multifd_send_prepare_header(MultiFDSendParams *p) void multifd_channel_connect(MultiFDSendParams *p, QIOChannel *ioc); bool multifd_send(MultiFDSendData **send_data); MultiFDSendData *multifd_send_data_alloc(void); +void multifd_send_data_clear(MultiFDSendData *data); +void multifd_send_data_free(MultiFDSendData *data); static inline uint32_t multifd_ram_page_size(void) { From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> A new function multifd_queue_device_state() is provided for device to queue its state for transmission via a multifd channel. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/migration/misc.h | 4 ++ migration/meson.build | 1 + migration/multifd-device-state.c | 115 +++++++++++++++++++++++++++++++ migration/multifd-nocomp.c | 14 +++- migration/multifd.c | 42 +++++++++-- migration/multifd.h | 27 +++++--- 6 files changed, 187 insertions(+), 16 deletions(-) create mode 100644 migration/multifd-device-state.c diff --git a/include/migration/misc.h b/include/migration/misc.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/misc.h +++ b/include/migration/misc.h @@ -XXX,XX +XXX,XX @@ bool migrate_is_uri(const char *uri); bool migrate_uri_parse(const char *uri, MigrationChannel **channel, Error **errp); +/* migration/multifd-device-state.c */ +bool multifd_queue_device_state(char *idstr, uint32_t instance_id, + char *data, size_t len); + #endif diff --git a/migration/meson.build b/migration/meson.build index XXXXXXX..XXXXXXX 100644 --- a/migration/meson.build +++ b/migration/meson.build @@ -XXX,XX +XXX,XX @@ system_ss.add(files( 'migration-hmp-cmds.c', 'migration.c', 'multifd.c', + 'multifd-device-state.c', 'multifd-nocomp.c', 'multifd-zlib.c', 'multifd-zero-page.c', diff --git a/migration/multifd-device-state.c b/migration/multifd-device-state.c new file mode 100644 index XXXXXXX..XXXXXXX --- /dev/null +++ b/migration/multifd-device-state.c @@ -XXX,XX +XXX,XX @@ +/* + * Multifd device state migration + * + * Copyright (C) 2024,2025 Oracle and/or its affiliates. + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#include "qemu/osdep.h" +#include "qemu/lockable.h" +#include "migration/misc.h" +#include "multifd.h" + +static struct { + QemuMutex queue_job_mutex; + + MultiFDSendData *send_data; +} *multifd_send_device_state; + +size_t multifd_device_state_payload_size(void) +{ + return sizeof(MultiFDDeviceState_t); +} + +void multifd_device_state_send_setup(void) +{ + assert(!multifd_send_device_state); + multifd_send_device_state = g_malloc(sizeof(*multifd_send_device_state)); + + qemu_mutex_init(&multifd_send_device_state->queue_job_mutex); + + multifd_send_device_state->send_data = multifd_send_data_alloc(); +} + +void multifd_device_state_send_cleanup(void) +{ + g_clear_pointer(&multifd_send_device_state->send_data, + multifd_send_data_free); + + qemu_mutex_destroy(&multifd_send_device_state->queue_job_mutex); + + g_clear_pointer(&multifd_send_device_state, g_free); +} + +void multifd_send_data_clear_device_state(MultiFDDeviceState_t *device_state) +{ + g_clear_pointer(&device_state->idstr, g_free); + g_clear_pointer(&device_state->buf, g_free); +} + +static void multifd_device_state_fill_packet(MultiFDSendParams *p) +{ + MultiFDDeviceState_t *device_state = &p->data->u.device_state; + MultiFDPacketDeviceState_t *packet = p->packet_device_state; + + packet->hdr.flags = cpu_to_be32(p->flags); + strncpy(packet->idstr, device_state->idstr, sizeof(packet->idstr)); + packet->instance_id = cpu_to_be32(device_state->instance_id); + packet->next_packet_size = cpu_to_be32(p->next_packet_size); +} + +static void multifd_prepare_header_device_state(MultiFDSendParams *p) +{ + p->iov[0].iov_len = sizeof(*p->packet_device_state); + p->iov[0].iov_base = p->packet_device_state; + p->iovs_num++; +} + +void multifd_device_state_send_prepare(MultiFDSendParams *p) +{ + MultiFDDeviceState_t *device_state = &p->data->u.device_state; + + assert(multifd_payload_device_state(p->data)); + + multifd_prepare_header_device_state(p); + + assert(!(p->flags & MULTIFD_FLAG_SYNC)); + + p->next_packet_size = device_state->buf_len; + if (p->next_packet_size > 0) { + p->iov[p->iovs_num].iov_base = device_state->buf; + p->iov[p->iovs_num].iov_len = p->next_packet_size; + p->iovs_num++; + } + + p->flags |= MULTIFD_FLAG_NOCOMP | MULTIFD_FLAG_DEVICE_STATE; + + multifd_device_state_fill_packet(p); +} + +bool multifd_queue_device_state(char *idstr, uint32_t instance_id, + char *data, size_t len) +{ + /* Device state submissions can come from multiple threads */ + QEMU_LOCK_GUARD(&multifd_send_device_state->queue_job_mutex); + MultiFDDeviceState_t *device_state; + + assert(multifd_payload_empty(multifd_send_device_state->send_data)); + + multifd_set_payload_type(multifd_send_device_state->send_data, + MULTIFD_PAYLOAD_DEVICE_STATE); + device_state = &multifd_send_device_state->send_data->u.device_state; + device_state->idstr = g_strdup(idstr); + device_state->instance_id = instance_id; + device_state->buf = g_memdup2(data, len); + device_state->buf_len = len; + + if (!multifd_send(&multifd_send_device_state->send_data)) { + multifd_send_data_clear(multifd_send_device_state->send_data); + return false; + } + + return true; +} diff --git a/migration/multifd-nocomp.c b/migration/multifd-nocomp.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd-nocomp.c +++ b/migration/multifd-nocomp.c @@ -XXX,XX +XXX,XX @@ #include "exec/ramblock.h" #include "exec/target_page.h" #include "file.h" +#include "migration-stats.h" #include "multifd.h" #include "options.h" #include "qapi/error.h" @@ -XXX,XX +XXX,XX @@ static void multifd_nocomp_send_cleanup(MultiFDSendParams *p, Error **errp) return; } +static void multifd_ram_prepare_header(MultiFDSendParams *p) +{ + p->iov[0].iov_len = p->packet_len; + p->iov[0].iov_base = p->packet; + p->iovs_num++; +} + static void multifd_send_prepare_iovs(MultiFDSendParams *p) { MultiFDPages_t *pages = &p->data->u.ram; @@ -XXX,XX +XXX,XX @@ static int multifd_nocomp_send_prepare(MultiFDSendParams *p, Error **errp) * Only !zerocopy needs the header in IOV; zerocopy will * send it separately. */ - multifd_send_prepare_header(p); + multifd_ram_prepare_header(p); } multifd_send_prepare_iovs(p); @@ -XXX,XX +XXX,XX @@ static int multifd_nocomp_send_prepare(MultiFDSendParams *p, Error **errp) if (ret != 0) { return -1; } + + stat64_add(&mig_stats.multifd_bytes, p->packet_len); } return 0; @@ -XXX,XX +XXX,XX @@ int multifd_ram_flush_and_sync(QEMUFile *f) bool multifd_send_prepare_common(MultiFDSendParams *p) { MultiFDPages_t *pages = &p->data->u.ram; - multifd_send_prepare_header(p); + multifd_ram_prepare_header(p); multifd_send_zero_page_detect(p); if (!pages->normal_num) { diff --git a/migration/multifd.c b/migration/multifd.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -XXX,XX +XXX,XX @@ #include "qemu/osdep.h" #include "qemu/cutils.h" +#include "qemu/iov.h" #include "qemu/rcu.h" #include "exec/target_page.h" #include "system/system.h" @@ -XXX,XX +XXX,XX @@ #include "qemu/error-report.h" #include "qapi/error.h" #include "file.h" +#include "migration/misc.h" #include "migration.h" #include "migration-stats.h" #include "savevm.h" @@ -XXX,XX +XXX,XX @@ MultiFDSendData *multifd_send_data_alloc(void) * added to the union in the future are larger than * (MultiFDPages_t + flex array). */ - max_payload_size = MAX(multifd_ram_payload_size(), sizeof(MultiFDPayload)); + max_payload_size = MAX(multifd_ram_payload_size(), + multifd_device_state_payload_size()); + max_payload_size = MAX(max_payload_size, sizeof(MultiFDPayload)); /* * Account for any holes the compiler might insert. We can't pack @@ -XXX,XX +XXX,XX @@ void multifd_send_data_clear(MultiFDSendData *data) } switch (data->type) { + case MULTIFD_PAYLOAD_DEVICE_STATE: + multifd_send_data_clear_device_state(&data->u.device_state); + break; default: /* Nothing to do */ break; @@ -XXX,XX +XXX,XX @@ static int multifd_recv_initial_packet(QIOChannel *c, Error **errp) return msg.id; } +/* Fills a RAM multifd packet */ void multifd_send_fill_packet(MultiFDSendParams *p) { MultiFDPacket_t *packet = p->packet; @@ -XXX,XX +XXX,XX @@ static bool multifd_send_cleanup_channel(MultiFDSendParams *p, Error **errp) p->name = NULL; g_clear_pointer(&p->data, multifd_send_data_free); p->packet_len = 0; + g_clear_pointer(&p->packet_device_state, g_free); g_free(p->packet); p->packet = NULL; multifd_send_state->ops->send_cleanup(p, errp); @@ -XXX,XX +XXX,XX @@ static void multifd_send_cleanup_state(void) { file_cleanup_outgoing_migration(); socket_cleanup_outgoing_migration(); + multifd_device_state_send_cleanup(); qemu_sem_destroy(&multifd_send_state->channels_created); qemu_sem_destroy(&multifd_send_state->channels_ready); qemu_mutex_destroy(&multifd_send_state->multifd_send_mutex); @@ -XXX,XX +XXX,XX @@ static void *multifd_send_thread(void *opaque) * qatomic_store_release() in multifd_send(). */ if (qatomic_load_acquire(&p->pending_job)) { + bool is_device_state = multifd_payload_device_state(p->data); + size_t total_size; + p->flags = 0; p->iovs_num = 0; assert(!multifd_payload_empty(p->data)); - ret = multifd_send_state->ops->send_prepare(p, &local_err); - if (ret != 0) { - break; + if (is_device_state) { + multifd_device_state_send_prepare(p); + } else { + ret = multifd_send_state->ops->send_prepare(p, &local_err); + if (ret != 0) { + break; + } } + /* + * The packet header in the zerocopy RAM case is accounted for + * in multifd_nocomp_send_prepare() - where it is actually + * being sent. + */ + total_size = iov_size(p->iov, p->iovs_num); + if (migrate_mapped_ram()) { + assert(!is_device_state); + ret = file_write_ramblock_iov(p->c, p->iov, p->iovs_num, &p->data->u.ram, &local_err); } else { @@ -XXX,XX +XXX,XX @@ static void *multifd_send_thread(void *opaque) break; } - stat64_add(&mig_stats.multifd_bytes, - (uint64_t)p->next_packet_size + p->packet_len); + stat64_add(&mig_stats.multifd_bytes, total_size); p->next_packet_size = 0; multifd_send_data_clear(p->data); @@ -XXX,XX +XXX,XX @@ bool multifd_send_setup(void) p->packet_len = sizeof(MultiFDPacket_t) + sizeof(uint64_t) * page_count; p->packet = g_malloc0(p->packet_len); + p->packet_device_state = g_malloc0(sizeof(*p->packet_device_state)); + p->packet_device_state->hdr.magic = cpu_to_be32(MULTIFD_MAGIC); + p->packet_device_state->hdr.version = cpu_to_be32(MULTIFD_VERSION); } p->name = g_strdup_printf(MIGRATION_THREAD_SRC_MULTIFD, i); p->write_flags = 0; @@ -XXX,XX +XXX,XX @@ bool multifd_send_setup(void) assert(p->iov); } + multifd_device_state_send_setup(); + return true; err: diff --git a/migration/multifd.h b/migration/multifd.h index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -XXX,XX +XXX,XX @@ typedef struct { typedef enum { MULTIFD_PAYLOAD_NONE, MULTIFD_PAYLOAD_RAM, + MULTIFD_PAYLOAD_DEVICE_STATE, } MultiFDPayloadType; typedef union MultiFDPayload { MultiFDPages_t ram; + MultiFDDeviceState_t device_state; } MultiFDPayload; struct MultiFDSendData { @@ -XXX,XX +XXX,XX @@ static inline bool multifd_payload_empty(MultiFDSendData *data) return data->type == MULTIFD_PAYLOAD_NONE; } +static inline bool multifd_payload_device_state(MultiFDSendData *data) +{ + return data->type == MULTIFD_PAYLOAD_DEVICE_STATE; +} + static inline void multifd_set_payload_type(MultiFDSendData *data, MultiFDPayloadType type) { @@ -XXX,XX +XXX,XX @@ typedef struct { /* thread local variables. No locking required */ - /* pointer to the packet */ + /* pointers to the possible packet types */ MultiFDPacket_t *packet; + MultiFDPacketDeviceState_t *packet_device_state; /* size of the next packet that contains pages */ uint32_t next_packet_size; /* packets sent through this channel */ @@ -XXX,XX +XXX,XX @@ bool multifd_send_prepare_common(MultiFDSendParams *p); void multifd_send_zero_page_detect(MultiFDSendParams *p); void multifd_recv_zero_page_process(MultiFDRecvParams *p); -static inline void multifd_send_prepare_header(MultiFDSendParams *p) -{ - p->iov[0].iov_len = p->packet_len; - p->iov[0].iov_base = p->packet; - p->iovs_num++; -} - void multifd_channel_connect(MultiFDSendParams *p, QIOChannel *ioc); bool multifd_send(MultiFDSendData **send_data); MultiFDSendData *multifd_send_data_alloc(void); @@ -XXX,XX +XXX,XX @@ bool multifd_ram_sync_per_section(void); size_t multifd_ram_payload_size(void); void multifd_ram_fill_packet(MultiFDSendParams *p); int multifd_ram_unfill_packet(MultiFDRecvParams *p, Error **errp); + +size_t multifd_device_state_payload_size(void); + +void multifd_send_data_clear_device_state(MultiFDDeviceState_t *device_state); + +void multifd_device_state_send_setup(void); +void multifd_device_state_send_cleanup(void); + +void multifd_device_state_send_prepare(MultiFDSendParams *p); + #endif From: Peter Xu <peterx@redhat.com> The newly introduced device state buffer can be used for either storing VFIO's read() raw data, but already also possible to store generic device states. After noticing that device states may not easily provide a max buffer size (also the fact that RAM MultiFDPages_t after all also want to have flexibility on managing offset[] array), it may not be a good idea to stick with union on MultiFDSendData.. as it won't play well with such flexibility. Switch MultiFDSendData to a struct. It won't consume a lot more space in reality, after all the real buffers were already dynamically allocated, so it's so far only about the two structs (pages, device_state) that will be duplicated, but they're small. With this, we can remove the pretty hard to understand alloc size logic. Because now we can allocate offset[] together with the SendData, and properly free it when the SendData is freed. Signed-off-by: Peter Xu <peterx@redhat.com> [MSS: Make sure to clear possible device state payload before freeing MultiFDSendData, remove placeholders for other patches not included] Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- migration/multifd-device-state.c | 5 ----- migration/multifd-nocomp.c | 13 ++++++------- migration/multifd.c | 25 +++++++------------------ migration/multifd.h | 15 +++++++++------ 4 files changed, 22 insertions(+), 36 deletions(-) diff --git a/migration/multifd-device-state.c b/migration/multifd-device-state.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd-device-state.c +++ b/migration/multifd-device-state.c @@ -XXX,XX +XXX,XX @@ static struct { MultiFDSendData *send_data; } *multifd_send_device_state; -size_t multifd_device_state_payload_size(void) -{ - return sizeof(MultiFDDeviceState_t); -} - void multifd_device_state_send_setup(void) { assert(!multifd_send_device_state); diff --git a/migration/multifd-nocomp.c b/migration/multifd-nocomp.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd-nocomp.c +++ b/migration/multifd-nocomp.c @@ -XXX,XX +XXX,XX @@ static MultiFDSendData *multifd_ram_send; -size_t multifd_ram_payload_size(void) +void multifd_ram_payload_alloc(MultiFDPages_t *pages) { - uint32_t n = multifd_ram_page_count(); + pages->offset = g_new0(ram_addr_t, multifd_ram_page_count()); +} - /* - * We keep an array of page offsets at the end of MultiFDPages_t, - * add space for it in the allocation. - */ - return sizeof(MultiFDPages_t) + n * sizeof(ram_addr_t); +void multifd_ram_payload_free(MultiFDPages_t *pages) +{ + g_clear_pointer(&pages->offset, g_free); } void multifd_ram_save_setup(void) diff --git a/migration/multifd.c b/migration/multifd.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -XXX,XX +XXX,XX @@ struct { MultiFDSendData *multifd_send_data_alloc(void) { - size_t max_payload_size, size_minus_payload; + MultiFDSendData *new = g_new0(MultiFDSendData, 1); - /* - * MultiFDPages_t has a flexible array at the end, account for it - * when allocating MultiFDSendData. Use max() in case other types - * added to the union in the future are larger than - * (MultiFDPages_t + flex array). - */ - max_payload_size = MAX(multifd_ram_payload_size(), - multifd_device_state_payload_size()); - max_payload_size = MAX(max_payload_size, sizeof(MultiFDPayload)); - - /* - * Account for any holes the compiler might insert. We can't pack - * the structure because that misaligns the members and triggers - * Waddress-of-packed-member. - */ - size_minus_payload = sizeof(MultiFDSendData) - sizeof(MultiFDPayload); + multifd_ram_payload_alloc(&new->u.ram); + /* Device state allocates its payload on-demand */ - return g_malloc0(size_minus_payload + max_payload_size); + return new; } void multifd_send_data_clear(MultiFDSendData *data) @@ -XXX,XX +XXX,XX @@ void multifd_send_data_free(MultiFDSendData *data) return; } + /* This also free's device state payload */ multifd_send_data_clear(data); + multifd_ram_payload_free(&data->u.ram); + g_free(data); } diff --git a/migration/multifd.h b/migration/multifd.h index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -XXX,XX +XXX,XX @@ typedef struct { uint32_t num; /* number of normal pages */ uint32_t normal_num; + /* + * Pointer to the ramblock. NOTE: it's caller's responsibility to make + * sure the pointer is always valid! + */ RAMBlock *block; - /* offset of each page */ - ram_addr_t offset[]; + /* offset array of each page, managed by multifd */ + ram_addr_t *offset; } MultiFDPages_t; struct MultiFDRecvData { @@ -XXX,XX +XXX,XX @@ typedef enum { MULTIFD_PAYLOAD_DEVICE_STATE, } MultiFDPayloadType; -typedef union MultiFDPayload { +typedef struct MultiFDPayload { MultiFDPages_t ram; MultiFDDeviceState_t device_state; } MultiFDPayload; @@ -XXX,XX +XXX,XX @@ void multifd_ram_save_cleanup(void); int multifd_ram_flush_and_sync(QEMUFile *f); bool multifd_ram_sync_per_round(void); bool multifd_ram_sync_per_section(void); -size_t multifd_ram_payload_size(void); +void multifd_ram_payload_alloc(MultiFDPages_t *pages); +void multifd_ram_payload_free(MultiFDPages_t *pages); void multifd_ram_fill_packet(MultiFDSendParams *p); int multifd_ram_unfill_packet(MultiFDRecvParams *p, Error **errp); -size_t multifd_device_state_payload_size(void); - void multifd_send_data_clear_device_state(MultiFDDeviceState_t *device_state); void multifd_device_state_send_setup(void); From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Since device state transfer via multifd channels requires multifd channels with packets and is currently not compatible with multifd compression add an appropriate query function so device can learn whether it can actually make use of it. Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/migration/misc.h | 1 + migration/multifd-device-state.c | 7 +++++++ 2 files changed, 8 insertions(+) diff --git a/include/migration/misc.h b/include/migration/misc.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/misc.h +++ b/include/migration/misc.h @@ -XXX,XX +XXX,XX @@ bool migrate_uri_parse(const char *uri, MigrationChannel **channel, /* migration/multifd-device-state.c */ bool multifd_queue_device_state(char *idstr, uint32_t instance_id, char *data, size_t len); +bool multifd_device_state_supported(void); #endif diff --git a/migration/multifd-device-state.c b/migration/multifd-device-state.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd-device-state.c +++ b/migration/multifd-device-state.c @@ -XXX,XX +XXX,XX @@ #include "qemu/lockable.h" #include "migration/misc.h" #include "multifd.h" +#include "options.h" static struct { QemuMutex queue_job_mutex; @@ -XXX,XX +XXX,XX @@ bool multifd_queue_device_state(char *idstr, uint32_t instance_id, return true; } + +bool multifd_device_state_supported(void) +{ + return migrate_multifd() && !migrate_mapped_ram() && + migrate_multifd_compression() == MULTIFD_COMPRESSION_NONE; +} From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This SaveVMHandler helps device provide its own asynchronous transmission of the remaining data at the end of a precopy phase via multifd channels, in parallel with the transfer done by save_live_complete_precopy handlers. These threads are launched only when multifd device state transfer is supported. Management of these threads in done in the multifd migration code, wrapping them in the generic thread pool. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/migration/misc.h | 17 +++++++ include/migration/register.h | 19 +++++++ include/qemu/typedefs.h | 3 ++ migration/multifd-device-state.c | 85 ++++++++++++++++++++++++++++++++ migration/savevm.c | 35 ++++++++++++- 5 files changed, 158 insertions(+), 1 deletion(-) diff --git a/include/migration/misc.h b/include/migration/misc.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/misc.h +++ b/include/migration/misc.h @@ -XXX,XX +XXX,XX @@ bool migrate_uri_parse(const char *uri, MigrationChannel **channel, Error **errp); /* migration/multifd-device-state.c */ +typedef struct SaveLiveCompletePrecopyThreadData { + SaveLiveCompletePrecopyThreadHandler hdlr; + char *idstr; + uint32_t instance_id; + void *handler_opaque; +} SaveLiveCompletePrecopyThreadData; + bool multifd_queue_device_state(char *idstr, uint32_t instance_id, char *data, size_t len); bool multifd_device_state_supported(void); +void +multifd_spawn_device_state_save_thread(SaveLiveCompletePrecopyThreadHandler hdlr, + char *idstr, uint32_t instance_id, + void *opaque); + +bool multifd_device_state_save_thread_should_exit(void); + +void multifd_abort_device_state_save_threads(void); +bool multifd_join_device_state_save_threads(void); + #endif diff --git a/include/migration/register.h b/include/migration/register.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/register.h +++ b/include/migration/register.h @@ -XXX,XX +XXX,XX @@ typedef struct SaveVMHandlers { */ int (*save_live_complete_precopy)(QEMUFile *f, void *opaque); + /** + * @save_live_complete_precopy_thread (invoked in a separate thread) + * + * Called at the end of a precopy phase from a separate worker thread + * in configurations where multifd device state transfer is supported + * in order to perform asynchronous transmission of the remaining data in + * parallel with @save_live_complete_precopy handlers. + * When postcopy is enabled, devices that support postcopy will skip this + * step. + * + * @d: a #SaveLiveCompletePrecopyThreadData containing parameters that the + * handler may need, including this device section idstr and instance_id, + * and opaque data pointer passed to register_savevm_live(). + * @errp: pointer to Error*, to store an error if it happens. + * + * Returns true to indicate success and false for errors. + */ + SaveLiveCompletePrecopyThreadHandler save_live_complete_precopy_thread; + /* This runs both outside and inside the BQL. */ /** diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h index XXXXXXX..XXXXXXX 100644 --- a/include/qemu/typedefs.h +++ b/include/qemu/typedefs.h @@ -XXX,XX +XXX,XX @@ typedef struct QString QString; typedef struct RAMBlock RAMBlock; typedef struct Range Range; typedef struct ReservedRegion ReservedRegion; +typedef struct SaveLiveCompletePrecopyThreadData SaveLiveCompletePrecopyThreadData; typedef struct SHPCDevice SHPCDevice; typedef struct SSIBus SSIBus; typedef struct TCGCPUOps TCGCPUOps; @@ -XXX,XX +XXX,XX @@ typedef struct IRQState *qemu_irq; typedef void (*qemu_irq_handler)(void *opaque, int n, int level); typedef bool (*MigrationLoadThread)(void *opaque, bool *should_quit, Error **errp); +typedef bool (*SaveLiveCompletePrecopyThreadHandler)(SaveLiveCompletePrecopyThreadData *d, + Error **errp); #endif /* QEMU_TYPEDEFS_H */ diff --git a/migration/multifd-device-state.c b/migration/multifd-device-state.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd-device-state.c +++ b/migration/multifd-device-state.c @@ -XXX,XX +XXX,XX @@ */ #include "qemu/osdep.h" +#include "qapi/error.h" #include "qemu/lockable.h" +#include "block/thread-pool.h" +#include "migration.h" #include "migration/misc.h" #include "multifd.h" #include "options.h" @@ -XXX,XX +XXX,XX @@ static struct { QemuMutex queue_job_mutex; MultiFDSendData *send_data; + + ThreadPool *threads; + bool threads_abort; } *multifd_send_device_state; void multifd_device_state_send_setup(void) @@ -XXX,XX +XXX,XX @@ void multifd_device_state_send_setup(void) qemu_mutex_init(&multifd_send_device_state->queue_job_mutex); multifd_send_device_state->send_data = multifd_send_data_alloc(); + + multifd_send_device_state->threads = thread_pool_new(); + multifd_send_device_state->threads_abort = false; } void multifd_device_state_send_cleanup(void) { + g_clear_pointer(&multifd_send_device_state->threads, thread_pool_free); g_clear_pointer(&multifd_send_device_state->send_data, multifd_send_data_free); @@ -XXX,XX +XXX,XX @@ bool multifd_device_state_supported(void) return migrate_multifd() && !migrate_mapped_ram() && migrate_multifd_compression() == MULTIFD_COMPRESSION_NONE; } + +static void multifd_device_state_save_thread_data_free(void *opaque) +{ + SaveLiveCompletePrecopyThreadData *data = opaque; + + g_clear_pointer(&data->idstr, g_free); + g_free(data); +} + +static int multifd_device_state_save_thread(void *opaque) +{ + SaveLiveCompletePrecopyThreadData *data = opaque; + g_autoptr(Error) local_err = NULL; + + if (!data->hdlr(data, &local_err)) { + MigrationState *s = migrate_get_current(); + + assert(local_err); + + /* + * In case of multiple save threads failing which thread error + * return we end setting is purely arbitrary. + */ + migrate_set_error(s, local_err); + } + + return 0; +} + +bool multifd_device_state_save_thread_should_exit(void) +{ + return qatomic_read(&multifd_send_device_state->threads_abort); +} + +void +multifd_spawn_device_state_save_thread(SaveLiveCompletePrecopyThreadHandler hdlr, + char *idstr, uint32_t instance_id, + void *opaque) +{ + SaveLiveCompletePrecopyThreadData *data; + + assert(multifd_device_state_supported()); + assert(multifd_send_device_state); + + assert(!qatomic_read(&multifd_send_device_state->threads_abort)); + + data = g_new(SaveLiveCompletePrecopyThreadData, 1); + data->hdlr = hdlr; + data->idstr = g_strdup(idstr); + data->instance_id = instance_id; + data->handler_opaque = opaque; + + thread_pool_submit_immediate(multifd_send_device_state->threads, + multifd_device_state_save_thread, + data, + multifd_device_state_save_thread_data_free); +} + +void multifd_abort_device_state_save_threads(void) +{ + assert(multifd_device_state_supported()); + + qatomic_set(&multifd_send_device_state->threads_abort, true); +} + +bool multifd_join_device_state_save_threads(void) +{ + MigrationState *s = migrate_get_current(); + + assert(multifd_device_state_supported()); + + thread_pool_wait(multifd_send_device_state->threads); + + return !migrate_has_error(s); +} diff --git a/migration/savevm.c b/migration/savevm.c index XXXXXXX..XXXXXXX 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -XXX,XX +XXX,XX @@ #include "migration/register.h" #include "migration/global_state.h" #include "migration/channel-block.h" +#include "multifd.h" #include "ram.h" #include "qemu-file.h" #include "savevm.h" @@ -XXX,XX +XXX,XX @@ int qemu_savevm_state_complete_precopy_iterable(QEMUFile *f, bool in_postcopy) int64_t start_ts_each, end_ts_each; SaveStateEntry *se; int ret; + bool multifd_device_state = multifd_device_state_supported(); + + if (multifd_device_state) { + QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { + SaveLiveCompletePrecopyThreadHandler hdlr; + + if (!se->ops || (in_postcopy && se->ops->has_postcopy && + se->ops->has_postcopy(se->opaque)) || + !se->ops->save_live_complete_precopy_thread) { + continue; + } + + hdlr = se->ops->save_live_complete_precopy_thread; + multifd_spawn_device_state_save_thread(hdlr, + se->idstr, se->instance_id, + se->opaque); + } + } QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (!se->ops || @@ -XXX,XX +XXX,XX @@ int qemu_savevm_state_complete_precopy_iterable(QEMUFile *f, bool in_postcopy) save_section_footer(f, se); if (ret < 0) { qemu_file_set_error(f, ret); - return -1; + goto ret_fail_abort_threads; } end_ts_each = qemu_clock_get_us(QEMU_CLOCK_REALTIME); trace_vmstate_downtime_save("iterable", se->idstr, se->instance_id, end_ts_each - start_ts_each); } + if (multifd_device_state && + !multifd_join_device_state_save_threads()) { + qemu_file_set_error(f, -EINVAL); + return -1; + } + trace_vmstate_downtime_checkpoint("src-iterable-saved"); return 0; + +ret_fail_abort_threads: + if (multifd_device_state) { + multifd_abort_device_state_save_threads(); + multifd_join_device_state_save_threads(); + } + + return -1; } int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f, From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> And rename existing load_device_config_state trace event to load_device_config_state_end for consistency since it is triggered at the end of loading of the VFIO device config state. This way both the start and end points of particular device config loading operation (a long, BQL-serialized operation) are known. Reviewed-by: Cédric Le Goater <clg@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration.c | 4 +++- hw/vfio/trace-events | 3 ++- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ static int vfio_load_device_config_state(QEMUFile *f, void *opaque) VFIODevice *vbasedev = opaque; uint64_t data; + trace_vfio_load_device_config_state_start(vbasedev->name); + if (vbasedev->ops && vbasedev->ops->vfio_load_config) { int ret; @@ -XXX,XX +XXX,XX @@ static int vfio_load_device_config_state(QEMUFile *f, void *opaque) return -EINVAL; } - trace_vfio_load_device_config_state(vbasedev->name); + trace_vfio_load_device_config_state_end(vbasedev->name); return qemu_file_get_error(f); } diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/trace-events +++ b/hw/vfio/trace-events @@ -XXX,XX +XXX,XX @@ vfio_display_edid_write_error(void) "" # migration.c vfio_load_cleanup(const char *name) " (%s)" -vfio_load_device_config_state(const char *name) " (%s)" +vfio_load_device_config_state_start(const char *name) " (%s)" +vfio_load_device_config_state_end(const char *name) " (%s)" vfio_load_state(const char *name, uint64_t data) " (%s) data 0x%"PRIx64 vfio_load_state_device_data(const char *name, uint64_t data_size, int ret) " (%s) size %"PRIu64" ret %d" vfio_migration_realize(const char *name) " (%s)" From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> So it can be safety accessed from multiple threads. This variable type needs to be changed to unsigned long since 32-bit host platforms lack the necessary addition atomics on 64-bit variables. Using 32-bit counters on 32-bit host platforms should not be a problem in practice since they can't realistically address more memory anyway. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ */ #define VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE (1 * MiB) -static int64_t bytes_transferred; +static unsigned long bytes_transferred; static const char *mig_state_to_str(enum vfio_device_mig_state state) { @@ -XXX,XX +XXX,XX @@ static ssize_t vfio_save_block(QEMUFile *f, VFIOMigration *migration) qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE); qemu_put_be64(f, data_size); qemu_put_buffer(f, migration->data_buffer, data_size); - bytes_transferred += data_size; + qatomic_add(&bytes_transferred, data_size); trace_vfio_save_block(migration->vbasedev->name, data_size); @@ -XXX,XX +XXX,XX @@ static int vfio_block_migration(VFIODevice *vbasedev, Error *err, Error **errp) int64_t vfio_mig_bytes_transferred(void) { - return bytes_transferred; + return MIN(qatomic_read(&bytes_transferred), INT64_MAX); } void vfio_reset_bytes_transferred(void) { - bytes_transferred = 0; + qatomic_set(&bytes_transferred, 0); } /* From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This way bytes_transferred can also be incremented in other translation units than migration.c. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration.c | 7 ++++++- include/hw/vfio/vfio-common.h | 1 + 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ static ssize_t vfio_save_block(QEMUFile *f, VFIOMigration *migration) qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE); qemu_put_be64(f, data_size); qemu_put_buffer(f, migration->data_buffer, data_size); - qatomic_add(&bytes_transferred, data_size); + vfio_add_bytes_transferred(data_size); trace_vfio_save_block(migration->vbasedev->name, data_size); @@ -XXX,XX +XXX,XX @@ void vfio_reset_bytes_transferred(void) qatomic_set(&bytes_transferred, 0); } +void vfio_add_bytes_transferred(unsigned long val) +{ + qatomic_add(&bytes_transferred, val); +} + /* * Return true when either migration initialized or blocker registered. * Currently only return false when adding blocker fails which will diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -XXX,XX +XXX,XX @@ void vfio_unblock_multiple_devices_migration(void); bool vfio_viommu_preset(VFIODevice *vbasedev); int64_t vfio_mig_bytes_transferred(void); void vfio_reset_bytes_transferred(void); +void vfio_add_bytes_transferred(unsigned long val); bool vfio_device_state_is_running(VFIODevice *vbasedev); bool vfio_device_state_is_precopy(VFIODevice *vbasedev); From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This way they can also be referenced in other translation units than migration.c. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration.c | 17 ----------------- include/hw/vfio/vfio-common.h | 17 +++++++++++++++++ 2 files changed, 17 insertions(+), 17 deletions(-) diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ #include "trace.h" #include "hw/hw.h" -/* - * Flags to be used as unique delimiters for VFIO devices in the migration - * stream. These flags are composed as: - * 0xffffffff => MSB 32-bit all 1s - * 0xef10 => Magic ID, represents emulated (virtual) function IO - * 0x0000 => 16-bits reserved for flags - * - * The beginning of state information is marked by _DEV_CONFIG_STATE, - * _DEV_SETUP_STATE, or _DEV_DATA_STATE, respectively. The end of a - * certain state information is marked by _END_OF_STATE. - */ -#define VFIO_MIG_FLAG_END_OF_STATE (0xffffffffef100001ULL) -#define VFIO_MIG_FLAG_DEV_CONFIG_STATE (0xffffffffef100002ULL) -#define VFIO_MIG_FLAG_DEV_SETUP_STATE (0xffffffffef100003ULL) -#define VFIO_MIG_FLAG_DEV_DATA_STATE (0xffffffffef100004ULL) -#define VFIO_MIG_FLAG_DEV_INIT_DATA_SENT (0xffffffffef100005ULL) - /* * This is an arbitrary size based on migration of mlx5 devices, where typically * total device migration size is on the order of 100s of MB. Testing with diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -XXX,XX +XXX,XX @@ #define VFIO_MSG_PREFIX "vfio %s: " +/* + * Flags to be used as unique delimiters for VFIO devices in the migration + * stream. These flags are composed as: + * 0xffffffff => MSB 32-bit all 1s + * 0xef10 => Magic ID, represents emulated (virtual) function IO + * 0x0000 => 16-bits reserved for flags + * + * The beginning of state information is marked by _DEV_CONFIG_STATE, + * _DEV_SETUP_STATE, or _DEV_DATA_STATE, respectively. The end of a + * certain state information is marked by _END_OF_STATE. + */ +#define VFIO_MIG_FLAG_END_OF_STATE (0xffffffffef100001ULL) +#define VFIO_MIG_FLAG_DEV_CONFIG_STATE (0xffffffffef100002ULL) +#define VFIO_MIG_FLAG_DEV_SETUP_STATE (0xffffffffef100003ULL) +#define VFIO_MIG_FLAG_DEV_DATA_STATE (0xffffffffef100004ULL) +#define VFIO_MIG_FLAG_DEV_INIT_DATA_SENT (0xffffffffef100005ULL) + enum { VFIO_DEVICE_TYPE_PCI = 0, VFIO_DEVICE_TYPE_PLATFORM = 1, From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Add basic types and flags used by VFIO multifd device state transfer support. Since we'll be introducing a lot of multifd transfer specific code, add a new file migration-multifd.c to home it, wired into main VFIO migration code (migration.c) via migration-multifd.h header file. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/meson.build | 1 + hw/vfio/migration-multifd.c | 31 +++++++++++++++++++++++++++++++ hw/vfio/migration-multifd.h | 15 +++++++++++++++ hw/vfio/migration.c | 1 + 4 files changed, 48 insertions(+) create mode 100644 hw/vfio/migration-multifd.c create mode 100644 hw/vfio/migration-multifd.h diff --git a/hw/vfio/meson.build b/hw/vfio/meson.build index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/meson.build +++ b/hw/vfio/meson.build @@ -XXX,XX +XXX,XX @@ vfio_ss.add(files( 'container-base.c', 'container.c', 'migration.c', + 'migration-multifd.c', 'cpr.c', )) vfio_ss.add(when: 'CONFIG_PSERIES', if_true: files('spapr.c')) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c new file mode 100644 index XXXXXXX..XXXXXXX --- /dev/null +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ +/* + * Multifd VFIO migration + * + * Copyright (C) 2024,2025 Oracle and/or its affiliates. + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#include "qemu/osdep.h" +#include "hw/vfio/vfio-common.h" +#include "migration/misc.h" +#include "qapi/error.h" +#include "qemu/error-report.h" +#include "qemu/lockable.h" +#include "qemu/main-loop.h" +#include "qemu/thread.h" +#include "migration/qemu-file.h" +#include "migration-multifd.h" +#include "trace.h" + +#define VFIO_DEVICE_STATE_CONFIG_STATE (1) + +#define VFIO_DEVICE_STATE_PACKET_VER_CURRENT (0) + +typedef struct VFIODeviceStatePacket { + uint32_t version; + uint32_t idx; + uint32_t flags; + uint8_t data[0]; +} QEMU_PACKED VFIODeviceStatePacket; diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h new file mode 100644 index XXXXXXX..XXXXXXX --- /dev/null +++ b/hw/vfio/migration-multifd.h @@ -XXX,XX +XXX,XX @@ +/* + * Multifd VFIO migration + * + * Copyright (C) 2024,2025 Oracle and/or its affiliates. + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#ifndef HW_VFIO_MIGRATION_MULTIFD_H +#define HW_VFIO_MIGRATION_MULTIFD_H + +#include "hw/vfio/vfio-common.h" + +#endif diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ #include "migration/qemu-file.h" #include "migration/register.h" #include "migration/blocker.h" +#include "migration-multifd.h" #include "qapi/error.h" #include "qapi/qapi-events-vfio.h" #include "exec/ramlist.h" From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Add VFIOStateBuffer(s) types and the associated methods. These store received device state buffers and config state waiting to get loaded into the device. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 54 +++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ typedef struct VFIODeviceStatePacket { uint32_t flags; uint8_t data[0]; } QEMU_PACKED VFIODeviceStatePacket; + +/* type safety */ +typedef struct VFIOStateBuffers { + GArray *array; +} VFIOStateBuffers; + +typedef struct VFIOStateBuffer { + bool is_present; + char *data; + size_t len; +} VFIOStateBuffer; + +static void vfio_state_buffer_clear(gpointer data) +{ + VFIOStateBuffer *lb = data; + + if (!lb->is_present) { + return; + } + + g_clear_pointer(&lb->data, g_free); + lb->is_present = false; +} + +static void vfio_state_buffers_init(VFIOStateBuffers *bufs) +{ + bufs->array = g_array_new(FALSE, TRUE, sizeof(VFIOStateBuffer)); + g_array_set_clear_func(bufs->array, vfio_state_buffer_clear); +} + +static void vfio_state_buffers_destroy(VFIOStateBuffers *bufs) +{ + g_clear_pointer(&bufs->array, g_array_unref); +} + +static void vfio_state_buffers_assert_init(VFIOStateBuffers *bufs) +{ + assert(bufs->array); +} + +static guint vfio_state_buffers_size_get(VFIOStateBuffers *bufs) +{ + return bufs->array->len; +} + +static void vfio_state_buffers_size_set(VFIOStateBuffers *bufs, guint size) +{ + g_array_set_size(bufs->array, size); +} + +static VFIOStateBuffer *vfio_state_buffers_at(VFIOStateBuffers *bufs, guint idx) +{ + return &g_array_index(bufs->array, VFIOStateBuffer, idx); +} From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Add vfio_multifd_transfer_supported() function that tells whether the multifd device state transfer is supported. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 6 ++++++ hw/vfio/migration-multifd.h | 2 ++ 2 files changed, 8 insertions(+) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ static VFIOStateBuffer *vfio_state_buffers_at(VFIOStateBuffers *bufs, guint idx) { return &g_array_index(bufs->array, VFIOStateBuffer, idx); } + +bool vfio_multifd_transfer_supported(void) +{ + return multifd_device_state_supported() && + migrate_send_switchover_start(); +} diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.h +++ b/hw/vfio/migration-multifd.h @@ -XXX,XX +XXX,XX @@ #include "hw/vfio/vfio-common.h" +bool vfio_multifd_transfer_supported(void); + #endif From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Add support for VFIOMultifd data structure that will contain most of the receive-side data together with its init/cleanup methods. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 33 +++++++++++++++++++++++++++++++++ hw/vfio/migration-multifd.h | 8 ++++++++ hw/vfio/migration.c | 29 +++++++++++++++++++++++++++-- include/hw/vfio/vfio-common.h | 3 +++ 4 files changed, 71 insertions(+), 2 deletions(-) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ typedef struct VFIOStateBuffer { size_t len; } VFIOStateBuffer; +typedef struct VFIOMultifd { +} VFIOMultifd; + static void vfio_state_buffer_clear(gpointer data) { VFIOStateBuffer *lb = data; @@ -XXX,XX +XXX,XX @@ static VFIOStateBuffer *vfio_state_buffers_at(VFIOStateBuffers *bufs, guint idx) return &g_array_index(bufs->array, VFIOStateBuffer, idx); } +VFIOMultifd *vfio_multifd_new(void) +{ + VFIOMultifd *multifd = g_new(VFIOMultifd, 1); + + return multifd; +} + +void vfio_multifd_free(VFIOMultifd *multifd) +{ + g_free(multifd); +} + bool vfio_multifd_transfer_supported(void) { return multifd_device_state_supported() && migrate_send_switchover_start(); } + +bool vfio_multifd_transfer_enabled(VFIODevice *vbasedev) +{ + return false; +} + +bool vfio_multifd_transfer_setup(VFIODevice *vbasedev, Error **errp) +{ + if (vfio_multifd_transfer_enabled(vbasedev) && + !vfio_multifd_transfer_supported()) { + error_setg(errp, + "%s: Multifd device transfer requested but unsupported in the current config", + vbasedev->name); + return false; + } + + return true; +} diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.h +++ b/hw/vfio/migration-multifd.h @@ -XXX,XX +XXX,XX @@ #include "hw/vfio/vfio-common.h" +typedef struct VFIOMultifd VFIOMultifd; + +VFIOMultifd *vfio_multifd_new(void); +void vfio_multifd_free(VFIOMultifd *multifd); + bool vfio_multifd_transfer_supported(void); +bool vfio_multifd_transfer_enabled(VFIODevice *vbasedev); + +bool vfio_multifd_transfer_setup(VFIODevice *vbasedev, Error **errp); #endif diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ static void vfio_save_state(QEMUFile *f, void *opaque) static int vfio_load_setup(QEMUFile *f, void *opaque, Error **errp) { VFIODevice *vbasedev = opaque; + VFIOMigration *migration = vbasedev->migration; + int ret; + + if (!vfio_multifd_transfer_setup(vbasedev, errp)) { + return -EINVAL; + } + + ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING, + migration->device_state, errp); + if (ret) { + return ret; + } - return vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING, - vbasedev->migration->device_state, errp); + if (vfio_multifd_transfer_enabled(vbasedev)) { + assert(!migration->multifd); + migration->multifd = vfio_multifd_new(); + } + + return 0; +} + +static void vfio_multifd_cleanup(VFIODevice *vbasedev) +{ + VFIOMigration *migration = vbasedev->migration; + + g_clear_pointer(&migration->multifd, vfio_multifd_free); } static int vfio_load_cleanup(void *opaque) { VFIODevice *vbasedev = opaque; + vfio_multifd_cleanup(vbasedev); + vfio_migration_cleanup(vbasedev); trace_vfio_load_cleanup(vbasedev->name); diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -XXX,XX +XXX,XX @@ typedef struct VFIORegion { uint8_t nr; /* cache the region number for debug */ } VFIORegion; +typedef struct VFIOMultifd VFIOMultifd; + typedef struct VFIOMigration { struct VFIODevice *vbasedev; VMChangeStateEntry *vm_state; @@ -XXX,XX +XXX,XX @@ typedef struct VFIOMigration { uint64_t mig_flags; uint64_t precopy_init_size; uint64_t precopy_dirty_size; + VFIOMultifd *multifd; bool initial_data_sent; bool event_save_iterate_started; From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> The multifd received data needs to be reassembled since device state packets sent via different multifd channels can arrive out-of-order. Therefore, each VFIO device state packet carries a header indicating its position in the stream. The raw device state data is saved into a VFIOStateBuffer for later in-order loading into the device. The last such VFIO device state packet should have VFIO_DEVICE_STATE_CONFIG_STATE flag set and carry the device config state. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 103 ++++++++++++++++++++++++++++++++++++ hw/vfio/migration-multifd.h | 3 ++ hw/vfio/migration.c | 1 + hw/vfio/trace-events | 1 + 4 files changed, 108 insertions(+) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ typedef struct VFIOStateBuffer { } VFIOStateBuffer; typedef struct VFIOMultifd { + VFIOStateBuffers load_bufs; + QemuCond load_bufs_buffer_ready_cond; + QemuMutex load_bufs_mutex; /* Lock order: this lock -> BQL */ + uint32_t load_buf_idx; + uint32_t load_buf_idx_last; } VFIOMultifd; static void vfio_state_buffer_clear(gpointer data) @@ -XXX,XX +XXX,XX @@ static VFIOStateBuffer *vfio_state_buffers_at(VFIOStateBuffers *bufs, guint idx) return &g_array_index(bufs->array, VFIOStateBuffer, idx); } +static bool vfio_load_state_buffer_insert(VFIODevice *vbasedev, + VFIODeviceStatePacket *packet, + size_t packet_total_size, + Error **errp) +{ + VFIOMigration *migration = vbasedev->migration; + VFIOMultifd *multifd = migration->multifd; + VFIOStateBuffer *lb; + + vfio_state_buffers_assert_init(&multifd->load_bufs); + if (packet->idx >= vfio_state_buffers_size_get(&multifd->load_bufs)) { + vfio_state_buffers_size_set(&multifd->load_bufs, packet->idx + 1); + } + + lb = vfio_state_buffers_at(&multifd->load_bufs, packet->idx); + if (lb->is_present) { + error_setg(errp, "state buffer %" PRIu32 " already filled", + packet->idx); + return false; + } + + assert(packet->idx >= multifd->load_buf_idx); + + lb->data = g_memdup2(&packet->data, packet_total_size - sizeof(*packet)); + lb->len = packet_total_size - sizeof(*packet); + lb->is_present = true; + + return true; +} + +bool vfio_load_state_buffer(void *opaque, char *data, size_t data_size, + Error **errp) +{ + VFIODevice *vbasedev = opaque; + VFIOMigration *migration = vbasedev->migration; + VFIOMultifd *multifd = migration->multifd; + VFIODeviceStatePacket *packet = (VFIODeviceStatePacket *)data; + + /* + * Holding BQL here would violate the lock order and can cause + * a deadlock once we attempt to lock load_bufs_mutex below. + */ + assert(!bql_locked()); + + if (!vfio_multifd_transfer_enabled(vbasedev)) { + error_setg(errp, + "got device state packet but not doing multifd transfer"); + return false; + } + + assert(multifd); + + if (data_size < sizeof(*packet)) { + error_setg(errp, "packet too short at %zu (min is %zu)", + data_size, sizeof(*packet)); + return false; + } + + if (packet->version != VFIO_DEVICE_STATE_PACKET_VER_CURRENT) { + error_setg(errp, "packet has unknown version %" PRIu32, + packet->version); + return false; + } + + if (packet->idx == UINT32_MAX) { + error_setg(errp, "packet has too high idx"); + return false; + } + + trace_vfio_load_state_device_buffer_incoming(vbasedev->name, packet->idx); + + QEMU_LOCK_GUARD(&multifd->load_bufs_mutex); + + /* config state packet should be the last one in the stream */ + if (packet->flags & VFIO_DEVICE_STATE_CONFIG_STATE) { + multifd->load_buf_idx_last = packet->idx; + } + + if (!vfio_load_state_buffer_insert(vbasedev, packet, data_size, errp)) { + return false; + } + + qemu_cond_signal(&multifd->load_bufs_buffer_ready_cond); + + return true; +} + VFIOMultifd *vfio_multifd_new(void) { VFIOMultifd *multifd = g_new(VFIOMultifd, 1); + vfio_state_buffers_init(&multifd->load_bufs); + + qemu_mutex_init(&multifd->load_bufs_mutex); + + multifd->load_buf_idx = 0; + multifd->load_buf_idx_last = UINT32_MAX; + qemu_cond_init(&multifd->load_bufs_buffer_ready_cond); + return multifd; } void vfio_multifd_free(VFIOMultifd *multifd) { + qemu_cond_destroy(&multifd->load_bufs_buffer_ready_cond); + qemu_mutex_destroy(&multifd->load_bufs_mutex); + g_free(multifd); } diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.h +++ b/hw/vfio/migration-multifd.h @@ -XXX,XX +XXX,XX @@ bool vfio_multifd_transfer_enabled(VFIODevice *vbasedev); bool vfio_multifd_transfer_setup(VFIODevice *vbasedev, Error **errp); +bool vfio_load_state_buffer(void *opaque, char *data, size_t data_size, + Error **errp); + #endif diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ static const SaveVMHandlers savevm_vfio_handlers = { .load_setup = vfio_load_setup, .load_cleanup = vfio_load_cleanup, .load_state = vfio_load_state, + .load_state_buffer = vfio_load_state_buffer, .switchover_ack_needed = vfio_switchover_ack_needed, }; diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/trace-events +++ b/hw/vfio/trace-events @@ -XXX,XX +XXX,XX @@ vfio_load_device_config_state_start(const char *name) " (%s)" vfio_load_device_config_state_end(const char *name) " (%s)" vfio_load_state(const char *name, uint64_t data) " (%s) data 0x%"PRIx64 vfio_load_state_device_data(const char *name, uint64_t data_size, int ret) " (%s) size %"PRIu64" ret %d" +vfio_load_state_device_buffer_incoming(const char *name, uint32_t idx) " (%s) idx %"PRIu32 vfio_migration_realize(const char *name) " (%s)" vfio_migration_set_device_state(const char *name, const char *state) " (%s) state %s" vfio_migration_set_state(const char *name, const char *new_state, const char *recover_state) " (%s) new state %s, recover state %s" From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Since it's important to finish loading device state transferred via the main migration channel (via save_live_iterate SaveVMHandler) before starting loading the data asynchronously transferred via multifd the thread doing the actual loading of the multifd transferred data is only started from switchover_start SaveVMHandler. switchover_start handler is called when MIG_CMD_SWITCHOVER_START sub-command of QEMU_VM_COMMAND is received via the main migration channel. This sub-command is only sent after all save_live_iterate data have already been posted so it is safe to commence loading of the multifd-transferred device state upon receiving it - loading of save_live_iterate data happens synchronously in the main migration thread (much like the processing of MIG_CMD_SWITCHOVER_START) so by the time MIG_CMD_SWITCHOVER_START is processed all the proceeding data must have already been loaded. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 225 ++++++++++++++++++++++++++++++++++++ hw/vfio/migration-multifd.h | 2 + hw/vfio/migration.c | 12 ++ hw/vfio/trace-events | 5 + 4 files changed, 244 insertions(+) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ typedef struct VFIOStateBuffer { } VFIOStateBuffer; typedef struct VFIOMultifd { + QemuThread load_bufs_thread; + bool load_bufs_thread_running; + bool load_bufs_thread_want_exit; + VFIOStateBuffers load_bufs; QemuCond load_bufs_buffer_ready_cond; + QemuCond load_bufs_thread_finished_cond; QemuMutex load_bufs_mutex; /* Lock order: this lock -> BQL */ uint32_t load_buf_idx; uint32_t load_buf_idx_last; @@ -XXX,XX +XXX,XX @@ bool vfio_load_state_buffer(void *opaque, char *data, size_t data_size, return true; } +static int vfio_load_bufs_thread_load_config(VFIODevice *vbasedev) +{ + return -EINVAL; +} + +static VFIOStateBuffer *vfio_load_state_buffer_get(VFIOMultifd *multifd) +{ + VFIOStateBuffer *lb; + guint bufs_len; + + bufs_len = vfio_state_buffers_size_get(&multifd->load_bufs); + if (multifd->load_buf_idx >= bufs_len) { + assert(multifd->load_buf_idx == bufs_len); + return NULL; + } + + lb = vfio_state_buffers_at(&multifd->load_bufs, + multifd->load_buf_idx); + if (!lb->is_present) { + return NULL; + } + + return lb; +} + +static bool vfio_load_state_buffer_write(VFIODevice *vbasedev, + VFIOStateBuffer *lb, + Error **errp) +{ + VFIOMigration *migration = vbasedev->migration; + VFIOMultifd *multifd = migration->multifd; + g_autofree char *buf = NULL; + char *buf_cur; + size_t buf_len; + + if (!lb->len) { + return true; + } + + trace_vfio_load_state_device_buffer_load_start(vbasedev->name, + multifd->load_buf_idx); + + /* lb might become re-allocated when we drop the lock */ + buf = g_steal_pointer(&lb->data); + buf_cur = buf; + buf_len = lb->len; + while (buf_len > 0) { + ssize_t wr_ret; + int errno_save; + + /* + * Loading data to the device takes a while, + * drop the lock during this process. + */ + qemu_mutex_unlock(&multifd->load_bufs_mutex); + wr_ret = write(migration->data_fd, buf_cur, buf_len); + errno_save = errno; + qemu_mutex_lock(&multifd->load_bufs_mutex); + + if (wr_ret < 0) { + error_setg(errp, + "writing state buffer %" PRIu32 " failed: %d", + multifd->load_buf_idx, errno_save); + return false; + } + + assert(wr_ret <= buf_len); + buf_len -= wr_ret; + buf_cur += wr_ret; + } + + trace_vfio_load_state_device_buffer_load_end(vbasedev->name, + multifd->load_buf_idx); + + return true; +} + +static bool vfio_load_bufs_thread_want_exit(VFIOMultifd *multifd, + bool *should_quit) +{ + return multifd->load_bufs_thread_want_exit || qatomic_read(should_quit); +} + +/* + * This thread is spawned by vfio_multifd_switchover_start() which gets + * called upon encountering the switchover point marker in main migration + * stream. + * + * It exits after either: + * * completing loading the remaining device state and device config, OR: + * * encountering some error while doing the above, OR: + * * being forcefully aborted by the migration core by it setting should_quit + * or by vfio_load_cleanup_load_bufs_thread() setting + * multifd->load_bufs_thread_want_exit. + */ +static bool vfio_load_bufs_thread(void *opaque, bool *should_quit, Error **errp) +{ + VFIODevice *vbasedev = opaque; + VFIOMigration *migration = vbasedev->migration; + VFIOMultifd *multifd = migration->multifd; + bool ret = true; + int config_ret; + + assert(multifd); + QEMU_LOCK_GUARD(&multifd->load_bufs_mutex); + + assert(multifd->load_bufs_thread_running); + + while (true) { + VFIOStateBuffer *lb; + + /* + * Always check cancellation first after the buffer_ready wait below in + * case that cond was signalled by vfio_load_cleanup_load_bufs_thread(). + */ + if (vfio_load_bufs_thread_want_exit(multifd, should_quit)) { + error_setg(errp, "operation cancelled"); + ret = false; + goto ret_signal; + } + + assert(multifd->load_buf_idx <= multifd->load_buf_idx_last); + + lb = vfio_load_state_buffer_get(multifd); + if (!lb) { + trace_vfio_load_state_device_buffer_starved(vbasedev->name, + multifd->load_buf_idx); + qemu_cond_wait(&multifd->load_bufs_buffer_ready_cond, + &multifd->load_bufs_mutex); + continue; + } + + if (multifd->load_buf_idx == multifd->load_buf_idx_last) { + break; + } + + if (multifd->load_buf_idx == 0) { + trace_vfio_load_state_device_buffer_start(vbasedev->name); + } + + if (!vfio_load_state_buffer_write(vbasedev, lb, errp)) { + ret = false; + goto ret_signal; + } + + if (multifd->load_buf_idx == multifd->load_buf_idx_last - 1) { + trace_vfio_load_state_device_buffer_end(vbasedev->name); + } + + multifd->load_buf_idx++; + } + + config_ret = vfio_load_bufs_thread_load_config(vbasedev); + if (config_ret) { + error_setg(errp, "load config state failed: %d", config_ret); + ret = false; + } + +ret_signal: + /* + * Notify possibly waiting vfio_load_cleanup_load_bufs_thread() that + * this thread is exiting. + */ + multifd->load_bufs_thread_running = false; + qemu_cond_signal(&multifd->load_bufs_thread_finished_cond); + + return ret; +} + VFIOMultifd *vfio_multifd_new(void) { VFIOMultifd *multifd = g_new(VFIOMultifd, 1); @@ -XXX,XX +XXX,XX @@ VFIOMultifd *vfio_multifd_new(void) multifd->load_buf_idx_last = UINT32_MAX; qemu_cond_init(&multifd->load_bufs_buffer_ready_cond); + multifd->load_bufs_thread_running = false; + multifd->load_bufs_thread_want_exit = false; + qemu_cond_init(&multifd->load_bufs_thread_finished_cond); + return multifd; } +/* + * Terminates vfio_load_bufs_thread by setting + * multifd->load_bufs_thread_want_exit and signalling all the conditions + * the thread could be blocked on. + * + * Waits for the thread to signal that it had finished. + */ +static void vfio_load_cleanup_load_bufs_thread(VFIOMultifd *multifd) +{ + /* The lock order is load_bufs_mutex -> BQL so unlock BQL here first */ + bql_unlock(); + WITH_QEMU_LOCK_GUARD(&multifd->load_bufs_mutex) { + while (multifd->load_bufs_thread_running) { + multifd->load_bufs_thread_want_exit = true; + + qemu_cond_signal(&multifd->load_bufs_buffer_ready_cond); + qemu_cond_wait(&multifd->load_bufs_thread_finished_cond, + &multifd->load_bufs_mutex); + } + } + bql_lock(); +} + void vfio_multifd_free(VFIOMultifd *multifd) { + vfio_load_cleanup_load_bufs_thread(multifd); + + qemu_cond_destroy(&multifd->load_bufs_thread_finished_cond); + vfio_state_buffers_destroy(&multifd->load_bufs); qemu_cond_destroy(&multifd->load_bufs_buffer_ready_cond); qemu_mutex_destroy(&multifd->load_bufs_mutex); @@ -XXX,XX +XXX,XX @@ bool vfio_multifd_transfer_setup(VFIODevice *vbasedev, Error **errp) return true; } + +int vfio_multifd_switchover_start(VFIODevice *vbasedev) +{ + VFIOMigration *migration = vbasedev->migration; + VFIOMultifd *multifd = migration->multifd; + + assert(multifd); + + /* The lock order is load_bufs_mutex -> BQL so unlock BQL here first */ + bql_unlock(); + WITH_QEMU_LOCK_GUARD(&multifd->load_bufs_mutex) { + assert(!multifd->load_bufs_thread_running); + multifd->load_bufs_thread_running = true; + } + bql_lock(); + + qemu_loadvm_start_load_thread(vfio_load_bufs_thread, vbasedev); + + return 0; +} diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.h +++ b/hw/vfio/migration-multifd.h @@ -XXX,XX +XXX,XX @@ bool vfio_multifd_transfer_setup(VFIODevice *vbasedev, Error **errp); bool vfio_load_state_buffer(void *opaque, char *data, size_t data_size, Error **errp); +int vfio_multifd_switchover_start(VFIODevice *vbasedev); + #endif diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ static bool vfio_switchover_ack_needed(void *opaque) return vfio_precopy_supported(vbasedev); } +static int vfio_switchover_start(void *opaque) +{ + VFIODevice *vbasedev = opaque; + + if (vfio_multifd_transfer_enabled(vbasedev)) { + return vfio_multifd_switchover_start(vbasedev); + } + + return 0; +} + static const SaveVMHandlers savevm_vfio_handlers = { .save_prepare = vfio_save_prepare, .save_setup = vfio_save_setup, @@ -XXX,XX +XXX,XX @@ static const SaveVMHandlers savevm_vfio_handlers = { .load_state = vfio_load_state, .load_state_buffer = vfio_load_state_buffer, .switchover_ack_needed = vfio_switchover_ack_needed, + .switchover_start = vfio_switchover_start, }; /* ---------------------------------------------------------------------- */ diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/trace-events +++ b/hw/vfio/trace-events @@ -XXX,XX +XXX,XX @@ vfio_load_device_config_state_end(const char *name) " (%s)" vfio_load_state(const char *name, uint64_t data) " (%s) data 0x%"PRIx64 vfio_load_state_device_data(const char *name, uint64_t data_size, int ret) " (%s) size %"PRIu64" ret %d" vfio_load_state_device_buffer_incoming(const char *name, uint32_t idx) " (%s) idx %"PRIu32 +vfio_load_state_device_buffer_start(const char *name) " (%s)" +vfio_load_state_device_buffer_starved(const char *name, uint32_t idx) " (%s) idx %"PRIu32 +vfio_load_state_device_buffer_load_start(const char *name, uint32_t idx) " (%s) idx %"PRIu32 +vfio_load_state_device_buffer_load_end(const char *name, uint32_t idx) " (%s) idx %"PRIu32 +vfio_load_state_device_buffer_end(const char *name) " (%s)" vfio_migration_realize(const char *name) " (%s)" vfio_migration_set_device_state(const char *name, const char *state) " (%s) state %s" vfio_migration_set_state(const char *name, const char *new_state, const char *recover_state) " (%s) new state %s, recover state %s" From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Load device config received via multifd using the existing machinery behind vfio_load_device_config_state(). Also, make sure to process the relevant main migration channel flags. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 47 ++++++++++++++++++++++++++++++++++- hw/vfio/migration.c | 8 +++++- include/hw/vfio/vfio-common.h | 2 ++ 3 files changed, 55 insertions(+), 2 deletions(-) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ #include "qemu/lockable.h" #include "qemu/main-loop.h" #include "qemu/thread.h" +#include "io/channel-buffer.h" #include "migration/qemu-file.h" #include "migration-multifd.h" #include "trace.h" @@ -XXX,XX +XXX,XX @@ bool vfio_load_state_buffer(void *opaque, char *data, size_t data_size, static int vfio_load_bufs_thread_load_config(VFIODevice *vbasedev) { - return -EINVAL; + VFIOMigration *migration = vbasedev->migration; + VFIOMultifd *multifd = migration->multifd; + VFIOStateBuffer *lb; + g_autoptr(QIOChannelBuffer) bioc = NULL; + QEMUFile *f_out = NULL, *f_in = NULL; + uint64_t mig_header; + int ret; + + assert(multifd->load_buf_idx == multifd->load_buf_idx_last); + lb = vfio_state_buffers_at(&multifd->load_bufs, multifd->load_buf_idx); + assert(lb->is_present); + + bioc = qio_channel_buffer_new(lb->len); + qio_channel_set_name(QIO_CHANNEL(bioc), "vfio-device-config-load"); + + f_out = qemu_file_new_output(QIO_CHANNEL(bioc)); + qemu_put_buffer(f_out, (uint8_t *)lb->data, lb->len); + + ret = qemu_fflush(f_out); + if (ret) { + g_clear_pointer(&f_out, qemu_fclose); + return ret; + } + + qio_channel_io_seek(QIO_CHANNEL(bioc), 0, 0, NULL); + f_in = qemu_file_new_input(QIO_CHANNEL(bioc)); + + mig_header = qemu_get_be64(f_in); + if (mig_header != VFIO_MIG_FLAG_DEV_CONFIG_STATE) { + g_clear_pointer(&f_out, qemu_fclose); + g_clear_pointer(&f_in, qemu_fclose); + return -EINVAL; + } + + bql_lock(); + ret = vfio_load_device_config_state(f_in, vbasedev); + bql_unlock(); + + g_clear_pointer(&f_out, qemu_fclose); + g_clear_pointer(&f_in, qemu_fclose); + if (ret < 0) { + return ret; + } + + return 0; } static VFIOStateBuffer *vfio_load_state_buffer_get(VFIOMultifd *multifd) diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ static int vfio_save_device_config_state(QEMUFile *f, void *opaque, return ret; } -static int vfio_load_device_config_state(QEMUFile *f, void *opaque) +int vfio_load_device_config_state(QEMUFile *f, void *opaque) { VFIODevice *vbasedev = opaque; uint64_t data; @@ -XXX,XX +XXX,XX @@ static int vfio_load_state(QEMUFile *f, void *opaque, int version_id) switch (data) { case VFIO_MIG_FLAG_DEV_CONFIG_STATE: { + if (vfio_multifd_transfer_enabled(vbasedev)) { + error_report("%s: got DEV_CONFIG_STATE but doing multifd transfer", + vbasedev->name); + return -EINVAL; + } + return vfio_load_device_config_state(f, opaque); } case VFIO_MIG_FLAG_DEV_SETUP_STATE: diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -XXX,XX +XXX,XX @@ void vfio_add_bytes_transferred(unsigned long val); bool vfio_device_state_is_running(VFIODevice *vbasedev); bool vfio_device_state_is_precopy(VFIODevice *vbasedev); +int vfio_load_device_config_state(QEMUFile *f, void *opaque); + #ifdef CONFIG_LINUX int vfio_get_region_info(VFIODevice *vbasedev, int index, struct vfio_region_info **info); From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Automatic memory management helps avoid memory safety issues. Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- migration/qemu-file.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/migration/qemu-file.h b/migration/qemu-file.h index XXXXXXX..XXXXXXX 100644 --- a/migration/qemu-file.h +++ b/migration/qemu-file.h @@ -XXX,XX +XXX,XX @@ QEMUFile *qemu_file_new_input(QIOChannel *ioc); QEMUFile *qemu_file_new_output(QIOChannel *ioc); int qemu_fclose(QEMUFile *f); +G_DEFINE_AUTOPTR_CLEANUP_FUNC(QEMUFile, qemu_fclose) + /* * qemu_file_transferred: * From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Implement the multifd device state transfer via additional per-device thread inside save_live_complete_precopy_thread handler. Switch between doing the data transfer in the new handler and doing it in the old save_state handler depending on the x-migration-multifd-transfer device property value. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 139 ++++++++++++++++++++++++++++++++++ hw/vfio/migration-multifd.h | 5 ++ hw/vfio/migration.c | 26 +++++-- hw/vfio/trace-events | 2 + include/hw/vfio/vfio-common.h | 8 ++ 5 files changed, 174 insertions(+), 6 deletions(-) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ bool vfio_multifd_transfer_setup(VFIODevice *vbasedev, Error **errp) return true; } +void vfio_multifd_emit_dummy_eos(VFIODevice *vbasedev, QEMUFile *f) +{ + assert(vfio_multifd_transfer_enabled(vbasedev)); + + /* + * Emit dummy NOP data on the main migration channel since the actual + * device state transfer is done via multifd channels. + */ + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); +} + +static bool +vfio_save_complete_precopy_thread_config_state(VFIODevice *vbasedev, + char *idstr, + uint32_t instance_id, + uint32_t idx, + Error **errp) +{ + g_autoptr(QIOChannelBuffer) bioc = NULL; + g_autoptr(QEMUFile) f = NULL; + int ret; + g_autofree VFIODeviceStatePacket *packet = NULL; + size_t packet_len; + + bioc = qio_channel_buffer_new(0); + qio_channel_set_name(QIO_CHANNEL(bioc), "vfio-device-config-save"); + + f = qemu_file_new_output(QIO_CHANNEL(bioc)); + + if (vfio_save_device_config_state(f, vbasedev, errp)) { + return false; + } + + ret = qemu_fflush(f); + if (ret) { + error_setg(errp, "save config state flush failed: %d", ret); + return false; + } + + packet_len = sizeof(*packet) + bioc->usage; + packet = g_malloc0(packet_len); + packet->version = VFIO_DEVICE_STATE_PACKET_VER_CURRENT; + packet->idx = idx; + packet->flags = VFIO_DEVICE_STATE_CONFIG_STATE; + memcpy(&packet->data, bioc->data, bioc->usage); + + if (!multifd_queue_device_state(idstr, instance_id, + (char *)packet, packet_len)) { + error_setg(errp, "multifd config data queuing failed"); + return false; + } + + vfio_add_bytes_transferred(packet_len); + + return true; +} + +/* + * This thread is spawned by the migration core directly via + * .save_live_complete_precopy_thread SaveVMHandler. + * + * It exits after either: + * * completing saving the remaining device state and device config, OR: + * * encountering some error while doing the above, OR: + * * being forcefully aborted by the migration core by + * multifd_device_state_save_thread_should_exit() returning true. + */ +bool vfio_save_complete_precopy_thread(SaveLiveCompletePrecopyThreadData *d, + Error **errp) +{ + VFIODevice *vbasedev = d->handler_opaque; + VFIOMigration *migration = vbasedev->migration; + bool ret; + g_autofree VFIODeviceStatePacket *packet = NULL; + uint32_t idx; + + if (!vfio_multifd_transfer_enabled(vbasedev)) { + /* Nothing to do, vfio_save_complete_precopy() does the transfer. */ + return true; + } + + trace_vfio_save_complete_precopy_thread_start(vbasedev->name, + d->idstr, d->instance_id); + + /* We reach here with device state STOP or STOP_COPY only */ + if (vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_STOP_COPY, + VFIO_DEVICE_STATE_STOP, errp)) { + ret = false; + goto ret_finish; + } + + packet = g_malloc0(sizeof(*packet) + migration->data_buffer_size); + packet->version = VFIO_DEVICE_STATE_PACKET_VER_CURRENT; + + for (idx = 0; ; idx++) { + ssize_t data_size; + size_t packet_size; + + if (multifd_device_state_save_thread_should_exit()) { + error_setg(errp, "operation cancelled"); + ret = false; + goto ret_finish; + } + + data_size = read(migration->data_fd, &packet->data, + migration->data_buffer_size); + if (data_size < 0) { + error_setg(errp, "reading state buffer %" PRIu32 " failed: %d", + idx, errno); + ret = false; + goto ret_finish; + } else if (data_size == 0) { + break; + } + + packet->idx = idx; + packet_size = sizeof(*packet) + data_size; + + if (!multifd_queue_device_state(d->idstr, d->instance_id, + (char *)packet, packet_size)) { + error_setg(errp, "multifd data queuing failed"); + ret = false; + goto ret_finish; + } + + vfio_add_bytes_transferred(packet_size); + } + + ret = vfio_save_complete_precopy_thread_config_state(vbasedev, + d->idstr, + d->instance_id, + idx, errp); + +ret_finish: + trace_vfio_save_complete_precopy_thread_end(vbasedev->name, ret); + + return ret; +} + int vfio_multifd_switchover_start(VFIODevice *vbasedev) { VFIOMigration *migration = vbasedev->migration; diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.h +++ b/hw/vfio/migration-multifd.h @@ -XXX,XX +XXX,XX @@ bool vfio_multifd_transfer_setup(VFIODevice *vbasedev, Error **errp); bool vfio_load_state_buffer(void *opaque, char *data, size_t data_size, Error **errp); +void vfio_multifd_emit_dummy_eos(VFIODevice *vbasedev, QEMUFile *f); + +bool vfio_save_complete_precopy_thread(SaveLiveCompletePrecopyThreadData *d, + Error **errp); + int vfio_multifd_switchover_start(VFIODevice *vbasedev); #endif diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ static void vfio_migration_set_device_state(VFIODevice *vbasedev, vfio_migration_send_event(vbasedev); } -static int vfio_migration_set_state(VFIODevice *vbasedev, - enum vfio_device_mig_state new_state, - enum vfio_device_mig_state recover_state, - Error **errp) +int vfio_migration_set_state(VFIODevice *vbasedev, + enum vfio_device_mig_state new_state, + enum vfio_device_mig_state recover_state, + Error **errp) { VFIOMigration *migration = vbasedev->migration; uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) + @@ -XXX,XX +XXX,XX @@ static int vfio_load_buffer(QEMUFile *f, VFIODevice *vbasedev, return ret; } -static int vfio_save_device_config_state(QEMUFile *f, void *opaque, - Error **errp) +int vfio_save_device_config_state(QEMUFile *f, void *opaque, Error **errp) { VFIODevice *vbasedev = opaque; int ret; @@ -XXX,XX +XXX,XX @@ static int vfio_save_setup(QEMUFile *f, void *opaque, Error **errp) uint64_t stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE; int ret; + if (!vfio_multifd_transfer_setup(vbasedev, errp)) { + return -EINVAL; + } + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE); vfio_query_stop_copy_size(vbasedev, &stop_copy_size); @@ -XXX,XX +XXX,XX @@ static int vfio_save_complete_precopy(QEMUFile *f, void *opaque) int ret; Error *local_err = NULL; + if (vfio_multifd_transfer_enabled(vbasedev)) { + vfio_multifd_emit_dummy_eos(vbasedev, f); + return 0; + } + trace_vfio_save_complete_precopy_start(vbasedev->name); /* We reach here with device state STOP or STOP_COPY only */ @@ -XXX,XX +XXX,XX @@ static void vfio_save_state(QEMUFile *f, void *opaque) Error *local_err = NULL; int ret; + if (vfio_multifd_transfer_enabled(vbasedev)) { + vfio_multifd_emit_dummy_eos(vbasedev, f); + return; + } + ret = vfio_save_device_config_state(f, opaque, &local_err); if (ret) { error_prepend(&local_err, @@ -XXX,XX +XXX,XX @@ static const SaveVMHandlers savevm_vfio_handlers = { .is_active_iterate = vfio_is_active_iterate, .save_live_iterate = vfio_save_iterate, .save_live_complete_precopy = vfio_save_complete_precopy, + .save_live_complete_precopy_thread = vfio_save_complete_precopy_thread, .save_state = vfio_save_state, .load_setup = vfio_load_setup, .load_cleanup = vfio_load_cleanup, diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/trace-events +++ b/hw/vfio/trace-events @@ -XXX,XX +XXX,XX @@ vfio_save_block_precopy_empty_hit(const char *name) " (%s)" vfio_save_cleanup(const char *name) " (%s)" vfio_save_complete_precopy(const char *name, int ret) " (%s) ret %d" vfio_save_complete_precopy_start(const char *name) " (%s)" +vfio_save_complete_precopy_thread_start(const char *name, const char *idstr, uint32_t instance_id) " (%s) idstr %s instance %"PRIu32 +vfio_save_complete_precopy_thread_end(const char *name, int ret) " (%s) ret %d" vfio_save_device_config_state(const char *name) " (%s)" vfio_save_iterate(const char *name, uint64_t precopy_init_size, uint64_t precopy_dirty_size) " (%s) precopy initial size %"PRIu64" precopy dirty size %"PRIu64 vfio_save_iterate_start(const char *name) " (%s)" diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -XXX,XX +XXX,XX @@ void vfio_add_bytes_transferred(unsigned long val); bool vfio_device_state_is_running(VFIODevice *vbasedev); bool vfio_device_state_is_precopy(VFIODevice *vbasedev); +#ifdef CONFIG_LINUX +int vfio_migration_set_state(VFIODevice *vbasedev, + enum vfio_device_mig_state new_state, + enum vfio_device_mig_state recover_state, + Error **errp); +#endif + +int vfio_save_device_config_state(QEMUFile *f, void *opaque, Error **errp); int vfio_load_device_config_state(QEMUFile *f, void *opaque); #ifdef CONFIG_LINUX From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This property allows configuring at runtime whether to transfer the particular device state via multifd channels when live migrating that device. It defaults to AUTO, which means that VFIO device state transfer via multifd channels is attempted in configurations that otherwise support it. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 17 ++++++++++++++++- hw/vfio/pci.c | 3 +++ include/hw/vfio/vfio-common.h | 2 ++ 3 files changed, 21 insertions(+), 1 deletion(-) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ bool vfio_multifd_transfer_supported(void) bool vfio_multifd_transfer_enabled(VFIODevice *vbasedev) { - return false; + VFIOMigration *migration = vbasedev->migration; + + return migration->multifd_transfer; } bool vfio_multifd_transfer_setup(VFIODevice *vbasedev, Error **errp) { + VFIOMigration *migration = vbasedev->migration; + + /* + * Make a copy of this setting at the start in case it is changed + * mid-migration. + */ + if (vbasedev->migration_multifd_transfer == ON_OFF_AUTO_AUTO) { + migration->multifd_transfer = vfio_multifd_transfer_supported(); + } else { + migration->multifd_transfer = + vbasedev->migration_multifd_transfer == ON_OFF_AUTO_ON; + } + if (vfio_multifd_transfer_enabled(vbasedev) && !vfio_multifd_transfer_supported()) { error_setg(errp, diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -XXX,XX +XXX,XX @@ static const Property vfio_pci_dev_properties[] = { VFIO_FEATURE_ENABLE_IGD_OPREGION_BIT, false), DEFINE_PROP_ON_OFF_AUTO("enable-migration", VFIOPCIDevice, vbasedev.enable_migration, ON_OFF_AUTO_AUTO), + DEFINE_PROP_ON_OFF_AUTO("x-migration-multifd-transfer", VFIOPCIDevice, + vbasedev.migration_multifd_transfer, + ON_OFF_AUTO_AUTO), DEFINE_PROP_BOOL("migration-events", VFIOPCIDevice, vbasedev.migration_events, false), DEFINE_PROP_BOOL("x-no-mmap", VFIOPCIDevice, vbasedev.no_mmap, false), diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -XXX,XX +XXX,XX @@ typedef struct VFIOMigration { uint64_t mig_flags; uint64_t precopy_init_size; uint64_t precopy_dirty_size; + bool multifd_transfer; VFIOMultifd *multifd; bool initial_data_sent; @@ -XXX,XX +XXX,XX @@ typedef struct VFIODevice { bool no_mmap; bool ram_block_discard_allowed; OnOffAuto enable_migration; + OnOffAuto migration_multifd_transfer; bool migration_events; VFIODeviceOps *ops; unsigned int num_irqs; From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> DEFINE_PROP_ON_OFF_AUTO() property isn't runtime-mutable so using it would mean that the source VM would need to decide upfront at startup time whether it wants to do a multifd device state transfer at some point. Source VM can run for a long time before being migrated so it is desirable to have a fallback mechanism to the old way of transferring VFIO device state if it turns to be necessary. This brings this property to the same mutability level as ordinary migration parameters, which too can be adjusted at the run time. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/pci.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -XXX,XX +XXX,XX @@ static void vfio_instance_init(Object *obj) pci_dev->cap_present |= QEMU_PCI_CAP_EXPRESS; } +static PropertyInfo qdev_prop_on_off_auto_mutable; + static const Property vfio_pci_dev_properties[] = { DEFINE_PROP_PCI_HOST_DEVADDR("host", VFIOPCIDevice, host), DEFINE_PROP_UUID_NODEFAULT("vf-token", VFIOPCIDevice, vf_token), @@ -XXX,XX +XXX,XX @@ static const Property vfio_pci_dev_properties[] = { VFIO_FEATURE_ENABLE_IGD_OPREGION_BIT, false), DEFINE_PROP_ON_OFF_AUTO("enable-migration", VFIOPCIDevice, vbasedev.enable_migration, ON_OFF_AUTO_AUTO), - DEFINE_PROP_ON_OFF_AUTO("x-migration-multifd-transfer", VFIOPCIDevice, - vbasedev.migration_multifd_transfer, - ON_OFF_AUTO_AUTO), + DEFINE_PROP("x-migration-multifd-transfer", VFIOPCIDevice, + vbasedev.migration_multifd_transfer, + qdev_prop_on_off_auto_mutable, OnOffAuto, + .set_default = true, .defval.i = ON_OFF_AUTO_AUTO), DEFINE_PROP_BOOL("migration-events", VFIOPCIDevice, vbasedev.migration_events, false), DEFINE_PROP_BOOL("x-no-mmap", VFIOPCIDevice, vbasedev.no_mmap, false), @@ -XXX,XX +XXX,XX @@ static const TypeInfo vfio_pci_nohotplug_dev_info = { static void register_vfio_pci_dev_type(void) { + qdev_prop_on_off_auto_mutable = qdev_prop_on_off_auto; + qdev_prop_on_off_auto_mutable.realized_set_allowed = true; + type_register_static(&vfio_pci_dev_info); type_register_static(&vfio_pci_nohotplug_dev_info); } From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Add a hw_compat entry for recently added x-migration-multifd-transfer VFIO property. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/core/machine.c | 1 + 1 file changed, 1 insertion(+) diff --git a/hw/core/machine.c b/hw/core/machine.c index XXXXXXX..XXXXXXX 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -XXX,XX +XXX,XX @@ GlobalProperty hw_compat_9_2[] = { { "virtio-mem-pci", "vectors", "0" }, { "migration", "multifd-clean-tls-termination", "false" }, { "migration", "send-switchover-start", "off"}, + { "vfio-pci", "x-migration-multifd-transfer", "off" }, }; const size_t hw_compat_9_2_len = G_N_ELEMENTS(hw_compat_9_2); From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Allow capping the maximum count of in-flight VFIO device state buffers queued at the destination, otherwise a malicious QEMU source could theoretically cause the target QEMU to allocate unlimited amounts of memory for buffers-in-flight. Since this is not expected to be a realistic threat in most of VFIO live migration use cases and the right value depends on the particular setup disable the limit by default by setting it to UINT64_MAX. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 14 ++++++++++++++ hw/vfio/pci.c | 2 ++ include/hw/vfio/vfio-common.h | 1 + 3 files changed, 17 insertions(+) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ typedef struct VFIOMultifd { QemuMutex load_bufs_mutex; /* Lock order: this lock -> BQL */ uint32_t load_buf_idx; uint32_t load_buf_idx_last; + uint32_t load_buf_queued_pending_buffers; } VFIOMultifd; static void vfio_state_buffer_clear(gpointer data) @@ -XXX,XX +XXX,XX @@ static bool vfio_load_state_buffer_insert(VFIODevice *vbasedev, assert(packet->idx >= multifd->load_buf_idx); + multifd->load_buf_queued_pending_buffers++; + if (multifd->load_buf_queued_pending_buffers > + vbasedev->migration_max_queued_buffers) { + error_setg(errp, + "queuing state buffer %" PRIu32 " would exceed the max of %" PRIu64, + packet->idx, vbasedev->migration_max_queued_buffers); + return false; + } + lb->data = g_memdup2(&packet->data, packet_total_size - sizeof(*packet)); lb->len = packet_total_size - sizeof(*packet); lb->is_present = true; @@ -XXX,XX +XXX,XX @@ static bool vfio_load_bufs_thread(void *opaque, bool *should_quit, Error **errp) goto ret_signal; } + assert(multifd->load_buf_queued_pending_buffers > 0); + multifd->load_buf_queued_pending_buffers--; + if (multifd->load_buf_idx == multifd->load_buf_idx_last - 1) { trace_vfio_load_state_device_buffer_end(vbasedev->name); } @@ -XXX,XX +XXX,XX @@ VFIOMultifd *vfio_multifd_new(void) multifd->load_buf_idx = 0; multifd->load_buf_idx_last = UINT32_MAX; + multifd->load_buf_queued_pending_buffers = 0; qemu_cond_init(&multifd->load_bufs_buffer_ready_cond); multifd->load_bufs_thread_running = false; diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -XXX,XX +XXX,XX @@ static const Property vfio_pci_dev_properties[] = { vbasedev.migration_multifd_transfer, qdev_prop_on_off_auto_mutable, OnOffAuto, .set_default = true, .defval.i = ON_OFF_AUTO_AUTO), + DEFINE_PROP_UINT64("x-migration-max-queued-buffers", VFIOPCIDevice, + vbasedev.migration_max_queued_buffers, UINT64_MAX), DEFINE_PROP_BOOL("migration-events", VFIOPCIDevice, vbasedev.migration_events, false), DEFINE_PROP_BOOL("x-no-mmap", VFIOPCIDevice, vbasedev.no_mmap, false), diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -XXX,XX +XXX,XX @@ typedef struct VFIODevice { bool ram_block_discard_allowed; OnOffAuto enable_migration; OnOffAuto migration_multifd_transfer; + uint64_t migration_max_queued_buffers; bool migration_events; VFIODeviceOps *ops; unsigned int num_irqs; From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This property allows configuring whether to start the config load only after all iterables were loaded. Such interlocking is required for ARM64 due to this platform VFIO dependency on interrupt controller being loaded first. The property defaults to AUTO, which means ON for ARM, OFF for other platforms. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 92 +++++++++++++++++++++++++++++++++++ hw/vfio/migration-multifd.h | 3 ++ hw/vfio/migration.c | 10 +++- hw/vfio/pci.c | 3 ++ include/hw/vfio/vfio-common.h | 2 + 5 files changed, 109 insertions(+), 1 deletion(-) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ typedef struct VFIODeviceStatePacket { uint8_t data[0]; } QEMU_PACKED VFIODeviceStatePacket; +bool vfio_load_config_after_iter(VFIODevice *vbasedev) +{ + if (vbasedev->migration_load_config_after_iter == ON_OFF_AUTO_ON) { + return true; + } else if (vbasedev->migration_load_config_after_iter == ON_OFF_AUTO_OFF) { + return false; + } + + assert(vbasedev->migration_load_config_after_iter == ON_OFF_AUTO_AUTO); + + /* + * Starting the config load only after all iterables were loaded is required + * for ARM64 due to this platform VFIO dependency on interrupt controller + * being loaded first. + * + * See commit d329f5032e17 ("vfio: Move the saving of the config space to + * the right place in VFIO migration"). + */ +#if defined(TARGET_ARM) + return true; +#else + return false; +#endif +} + /* type safety */ typedef struct VFIOStateBuffers { GArray *array; @@ -XXX,XX +XXX,XX @@ typedef struct VFIOMultifd { bool load_bufs_thread_running; bool load_bufs_thread_want_exit; + bool load_bufs_iter_done; + QemuCond load_bufs_iter_done_cond; + VFIOStateBuffers load_bufs; QemuCond load_bufs_buffer_ready_cond; QemuCond load_bufs_thread_finished_cond; @@ -XXX,XX +XXX,XX @@ static bool vfio_load_bufs_thread(void *opaque, bool *should_quit, Error **errp) multifd->load_buf_idx++; } + if (vfio_load_config_after_iter(vbasedev)) { + while (!multifd->load_bufs_iter_done) { + qemu_cond_wait(&multifd->load_bufs_iter_done_cond, + &multifd->load_bufs_mutex); + + /* + * Need to re-check cancellation immediately after wait in case + * cond was signalled by vfio_load_cleanup_load_bufs_thread(). + */ + if (vfio_load_bufs_thread_want_exit(multifd, should_quit)) { + error_setg(errp, "operation cancelled"); + ret = false; + goto ret_signal; + } + } + } + config_ret = vfio_load_bufs_thread_load_config(vbasedev); if (config_ret) { error_setg(errp, "load config state failed: %d", config_ret); @@ -XXX,XX +XXX,XX @@ ret_signal: return ret; } +int vfio_load_state_config_load_ready(VFIODevice *vbasedev) +{ + VFIOMigration *migration = vbasedev->migration; + VFIOMultifd *multifd = migration->multifd; + int ret = 0; + + if (!vfio_multifd_transfer_enabled(vbasedev)) { + error_report("%s: got DEV_CONFIG_LOAD_READY outside multifd transfer", + vbasedev->name); + return -EINVAL; + } + + if (!vfio_load_config_after_iter(vbasedev)) { + error_report("%s: got DEV_CONFIG_LOAD_READY but was disabled", + vbasedev->name); + return -EINVAL; + } + + assert(multifd); + + /* The lock order is load_bufs_mutex -> BQL so unlock BQL here first */ + bql_unlock(); + WITH_QEMU_LOCK_GUARD(&multifd->load_bufs_mutex) { + if (multifd->load_bufs_iter_done) { + /* Can't print error here as we're outside BQL */ + ret = -EINVAL; + break; + } + + multifd->load_bufs_iter_done = true; + qemu_cond_signal(&multifd->load_bufs_iter_done_cond); + } + bql_lock(); + + if (ret) { + error_report("%s: duplicate DEV_CONFIG_LOAD_READY", + vbasedev->name); + } + + return ret; +} + VFIOMultifd *vfio_multifd_new(void) { VFIOMultifd *multifd = g_new(VFIOMultifd, 1); @@ -XXX,XX +XXX,XX @@ VFIOMultifd *vfio_multifd_new(void) multifd->load_buf_queued_pending_buffers = 0; qemu_cond_init(&multifd->load_bufs_buffer_ready_cond); + multifd->load_bufs_iter_done = false; + qemu_cond_init(&multifd->load_bufs_iter_done_cond); + multifd->load_bufs_thread_running = false; multifd->load_bufs_thread_want_exit = false; qemu_cond_init(&multifd->load_bufs_thread_finished_cond); @@ -XXX,XX +XXX,XX @@ static void vfio_load_cleanup_load_bufs_thread(VFIOMultifd *multifd) multifd->load_bufs_thread_want_exit = true; qemu_cond_signal(&multifd->load_bufs_buffer_ready_cond); + qemu_cond_signal(&multifd->load_bufs_iter_done_cond); qemu_cond_wait(&multifd->load_bufs_thread_finished_cond, &multifd->load_bufs_mutex); } @@ -XXX,XX +XXX,XX @@ void vfio_multifd_free(VFIOMultifd *multifd) vfio_load_cleanup_load_bufs_thread(multifd); qemu_cond_destroy(&multifd->load_bufs_thread_finished_cond); + qemu_cond_destroy(&multifd->load_bufs_iter_done_cond); vfio_state_buffers_destroy(&multifd->load_bufs); qemu_cond_destroy(&multifd->load_bufs_buffer_ready_cond); qemu_mutex_destroy(&multifd->load_bufs_mutex); diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.h +++ b/hw/vfio/migration-multifd.h @@ -XXX,XX +XXX,XX @@ bool vfio_multifd_transfer_enabled(VFIODevice *vbasedev); bool vfio_multifd_transfer_setup(VFIODevice *vbasedev, Error **errp); +bool vfio_load_config_after_iter(VFIODevice *vbasedev); bool vfio_load_state_buffer(void *opaque, char *data, size_t data_size, Error **errp); +int vfio_load_state_config_load_ready(VFIODevice *vbasedev); + void vfio_multifd_emit_dummy_eos(VFIODevice *vbasedev, QEMUFile *f); bool vfio_save_complete_precopy_thread(SaveLiveCompletePrecopyThreadData *d, diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ static void vfio_save_state(QEMUFile *f, void *opaque) int ret; if (vfio_multifd_transfer_enabled(vbasedev)) { - vfio_multifd_emit_dummy_eos(vbasedev, f); + if (vfio_load_config_after_iter(vbasedev)) { + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_CONFIG_LOAD_READY); + } else { + vfio_multifd_emit_dummy_eos(vbasedev, f); + } return; } @@ -XXX,XX +XXX,XX @@ static int vfio_load_state(QEMUFile *f, void *opaque, int version_id) return ret; } + case VFIO_MIG_FLAG_DEV_CONFIG_LOAD_READY: + { + return vfio_load_state_config_load_ready(vbasedev); + } default: error_report("%s: Unknown tag 0x%"PRIx64, vbasedev->name, data); return -EINVAL; diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -XXX,XX +XXX,XX @@ static const Property vfio_pci_dev_properties[] = { vbasedev.migration_multifd_transfer, qdev_prop_on_off_auto_mutable, OnOffAuto, .set_default = true, .defval.i = ON_OFF_AUTO_AUTO), + DEFINE_PROP_ON_OFF_AUTO("x-migration-load-config-after-iter", VFIOPCIDevice, + vbasedev.migration_load_config_after_iter, + ON_OFF_AUTO_AUTO), DEFINE_PROP_UINT64("x-migration-max-queued-buffers", VFIOPCIDevice, vbasedev.migration_max_queued_buffers, UINT64_MAX), DEFINE_PROP_BOOL("migration-events", VFIOPCIDevice, diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -XXX,XX +XXX,XX @@ #define VFIO_MIG_FLAG_DEV_SETUP_STATE (0xffffffffef100003ULL) #define VFIO_MIG_FLAG_DEV_DATA_STATE (0xffffffffef100004ULL) #define VFIO_MIG_FLAG_DEV_INIT_DATA_SENT (0xffffffffef100005ULL) +#define VFIO_MIG_FLAG_DEV_CONFIG_LOAD_READY (0xffffffffef100006ULL) enum { VFIO_DEVICE_TYPE_PCI = 0, @@ -XXX,XX +XXX,XX @@ typedef struct VFIODevice { bool ram_block_discard_allowed; OnOffAuto enable_migration; OnOffAuto migration_multifd_transfer; + OnOffAuto migration_load_config_after_iter; uint64_t migration_max_queued_buffers; bool migration_events; VFIODeviceOps *ops; From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Update the VFIO documentation at docs/devel/migration describing the changes brought by the multifd device state transfer. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- docs/devel/migration/vfio.rst | 80 +++++++++++++++++++++++++++++++---- 1 file changed, 71 insertions(+), 9 deletions(-) diff --git a/docs/devel/migration/vfio.rst b/docs/devel/migration/vfio.rst index XXXXXXX..XXXXXXX 100644 --- a/docs/devel/migration/vfio.rst +++ b/docs/devel/migration/vfio.rst @@ -XXX,XX +XXX,XX @@ helps to reduce the total downtime of the VM. VFIO devices opt-in to pre-copy support by reporting the VFIO_MIGRATION_PRE_COPY flag in the VFIO_DEVICE_FEATURE_MIGRATION ioctl. +Starting from QEMU version 10.0 there's a possibility to transfer VFIO device +_STOP_COPY state via multifd channels. This helps reduce downtime - especially +with multiple VFIO devices or with devices having a large migration state. +As an additional benefit, setting the VFIO device to _STOP_COPY state and +saving its config space is also parallelized (run in a separate thread) in +such migration mode. + +The multifd VFIO device state transfer is controlled by +"x-migration-multifd-transfer" VFIO device property. This property defaults to +AUTO, which means that VFIO device state transfer via multifd channels is +attempted in configurations that otherwise support it. + +Since the target QEMU needs to load device state buffers in-order it needs to +queue incoming buffers until they can be loaded into the device. +This means that a malicious QEMU source could theoretically cause the target +QEMU to allocate unlimited amounts of memory for such buffers-in-flight. + +The "x-migration-max-queued-buffers" property allows capping the maximum count +of these VFIO device state buffers queued at the destination. + +Because a malicious QEMU source causing OOM on the target is not expected to be +a realistic threat in most of VFIO live migration use cases and the right value +depends on the particular setup by default this queued buffers limit is +disabled by setting it to UINT64_MAX. + +Some host platforms (like ARM64) require that VFIO device config is loaded only +after all iterables were loaded. +Such interlocking is controlled by "x-migration-load-config-after-iter" VFIO +device property, which in its default setting (AUTO) does so only on platforms +that actually require it. + When pre-copy is supported, it's possible to further reduce downtime by enabling "switchover-ack" migration capability. VFIO migration uAPI defines "initial bytes" as part of its pre-copy data stream @@ -XXX,XX +XXX,XX @@ VFIO implements the device hooks for the iterative approach as follows: * A ``switchover_ack_needed`` function that checks if the VFIO device uses "switchover-ack" migration capability when this capability is enabled. -* A ``save_state`` function to save the device config space if it is present. - -* A ``save_live_complete_precopy`` function that sets the VFIO device in - _STOP_COPY state and iteratively copies the data for the VFIO device until - the vendor driver indicates that no data remains. - -* A ``load_state`` function that loads the config section and the data - sections that are generated by the save functions above. +* A ``switchover_start`` function that in the multifd mode starts a thread that + reassembles the multifd received data and loads it in-order into the device. + In the non-multifd mode this function is a NOP. + +* A ``save_state`` function to save the device config space if it is present + in the non-multifd mode. + In the multifd mode it just emits either a dummy EOS marker or + "all iterables were loaded" flag for configurations that need to defer + loading device config space after them. + +* A ``save_live_complete_precopy`` function that in the non-multifd mode sets + the VFIO device in _STOP_COPY state and iteratively copies the data for the + VFIO device until the vendor driver indicates that no data remains. + In the multifd mode it just emits a dummy EOS marker. + +* A ``save_live_complete_precopy_thread`` function that in the multifd mode + provides thread handler performing multifd device state transfer. + It sets the VFIO device to _STOP_COPY state, iteratively reads the data + from the VFIO device and queues it for multifd transmission until the vendor + driver indicates that no data remains. + After that, it saves the device config space and queues it for multifd + transfer too. + In the non-multifd mode this thread is a NOP. + +* A ``load_state`` function that loads the data sections that are generated + by the main migration channel save functions above. + In the non-multifd mode it also loads the config section, while in the + multifd mode it handles the optional "all iterables were loaded" flag if + it is in use. + +* A ``load_state_buffer`` function that loads the device state and the device + config that arrived via multifd channels. + It's used only in the multifd mode. * ``cleanup`` functions for both save and load that perform any migration related cleanup. @@ -XXX,XX +XXX,XX @@ Live migration save path Then the VFIO device is put in _STOP_COPY state (FINISH_MIGRATE, _ACTIVE, _STOP_COPY) .save_live_complete_precopy() is called for each active device - For the VFIO device, iterate in .save_live_complete_precopy() until + For the VFIO device: in the non-multifd mode iterate in + .save_live_complete_precopy() until pending data is 0 + In the multifd mode this iteration is done in + .save_live_complete_precopy_thread() instead. | (POSTMIGRATE, _COMPLETED, _STOP_COPY) Migraton thread schedules cleanup bottom half and exits @@ -XXX,XX +XXX,XX @@ Live migration resume path (RESTORE_VM, _ACTIVE, _STOP) | For each device, .load_state() is called for that device section data + transmitted via the main migration channel. + For data transmitted via multifd channels .load_state_buffer() is called + instead. (RESTORE_VM, _ACTIVE, _RESUMING) | At the end, .load_cleanup() is called for each device and vCPUs are started From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This is an updated v6 patch series of the v5 series located here: https://lore.kernel.org/qemu-devel/cover.1739994627.git.maciej.szmigiero@oracle.com/ What this patch set is about? Current live migration device state transfer is done via the main (single) migration channel, which reduces performance and severally impacts the migration downtime for VMs having large device state that needs to be transferred during the switchover phase. Example devices that have such large switchover phase device state are some types of VFIO SmartNICs and GPUs. This patch set allows parallelizing this transfer by using multifd channels for it. It also introduces new load and save threads per VFIO device for decoupling these operations from the main migration thread. These threads run on newly introduced generic (non-AIO) thread pools, instantiated by the core migration core. Changes from v5: * Add bql_locked() assertion to migration_incoming_state_destroy() with a comment describing why holding BQL there is necessary. * Add SPDX-License-Identifier to newly added files. * Move consistency of multfd transfer settings check to the patch adding x-migration-multifd-transfer property. * Change packet->idx == UINT32_MAX message to the suggested one. * Use WITH_QEMU_LOCK_GUARD() in vfio_load_state_buffer(). * Add vfio_load_bufs_thread_{start,end} trace events. * Invert "ret" value computation logic in vfio_load_bufs_thread() and vfio_multifd_save_complete_precopy_thread() - initialize "ret" to false at definition, remove "ret = false" at every failure/early exit block and add "ret = true" just before the early exit jump label. * Make vfio_load_bufs_thread_load_config() return a bool and take an "Error **" parameter. * Make vfio_multifd_setup() (previously called vfio_multifd_transfer_setup()) allocate struct VFIOMultifd if requested by "alloc_multifd" parameter. * Add vfio_multifd_cleanup() call to vfio_save_cleanup() (for consistency with the load code), with a comment describing that it is currently a NOP there. * Move vfio_multifd_cleanup() to migration-multifd.c. * Move general multifd migration description in docs/devel/migration/vfio.rst from the top section to new "Multifd" section at the bottom. * Add comment describing why x-migration-multifd-transfer needs to be a custom property above the variable containing that custom property type in register_vfio_pci_dev_type(). * Add object_class_property_set_description() description for all 3 newly added parameters: x-migration-multifd-transfer, x-migration-load-config-after-iter and x-migration-max-queued-buffers. * Split out wiring vfio_multifd_setup() and vfio_multifd_cleanup() into general VFIO load/save setup and cleanup methods into a brand new patch/commit. * Squash the patch introducing VFIOStateBuffer(s) into the "received buffers queuing" commit to fix building the interim code form at the time of this patch with "-Werror". * Change device state packet "idstr" field to NULL-terminated and drop QEMU_NONSTRING marking from its definition. * Add vbasedev->name to VFIO error messages to know which device caused that error. * Move BQL lock ordering assert closer to the other lock in the lock order in vfio_load_state_buffer(). * Drop orphan "QemuThread load_bufs_thread" VFIOMultifd member leftover from the days of the version 2 of this patch set. * Change "guint" into an "unsigned int" where it was present in this patch set. * Use g_autoptr() for QEMUFile also in vfio_load_bufs_thread_load_config(). * Call multifd_abort_device_state_save_threads() if a migration error is already set in the save path to avoid needlessly waiting for the remaining threads to do all of their normal work. * Other minor changes that should not have functional impact, like: renamed functions/labels, moved code lines between patches contained in this patch set, added review tags, code formatting, rebased on top of the latest QEMU git master, etc. ======================================================================== This patch set is targeting QEMU 10.0. It is also exported as a git tree: https://gitlab.com/maciejsszmigiero/qemu/-/commits/multifd-device-state-transfer-vfio ======================================================================== Maciej S. Szmigiero (35): migration: Clarify that {load,save}_cleanup handlers can run without setup thread-pool: Remove thread_pool_submit() function thread-pool: Rename AIO pool functions to *_aio() and data types to *Aio thread-pool: Implement generic (non-AIO) pool support migration: Add MIG_CMD_SWITCHOVER_START and its load handler migration: Add qemu_loadvm_load_state_buffer() and its handler migration: postcopy_ram_listen_thread() should take BQL for some calls error: define g_autoptr() cleanup function for the Error type migration: Add thread pool of optional load threads migration/multifd: Split packet into header and RAM data migration/multifd: Device state transfer support - receive side migration/multifd: Make multifd_send() thread safe migration/multifd: Add an explicit MultiFDSendData destructor migration/multifd: Device state transfer support - send side migration/multifd: Add multifd_device_state_supported() migration: Add save_live_complete_precopy_thread handler vfio/migration: Add load_device_config_state_start trace event vfio/migration: Convert bytes_transferred counter to atomic vfio/migration: Add vfio_add_bytes_transferred() vfio/migration: Move migration channel flags to vfio-common.h header file vfio/migration: Multifd device state transfer support - basic types vfio/migration: Multifd device state transfer - add support checking function vfio/migration: Multifd setup/cleanup functions and associated VFIOMultifd vfio/migration: Setup and cleanup multifd transfer in these general methods vfio/migration: Multifd device state transfer support - received buffers queuing vfio/migration: Multifd device state transfer support - load thread migration/qemu-file: Define g_autoptr() cleanup function for QEMUFile vfio/migration: Multifd device state transfer support - config loading support vfio/migration: Multifd device state transfer support - send side vfio/migration: Add x-migration-multifd-transfer VFIO property vfio/migration: Make x-migration-multifd-transfer VFIO property mutable hw/core/machine: Add compat for x-migration-multifd-transfer VFIO property vfio/migration: Max in-flight VFIO device state buffer count limit vfio/migration: Add x-migration-load-config-after-iter VFIO property vfio/migration: Update VFIO migration documentation Peter Xu (1): migration/multifd: Make MultiFDSendData a struct docs/devel/migration/vfio.rst | 79 ++- hw/core/machine.c | 2 + hw/vfio/meson.build | 1 + hw/vfio/migration-multifd.c | 786 +++++++++++++++++++++++++++++ hw/vfio/migration-multifd.h | 37 ++ hw/vfio/migration.c | 111 ++-- hw/vfio/pci.c | 40 ++ hw/vfio/trace-events | 13 +- include/block/aio.h | 8 +- include/block/thread-pool.h | 62 ++- include/hw/vfio/vfio-common.h | 34 ++ include/migration/client-options.h | 4 + include/migration/misc.h | 25 + include/migration/register.h | 52 +- include/qapi/error.h | 2 + include/qemu/typedefs.h | 5 + migration/colo.c | 3 + migration/meson.build | 1 + migration/migration-hmp-cmds.c | 2 + migration/migration.c | 20 +- migration/migration.h | 7 + migration/multifd-device-state.c | 212 ++++++++ migration/multifd-nocomp.c | 30 +- migration/multifd.c | 248 +++++++-- migration/multifd.h | 74 ++- migration/options.c | 9 + migration/qemu-file.h | 2 + migration/savevm.c | 201 +++++++- migration/savevm.h | 6 +- migration/trace-events | 1 + scripts/analyze-migration.py | 11 + tests/unit/test-thread-pool.c | 6 +- util/async.c | 6 +- util/thread-pool.c | 184 +++++-- util/trace-events | 6 +- 35 files changed, 2125 insertions(+), 165 deletions(-) create mode 100644 hw/vfio/migration-multifd.c create mode 100644 hw/vfio/migration-multifd.h create mode 100644 migration/multifd-device-state.c From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> There's already a max in-flight VFIO device state buffers *count* limit, add also max queued buffers *size* limit. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- docs/devel/migration/vfio.rst | 8 +++++--- hw/vfio/migration-multifd.c | 21 +++++++++++++++++++-- hw/vfio/pci.c | 9 +++++++++ include/hw/vfio/vfio-common.h | 1 + 4 files changed, 34 insertions(+), 5 deletions(-) diff --git a/docs/devel/migration/vfio.rst b/docs/devel/migration/vfio.rst index XXXXXXX..XXXXXXX 100644 --- a/docs/devel/migration/vfio.rst +++ b/docs/devel/migration/vfio.rst @@ -XXX,XX +XXX,XX @@ This means that a malicious QEMU source could theoretically cause the target QEMU to allocate unlimited amounts of memory for such buffers-in-flight. The "x-migration-max-queued-buffers" property allows capping the maximum count -of these VFIO device state buffers queued at the destination. +of these VFIO device state buffers queued at the destination while +"x-migration-max-queued-buffers-size" property allows capping their total queued +size. Because a malicious QEMU source causing OOM on the target is not expected to be a realistic threat in most of VFIO live migration use cases and the right value -depends on the particular setup by default this queued buffers limit is -disabled by setting it to UINT64_MAX. +depends on the particular setup by default these queued buffers limits are +disabled by setting them to UINT64_MAX. Some host platforms (like ARM64) require that VFIO device config is loaded only after all iterables were loaded. diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ typedef struct VFIOMultifd { uint32_t load_buf_idx; uint32_t load_buf_idx_last; uint32_t load_buf_queued_pending_buffers; + size_t load_buf_queued_pending_buffers_size; } VFIOMultifd; static void vfio_state_buffer_clear(gpointer data) @@ -XXX,XX +XXX,XX @@ static bool vfio_load_state_buffer_insert(VFIODevice *vbasedev, VFIOMigration *migration = vbasedev->migration; VFIOMultifd *multifd = migration->multifd; VFIOStateBuffer *lb; + size_t data_size = packet_total_size - sizeof(*packet); vfio_state_buffers_assert_init(&multifd->load_bufs); if (packet->idx >= vfio_state_buffers_size_get(&multifd->load_bufs)) { @@ -XXX,XX +XXX,XX @@ static bool vfio_load_state_buffer_insert(VFIODevice *vbasedev, return false; } - lb->data = g_memdup2(&packet->data, packet_total_size - sizeof(*packet)); - lb->len = packet_total_size - sizeof(*packet); + multifd->load_buf_queued_pending_buffers_size += data_size; + if (multifd->load_buf_queued_pending_buffers_size > + vbasedev->migration_max_queued_buffers_size) { + error_setg(errp, + "%s: queuing state buffer %" PRIu32 + " would exceed the size max of %" PRIu64, + vbasedev->name, packet->idx, + vbasedev->migration_max_queued_buffers_size); + return false; + } + + lb->data = g_memdup2(&packet->data, data_size); + lb->len = data_size; lb->is_present = true; return true; @@ -XXX,XX +XXX,XX @@ static bool vfio_load_state_buffer_write(VFIODevice *vbasedev, assert(wr_ret <= buf_len); buf_len -= wr_ret; buf_cur += wr_ret; + + assert(multifd->load_buf_queued_pending_buffers_size >= wr_ret); + multifd->load_buf_queued_pending_buffers_size -= wr_ret; } trace_vfio_load_state_device_buffer_load_end(vbasedev->name, @@ -XXX,XX +XXX,XX @@ static VFIOMultifd *vfio_multifd_new(void) multifd->load_buf_idx = 0; multifd->load_buf_idx_last = UINT32_MAX; multifd->load_buf_queued_pending_buffers = 0; + multifd->load_buf_queued_pending_buffers_size = 0; qemu_cond_init(&multifd->load_bufs_buffer_ready_cond); multifd->load_bufs_iter_done = false; diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -XXX,XX +XXX,XX @@ static const Property vfio_pci_dev_properties[] = { ON_OFF_AUTO_AUTO), DEFINE_PROP_UINT64("x-migration-max-queued-buffers", VFIOPCIDevice, vbasedev.migration_max_queued_buffers, UINT64_MAX), + DEFINE_PROP_SIZE("x-migration-max-queued-buffers-size", VFIOPCIDevice, + vbasedev.migration_max_queued_buffers_size, UINT64_MAX), DEFINE_PROP_BOOL("migration-events", VFIOPCIDevice, vbasedev.migration_events, false), DEFINE_PROP_BOOL("x-no-mmap", VFIOPCIDevice, vbasedev.no_mmap, false), @@ -XXX,XX +XXX,XX @@ static void vfio_pci_dev_class_init(ObjectClass *klass, void *data) "destination when doing live " "migration of device state via " "multifd channels"); + object_class_property_set_description(klass, /* 10.0 */ + "x-migration-max-queued-buffers-size", + "Maximum size of in-flight VFIO " + "device state buffers queued at the " + "destination when doing live " + "migration of device state via " + "multifd channels"); } static const TypeInfo vfio_pci_dev_info = { diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -XXX,XX +XXX,XX @@ typedef struct VFIODevice { OnOffAuto migration_multifd_transfer; OnOffAuto migration_load_config_after_iter; uint64_t migration_max_queued_buffers; + uint64_t migration_max_queued_buffers_size; bool migration_events; VFIODeviceOps *ops; unsigned int num_irqs; From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> It's possible for {load,save}_cleanup SaveVMHandlers to get called without the corresponding {load,save}_setup handler being called first. One such example is if {load,save}_setup handler of a proceeding device returns error. In this case the migration core cleanup code will call all corresponding cleanup handlers, even for these devices which haven't had its setup handler called. Since this behavior can generate some surprises let's clearly document it in these SaveVMHandlers description. Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Cédric Le Goater <clg@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/migration/register.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/include/migration/register.h b/include/migration/register.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/register.h +++ b/include/migration/register.h @@ -XXX,XX +XXX,XX @@ typedef struct SaveVMHandlers { /** * @save_cleanup * - * Uninitializes the data structures on the source + * Uninitializes the data structures on the source. + * Note that this handler can be called even if save_setup + * wasn't called earlier. * * @opaque: data pointer passed to register_savevm_live() */ @@ -XXX,XX +XXX,XX @@ typedef struct SaveVMHandlers { * @load_cleanup * * Uninitializes the data structures on the destination. + * Note that this handler can be called even if load_setup + * wasn't called earlier. * * @opaque: data pointer passed to register_savevm_live() * From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This function name conflicts with one used by a future generic thread pool function and it was only used by one test anyway. Update the trace event name in thread_pool_submit_aio() accordingly. Acked-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Cédric Le Goater <clg@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/block/thread-pool.h | 3 +-- tests/unit/test-thread-pool.c | 6 +++--- util/thread-pool.c | 7 +------ util/trace-events | 2 +- 4 files changed, 6 insertions(+), 12 deletions(-) diff --git a/include/block/thread-pool.h b/include/block/thread-pool.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/thread-pool.h +++ b/include/block/thread-pool.h @@ -XXX,XX +XXX,XX @@ ThreadPool *thread_pool_new(struct AioContext *ctx); void thread_pool_free(ThreadPool *pool); /* - * thread_pool_submit* API: submit I/O requests in the thread's + * thread_pool_submit_{aio,co} API: submit I/O requests in the thread's * current AioContext. */ BlockAIOCB *thread_pool_submit_aio(ThreadPoolFunc *func, void *arg, BlockCompletionFunc *cb, void *opaque); int coroutine_fn thread_pool_submit_co(ThreadPoolFunc *func, void *arg); -void thread_pool_submit(ThreadPoolFunc *func, void *arg); void thread_pool_update_params(ThreadPool *pool, struct AioContext *ctx); diff --git a/tests/unit/test-thread-pool.c b/tests/unit/test-thread-pool.c index XXXXXXX..XXXXXXX 100644 --- a/tests/unit/test-thread-pool.c +++ b/tests/unit/test-thread-pool.c @@ -XXX,XX +XXX,XX @@ static void done_cb(void *opaque, int ret) active--; } -static void test_submit(void) +static void test_submit_no_complete(void) { WorkerTestData data = { .n = 0 }; - thread_pool_submit(worker_cb, &data); + thread_pool_submit_aio(worker_cb, &data, NULL, NULL); while (data.n == 0) { aio_poll(ctx, true); } @@ -XXX,XX +XXX,XX @@ int main(int argc, char **argv) ctx = qemu_get_current_aio_context(); g_test_init(&argc, &argv, NULL); - g_test_add_func("/thread-pool/submit", test_submit); + g_test_add_func("/thread-pool/submit-no-complete", test_submit_no_complete); g_test_add_func("/thread-pool/submit-aio", test_submit_aio); g_test_add_func("/thread-pool/submit-co", test_submit_co); g_test_add_func("/thread-pool/submit-many", test_submit_many); diff --git a/util/thread-pool.c b/util/thread-pool.c index XXXXXXX..XXXXXXX 100644 --- a/util/thread-pool.c +++ b/util/thread-pool.c @@ -XXX,XX +XXX,XX @@ BlockAIOCB *thread_pool_submit_aio(ThreadPoolFunc *func, void *arg, QLIST_INSERT_HEAD(&pool->head, req, all); - trace_thread_pool_submit(pool, req, arg); + trace_thread_pool_submit_aio(pool, req, arg); qemu_mutex_lock(&pool->lock); if (pool->idle_threads == 0 && pool->cur_threads < pool->max_threads) { @@ -XXX,XX +XXX,XX @@ int coroutine_fn thread_pool_submit_co(ThreadPoolFunc *func, void *arg) return tpc.ret; } -void thread_pool_submit(ThreadPoolFunc *func, void *arg) -{ - thread_pool_submit_aio(func, arg, NULL, NULL); -} - void thread_pool_update_params(ThreadPool *pool, AioContext *ctx) { qemu_mutex_lock(&pool->lock); diff --git a/util/trace-events b/util/trace-events index XXXXXXX..XXXXXXX 100644 --- a/util/trace-events +++ b/util/trace-events @@ -XXX,XX +XXX,XX @@ aio_co_schedule_bh_cb(void *ctx, void *co) "ctx %p co %p" reentrant_aio(void *ctx, const char *name) "ctx %p name %s" # thread-pool.c -thread_pool_submit(void *pool, void *req, void *opaque) "pool %p req %p opaque %p" +thread_pool_submit_aio(void *pool, void *req, void *opaque) "pool %p req %p opaque %p" thread_pool_complete(void *pool, void *req, void *opaque, int ret) "pool %p req %p opaque %p ret %d" thread_pool_cancel(void *req, void *opaque) "req %p opaque %p" From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Wire data commonly use BE byte order (including in the existing migration protocol), use it also for for VFIO device state packets. Fixes: 3228d311ab18 ("vfio/migration: Multifd device state transfer support - received buffers queuing") Fixes: 6d644baef203 ("vfio/migration: Multifd device state transfer support - send side") Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ #include "hw/vfio/vfio-common.h" #include "migration/misc.h" #include "qapi/error.h" +#include "qemu/bswap.h" #include "qemu/error-report.h" #include "qemu/lockable.h" #include "qemu/main-loop.h" @@ -XXX,XX +XXX,XX @@ bool vfio_multifd_load_state_buffer(void *opaque, char *data, size_t data_size, return false; } + packet->version = be32_to_cpu(packet->version); if (packet->version != VFIO_DEVICE_STATE_PACKET_VER_CURRENT) { error_setg(errp, "%s: packet has unknown version %" PRIu32, vbasedev->name, packet->version); return false; } + packet->idx = be32_to_cpu(packet->idx); + packet->flags = be32_to_cpu(packet->flags); + if (packet->idx == UINT32_MAX) { error_setg(errp, "%s: packet index is invalid", vbasedev->name); return false; @@ -XXX,XX +XXX,XX @@ vfio_save_complete_precopy_thread_config_state(VFIODevice *vbasedev, packet_len = sizeof(*packet) + bioc->usage; packet = g_malloc0(packet_len); - packet->version = VFIO_DEVICE_STATE_PACKET_VER_CURRENT; - packet->idx = idx; - packet->flags = VFIO_DEVICE_STATE_CONFIG_STATE; + packet->version = cpu_to_be32(VFIO_DEVICE_STATE_PACKET_VER_CURRENT); + packet->idx = cpu_to_be32(idx); + packet->flags = cpu_to_be32(VFIO_DEVICE_STATE_CONFIG_STATE); memcpy(&packet->data, bioc->data, bioc->usage); if (!multifd_queue_device_state(idstr, instance_id, @@ -XXX,XX +XXX,XX @@ vfio_multifd_save_complete_precopy_thread(SaveLiveCompletePrecopyThreadData *d, } packet = g_malloc0(sizeof(*packet) + migration->data_buffer_size); - packet->version = VFIO_DEVICE_STATE_PACKET_VER_CURRENT; + packet->version = cpu_to_be32(VFIO_DEVICE_STATE_PACKET_VER_CURRENT); for (idx = 0; ; idx++) { ssize_t data_size; @@ -XXX,XX +XXX,XX @@ vfio_multifd_save_complete_precopy_thread(SaveLiveCompletePrecopyThreadData *d, break; } - packet->idx = idx; + packet->idx = cpu_to_be32(idx); packet_size = sizeof(*packet) + data_size; if (!multifd_queue_device_state(d->idstr, d->instance_id, From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> These names conflict with ones used by future generic thread pool equivalents. Generic names should belong to the generic pool type, not specific (AIO) type. Acked-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Cédric Le Goater <clg@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/block/aio.h | 8 ++--- include/block/thread-pool.h | 8 ++--- util/async.c | 6 ++-- util/thread-pool.c | 58 ++++++++++++++++++------------------- util/trace-events | 4 +-- 5 files changed, 42 insertions(+), 42 deletions(-) diff --git a/include/block/aio.h b/include/block/aio.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/aio.h +++ b/include/block/aio.h @@ -XXX,XX +XXX,XX @@ typedef void QEMUBHFunc(void *opaque); typedef bool AioPollFn(void *opaque); typedef void IOHandler(void *opaque); -struct ThreadPool; +struct ThreadPoolAio; struct LinuxAioState; typedef struct LuringState LuringState; @@ -XXX,XX +XXX,XX @@ struct AioContext { /* Thread pool for performing work and receiving completion callbacks. * Has its own locking. */ - struct ThreadPool *thread_pool; + struct ThreadPoolAio *thread_pool; #ifdef CONFIG_LINUX_AIO struct LinuxAioState *linux_aio; @@ -XXX,XX +XXX,XX @@ void aio_set_event_notifier_poll(AioContext *ctx, */ GSource *aio_get_g_source(AioContext *ctx); -/* Return the ThreadPool bound to this AioContext */ -struct ThreadPool *aio_get_thread_pool(AioContext *ctx); +/* Return the ThreadPoolAio bound to this AioContext */ +struct ThreadPoolAio *aio_get_thread_pool(AioContext *ctx); /* Setup the LinuxAioState bound to this AioContext */ struct LinuxAioState *aio_setup_linux_aio(AioContext *ctx, Error **errp); diff --git a/include/block/thread-pool.h b/include/block/thread-pool.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/thread-pool.h +++ b/include/block/thread-pool.h @@ -XXX,XX +XXX,XX @@ typedef int ThreadPoolFunc(void *opaque); -typedef struct ThreadPool ThreadPool; +typedef struct ThreadPoolAio ThreadPoolAio; -ThreadPool *thread_pool_new(struct AioContext *ctx); -void thread_pool_free(ThreadPool *pool); +ThreadPoolAio *thread_pool_new_aio(struct AioContext *ctx); +void thread_pool_free_aio(ThreadPoolAio *pool); /* * thread_pool_submit_{aio,co} API: submit I/O requests in the thread's @@ -XXX,XX +XXX,XX @@ void thread_pool_free(ThreadPool *pool); BlockAIOCB *thread_pool_submit_aio(ThreadPoolFunc *func, void *arg, BlockCompletionFunc *cb, void *opaque); int coroutine_fn thread_pool_submit_co(ThreadPoolFunc *func, void *arg); +void thread_pool_update_params(ThreadPoolAio *pool, struct AioContext *ctx); -void thread_pool_update_params(ThreadPool *pool, struct AioContext *ctx); #endif diff --git a/util/async.c b/util/async.c index XXXXXXX..XXXXXXX 100644 --- a/util/async.c +++ b/util/async.c @@ -XXX,XX +XXX,XX @@ aio_ctx_finalize(GSource *source) QEMUBH *bh; unsigned flags; - thread_pool_free(ctx->thread_pool); + thread_pool_free_aio(ctx->thread_pool); #ifdef CONFIG_LINUX_AIO if (ctx->linux_aio) { @@ -XXX,XX +XXX,XX @@ GSource *aio_get_g_source(AioContext *ctx) return &ctx->source; } -ThreadPool *aio_get_thread_pool(AioContext *ctx) +ThreadPoolAio *aio_get_thread_pool(AioContext *ctx) { if (!ctx->thread_pool) { - ctx->thread_pool = thread_pool_new(ctx); + ctx->thread_pool = thread_pool_new_aio(ctx); } return ctx->thread_pool; } diff --git a/util/thread-pool.c b/util/thread-pool.c index XXXXXXX..XXXXXXX 100644 --- a/util/thread-pool.c +++ b/util/thread-pool.c @@ -XXX,XX +XXX,XX @@ #include "block/thread-pool.h" #include "qemu/main-loop.h" -static void do_spawn_thread(ThreadPool *pool); +static void do_spawn_thread(ThreadPoolAio *pool); -typedef struct ThreadPoolElement ThreadPoolElement; +typedef struct ThreadPoolElementAio ThreadPoolElementAio; enum ThreadState { THREAD_QUEUED, @@ -XXX,XX +XXX,XX @@ enum ThreadState { THREAD_DONE, }; -struct ThreadPoolElement { +struct ThreadPoolElementAio { BlockAIOCB common; - ThreadPool *pool; + ThreadPoolAio *pool; ThreadPoolFunc *func; void *arg; @@ -XXX,XX +XXX,XX @@ struct ThreadPoolElement { int ret; /* Access to this list is protected by lock. */ - QTAILQ_ENTRY(ThreadPoolElement) reqs; + QTAILQ_ENTRY(ThreadPoolElementAio) reqs; /* This list is only written by the thread pool's mother thread. */ - QLIST_ENTRY(ThreadPoolElement) all; + QLIST_ENTRY(ThreadPoolElementAio) all; }; -struct ThreadPool { +struct ThreadPoolAio { AioContext *ctx; QEMUBH *completion_bh; QemuMutex lock; @@ -XXX,XX +XXX,XX @@ struct ThreadPool { QEMUBH *new_thread_bh; /* The following variables are only accessed from one AioContext. */ - QLIST_HEAD(, ThreadPoolElement) head; + QLIST_HEAD(, ThreadPoolElementAio) head; /* The following variables are protected by lock. */ - QTAILQ_HEAD(, ThreadPoolElement) request_list; + QTAILQ_HEAD(, ThreadPoolElementAio) request_list; int cur_threads; int idle_threads; int new_threads; /* backlog of threads we need to create */ @@ -XXX,XX +XXX,XX @@ struct ThreadPool { static void *worker_thread(void *opaque) { - ThreadPool *pool = opaque; + ThreadPoolAio *pool = opaque; qemu_mutex_lock(&pool->lock); pool->pending_threads--; do_spawn_thread(pool); while (pool->cur_threads <= pool->max_threads) { - ThreadPoolElement *req; + ThreadPoolElementAio *req; int ret; if (QTAILQ_EMPTY(&pool->request_list)) { @@ -XXX,XX +XXX,XX @@ static void *worker_thread(void *opaque) return NULL; } -static void do_spawn_thread(ThreadPool *pool) +static void do_spawn_thread(ThreadPoolAio *pool) { QemuThread t; @@ -XXX,XX +XXX,XX @@ static void do_spawn_thread(ThreadPool *pool) static void spawn_thread_bh_fn(void *opaque) { - ThreadPool *pool = opaque; + ThreadPoolAio *pool = opaque; qemu_mutex_lock(&pool->lock); do_spawn_thread(pool); qemu_mutex_unlock(&pool->lock); } -static void spawn_thread(ThreadPool *pool) +static void spawn_thread(ThreadPoolAio *pool) { pool->cur_threads++; pool->new_threads++; @@ -XXX,XX +XXX,XX @@ static void spawn_thread(ThreadPool *pool) static void thread_pool_completion_bh(void *opaque) { - ThreadPool *pool = opaque; - ThreadPoolElement *elem, *next; + ThreadPoolAio *pool = opaque; + ThreadPoolElementAio *elem, *next; defer_call_begin(); /* cb() may use defer_call() to coalesce work */ @@ -XXX,XX +XXX,XX @@ restart: continue; } - trace_thread_pool_complete(pool, elem, elem->common.opaque, - elem->ret); + trace_thread_pool_complete_aio(pool, elem, elem->common.opaque, + elem->ret); QLIST_REMOVE(elem, all); if (elem->common.cb) { @@ -XXX,XX +XXX,XX @@ restart: static void thread_pool_cancel(BlockAIOCB *acb) { - ThreadPoolElement *elem = (ThreadPoolElement *)acb; - ThreadPool *pool = elem->pool; + ThreadPoolElementAio *elem = (ThreadPoolElementAio *)acb; + ThreadPoolAio *pool = elem->pool; - trace_thread_pool_cancel(elem, elem->common.opaque); + trace_thread_pool_cancel_aio(elem, elem->common.opaque); QEMU_LOCK_GUARD(&pool->lock); if (elem->state == THREAD_QUEUED) { @@ -XXX,XX +XXX,XX @@ static void thread_pool_cancel(BlockAIOCB *acb) } static const AIOCBInfo thread_pool_aiocb_info = { - .aiocb_size = sizeof(ThreadPoolElement), + .aiocb_size = sizeof(ThreadPoolElementAio), .cancel_async = thread_pool_cancel, }; BlockAIOCB *thread_pool_submit_aio(ThreadPoolFunc *func, void *arg, BlockCompletionFunc *cb, void *opaque) { - ThreadPoolElement *req; + ThreadPoolElementAio *req; AioContext *ctx = qemu_get_current_aio_context(); - ThreadPool *pool = aio_get_thread_pool(ctx); + ThreadPoolAio *pool = aio_get_thread_pool(ctx); /* Assert that the thread submitting work is the same running the pool */ assert(pool->ctx == qemu_get_current_aio_context()); @@ -XXX,XX +XXX,XX @@ int coroutine_fn thread_pool_submit_co(ThreadPoolFunc *func, void *arg) return tpc.ret; } -void thread_pool_update_params(ThreadPool *pool, AioContext *ctx) +void thread_pool_update_params(ThreadPoolAio *pool, AioContext *ctx) { qemu_mutex_lock(&pool->lock); @@ -XXX,XX +XXX,XX @@ void thread_pool_update_params(ThreadPool *pool, AioContext *ctx) qemu_mutex_unlock(&pool->lock); } -static void thread_pool_init_one(ThreadPool *pool, AioContext *ctx) +static void thread_pool_init_one(ThreadPoolAio *pool, AioContext *ctx) { if (!ctx) { ctx = qemu_get_aio_context(); @@ -XXX,XX +XXX,XX @@ static void thread_pool_init_one(ThreadPool *pool, AioContext *ctx) thread_pool_update_params(pool, ctx); } -ThreadPool *thread_pool_new(AioContext *ctx) +ThreadPoolAio *thread_pool_new_aio(AioContext *ctx) { - ThreadPool *pool = g_new(ThreadPool, 1); + ThreadPoolAio *pool = g_new(ThreadPoolAio, 1); thread_pool_init_one(pool, ctx); return pool; } -void thread_pool_free(ThreadPool *pool) +void thread_pool_free_aio(ThreadPoolAio *pool) { if (!pool) { return; diff --git a/util/trace-events b/util/trace-events index XXXXXXX..XXXXXXX 100644 --- a/util/trace-events +++ b/util/trace-events @@ -XXX,XX +XXX,XX @@ reentrant_aio(void *ctx, const char *name) "ctx %p name %s" # thread-pool.c thread_pool_submit_aio(void *pool, void *req, void *opaque) "pool %p req %p opaque %p" -thread_pool_complete(void *pool, void *req, void *opaque, int ret) "pool %p req %p opaque %p ret %d" -thread_pool_cancel(void *req, void *opaque) "req %p opaque %p" +thread_pool_complete_aio(void *pool, void *req, void *opaque, int ret) "pool %p req %p opaque %p ret %d" +thread_pool_cancel_aio(void *req, void *opaque) "req %p opaque %p" # buffer.c buffer_resize(const char *buf, size_t olen, size_t len) "%s: old %zd, new %zd" From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Migration code wants to manage device data sending threads in one place. QEMU has an existing thread pool implementation, however it is limited to queuing AIO operations only and essentially has a 1:1 mapping between the current AioContext and the AIO ThreadPool in use. Implement generic (non-AIO) ThreadPool by essentially wrapping Glib's GThreadPool. This brings a few new operations on a pool: * thread_pool_wait() operation waits until all the submitted work requests have finished. * thread_pool_set_max_threads() explicitly sets the maximum thread count in the pool. * thread_pool_adjust_max_threads_to_work() adjusts the maximum thread count in the pool to equal the number of still waiting in queue or unfinished work. Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/block/thread-pool.h | 51 ++++++++++++++++ util/thread-pool.c | 119 ++++++++++++++++++++++++++++++++++++ 2 files changed, 170 insertions(+) diff --git a/include/block/thread-pool.h b/include/block/thread-pool.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/thread-pool.h +++ b/include/block/thread-pool.h @@ -XXX,XX +XXX,XX @@ BlockAIOCB *thread_pool_submit_aio(ThreadPoolFunc *func, void *arg, int coroutine_fn thread_pool_submit_co(ThreadPoolFunc *func, void *arg); void thread_pool_update_params(ThreadPoolAio *pool, struct AioContext *ctx); +/* ------------------------------------------- */ +/* Generic thread pool types and methods below */ +typedef struct ThreadPool ThreadPool; + +/* Create a new thread pool. Never returns NULL. */ +ThreadPool *thread_pool_new(void); + +/* + * Free the thread pool. + * Waits for all the previously submitted work to complete before performing + * the actual freeing operation. + */ +void thread_pool_free(ThreadPool *pool); + +/* + * Submit a new work (task) for the pool. + * + * @opaque_destroy is an optional GDestroyNotify for the @opaque argument + * to the work function at @func. + */ +void thread_pool_submit(ThreadPool *pool, ThreadPoolFunc *func, + void *opaque, GDestroyNotify opaque_destroy); + +/* + * Submit a new work (task) for the pool, making sure it starts getting + * processed immediately, launching a new thread for it if necessary. + * + * @opaque_destroy is an optional GDestroyNotify for the @opaque argument + * to the work function at @func. + */ +void thread_pool_submit_immediate(ThreadPool *pool, ThreadPoolFunc *func, + void *opaque, GDestroyNotify opaque_destroy); + +/* + * Wait for all previously submitted work to complete before returning. + * + * Can be used as a barrier between two sets of tasks executed on a thread + * pool without destroying it or in a performance sensitive path where the + * caller just wants to wait for all tasks to complete while deferring the + * pool free operation for later, less performance sensitive time. + */ +void thread_pool_wait(ThreadPool *pool); + +/* Set the maximum number of threads in the pool. */ +bool thread_pool_set_max_threads(ThreadPool *pool, int max_threads); + +/* + * Adjust the maximum number of threads in the pool to give each task its + * own thread (exactly one thread per task). + */ +bool thread_pool_adjust_max_threads_to_work(ThreadPool *pool); #endif diff --git a/util/thread-pool.c b/util/thread-pool.c index XXXXXXX..XXXXXXX 100644 --- a/util/thread-pool.c +++ b/util/thread-pool.c @@ -XXX,XX +XXX,XX @@ void thread_pool_free_aio(ThreadPoolAio *pool) qemu_mutex_destroy(&pool->lock); g_free(pool); } + +struct ThreadPool { + GThreadPool *t; + size_t cur_work; + QemuMutex cur_work_lock; + QemuCond all_finished_cond; +}; + +typedef struct { + ThreadPoolFunc *func; + void *opaque; + GDestroyNotify opaque_destroy; +} ThreadPoolElement; + +static void thread_pool_func(gpointer data, gpointer user_data) +{ + ThreadPool *pool = user_data; + g_autofree ThreadPoolElement *el = data; + + el->func(el->opaque); + + if (el->opaque_destroy) { + el->opaque_destroy(el->opaque); + } + + QEMU_LOCK_GUARD(&pool->cur_work_lock); + + assert(pool->cur_work > 0); + pool->cur_work--; + + if (pool->cur_work == 0) { + qemu_cond_signal(&pool->all_finished_cond); + } +} + +ThreadPool *thread_pool_new(void) +{ + ThreadPool *pool = g_new(ThreadPool, 1); + + pool->cur_work = 0; + qemu_mutex_init(&pool->cur_work_lock); + qemu_cond_init(&pool->all_finished_cond); + + pool->t = g_thread_pool_new(thread_pool_func, pool, 0, TRUE, NULL); + /* + * g_thread_pool_new() can only return errors if initial thread(s) + * creation fails but we ask for 0 initial threads above. + */ + assert(pool->t); + + return pool; +} + +void thread_pool_free(ThreadPool *pool) +{ + /* + * With _wait = TRUE this effectively waits for all + * previously submitted work to complete first. + */ + g_thread_pool_free(pool->t, FALSE, TRUE); + + qemu_cond_destroy(&pool->all_finished_cond); + qemu_mutex_destroy(&pool->cur_work_lock); + + g_free(pool); +} + +void thread_pool_submit(ThreadPool *pool, ThreadPoolFunc *func, + void *opaque, GDestroyNotify opaque_destroy) +{ + ThreadPoolElement *el = g_new(ThreadPoolElement, 1); + + el->func = func; + el->opaque = opaque; + el->opaque_destroy = opaque_destroy; + + WITH_QEMU_LOCK_GUARD(&pool->cur_work_lock) { + pool->cur_work++; + } + + /* + * Ignore the return value since this function can only return errors + * if creation of an additional thread fails but even in this case the + * provided work is still getting queued (just for the existing threads). + */ + g_thread_pool_push(pool->t, el, NULL); +} + +void thread_pool_submit_immediate(ThreadPool *pool, ThreadPoolFunc *func, + void *opaque, GDestroyNotify opaque_destroy) +{ + thread_pool_submit(pool, func, opaque, opaque_destroy); + thread_pool_adjust_max_threads_to_work(pool); +} + +void thread_pool_wait(ThreadPool *pool) +{ + QEMU_LOCK_GUARD(&pool->cur_work_lock); + + while (pool->cur_work > 0) { + qemu_cond_wait(&pool->all_finished_cond, + &pool->cur_work_lock); + } +} + +bool thread_pool_set_max_threads(ThreadPool *pool, + int max_threads) +{ + assert(max_threads > 0); + + return g_thread_pool_set_max_threads(pool->t, max_threads, NULL); +} + +bool thread_pool_adjust_max_threads_to_work(ThreadPool *pool) +{ + QEMU_LOCK_GUARD(&pool->cur_work_lock); + + return thread_pool_set_max_threads(pool, pool->cur_work); +} From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This QEMU_VM_COMMAND sub-command and its switchover_start SaveVMHandler is used to mark the switchover point in main migration stream. It can be used to inform the destination that all pre-switchover main migration stream data has been sent/received so it can start to process post-switchover data that it might have received via other migration channels like the multifd ones. Add also the relevant MigrationState bit stream compatibility property and its hw_compat entry. Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Zhang Chen <zhangckid@gmail.com> # for the COLO part Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/core/machine.c | 1 + include/migration/client-options.h | 4 +++ include/migration/register.h | 12 +++++++++ migration/colo.c | 3 +++ migration/migration-hmp-cmds.c | 2 ++ migration/migration.c | 2 ++ migration/migration.h | 2 ++ migration/options.c | 9 +++++++ migration/savevm.c | 39 ++++++++++++++++++++++++++++++ migration/savevm.h | 1 + migration/trace-events | 1 + scripts/analyze-migration.py | 11 +++++++++ 12 files changed, 87 insertions(+) diff --git a/hw/core/machine.c b/hw/core/machine.c index XXXXXXX..XXXXXXX 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -XXX,XX +XXX,XX @@ GlobalProperty hw_compat_9_2[] = { { "virtio-balloon-pci-non-transitional", "vectors", "0" }, { "virtio-mem-pci", "vectors", "0" }, { "migration", "multifd-clean-tls-termination", "false" }, + { "migration", "send-switchover-start", "off"}, }; const size_t hw_compat_9_2_len = G_N_ELEMENTS(hw_compat_9_2); diff --git a/include/migration/client-options.h b/include/migration/client-options.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/client-options.h +++ b/include/migration/client-options.h @@ -XXX,XX +XXX,XX @@ #ifndef QEMU_MIGRATION_CLIENT_OPTIONS_H #define QEMU_MIGRATION_CLIENT_OPTIONS_H + +/* properties */ +bool migrate_send_switchover_start(void); + /* capabilities */ bool migrate_background_snapshot(void); diff --git a/include/migration/register.h b/include/migration/register.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/register.h +++ b/include/migration/register.h @@ -XXX,XX +XXX,XX @@ typedef struct SaveVMHandlers { * otherwise */ bool (*switchover_ack_needed)(void *opaque); + + /** + * @switchover_start + * + * Notifies that the switchover has started. Called only on + * the destination. + * + * @opaque: data pointer passed to register_savevm_live() + * + * Returns zero to indicate success and negative for error + */ + int (*switchover_start)(void *opaque); } SaveVMHandlers; /** diff --git a/migration/colo.c b/migration/colo.c index XXXXXXX..XXXXXXX 100644 --- a/migration/colo.c +++ b/migration/colo.c @@ -XXX,XX +XXX,XX @@ static int colo_do_checkpoint_transaction(MigrationState *s, bql_unlock(); goto out; } + + qemu_savevm_maybe_send_switchover_start(s->to_dst_file); + /* Note: device state is saved into buffer */ ret = qemu_save_device_state(fb); diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c index XXXXXXX..XXXXXXX 100644 --- a/migration/migration-hmp-cmds.c +++ b/migration/migration-hmp-cmds.c @@ -XXX,XX +XXX,XX @@ static void migration_global_dump(Monitor *mon) ms->send_configuration ? "on" : "off"); monitor_printf(mon, "send-section-footer: %s\n", ms->send_section_footer ? "on" : "off"); + monitor_printf(mon, "send-switchover-start: %s\n", + ms->send_switchover_start ? "on" : "off"); monitor_printf(mon, "clear-bitmap-shift: %u\n", ms->clear_bitmap_shift); } diff --git a/migration/migration.c b/migration/migration.c index XXXXXXX..XXXXXXX 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -XXX,XX +XXX,XX @@ static bool migration_switchover_start(MigrationState *s, Error **errp) precopy_notify_complete(); + qemu_savevm_maybe_send_switchover_start(s->to_dst_file); + return true; } diff --git a/migration/migration.h b/migration/migration.h index XXXXXXX..XXXXXXX 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -XXX,XX +XXX,XX @@ struct MigrationState { bool send_configuration; /* Whether we send section footer during migration */ bool send_section_footer; + /* Whether we send switchover start notification during migration */ + bool send_switchover_start; /* Needed by postcopy-pause state */ QemuSemaphore postcopy_pause_sem; diff --git a/migration/options.c b/migration/options.c index XXXXXXX..XXXXXXX 100644 --- a/migration/options.c +++ b/migration/options.c @@ -XXX,XX +XXX,XX @@ const Property migration_properties[] = { send_configuration, true), DEFINE_PROP_BOOL("send-section-footer", MigrationState, send_section_footer, true), + DEFINE_PROP_BOOL("send-switchover-start", MigrationState, + send_switchover_start, true), DEFINE_PROP_BOOL("multifd-flush-after-each-section", MigrationState, multifd_flush_after_each_section, false), DEFINE_PROP_UINT8("x-clear-bitmap-shift", MigrationState, @@ -XXX,XX +XXX,XX @@ bool migrate_auto_converge(void) return s->capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE]; } +bool migrate_send_switchover_start(void) +{ + MigrationState *s = migrate_get_current(); + + return s->send_switchover_start; +} + bool migrate_background_snapshot(void) { MigrationState *s = migrate_get_current(); diff --git a/migration/savevm.c b/migration/savevm.c index XXXXXXX..XXXXXXX 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -XXX,XX +XXX,XX @@ enum qemu_vm_cmd { MIG_CMD_ENABLE_COLO, /* Enable COLO */ MIG_CMD_POSTCOPY_RESUME, /* resume postcopy on dest */ MIG_CMD_RECV_BITMAP, /* Request for recved bitmap on dst */ + MIG_CMD_SWITCHOVER_START, /* Switchover start notification */ MIG_CMD_MAX }; @@ -XXX,XX +XXX,XX @@ static struct mig_cmd_args { [MIG_CMD_POSTCOPY_RESUME] = { .len = 0, .name = "POSTCOPY_RESUME" }, [MIG_CMD_PACKAGED] = { .len = 4, .name = "PACKAGED" }, [MIG_CMD_RECV_BITMAP] = { .len = -1, .name = "RECV_BITMAP" }, + [MIG_CMD_SWITCHOVER_START] = { .len = 0, .name = "SWITCHOVER_START" }, [MIG_CMD_MAX] = { .len = -1, .name = "MAX" }, }; @@ -XXX,XX +XXX,XX @@ void qemu_savevm_send_recv_bitmap(QEMUFile *f, char *block_name) qemu_savevm_command_send(f, MIG_CMD_RECV_BITMAP, len + 1, (uint8_t *)buf); } +static void qemu_savevm_send_switchover_start(QEMUFile *f) +{ + trace_savevm_send_switchover_start(); + qemu_savevm_command_send(f, MIG_CMD_SWITCHOVER_START, 0, NULL); +} + +void qemu_savevm_maybe_send_switchover_start(QEMUFile *f) +{ + if (migrate_send_switchover_start()) { + qemu_savevm_send_switchover_start(f); + } +} + bool qemu_savevm_state_blocked(Error **errp) { SaveStateEntry *se; @@ -XXX,XX +XXX,XX @@ static int qemu_savevm_state(QEMUFile *f, Error **errp) ret = qemu_file_get_error(f); if (ret == 0) { + qemu_savevm_maybe_send_switchover_start(f); qemu_savevm_state_complete_precopy(f, false); ret = qemu_file_get_error(f); } @@ -XXX,XX +XXX,XX @@ static int loadvm_process_enable_colo(MigrationIncomingState *mis) return ret; } +static int loadvm_postcopy_handle_switchover_start(void) +{ + SaveStateEntry *se; + + QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { + int ret; + + if (!se->ops || !se->ops->switchover_start) { + continue; + } + + ret = se->ops->switchover_start(se->opaque); + if (ret < 0) { + return ret; + } + } + + return 0; +} + /* * Process an incoming 'QEMU_VM_COMMAND' * 0 just a normal return @@ -XXX,XX +XXX,XX @@ static int loadvm_process_command(QEMUFile *f) case MIG_CMD_ENABLE_COLO: return loadvm_process_enable_colo(mis); + + case MIG_CMD_SWITCHOVER_START: + return loadvm_postcopy_handle_switchover_start(); } return 0; diff --git a/migration/savevm.h b/migration/savevm.h index XXXXXXX..XXXXXXX 100644 --- a/migration/savevm.h +++ b/migration/savevm.h @@ -XXX,XX +XXX,XX @@ void qemu_savevm_send_postcopy_listen(QEMUFile *f); void qemu_savevm_send_postcopy_run(QEMUFile *f); void qemu_savevm_send_postcopy_resume(QEMUFile *f); void qemu_savevm_send_recv_bitmap(QEMUFile *f, char *block_name); +void qemu_savevm_maybe_send_switchover_start(QEMUFile *f); void qemu_savevm_send_postcopy_ram_discard(QEMUFile *f, const char *name, uint16_t len, diff --git a/migration/trace-events b/migration/trace-events index XXXXXXX..XXXXXXX 100644 --- a/migration/trace-events +++ b/migration/trace-events @@ -XXX,XX +XXX,XX @@ savevm_send_postcopy_run(void) "" savevm_send_postcopy_resume(void) "" savevm_send_colo_enable(void) "" savevm_send_recv_bitmap(char *name) "%s" +savevm_send_switchover_start(void) "" savevm_state_setup(void) "" savevm_state_resume_prepare(void) "" savevm_state_header(void) "" diff --git a/scripts/analyze-migration.py b/scripts/analyze-migration.py index XXXXXXX..XXXXXXX 100755 --- a/scripts/analyze-migration.py +++ b/scripts/analyze-migration.py @@ -XXX,XX +XXX,XX @@ class MigrationDump(object): QEMU_VM_SUBSECTION = 0x05 QEMU_VM_VMDESCRIPTION = 0x06 QEMU_VM_CONFIGURATION = 0x07 + QEMU_VM_COMMAND = 0x08 QEMU_VM_SECTION_FOOTER= 0x7e + QEMU_MIG_CMD_SWITCHOVER_START = 0x0b def __init__(self, filename): self.section_classes = { @@ -XXX,XX +XXX,XX @@ def read(self, desc_only = False, dump_memory = False, elif section_type == self.QEMU_VM_SECTION_PART or section_type == self.QEMU_VM_SECTION_END: section_id = file.read32() self.sections[section_id].read() + elif section_type == self.QEMU_VM_COMMAND: + command_type = file.read16() + command_data_len = file.read16() + if command_type != self.QEMU_MIG_CMD_SWITCHOVER_START: + raise Exception("Unknown QEMU_VM_COMMAND: %x" % + (command_type)) + if command_data_len != 0: + raise Exception("Invalid SWITCHOVER_START length: %x" % + (command_data_len)) elif section_type == self.QEMU_VM_SECTION_FOOTER: read_section_id = file.read32() if read_section_id != section_id: From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> qemu_loadvm_load_state_buffer() and its load_state_buffer SaveVMHandler allow providing device state buffer to explicitly specified device via its idstr and instance id. Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/migration/register.h | 15 +++++++++++++++ migration/savevm.c | 23 +++++++++++++++++++++++ migration/savevm.h | 3 +++ 3 files changed, 41 insertions(+) diff --git a/include/migration/register.h b/include/migration/register.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/register.h +++ b/include/migration/register.h @@ -XXX,XX +XXX,XX @@ typedef struct SaveVMHandlers { */ int (*load_state)(QEMUFile *f, void *opaque, int version_id); + /** + * @load_state_buffer (invoked outside the BQL) + * + * Load device state buffer provided to qemu_loadvm_load_state_buffer(). + * + * @opaque: data pointer passed to register_savevm_live() + * @buf: the data buffer to load + * @len: the data length in buffer + * @errp: pointer to Error*, to store an error if it happens. + * + * Returns true to indicate success and false for errors. + */ + bool (*load_state_buffer)(void *opaque, char *buf, size_t len, + Error **errp); + /** * @load_setup * diff --git a/migration/savevm.c b/migration/savevm.c index XXXXXXX..XXXXXXX 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -XXX,XX +XXX,XX @@ int qemu_loadvm_approve_switchover(void) return migrate_send_rp_switchover_ack(mis); } +bool qemu_loadvm_load_state_buffer(const char *idstr, uint32_t instance_id, + char *buf, size_t len, Error **errp) +{ + SaveStateEntry *se; + + se = find_se(idstr, instance_id); + if (!se) { + error_setg(errp, + "Unknown idstr %s or instance id %u for load state buffer", + idstr, instance_id); + return false; + } + + if (!se->ops || !se->ops->load_state_buffer) { + error_setg(errp, + "idstr %s / instance %u has no load state buffer operation", + idstr, instance_id); + return false; + } + + return se->ops->load_state_buffer(se->opaque, buf, len, errp); +} + bool save_snapshot(const char *name, bool overwrite, const char *vmstate, bool has_devices, strList *devices, Error **errp) { diff --git a/migration/savevm.h b/migration/savevm.h index XXXXXXX..XXXXXXX 100644 --- a/migration/savevm.h +++ b/migration/savevm.h @@ -XXX,XX +XXX,XX @@ int qemu_loadvm_approve_switchover(void); int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f, bool in_postcopy); +bool qemu_loadvm_load_state_buffer(const char *idstr, uint32_t instance_id, + char *buf, size_t len, Error **errp); + #endif From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> All callers to migration_incoming_state_destroy() other than postcopy_ram_listen_thread() do this call with BQL held. Since migration_incoming_state_destroy() ultimately calls "load_cleanup" SaveVMHandlers and it will soon call BQL-sensitive code it makes sense to always call that function under BQL rather than to have it deal with both cases (with BQL and without BQL). Add the necessary bql_lock() and bql_unlock() to postcopy_ram_listen_thread(). qemu_loadvm_state_main() in postcopy_ram_listen_thread() could call "load_state" SaveVMHandlers that are expecting BQL to be held. In principle, the only devices that should be arriving on migration channel serviced by postcopy_ram_listen_thread() are those that are postcopiable and whose load handlers are safe to be called without BQL being held. But nothing currently prevents the source from sending data for "unsafe" devices which would cause trouble there. Add a TODO comment there so it's clear that it would be good to improve handling of such (erroneous) case in the future. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- migration/migration.c | 16 ++++++++++++++++ migration/savevm.c | 4 ++++ 2 files changed, 20 insertions(+) diff --git a/migration/migration.c b/migration/migration.c index XXXXXXX..XXXXXXX 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -XXX,XX +XXX,XX @@ void migration_incoming_state_destroy(void) struct MigrationIncomingState *mis = migration_incoming_get_current(); multifd_recv_cleanup(); + /* * RAM state cleanup needs to happen after multifd cleanup, because * multifd threads can use some of its states (receivedmap). + * + * This call also needs BQL held since it calls all registered + * load_cleanup SaveVMHandlers and at least the VFIO implementation is + * BQL-sensitive. + * + * In addition to the above, it also performs cleanup of load threads + * thread pool. + * This cleanup operation is BQL-sensitive as it requires unlocking BQL + * so a thread possibly waiting for it could get unblocked and finally + * exit. + * The reason why a load thread may need to hold BQL in the first place + * is because address space modification operations require it. + * + * Check proper BQL state here rather than risk possible deadlock later. */ + assert(bql_locked()); qemu_loadvm_state_cleanup(); if (mis->to_src_file) { diff --git a/migration/savevm.c b/migration/savevm.c index XXXXXXX..XXXXXXX 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -XXX,XX +XXX,XX @@ static void *postcopy_ram_listen_thread(void *opaque) * in qemu_file, and thus we must be blocking now. */ qemu_file_set_blocking(f, true); + + /* TODO: sanity check that only postcopiable data will be loaded here */ load_res = qemu_loadvm_state_main(f, mis); /* @@ -XXX,XX +XXX,XX @@ static void *postcopy_ram_listen_thread(void *opaque) * (If something broke then qemu will have to exit anyway since it's * got a bad migration state). */ + bql_lock(); migration_incoming_state_destroy(); + bql_unlock(); rcu_unregister_thread(); mis->have_listen_thread = false; From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Automatic memory management helps avoid memory safety issues. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/qapi/error.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/qapi/error.h b/include/qapi/error.h index XXXXXXX..XXXXXXX 100644 --- a/include/qapi/error.h +++ b/include/qapi/error.h @@ -XXX,XX +XXX,XX @@ Error *error_copy(const Error *err); */ void error_free(Error *err); +G_DEFINE_AUTOPTR_CLEANUP_FUNC(Error, error_free) + /* * Convenience function to assert that *@errp is set, then silently free it. */ From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Some drivers might want to make use of auxiliary helper threads during VM state loading, for example to make sure that their blocking (sync) I/O operations don't block the rest of the migration process. Add a migration core managed thread pool to facilitate this use case. The migration core will wait for these threads to finish before (re)starting the VM at destination. Reviewed-by: Fabiano Rosas <farosas@suse.de> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/migration/misc.h | 3 ++ include/qemu/typedefs.h | 2 + migration/migration.c | 2 +- migration/migration.h | 5 +++ migration/savevm.c | 95 +++++++++++++++++++++++++++++++++++++++- migration/savevm.h | 2 +- 6 files changed, 105 insertions(+), 4 deletions(-) diff --git a/include/migration/misc.h b/include/migration/misc.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/misc.h +++ b/include/migration/misc.h @@ -XXX,XX +XXX,XX @@ bool migrate_ram_is_ignored(RAMBlock *block); /* migration/block.c */ AnnounceParameters *migrate_announce_params(void); + /* migration/savevm.c */ void dump_vmstate_json_to_file(FILE *out_fp); +void qemu_loadvm_start_load_thread(MigrationLoadThread function, + void *opaque); /* migration/migration.c */ void migration_object_init(void); diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h index XXXXXXX..XXXXXXX 100644 --- a/include/qemu/typedefs.h +++ b/include/qemu/typedefs.h @@ -XXX,XX +XXX,XX @@ typedef struct IRQState *qemu_irq; * Function types */ typedef void (*qemu_irq_handler)(void *opaque, int n, int level); +typedef bool (*MigrationLoadThread)(void *opaque, bool *should_quit, + Error **errp); #endif /* QEMU_TYPEDEFS_H */ diff --git a/migration/migration.c b/migration/migration.c index XXXXXXX..XXXXXXX 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -XXX,XX +XXX,XX @@ void migration_incoming_state_destroy(void) * Check proper BQL state here rather than risk possible deadlock later. */ assert(bql_locked()); - qemu_loadvm_state_cleanup(); + qemu_loadvm_state_cleanup(mis); if (mis->to_src_file) { /* Tell source that we are done */ diff --git a/migration/migration.h b/migration/migration.h index XXXXXXX..XXXXXXX 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -XXX,XX +XXX,XX @@ #define MIGRATION_THREAD_DST_PREEMPT "mig/dst/preempt" struct PostcopyBlocktimeContext; +typedef struct ThreadPool ThreadPool; #define MIGRATION_RESUME_ACK_VALUE (1) @@ -XXX,XX +XXX,XX @@ struct MigrationIncomingState { Coroutine *colo_incoming_co; QemuSemaphore colo_incoming_sem; + /* Optional load threads pool and its thread exit request flag */ + ThreadPool *load_threads; + bool load_threads_abort; + /* * PostcopyBlocktimeContext to keep information for postcopy * live migration, to calculate vCPU block time diff --git a/migration/savevm.c b/migration/savevm.c index XXXXXXX..XXXXXXX 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -XXX,XX +XXX,XX @@ #include "qemu/job.h" #include "qemu/main-loop.h" #include "block/snapshot.h" +#include "block/thread-pool.h" #include "qemu/cutils.h" #include "io/channel-buffer.h" #include "io/channel-file.h" @@ -XXX,XX +XXX,XX @@ static struct mig_cmd_args { * generic extendable format with an exception for two old entities. */ +/***********************************************************/ +/* Optional load threads pool support */ + +static void qemu_loadvm_thread_pool_create(MigrationIncomingState *mis) +{ + assert(!mis->load_threads); + mis->load_threads = thread_pool_new(); + mis->load_threads_abort = false; +} + +static void qemu_loadvm_thread_pool_destroy(MigrationIncomingState *mis) +{ + qatomic_set(&mis->load_threads_abort, true); + + bql_unlock(); /* Load threads might be waiting for BQL */ + g_clear_pointer(&mis->load_threads, thread_pool_free); + bql_lock(); +} + +static bool qemu_loadvm_thread_pool_wait(MigrationState *s, + MigrationIncomingState *mis) +{ + bql_unlock(); /* Let load threads do work requiring BQL */ + thread_pool_wait(mis->load_threads); + bql_lock(); + + return !migrate_has_error(s); +} + /***********************************************************/ /* savevm/loadvm support */ @@ -XXX,XX +XXX,XX @@ static int qemu_loadvm_state_setup(QEMUFile *f, Error **errp) return 0; } -void qemu_loadvm_state_cleanup(void) +struct LoadThreadData { + MigrationLoadThread function; + void *opaque; +}; + +static int qemu_loadvm_load_thread(void *thread_opaque) +{ + struct LoadThreadData *data = thread_opaque; + MigrationIncomingState *mis = migration_incoming_get_current(); + g_autoptr(Error) local_err = NULL; + + if (!data->function(data->opaque, &mis->load_threads_abort, &local_err)) { + MigrationState *s = migrate_get_current(); + + /* + * Can't set load_threads_abort here since processing of main migration + * channel data could still be happening, resulting in launching of new + * load threads. + */ + + assert(local_err); + + /* + * In case of multiple load threads failing which thread error + * return we end setting is purely arbitrary. + */ + migrate_set_error(s, local_err); + } + + return 0; +} + +void qemu_loadvm_start_load_thread(MigrationLoadThread function, + void *opaque) +{ + MigrationIncomingState *mis = migration_incoming_get_current(); + struct LoadThreadData *data; + + /* We only set it from this thread so it's okay to read it directly */ + assert(!mis->load_threads_abort); + + data = g_new(struct LoadThreadData, 1); + data->function = function; + data->opaque = opaque; + + thread_pool_submit_immediate(mis->load_threads, qemu_loadvm_load_thread, + data, g_free); +} + +void qemu_loadvm_state_cleanup(MigrationIncomingState *mis) { SaveStateEntry *se; trace_loadvm_state_cleanup(); + QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (se->ops && se->ops->load_cleanup) { se->ops->load_cleanup(se->opaque); } } + + qemu_loadvm_thread_pool_destroy(mis); } /* Return true if we should continue the migration, or false. */ @@ -XXX,XX +XXX,XX @@ out: int qemu_loadvm_state(QEMUFile *f) { + MigrationState *s = migrate_get_current(); MigrationIncomingState *mis = migration_incoming_get_current(); Error *local_err = NULL; int ret; @@ -XXX,XX +XXX,XX @@ int qemu_loadvm_state(QEMUFile *f) return -EINVAL; } + qemu_loadvm_thread_pool_create(mis); + ret = qemu_loadvm_state_header(f); if (ret) { return ret; @@ -XXX,XX +XXX,XX @@ int qemu_loadvm_state(QEMUFile *f) /* When reaching here, it must be precopy */ if (ret == 0) { - if (migrate_has_error(migrate_get_current())) { + if (migrate_has_error(migrate_get_current()) || + !qemu_loadvm_thread_pool_wait(s, mis)) { ret = -EINVAL; } else { ret = qemu_file_get_error(f); } } + /* + * Set this flag unconditionally so we'll catch further attempts to + * start additional threads via an appropriate assert() + */ + qatomic_set(&mis->load_threads_abort, true); /* * Try to read in the VMDESC section as well, so that dumping tools that diff --git a/migration/savevm.h b/migration/savevm.h index XXXXXXX..XXXXXXX 100644 --- a/migration/savevm.h +++ b/migration/savevm.h @@ -XXX,XX +XXX,XX @@ void qemu_savevm_live_state(QEMUFile *f); int qemu_save_device_state(QEMUFile *f); int qemu_loadvm_state(QEMUFile *f); -void qemu_loadvm_state_cleanup(void); +void qemu_loadvm_state_cleanup(MigrationIncomingState *mis); int qemu_loadvm_state_main(QEMUFile *f, MigrationIncomingState *mis); int qemu_load_device_state(QEMUFile *f); int qemu_loadvm_approve_switchover(void); From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Read packet header first so in the future we will be able to differentiate between a RAM multifd packet and a device state multifd packet. Since these two are of different size we can't read the packet body until we know which packet type it is. Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- migration/multifd.c | 55 ++++++++++++++++++++++++++++++++++++--------- migration/multifd.h | 5 +++++ 2 files changed, 49 insertions(+), 11 deletions(-) diff --git a/migration/multifd.c b/migration/multifd.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -XXX,XX +XXX,XX @@ void multifd_send_fill_packet(MultiFDSendParams *p) memset(packet, 0, p->packet_len); - packet->magic = cpu_to_be32(MULTIFD_MAGIC); - packet->version = cpu_to_be32(MULTIFD_VERSION); + packet->hdr.magic = cpu_to_be32(MULTIFD_MAGIC); + packet->hdr.version = cpu_to_be32(MULTIFD_VERSION); - packet->flags = cpu_to_be32(p->flags); + packet->hdr.flags = cpu_to_be32(p->flags); packet->next_packet_size = cpu_to_be32(p->next_packet_size); packet_num = qatomic_fetch_inc(&multifd_send_state->packet_num); @@ -XXX,XX +XXX,XX @@ void multifd_send_fill_packet(MultiFDSendParams *p) p->flags, p->next_packet_size); } -static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) +static int multifd_recv_unfill_packet_header(MultiFDRecvParams *p, + const MultiFDPacketHdr_t *hdr, + Error **errp) { - const MultiFDPacket_t *packet = p->packet; - uint32_t magic = be32_to_cpu(packet->magic); - uint32_t version = be32_to_cpu(packet->version); - int ret = 0; + uint32_t magic = be32_to_cpu(hdr->magic); + uint32_t version = be32_to_cpu(hdr->version); if (magic != MULTIFD_MAGIC) { error_setg(errp, "multifd: received packet magic %x, expected %x", @@ -XXX,XX +XXX,XX @@ static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) return -1; } - p->flags = be32_to_cpu(packet->flags); + p->flags = be32_to_cpu(hdr->flags); + + return 0; +} + +static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) +{ + const MultiFDPacket_t *packet = p->packet; + int ret = 0; + p->next_packet_size = be32_to_cpu(packet->next_packet_size); p->packet_num = be64_to_cpu(packet->packet_num); p->packets_recved++; @@ -XXX,XX +XXX,XX @@ static void *multifd_recv_thread(void *opaque) } while (true) { + MultiFDPacketHdr_t hdr; uint32_t flags = 0; bool has_data = false; + uint8_t *pkt_buf; + size_t pkt_len; + p->normal_num = 0; if (use_packets) { struct iovec iov = { - .iov_base = (void *)p->packet, - .iov_len = p->packet_len + .iov_base = (void *)&hdr, + .iov_len = sizeof(hdr) }; if (multifd_recv_should_exit()) { @@ -XXX,XX +XXX,XX @@ static void *multifd_recv_thread(void *opaque) break; } + ret = multifd_recv_unfill_packet_header(p, &hdr, &local_err); + if (ret) { + break; + } + + pkt_buf = (uint8_t *)p->packet + sizeof(hdr); + pkt_len = p->packet_len - sizeof(hdr); + + ret = qio_channel_read_all_eof(p->c, (char *)pkt_buf, pkt_len, + &local_err); + if (!ret) { + /* EOF */ + error_setg(&local_err, "multifd: unexpected EOF after packet header"); + break; + } + + if (ret == -1) { + break; + } + qemu_mutex_lock(&p->mutex); ret = multifd_recv_unfill_packet(p, &local_err); if (ret) { diff --git a/migration/multifd.h b/migration/multifd.h index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -XXX,XX +XXX,XX @@ typedef struct { uint32_t magic; uint32_t version; uint32_t flags; +} __attribute__((packed)) MultiFDPacketHdr_t; + +typedef struct { + MultiFDPacketHdr_t hdr; + /* maximum number of allocated pages */ uint32_t pages_alloc; /* non zero pages */ From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Add a basic support for receiving device state via multifd channels - channels that are shared with RAM transfers. Depending whether MULTIFD_FLAG_DEVICE_STATE flag is present or not in the packet header either device state (MultiFDPacketDeviceState_t) or RAM data (existing MultiFDPacket_t) is read. The received device state data is provided to qemu_loadvm_load_state_buffer() function for processing in the device's load_state_buffer handler. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- migration/multifd.c | 101 +++++++++++++++++++++++++++++++++++++++----- migration/multifd.h | 19 ++++++++- 2 files changed, 108 insertions(+), 12 deletions(-) diff --git a/migration/multifd.c b/migration/multifd.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -XXX,XX +XXX,XX @@ #include "file.h" #include "migration.h" #include "migration-stats.h" +#include "savevm.h" #include "socket.h" #include "tls.h" #include "qemu-file.h" @@ -XXX,XX +XXX,XX @@ static int multifd_recv_unfill_packet_header(MultiFDRecvParams *p, return 0; } -static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) +static int multifd_recv_unfill_packet_device_state(MultiFDRecvParams *p, + Error **errp) +{ + MultiFDPacketDeviceState_t *packet = p->packet_dev_state; + + packet->instance_id = be32_to_cpu(packet->instance_id); + p->next_packet_size = be32_to_cpu(packet->next_packet_size); + + return 0; +} + +static int multifd_recv_unfill_packet_ram(MultiFDRecvParams *p, Error **errp) { const MultiFDPacket_t *packet = p->packet; int ret = 0; p->next_packet_size = be32_to_cpu(packet->next_packet_size); p->packet_num = be64_to_cpu(packet->packet_num); - p->packets_recved++; /* Always unfill, old QEMUs (<9.0) send data along with SYNC */ ret = multifd_ram_unfill_packet(p, errp); @@ -XXX,XX +XXX,XX @@ static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) return ret; } +static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) +{ + p->packets_recved++; + + if (p->flags & MULTIFD_FLAG_DEVICE_STATE) { + return multifd_recv_unfill_packet_device_state(p, errp); + } + + return multifd_recv_unfill_packet_ram(p, errp); +} + static bool multifd_send_should_exit(void) { return qatomic_read(&multifd_send_state->exiting); @@ -XXX,XX +XXX,XX @@ static void multifd_recv_cleanup_channel(MultiFDRecvParams *p) p->packet_len = 0; g_free(p->packet); p->packet = NULL; + g_clear_pointer(&p->packet_dev_state, g_free); g_free(p->normal); p->normal = NULL; g_free(p->zero); @@ -XXX,XX +XXX,XX @@ void multifd_recv_sync_main(void) trace_multifd_recv_sync_main(multifd_recv_state->packet_num); } +static int multifd_device_state_recv(MultiFDRecvParams *p, Error **errp) +{ + g_autofree char *dev_state_buf = NULL; + int ret; + + dev_state_buf = g_malloc(p->next_packet_size); + + ret = qio_channel_read_all(p->c, dev_state_buf, p->next_packet_size, errp); + if (ret != 0) { + return ret; + } + + if (p->packet_dev_state->idstr[sizeof(p->packet_dev_state->idstr) - 1] + != 0) { + error_setg(errp, "unterminated multifd device state idstr"); + return -1; + } + + if (!qemu_loadvm_load_state_buffer(p->packet_dev_state->idstr, + p->packet_dev_state->instance_id, + dev_state_buf, p->next_packet_size, + errp)) { + ret = -1; + } + + return ret; +} + static void *multifd_recv_thread(void *opaque) { MigrationState *s = migrate_get_current(); @@ -XXX,XX +XXX,XX @@ static void *multifd_recv_thread(void *opaque) while (true) { MultiFDPacketHdr_t hdr; uint32_t flags = 0; + bool is_device_state = false; bool has_data = false; uint8_t *pkt_buf; size_t pkt_len; @@ -XXX,XX +XXX,XX @@ static void *multifd_recv_thread(void *opaque) break; } - pkt_buf = (uint8_t *)p->packet + sizeof(hdr); - pkt_len = p->packet_len - sizeof(hdr); + is_device_state = p->flags & MULTIFD_FLAG_DEVICE_STATE; + if (is_device_state) { + pkt_buf = (uint8_t *)p->packet_dev_state + sizeof(hdr); + pkt_len = sizeof(*p->packet_dev_state) - sizeof(hdr); + } else { + pkt_buf = (uint8_t *)p->packet + sizeof(hdr); + pkt_len = p->packet_len - sizeof(hdr); + } ret = qio_channel_read_all_eof(p->c, (char *)pkt_buf, pkt_len, &local_err); @@ -XXX,XX +XXX,XX @@ static void *multifd_recv_thread(void *opaque) /* recv methods don't know how to handle the SYNC flag */ p->flags &= ~MULTIFD_FLAG_SYNC; - /* - * Even if it's a SYNC packet, this needs to be set - * because older QEMUs (<9.0) still send data along with - * the SYNC packet. - */ - has_data = p->normal_num || p->zero_num; + if (is_device_state) { + has_data = p->next_packet_size > 0; + } else { + /* + * Even if it's a SYNC packet, this needs to be set + * because older QEMUs (<9.0) still send data along with + * the SYNC packet. + */ + has_data = p->normal_num || p->zero_num; + } + qemu_mutex_unlock(&p->mutex); } else { /* @@ -XXX,XX +XXX,XX @@ static void *multifd_recv_thread(void *opaque) } if (has_data) { - ret = multifd_recv_state->ops->recv(p, &local_err); + if (is_device_state) { + assert(use_packets); + ret = multifd_device_state_recv(p, &local_err); + } else { + ret = multifd_recv_state->ops->recv(p, &local_err); + } if (ret != 0) { break; } + } else if (is_device_state) { + error_setg(&local_err, + "multifd: received empty device state packet"); + break; } if (use_packets) { if (flags & MULTIFD_FLAG_SYNC) { + if (is_device_state) { + error_setg(&local_err, + "multifd: received SYNC device state packet"); + break; + } + qemu_sem_post(&multifd_recv_state->sem_sync); qemu_sem_wait(&p->sem_sync); } @@ -XXX,XX +XXX,XX @@ int multifd_recv_setup(Error **errp) p->packet_len = sizeof(MultiFDPacket_t) + sizeof(uint64_t) * page_count; p->packet = g_malloc0(p->packet_len); + p->packet_dev_state = g_malloc0(sizeof(*p->packet_dev_state)); } p->name = g_strdup_printf(MIGRATION_THREAD_DST_MULTIFD, i); p->normal = g_new0(ram_addr_t, page_count); diff --git a/migration/multifd.h b/migration/multifd.h index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -XXX,XX +XXX,XX @@ MultiFDRecvData *multifd_get_recv_data(void); #define MULTIFD_FLAG_UADK (8 << 1) #define MULTIFD_FLAG_QATZIP (16 << 1) +/* + * If set it means that this packet contains device state + * (MultiFDPacketDeviceState_t), not RAM data (MultiFDPacket_t). + */ +#define MULTIFD_FLAG_DEVICE_STATE (32 << 1) + /* This value needs to be a multiple of qemu_target_page_size() */ #define MULTIFD_PACKET_SIZE (512 * 1024) @@ -XXX,XX +XXX,XX @@ typedef struct { uint64_t offset[]; } __attribute__((packed)) MultiFDPacket_t; +typedef struct { + MultiFDPacketHdr_t hdr; + + char idstr[256]; + uint32_t instance_id; + + /* size of the next packet that contains the actual data */ + uint32_t next_packet_size; +} __attribute__((packed)) MultiFDPacketDeviceState_t; + typedef struct { /* number of used pages */ uint32_t num; @@ -XXX,XX +XXX,XX @@ typedef struct { /* thread local variables. No locking required */ - /* pointer to the packet */ + /* pointers to the possible packet types */ MultiFDPacket_t *packet; + MultiFDPacketDeviceState_t *packet_dev_state; /* size of the next packet that contains pages */ uint32_t next_packet_size; /* packets received through this channel */ From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> multifd_send() function is currently not thread safe, make it thread safe by holding a lock during its execution. This way it will be possible to safely call it concurrently from multiple threads. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- migration/multifd.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/migration/multifd.c b/migration/multifd.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -XXX,XX +XXX,XX @@ typedef struct { struct { MultiFDSendParams *params; + + /* multifd_send() body is not thread safe, needs serialization */ + QemuMutex multifd_send_mutex; + /* * Global number of generated multifd packets. * @@ -XXX,XX +XXX,XX @@ bool multifd_send(MultiFDSendData **send_data) return false; } + QEMU_LOCK_GUARD(&multifd_send_state->multifd_send_mutex); + /* We wait here, until at least one channel is ready */ qemu_sem_wait(&multifd_send_state->channels_ready); @@ -XXX,XX +XXX,XX @@ static void multifd_send_cleanup_state(void) socket_cleanup_outgoing_migration(); qemu_sem_destroy(&multifd_send_state->channels_created); qemu_sem_destroy(&multifd_send_state->channels_ready); + qemu_mutex_destroy(&multifd_send_state->multifd_send_mutex); g_free(multifd_send_state->params); multifd_send_state->params = NULL; g_free(multifd_send_state); @@ -XXX,XX +XXX,XX @@ bool multifd_send_setup(void) thread_count = migrate_multifd_channels(); multifd_send_state = g_malloc0(sizeof(*multifd_send_state)); multifd_send_state->params = g_new0(MultiFDSendParams, thread_count); + qemu_mutex_init(&multifd_send_state->multifd_send_mutex); qemu_sem_init(&multifd_send_state->channels_created, 0); qemu_sem_init(&multifd_send_state->channels_ready, 0); qatomic_set(&multifd_send_state->exiting, 0); From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This way if there are fields there that needs explicit disposal (like, for example, some attached buffers) they will be handled appropriately. Add a related assert to multifd_set_payload_type() in order to make sure that this function is only used to fill a previously empty MultiFDSendData with some payload, not the other way around. Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- migration/multifd-nocomp.c | 3 +-- migration/multifd.c | 31 ++++++++++++++++++++++++++++--- migration/multifd.h | 5 +++++ 3 files changed, 34 insertions(+), 5 deletions(-) diff --git a/migration/multifd-nocomp.c b/migration/multifd-nocomp.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd-nocomp.c +++ b/migration/multifd-nocomp.c @@ -XXX,XX +XXX,XX @@ void multifd_ram_save_setup(void) void multifd_ram_save_cleanup(void) { - g_free(multifd_ram_send); - multifd_ram_send = NULL; + g_clear_pointer(&multifd_ram_send, multifd_send_data_free); } static void multifd_set_file_bitmap(MultiFDSendParams *p) diff --git a/migration/multifd.c b/migration/multifd.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -XXX,XX +XXX,XX @@ MultiFDSendData *multifd_send_data_alloc(void) return g_malloc0(size_minus_payload + max_payload_size); } +void multifd_send_data_clear(MultiFDSendData *data) +{ + if (multifd_payload_empty(data)) { + return; + } + + switch (data->type) { + default: + /* Nothing to do */ + break; + } + + data->type = MULTIFD_PAYLOAD_NONE; +} + +void multifd_send_data_free(MultiFDSendData *data) +{ + if (!data) { + return; + } + + multifd_send_data_clear(data); + + g_free(data); +} + static bool multifd_use_packets(void) { return !migrate_mapped_ram(); @@ -XXX,XX +XXX,XX @@ static bool multifd_send_cleanup_channel(MultiFDSendParams *p, Error **errp) qemu_sem_destroy(&p->sem_sync); g_free(p->name); p->name = NULL; - g_free(p->data); - p->data = NULL; + g_clear_pointer(&p->data, multifd_send_data_free); p->packet_len = 0; g_free(p->packet); p->packet = NULL; @@ -XXX,XX +XXX,XX @@ static void *multifd_send_thread(void *opaque) (uint64_t)p->next_packet_size + p->packet_len); p->next_packet_size = 0; - multifd_set_payload_type(p->data, MULTIFD_PAYLOAD_NONE); + multifd_send_data_clear(p->data); /* * Making sure p->data is published before saying "we're diff --git a/migration/multifd.h b/migration/multifd.h index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -XXX,XX +XXX,XX @@ static inline bool multifd_payload_empty(MultiFDSendData *data) static inline void multifd_set_payload_type(MultiFDSendData *data, MultiFDPayloadType type) { + assert(multifd_payload_empty(data)); + assert(type != MULTIFD_PAYLOAD_NONE); + data->type = type; } @@ -XXX,XX +XXX,XX @@ static inline void multifd_send_prepare_header(MultiFDSendParams *p) void multifd_channel_connect(MultiFDSendParams *p, QIOChannel *ioc); bool multifd_send(MultiFDSendData **send_data); MultiFDSendData *multifd_send_data_alloc(void); +void multifd_send_data_clear(MultiFDSendData *data); +void multifd_send_data_free(MultiFDSendData *data); static inline uint32_t multifd_ram_page_size(void) { From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> A new function multifd_queue_device_state() is provided for device to queue its state for transmission via a multifd channel. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/migration/misc.h | 4 ++ migration/meson.build | 1 + migration/multifd-device-state.c | 118 +++++++++++++++++++++++++++++++ migration/multifd-nocomp.c | 14 +++- migration/multifd.c | 42 +++++++++-- migration/multifd.h | 34 ++++++--- 6 files changed, 197 insertions(+), 16 deletions(-) create mode 100644 migration/multifd-device-state.c diff --git a/include/migration/misc.h b/include/migration/misc.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/misc.h +++ b/include/migration/misc.h @@ -XXX,XX +XXX,XX @@ bool migrate_is_uri(const char *uri); bool migrate_uri_parse(const char *uri, MigrationChannel **channel, Error **errp); +/* migration/multifd-device-state.c */ +bool multifd_queue_device_state(char *idstr, uint32_t instance_id, + char *data, size_t len); + #endif diff --git a/migration/meson.build b/migration/meson.build index XXXXXXX..XXXXXXX 100644 --- a/migration/meson.build +++ b/migration/meson.build @@ -XXX,XX +XXX,XX @@ system_ss.add(files( 'migration-hmp-cmds.c', 'migration.c', 'multifd.c', + 'multifd-device-state.c', 'multifd-nocomp.c', 'multifd-zlib.c', 'multifd-zero-page.c', diff --git a/migration/multifd-device-state.c b/migration/multifd-device-state.c new file mode 100644 index XXXXXXX..XXXXXXX --- /dev/null +++ b/migration/multifd-device-state.c @@ -XXX,XX +XXX,XX @@ +/* + * Multifd device state migration + * + * Copyright (C) 2024,2025 Oracle and/or its affiliates. + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ + +#include "qemu/osdep.h" +#include "qemu/lockable.h" +#include "migration/misc.h" +#include "multifd.h" + +static struct { + QemuMutex queue_job_mutex; + + MultiFDSendData *send_data; +} *multifd_send_device_state; + +size_t multifd_device_state_payload_size(void) +{ + return sizeof(MultiFDDeviceState_t); +} + +void multifd_device_state_send_setup(void) +{ + assert(!multifd_send_device_state); + multifd_send_device_state = g_malloc(sizeof(*multifd_send_device_state)); + + qemu_mutex_init(&multifd_send_device_state->queue_job_mutex); + + multifd_send_device_state->send_data = multifd_send_data_alloc(); +} + +void multifd_device_state_send_cleanup(void) +{ + g_clear_pointer(&multifd_send_device_state->send_data, + multifd_send_data_free); + + qemu_mutex_destroy(&multifd_send_device_state->queue_job_mutex); + + g_clear_pointer(&multifd_send_device_state, g_free); +} + +void multifd_send_data_clear_device_state(MultiFDDeviceState_t *device_state) +{ + g_clear_pointer(&device_state->idstr, g_free); + g_clear_pointer(&device_state->buf, g_free); +} + +static void multifd_device_state_fill_packet(MultiFDSendParams *p) +{ + MultiFDDeviceState_t *device_state = &p->data->u.device_state; + MultiFDPacketDeviceState_t *packet = p->packet_device_state; + + packet->hdr.flags = cpu_to_be32(p->flags); + strncpy(packet->idstr, device_state->idstr, sizeof(packet->idstr) - 1); + packet->idstr[sizeof(packet->idstr) - 1] = 0; + packet->instance_id = cpu_to_be32(device_state->instance_id); + packet->next_packet_size = cpu_to_be32(p->next_packet_size); +} + +static void multifd_prepare_header_device_state(MultiFDSendParams *p) +{ + p->iov[0].iov_len = sizeof(*p->packet_device_state); + p->iov[0].iov_base = p->packet_device_state; + p->iovs_num++; +} + +void multifd_device_state_send_prepare(MultiFDSendParams *p) +{ + MultiFDDeviceState_t *device_state = &p->data->u.device_state; + + assert(multifd_payload_device_state(p->data)); + + multifd_prepare_header_device_state(p); + + assert(!(p->flags & MULTIFD_FLAG_SYNC)); + + p->next_packet_size = device_state->buf_len; + if (p->next_packet_size > 0) { + p->iov[p->iovs_num].iov_base = device_state->buf; + p->iov[p->iovs_num].iov_len = p->next_packet_size; + p->iovs_num++; + } + + p->flags |= MULTIFD_FLAG_NOCOMP | MULTIFD_FLAG_DEVICE_STATE; + + multifd_device_state_fill_packet(p); +} + +bool multifd_queue_device_state(char *idstr, uint32_t instance_id, + char *data, size_t len) +{ + /* Device state submissions can come from multiple threads */ + QEMU_LOCK_GUARD(&multifd_send_device_state->queue_job_mutex); + MultiFDDeviceState_t *device_state; + + assert(multifd_payload_empty(multifd_send_device_state->send_data)); + + multifd_set_payload_type(multifd_send_device_state->send_data, + MULTIFD_PAYLOAD_DEVICE_STATE); + device_state = &multifd_send_device_state->send_data->u.device_state; + device_state->idstr = g_strdup(idstr); + device_state->instance_id = instance_id; + device_state->buf = g_memdup2(data, len); + device_state->buf_len = len; + + if (!multifd_send(&multifd_send_device_state->send_data)) { + multifd_send_data_clear(multifd_send_device_state->send_data); + return false; + } + + return true; +} diff --git a/migration/multifd-nocomp.c b/migration/multifd-nocomp.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd-nocomp.c +++ b/migration/multifd-nocomp.c @@ -XXX,XX +XXX,XX @@ #include "exec/ramblock.h" #include "exec/target_page.h" #include "file.h" +#include "migration-stats.h" #include "multifd.h" #include "options.h" #include "qapi/error.h" @@ -XXX,XX +XXX,XX @@ static void multifd_nocomp_send_cleanup(MultiFDSendParams *p, Error **errp) return; } +static void multifd_ram_prepare_header(MultiFDSendParams *p) +{ + p->iov[0].iov_len = p->packet_len; + p->iov[0].iov_base = p->packet; + p->iovs_num++; +} + static void multifd_send_prepare_iovs(MultiFDSendParams *p) { MultiFDPages_t *pages = &p->data->u.ram; @@ -XXX,XX +XXX,XX @@ static int multifd_nocomp_send_prepare(MultiFDSendParams *p, Error **errp) * Only !zerocopy needs the header in IOV; zerocopy will * send it separately. */ - multifd_send_prepare_header(p); + multifd_ram_prepare_header(p); } multifd_send_prepare_iovs(p); @@ -XXX,XX +XXX,XX @@ static int multifd_nocomp_send_prepare(MultiFDSendParams *p, Error **errp) if (ret != 0) { return -1; } + + stat64_add(&mig_stats.multifd_bytes, p->packet_len); } return 0; @@ -XXX,XX +XXX,XX @@ int multifd_ram_flush_and_sync(QEMUFile *f) bool multifd_send_prepare_common(MultiFDSendParams *p) { MultiFDPages_t *pages = &p->data->u.ram; - multifd_send_prepare_header(p); + multifd_ram_prepare_header(p); multifd_send_zero_page_detect(p); if (!pages->normal_num) { diff --git a/migration/multifd.c b/migration/multifd.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -XXX,XX +XXX,XX @@ #include "qemu/osdep.h" #include "qemu/cutils.h" +#include "qemu/iov.h" #include "qemu/rcu.h" #include "exec/target_page.h" #include "system/system.h" @@ -XXX,XX +XXX,XX @@ #include "qemu/error-report.h" #include "qapi/error.h" #include "file.h" +#include "migration/misc.h" #include "migration.h" #include "migration-stats.h" #include "savevm.h" @@ -XXX,XX +XXX,XX @@ MultiFDSendData *multifd_send_data_alloc(void) * added to the union in the future are larger than * (MultiFDPages_t + flex array). */ - max_payload_size = MAX(multifd_ram_payload_size(), sizeof(MultiFDPayload)); + max_payload_size = MAX(multifd_ram_payload_size(), + multifd_device_state_payload_size()); + max_payload_size = MAX(max_payload_size, sizeof(MultiFDPayload)); /* * Account for any holes the compiler might insert. We can't pack @@ -XXX,XX +XXX,XX @@ void multifd_send_data_clear(MultiFDSendData *data) } switch (data->type) { + case MULTIFD_PAYLOAD_DEVICE_STATE: + multifd_send_data_clear_device_state(&data->u.device_state); + break; default: /* Nothing to do */ break; @@ -XXX,XX +XXX,XX @@ static int multifd_recv_initial_packet(QIOChannel *c, Error **errp) return msg.id; } +/* Fills a RAM multifd packet */ void multifd_send_fill_packet(MultiFDSendParams *p) { MultiFDPacket_t *packet = p->packet; @@ -XXX,XX +XXX,XX @@ static bool multifd_send_cleanup_channel(MultiFDSendParams *p, Error **errp) p->name = NULL; g_clear_pointer(&p->data, multifd_send_data_free); p->packet_len = 0; + g_clear_pointer(&p->packet_device_state, g_free); g_free(p->packet); p->packet = NULL; multifd_send_state->ops->send_cleanup(p, errp); @@ -XXX,XX +XXX,XX @@ static void multifd_send_cleanup_state(void) { file_cleanup_outgoing_migration(); socket_cleanup_outgoing_migration(); + multifd_device_state_send_cleanup(); qemu_sem_destroy(&multifd_send_state->channels_created); qemu_sem_destroy(&multifd_send_state->channels_ready); qemu_mutex_destroy(&multifd_send_state->multifd_send_mutex); @@ -XXX,XX +XXX,XX @@ static void *multifd_send_thread(void *opaque) * qatomic_store_release() in multifd_send(). */ if (qatomic_load_acquire(&p->pending_job)) { + bool is_device_state = multifd_payload_device_state(p->data); + size_t total_size; + p->flags = 0; p->iovs_num = 0; assert(!multifd_payload_empty(p->data)); - ret = multifd_send_state->ops->send_prepare(p, &local_err); - if (ret != 0) { - break; + if (is_device_state) { + multifd_device_state_send_prepare(p); + } else { + ret = multifd_send_state->ops->send_prepare(p, &local_err); + if (ret != 0) { + break; + } } + /* + * The packet header in the zerocopy RAM case is accounted for + * in multifd_nocomp_send_prepare() - where it is actually + * being sent. + */ + total_size = iov_size(p->iov, p->iovs_num); + if (migrate_mapped_ram()) { + assert(!is_device_state); + ret = file_write_ramblock_iov(p->c, p->iov, p->iovs_num, &p->data->u.ram, &local_err); } else { @@ -XXX,XX +XXX,XX @@ static void *multifd_send_thread(void *opaque) break; } - stat64_add(&mig_stats.multifd_bytes, - (uint64_t)p->next_packet_size + p->packet_len); + stat64_add(&mig_stats.multifd_bytes, total_size); p->next_packet_size = 0; multifd_send_data_clear(p->data); @@ -XXX,XX +XXX,XX @@ bool multifd_send_setup(void) p->packet_len = sizeof(MultiFDPacket_t) + sizeof(uint64_t) * page_count; p->packet = g_malloc0(p->packet_len); + p->packet_device_state = g_malloc0(sizeof(*p->packet_device_state)); + p->packet_device_state->hdr.magic = cpu_to_be32(MULTIFD_MAGIC); + p->packet_device_state->hdr.version = cpu_to_be32(MULTIFD_VERSION); } p->name = g_strdup_printf(MIGRATION_THREAD_SRC_MULTIFD, i); p->write_flags = 0; @@ -XXX,XX +XXX,XX @@ bool multifd_send_setup(void) assert(p->iov); } + multifd_device_state_send_setup(); + return true; err: diff --git a/migration/multifd.h b/migration/multifd.h index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -XXX,XX +XXX,XX @@ struct MultiFDRecvData { off_t file_offset; }; +typedef struct { + char *idstr; + uint32_t instance_id; + char *buf; + size_t buf_len; +} MultiFDDeviceState_t; + typedef enum { MULTIFD_PAYLOAD_NONE, MULTIFD_PAYLOAD_RAM, + MULTIFD_PAYLOAD_DEVICE_STATE, } MultiFDPayloadType; typedef union MultiFDPayload { MultiFDPages_t ram; + MultiFDDeviceState_t device_state; } MultiFDPayload; struct MultiFDSendData { @@ -XXX,XX +XXX,XX @@ static inline bool multifd_payload_empty(MultiFDSendData *data) return data->type == MULTIFD_PAYLOAD_NONE; } +static inline bool multifd_payload_device_state(MultiFDSendData *data) +{ + return data->type == MULTIFD_PAYLOAD_DEVICE_STATE; +} + static inline void multifd_set_payload_type(MultiFDSendData *data, MultiFDPayloadType type) { @@ -XXX,XX +XXX,XX @@ typedef struct { /* thread local variables. No locking required */ - /* pointer to the packet */ + /* pointers to the possible packet types */ MultiFDPacket_t *packet; + MultiFDPacketDeviceState_t *packet_device_state; /* size of the next packet that contains pages */ uint32_t next_packet_size; /* packets sent through this channel */ @@ -XXX,XX +XXX,XX @@ bool multifd_send_prepare_common(MultiFDSendParams *p); void multifd_send_zero_page_detect(MultiFDSendParams *p); void multifd_recv_zero_page_process(MultiFDRecvParams *p); -static inline void multifd_send_prepare_header(MultiFDSendParams *p) -{ - p->iov[0].iov_len = p->packet_len; - p->iov[0].iov_base = p->packet; - p->iovs_num++; -} - void multifd_channel_connect(MultiFDSendParams *p, QIOChannel *ioc); bool multifd_send(MultiFDSendData **send_data); MultiFDSendData *multifd_send_data_alloc(void); @@ -XXX,XX +XXX,XX @@ bool multifd_ram_sync_per_section(void); size_t multifd_ram_payload_size(void); void multifd_ram_fill_packet(MultiFDSendParams *p); int multifd_ram_unfill_packet(MultiFDRecvParams *p, Error **errp); + +size_t multifd_device_state_payload_size(void); + +void multifd_send_data_clear_device_state(MultiFDDeviceState_t *device_state); + +void multifd_device_state_send_setup(void); +void multifd_device_state_send_cleanup(void); + +void multifd_device_state_send_prepare(MultiFDSendParams *p); + #endif From: Peter Xu <peterx@redhat.com> The newly introduced device state buffer can be used for either storing VFIO's read() raw data, but already also possible to store generic device states. After noticing that device states may not easily provide a max buffer size (also the fact that RAM MultiFDPages_t after all also want to have flexibility on managing offset[] array), it may not be a good idea to stick with union on MultiFDSendData.. as it won't play well with such flexibility. Switch MultiFDSendData to a struct. It won't consume a lot more space in reality, after all the real buffers were already dynamically allocated, so it's so far only about the two structs (pages, device_state) that will be duplicated, but they're small. With this, we can remove the pretty hard to understand alloc size logic. Because now we can allocate offset[] together with the SendData, and properly free it when the SendData is freed. Signed-off-by: Peter Xu <peterx@redhat.com> [MSS: Make sure to clear possible device state payload before freeing MultiFDSendData, remove placeholders for other patches not included] Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- migration/multifd-device-state.c | 5 ----- migration/multifd-nocomp.c | 13 ++++++------- migration/multifd.c | 25 +++++++------------------ migration/multifd.h | 15 +++++++++------ 4 files changed, 22 insertions(+), 36 deletions(-) diff --git a/migration/multifd-device-state.c b/migration/multifd-device-state.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd-device-state.c +++ b/migration/multifd-device-state.c @@ -XXX,XX +XXX,XX @@ static struct { MultiFDSendData *send_data; } *multifd_send_device_state; -size_t multifd_device_state_payload_size(void) -{ - return sizeof(MultiFDDeviceState_t); -} - void multifd_device_state_send_setup(void) { assert(!multifd_send_device_state); diff --git a/migration/multifd-nocomp.c b/migration/multifd-nocomp.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd-nocomp.c +++ b/migration/multifd-nocomp.c @@ -XXX,XX +XXX,XX @@ static MultiFDSendData *multifd_ram_send; -size_t multifd_ram_payload_size(void) +void multifd_ram_payload_alloc(MultiFDPages_t *pages) { - uint32_t n = multifd_ram_page_count(); + pages->offset = g_new0(ram_addr_t, multifd_ram_page_count()); +} - /* - * We keep an array of page offsets at the end of MultiFDPages_t, - * add space for it in the allocation. - */ - return sizeof(MultiFDPages_t) + n * sizeof(ram_addr_t); +void multifd_ram_payload_free(MultiFDPages_t *pages) +{ + g_clear_pointer(&pages->offset, g_free); } void multifd_ram_save_setup(void) diff --git a/migration/multifd.c b/migration/multifd.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -XXX,XX +XXX,XX @@ struct { MultiFDSendData *multifd_send_data_alloc(void) { - size_t max_payload_size, size_minus_payload; + MultiFDSendData *new = g_new0(MultiFDSendData, 1); - /* - * MultiFDPages_t has a flexible array at the end, account for it - * when allocating MultiFDSendData. Use max() in case other types - * added to the union in the future are larger than - * (MultiFDPages_t + flex array). - */ - max_payload_size = MAX(multifd_ram_payload_size(), - multifd_device_state_payload_size()); - max_payload_size = MAX(max_payload_size, sizeof(MultiFDPayload)); + multifd_ram_payload_alloc(&new->u.ram); + /* Device state allocates its payload on-demand */ - /* - * Account for any holes the compiler might insert. We can't pack - * the structure because that misaligns the members and triggers - * Waddress-of-packed-member. - */ - size_minus_payload = sizeof(MultiFDSendData) - sizeof(MultiFDPayload); - - return g_malloc0(size_minus_payload + max_payload_size); + return new; } void multifd_send_data_clear(MultiFDSendData *data) @@ -XXX,XX +XXX,XX @@ void multifd_send_data_free(MultiFDSendData *data) return; } + /* This also free's device state payload */ multifd_send_data_clear(data); + multifd_ram_payload_free(&data->u.ram); + g_free(data); } diff --git a/migration/multifd.h b/migration/multifd.h index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -XXX,XX +XXX,XX @@ typedef struct { uint32_t num; /* number of normal pages */ uint32_t normal_num; + /* + * Pointer to the ramblock. NOTE: it's caller's responsibility to make + * sure the pointer is always valid! + */ RAMBlock *block; - /* offset of each page */ - ram_addr_t offset[]; + /* offset array of each page, managed by multifd */ + ram_addr_t *offset; } MultiFDPages_t; struct MultiFDRecvData { @@ -XXX,XX +XXX,XX @@ typedef enum { MULTIFD_PAYLOAD_DEVICE_STATE, } MultiFDPayloadType; -typedef union MultiFDPayload { +typedef struct MultiFDPayload { MultiFDPages_t ram; MultiFDDeviceState_t device_state; } MultiFDPayload; @@ -XXX,XX +XXX,XX @@ void multifd_ram_save_cleanup(void); int multifd_ram_flush_and_sync(QEMUFile *f); bool multifd_ram_sync_per_round(void); bool multifd_ram_sync_per_section(void); -size_t multifd_ram_payload_size(void); +void multifd_ram_payload_alloc(MultiFDPages_t *pages); +void multifd_ram_payload_free(MultiFDPages_t *pages); void multifd_ram_fill_packet(MultiFDSendParams *p); int multifd_ram_unfill_packet(MultiFDRecvParams *p, Error **errp); -size_t multifd_device_state_payload_size(void); - void multifd_send_data_clear_device_state(MultiFDDeviceState_t *device_state); void multifd_device_state_send_setup(void); From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Since device state transfer via multifd channels requires multifd channels with packets and is currently not compatible with multifd compression add an appropriate query function so device can learn whether it can actually make use of it. Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/migration/misc.h | 1 + migration/multifd-device-state.c | 7 +++++++ 2 files changed, 8 insertions(+) diff --git a/include/migration/misc.h b/include/migration/misc.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/misc.h +++ b/include/migration/misc.h @@ -XXX,XX +XXX,XX @@ bool migrate_uri_parse(const char *uri, MigrationChannel **channel, /* migration/multifd-device-state.c */ bool multifd_queue_device_state(char *idstr, uint32_t instance_id, char *data, size_t len); +bool multifd_device_state_supported(void); #endif diff --git a/migration/multifd-device-state.c b/migration/multifd-device-state.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd-device-state.c +++ b/migration/multifd-device-state.c @@ -XXX,XX +XXX,XX @@ #include "qemu/lockable.h" #include "migration/misc.h" #include "multifd.h" +#include "options.h" static struct { QemuMutex queue_job_mutex; @@ -XXX,XX +XXX,XX @@ bool multifd_queue_device_state(char *idstr, uint32_t instance_id, return true; } + +bool multifd_device_state_supported(void) +{ + return migrate_multifd() && !migrate_mapped_ram() && + migrate_multifd_compression() == MULTIFD_COMPRESSION_NONE; +} From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This SaveVMHandler helps device provide its own asynchronous transmission of the remaining data at the end of a precopy phase via multifd channels, in parallel with the transfer done by save_live_complete_precopy handlers. These threads are launched only when multifd device state transfer is supported. Management of these threads in done in the multifd migration code, wrapping them in the generic thread pool. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- include/migration/misc.h | 17 ++++++ include/migration/register.h | 19 +++++++ include/qemu/typedefs.h | 3 ++ migration/multifd-device-state.c | 92 ++++++++++++++++++++++++++++++++ migration/savevm.c | 40 +++++++++++++- 5 files changed, 170 insertions(+), 1 deletion(-) diff --git a/include/migration/misc.h b/include/migration/misc.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/misc.h +++ b/include/migration/misc.h @@ -XXX,XX +XXX,XX @@ bool migrate_uri_parse(const char *uri, MigrationChannel **channel, Error **errp); /* migration/multifd-device-state.c */ +typedef struct SaveLiveCompletePrecopyThreadData { + SaveLiveCompletePrecopyThreadHandler hdlr; + char *idstr; + uint32_t instance_id; + void *handler_opaque; +} SaveLiveCompletePrecopyThreadData; + bool multifd_queue_device_state(char *idstr, uint32_t instance_id, char *data, size_t len); bool multifd_device_state_supported(void); +void +multifd_spawn_device_state_save_thread(SaveLiveCompletePrecopyThreadHandler hdlr, + char *idstr, uint32_t instance_id, + void *opaque); + +bool multifd_device_state_save_thread_should_exit(void); + +void multifd_abort_device_state_save_threads(void); +bool multifd_join_device_state_save_threads(void); + #endif diff --git a/include/migration/register.h b/include/migration/register.h index XXXXXXX..XXXXXXX 100644 --- a/include/migration/register.h +++ b/include/migration/register.h @@ -XXX,XX +XXX,XX @@ typedef struct SaveVMHandlers { */ int (*save_live_complete_precopy)(QEMUFile *f, void *opaque); + /** + * @save_live_complete_precopy_thread (invoked in a separate thread) + * + * Called at the end of a precopy phase from a separate worker thread + * in configurations where multifd device state transfer is supported + * in order to perform asynchronous transmission of the remaining data in + * parallel with @save_live_complete_precopy handlers. + * When postcopy is enabled, devices that support postcopy will skip this + * step. + * + * @d: a #SaveLiveCompletePrecopyThreadData containing parameters that the + * handler may need, including this device section idstr and instance_id, + * and opaque data pointer passed to register_savevm_live(). + * @errp: pointer to Error*, to store an error if it happens. + * + * Returns true to indicate success and false for errors. + */ + SaveLiveCompletePrecopyThreadHandler save_live_complete_precopy_thread; + /* This runs both outside and inside the BQL. */ /** diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h index XXXXXXX..XXXXXXX 100644 --- a/include/qemu/typedefs.h +++ b/include/qemu/typedefs.h @@ -XXX,XX +XXX,XX @@ typedef struct QString QString; typedef struct RAMBlock RAMBlock; typedef struct Range Range; typedef struct ReservedRegion ReservedRegion; +typedef struct SaveLiveCompletePrecopyThreadData SaveLiveCompletePrecopyThreadData; typedef struct SHPCDevice SHPCDevice; typedef struct SSIBus SSIBus; typedef struct TCGCPUOps TCGCPUOps; @@ -XXX,XX +XXX,XX @@ typedef struct IRQState *qemu_irq; typedef void (*qemu_irq_handler)(void *opaque, int n, int level); typedef bool (*MigrationLoadThread)(void *opaque, bool *should_quit, Error **errp); +typedef bool (*SaveLiveCompletePrecopyThreadHandler)(SaveLiveCompletePrecopyThreadData *d, + Error **errp); #endif /* QEMU_TYPEDEFS_H */ diff --git a/migration/multifd-device-state.c b/migration/multifd-device-state.c index XXXXXXX..XXXXXXX 100644 --- a/migration/multifd-device-state.c +++ b/migration/multifd-device-state.c @@ -XXX,XX +XXX,XX @@ */ #include "qemu/osdep.h" +#include "qapi/error.h" #include "qemu/lockable.h" +#include "block/thread-pool.h" +#include "migration.h" #include "migration/misc.h" #include "multifd.h" #include "options.h" @@ -XXX,XX +XXX,XX @@ static struct { QemuMutex queue_job_mutex; MultiFDSendData *send_data; + + ThreadPool *threads; + bool threads_abort; } *multifd_send_device_state; void multifd_device_state_send_setup(void) @@ -XXX,XX +XXX,XX @@ void multifd_device_state_send_setup(void) qemu_mutex_init(&multifd_send_device_state->queue_job_mutex); multifd_send_device_state->send_data = multifd_send_data_alloc(); + + multifd_send_device_state->threads = thread_pool_new(); + multifd_send_device_state->threads_abort = false; } void multifd_device_state_send_cleanup(void) { + g_clear_pointer(&multifd_send_device_state->threads, thread_pool_free); g_clear_pointer(&multifd_send_device_state->send_data, multifd_send_data_free); @@ -XXX,XX +XXX,XX @@ bool multifd_device_state_supported(void) return migrate_multifd() && !migrate_mapped_ram() && migrate_multifd_compression() == MULTIFD_COMPRESSION_NONE; } + +static void multifd_device_state_save_thread_data_free(void *opaque) +{ + SaveLiveCompletePrecopyThreadData *data = opaque; + + g_clear_pointer(&data->idstr, g_free); + g_free(data); +} + +static int multifd_device_state_save_thread(void *opaque) +{ + SaveLiveCompletePrecopyThreadData *data = opaque; + g_autoptr(Error) local_err = NULL; + + if (!data->hdlr(data, &local_err)) { + MigrationState *s = migrate_get_current(); + + /* + * Can't call abort_device_state_save_threads() here since new + * save threads could still be in process of being launched + * (if, for example, the very first save thread launched exited + * with an error very quickly). + */ + + assert(local_err); + + /* + * In case of multiple save threads failing which thread error + * return we end setting is purely arbitrary. + */ + migrate_set_error(s, local_err); + } + + return 0; +} + +bool multifd_device_state_save_thread_should_exit(void) +{ + return qatomic_read(&multifd_send_device_state->threads_abort); +} + +void +multifd_spawn_device_state_save_thread(SaveLiveCompletePrecopyThreadHandler hdlr, + char *idstr, uint32_t instance_id, + void *opaque) +{ + SaveLiveCompletePrecopyThreadData *data; + + assert(multifd_device_state_supported()); + assert(multifd_send_device_state); + + assert(!qatomic_read(&multifd_send_device_state->threads_abort)); + + data = g_new(SaveLiveCompletePrecopyThreadData, 1); + data->hdlr = hdlr; + data->idstr = g_strdup(idstr); + data->instance_id = instance_id; + data->handler_opaque = opaque; + + thread_pool_submit_immediate(multifd_send_device_state->threads, + multifd_device_state_save_thread, + data, + multifd_device_state_save_thread_data_free); +} + +void multifd_abort_device_state_save_threads(void) +{ + assert(multifd_device_state_supported()); + + qatomic_set(&multifd_send_device_state->threads_abort, true); +} + +bool multifd_join_device_state_save_threads(void) +{ + MigrationState *s = migrate_get_current(); + + assert(multifd_device_state_supported()); + + thread_pool_wait(multifd_send_device_state->threads); + + return !migrate_has_error(s); +} diff --git a/migration/savevm.c b/migration/savevm.c index XXXXXXX..XXXXXXX 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -XXX,XX +XXX,XX @@ #include "migration/register.h" #include "migration/global_state.h" #include "migration/channel-block.h" +#include "multifd.h" #include "ram.h" #include "qemu-file.h" #include "savevm.h" @@ -XXX,XX +XXX,XX @@ int qemu_savevm_state_complete_precopy_iterable(QEMUFile *f, bool in_postcopy) int64_t start_ts_each, end_ts_each; SaveStateEntry *se; int ret; + bool multifd_device_state = multifd_device_state_supported(); + + if (multifd_device_state) { + QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { + SaveLiveCompletePrecopyThreadHandler hdlr; + + if (!se->ops || (in_postcopy && se->ops->has_postcopy && + se->ops->has_postcopy(se->opaque)) || + !se->ops->save_live_complete_precopy_thread) { + continue; + } + + hdlr = se->ops->save_live_complete_precopy_thread; + multifd_spawn_device_state_save_thread(hdlr, + se->idstr, se->instance_id, + se->opaque); + } + } QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (!se->ops || @@ -XXX,XX +XXX,XX @@ int qemu_savevm_state_complete_precopy_iterable(QEMUFile *f, bool in_postcopy) save_section_footer(f, se); if (ret < 0) { qemu_file_set_error(f, ret); - return -1; + goto ret_fail_abort_threads; } end_ts_each = qemu_clock_get_us(QEMU_CLOCK_REALTIME); trace_vmstate_downtime_save("iterable", se->idstr, se->instance_id, end_ts_each - start_ts_each); } + if (multifd_device_state) { + if (migrate_has_error(migrate_get_current())) { + multifd_abort_device_state_save_threads(); + } + + if (!multifd_join_device_state_save_threads()) { + qemu_file_set_error(f, -EINVAL); + return -1; + } + } + trace_vmstate_downtime_checkpoint("src-iterable-saved"); return 0; + +ret_fail_abort_threads: + if (multifd_device_state) { + multifd_abort_device_state_save_threads(); + multifd_join_device_state_save_threads(); + } + + return -1; } int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f, From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> And rename existing load_device_config_state trace event to load_device_config_state_end for consistency since it is triggered at the end of loading of the VFIO device config state. This way both the start and end points of particular device config loading operation (a long, BQL-serialized operation) are known. Reviewed-by: Cédric Le Goater <clg@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration.c | 4 +++- hw/vfio/trace-events | 3 ++- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ static int vfio_load_device_config_state(QEMUFile *f, void *opaque) VFIODevice *vbasedev = opaque; uint64_t data; + trace_vfio_load_device_config_state_start(vbasedev->name); + if (vbasedev->ops && vbasedev->ops->vfio_load_config) { int ret; @@ -XXX,XX +XXX,XX @@ static int vfio_load_device_config_state(QEMUFile *f, void *opaque) return -EINVAL; } - trace_vfio_load_device_config_state(vbasedev->name); + trace_vfio_load_device_config_state_end(vbasedev->name); return qemu_file_get_error(f); } diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/trace-events +++ b/hw/vfio/trace-events @@ -XXX,XX +XXX,XX @@ vfio_display_edid_write_error(void) "" # migration.c vfio_load_cleanup(const char *name) " (%s)" -vfio_load_device_config_state(const char *name) " (%s)" +vfio_load_device_config_state_start(const char *name) " (%s)" +vfio_load_device_config_state_end(const char *name) " (%s)" vfio_load_state(const char *name, uint64_t data) " (%s) data 0x%"PRIx64 vfio_load_state_device_data(const char *name, uint64_t data_size, int ret) " (%s) size %"PRIu64" ret %d" vfio_migration_realize(const char *name) " (%s)" From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> So it can be safety accessed from multiple threads. This variable type needs to be changed to unsigned long since 32-bit host platforms lack the necessary addition atomics on 64-bit variables. Using 32-bit counters on 32-bit host platforms should not be a problem in practice since they can't realistically address more memory anyway. Reviewed-by: Cédric Le Goater <clg@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ */ #define VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE (1 * MiB) -static int64_t bytes_transferred; +static unsigned long bytes_transferred; static const char *mig_state_to_str(enum vfio_device_mig_state state) { @@ -XXX,XX +XXX,XX @@ static ssize_t vfio_save_block(QEMUFile *f, VFIOMigration *migration) qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE); qemu_put_be64(f, data_size); qemu_put_buffer(f, migration->data_buffer, data_size); - bytes_transferred += data_size; + qatomic_add(&bytes_transferred, data_size); trace_vfio_save_block(migration->vbasedev->name, data_size); @@ -XXX,XX +XXX,XX @@ static int vfio_block_migration(VFIODevice *vbasedev, Error *err, Error **errp) int64_t vfio_mig_bytes_transferred(void) { - return bytes_transferred; + return MIN(qatomic_read(&bytes_transferred), INT64_MAX); } void vfio_reset_bytes_transferred(void) { - bytes_transferred = 0; + qatomic_set(&bytes_transferred, 0); } /* From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This way bytes_transferred can also be incremented in other translation units than migration.c. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration.c | 7 ++++++- include/hw/vfio/vfio-common.h | 1 + 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ static ssize_t vfio_save_block(QEMUFile *f, VFIOMigration *migration) qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE); qemu_put_be64(f, data_size); qemu_put_buffer(f, migration->data_buffer, data_size); - qatomic_add(&bytes_transferred, data_size); + vfio_mig_add_bytes_transferred(data_size); trace_vfio_save_block(migration->vbasedev->name, data_size); @@ -XXX,XX +XXX,XX @@ void vfio_reset_bytes_transferred(void) qatomic_set(&bytes_transferred, 0); } +void vfio_mig_add_bytes_transferred(unsigned long val) +{ + qatomic_add(&bytes_transferred, val); +} + /* * Return true when either migration initialized or blocker registered. * Currently only return false when adding blocker fails which will diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -XXX,XX +XXX,XX @@ void vfio_unblock_multiple_devices_migration(void); bool vfio_viommu_preset(VFIODevice *vbasedev); int64_t vfio_mig_bytes_transferred(void); void vfio_reset_bytes_transferred(void); +void vfio_mig_add_bytes_transferred(unsigned long val); bool vfio_device_state_is_running(VFIODevice *vbasedev); bool vfio_device_state_is_precopy(VFIODevice *vbasedev); From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This way they can also be referenced in other translation units than migration.c. Reviewed-by: Cédric Le Goater <clg@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration.c | 17 ----------------- include/hw/vfio/vfio-common.h | 17 +++++++++++++++++ 2 files changed, 17 insertions(+), 17 deletions(-) diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ #include "trace.h" #include "hw/hw.h" -/* - * Flags to be used as unique delimiters for VFIO devices in the migration - * stream. These flags are composed as: - * 0xffffffff => MSB 32-bit all 1s - * 0xef10 => Magic ID, represents emulated (virtual) function IO - * 0x0000 => 16-bits reserved for flags - * - * The beginning of state information is marked by _DEV_CONFIG_STATE, - * _DEV_SETUP_STATE, or _DEV_DATA_STATE, respectively. The end of a - * certain state information is marked by _END_OF_STATE. - */ -#define VFIO_MIG_FLAG_END_OF_STATE (0xffffffffef100001ULL) -#define VFIO_MIG_FLAG_DEV_CONFIG_STATE (0xffffffffef100002ULL) -#define VFIO_MIG_FLAG_DEV_SETUP_STATE (0xffffffffef100003ULL) -#define VFIO_MIG_FLAG_DEV_DATA_STATE (0xffffffffef100004ULL) -#define VFIO_MIG_FLAG_DEV_INIT_DATA_SENT (0xffffffffef100005ULL) - /* * This is an arbitrary size based on migration of mlx5 devices, where typically * total device migration size is on the order of 100s of MB. Testing with diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -XXX,XX +XXX,XX @@ #define VFIO_MSG_PREFIX "vfio %s: " +/* + * Flags to be used as unique delimiters for VFIO devices in the migration + * stream. These flags are composed as: + * 0xffffffff => MSB 32-bit all 1s + * 0xef10 => Magic ID, represents emulated (virtual) function IO + * 0x0000 => 16-bits reserved for flags + * + * The beginning of state information is marked by _DEV_CONFIG_STATE, + * _DEV_SETUP_STATE, or _DEV_DATA_STATE, respectively. The end of a + * certain state information is marked by _END_OF_STATE. + */ +#define VFIO_MIG_FLAG_END_OF_STATE (0xffffffffef100001ULL) +#define VFIO_MIG_FLAG_DEV_CONFIG_STATE (0xffffffffef100002ULL) +#define VFIO_MIG_FLAG_DEV_SETUP_STATE (0xffffffffef100003ULL) +#define VFIO_MIG_FLAG_DEV_DATA_STATE (0xffffffffef100004ULL) +#define VFIO_MIG_FLAG_DEV_INIT_DATA_SENT (0xffffffffef100005ULL) + enum { VFIO_DEVICE_TYPE_PCI = 0, VFIO_DEVICE_TYPE_PLATFORM = 1, From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Add basic types and flags used by VFIO multifd device state transfer support. Since we'll be introducing a lot of multifd transfer specific code, add a new file migration-multifd.c to home it, wired into main VFIO migration code (migration.c) via migration-multifd.h header file. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/meson.build | 1 + hw/vfio/migration-multifd.c | 33 +++++++++++++++++++++++++++++++++ hw/vfio/migration-multifd.h | 17 +++++++++++++++++ hw/vfio/migration.c | 1 + 4 files changed, 52 insertions(+) create mode 100644 hw/vfio/migration-multifd.c create mode 100644 hw/vfio/migration-multifd.h diff --git a/hw/vfio/meson.build b/hw/vfio/meson.build index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/meson.build +++ b/hw/vfio/meson.build @@ -XXX,XX +XXX,XX @@ vfio_ss.add(files( 'container-base.c', 'container.c', 'migration.c', + 'migration-multifd.c', 'cpr.c', )) vfio_ss.add(when: 'CONFIG_PSERIES', if_true: files('spapr.c')) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c new file mode 100644 index XXXXXXX..XXXXXXX --- /dev/null +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ +/* + * Multifd VFIO migration + * + * Copyright (C) 2024,2025 Oracle and/or its affiliates. + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ + +#include "qemu/osdep.h" +#include "hw/vfio/vfio-common.h" +#include "migration/misc.h" +#include "qapi/error.h" +#include "qemu/error-report.h" +#include "qemu/lockable.h" +#include "qemu/main-loop.h" +#include "qemu/thread.h" +#include "migration/qemu-file.h" +#include "migration-multifd.h" +#include "trace.h" + +#define VFIO_DEVICE_STATE_CONFIG_STATE (1) + +#define VFIO_DEVICE_STATE_PACKET_VER_CURRENT (0) + +typedef struct VFIODeviceStatePacket { + uint32_t version; + uint32_t idx; + uint32_t flags; + uint8_t data[0]; +} QEMU_PACKED VFIODeviceStatePacket; diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h new file mode 100644 index XXXXXXX..XXXXXXX --- /dev/null +++ b/hw/vfio/migration-multifd.h @@ -XXX,XX +XXX,XX @@ +/* + * Multifd VFIO migration + * + * Copyright (C) 2024,2025 Oracle and/or its affiliates. + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ + +#ifndef HW_VFIO_MIGRATION_MULTIFD_H +#define HW_VFIO_MIGRATION_MULTIFD_H + +#include "hw/vfio/vfio-common.h" + +#endif diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ #include "migration/qemu-file.h" #include "migration/register.h" #include "migration/blocker.h" +#include "migration-multifd.h" #include "qapi/error.h" #include "qapi/qapi-events-vfio.h" #include "exec/ramlist.h" From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Add vfio_multifd_transfer_supported() function that tells whether the multifd device state transfer is supported. Reviewed-by: Cédric Le Goater <clg@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 6 ++++++ hw/vfio/migration-multifd.h | 2 ++ 2 files changed, 8 insertions(+) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ typedef struct VFIODeviceStatePacket { uint32_t flags; uint8_t data[0]; } QEMU_PACKED VFIODeviceStatePacket; + +bool vfio_multifd_transfer_supported(void) +{ + return multifd_device_state_supported() && + migrate_send_switchover_start(); +} diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.h +++ b/hw/vfio/migration-multifd.h @@ -XXX,XX +XXX,XX @@ #include "hw/vfio/vfio-common.h" +bool vfio_multifd_transfer_supported(void); + #endif From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Add multifd setup/cleanup functions and an associated VFIOMultifd data structure that will contain most of the receive-side data together with its init/cleanup methods. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 44 +++++++++++++++++++++++++++++++++++ hw/vfio/migration-multifd.h | 4 ++++ include/hw/vfio/vfio-common.h | 3 +++ 3 files changed, 51 insertions(+) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ typedef struct VFIODeviceStatePacket { uint8_t data[0]; } QEMU_PACKED VFIODeviceStatePacket; +typedef struct VFIOMultifd { +} VFIOMultifd; + +static VFIOMultifd *vfio_multifd_new(void) +{ + VFIOMultifd *multifd = g_new(VFIOMultifd, 1); + + return multifd; +} + +static void vfio_multifd_free(VFIOMultifd *multifd) +{ + g_free(multifd); +} + +void vfio_multifd_cleanup(VFIODevice *vbasedev) +{ + VFIOMigration *migration = vbasedev->migration; + + g_clear_pointer(&migration->multifd, vfio_multifd_free); +} + bool vfio_multifd_transfer_supported(void) { return multifd_device_state_supported() && migrate_send_switchover_start(); } + +bool vfio_multifd_transfer_enabled(VFIODevice *vbasedev) +{ + return false; +} + +bool vfio_multifd_setup(VFIODevice *vbasedev, bool alloc_multifd, Error **errp) +{ + VFIOMigration *migration = vbasedev->migration; + + if (!vfio_multifd_transfer_enabled(vbasedev)) { + /* Nothing further to check or do */ + return true; + } + + if (alloc_multifd) { + assert(!migration->multifd); + migration->multifd = vfio_multifd_new(); + } + + return true; +} diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.h +++ b/hw/vfio/migration-multifd.h @@ -XXX,XX +XXX,XX @@ #include "hw/vfio/vfio-common.h" +bool vfio_multifd_setup(VFIODevice *vbasedev, bool alloc_multifd, Error **errp); +void vfio_multifd_cleanup(VFIODevice *vbasedev); + bool vfio_multifd_transfer_supported(void); +bool vfio_multifd_transfer_enabled(VFIODevice *vbasedev); #endif diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -XXX,XX +XXX,XX @@ typedef struct VFIORegion { uint8_t nr; /* cache the region number for debug */ } VFIORegion; +typedef struct VFIOMultifd VFIOMultifd; + typedef struct VFIOMigration { struct VFIODevice *vbasedev; VMChangeStateEntry *vm_state; @@ -XXX,XX +XXX,XX @@ typedef struct VFIOMigration { uint64_t mig_flags; uint64_t precopy_init_size; uint64_t precopy_dirty_size; + VFIOMultifd *multifd; bool initial_data_sent; bool event_save_iterate_started; From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Wire VFIO multifd transfer specific setup and cleanup functions into general VFIO load/save setup and cleanup methods. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ static int vfio_save_setup(QEMUFile *f, void *opaque, Error **errp) uint64_t stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE; int ret; + if (!vfio_multifd_setup(vbasedev, false, errp)) { + return -EINVAL; + } + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE); vfio_query_stop_copy_size(vbasedev, &stop_copy_size); @@ -XXX,XX +XXX,XX @@ static void vfio_save_cleanup(void *opaque) Error *local_err = NULL; int ret; + /* Currently a NOP, done for symmetry with load_cleanup() */ + vfio_multifd_cleanup(vbasedev); + /* * Changing device state from STOP_COPY to STOP can take time. Do it here, * after migration has completed, so it won't increase downtime. @@ -XXX,XX +XXX,XX @@ static void vfio_save_state(QEMUFile *f, void *opaque) static int vfio_load_setup(QEMUFile *f, void *opaque, Error **errp) { VFIODevice *vbasedev = opaque; + VFIOMigration *migration = vbasedev->migration; + int ret; - return vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING, - vbasedev->migration->device_state, errp); + if (!vfio_multifd_setup(vbasedev, true, errp)) { + return -EINVAL; + } + + ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING, + migration->device_state, errp); + if (ret) { + return ret; + } + + return 0; } static int vfio_load_cleanup(void *opaque) { VFIODevice *vbasedev = opaque; + vfio_multifd_cleanup(vbasedev); + vfio_migration_cleanup(vbasedev); trace_vfio_load_cleanup(vbasedev->name); From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> The multifd received data needs to be reassembled since device state packets sent via different multifd channels can arrive out-of-order. Therefore, each VFIO device state packet carries a header indicating its position in the stream. The raw device state data is saved into a VFIOStateBuffer for later in-order loading into the device. The last such VFIO device state packet should have VFIO_DEVICE_STATE_CONFIG_STATE flag set and carry the device config state. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 163 ++++++++++++++++++++++++++++++++++++ hw/vfio/migration-multifd.h | 3 + hw/vfio/migration.c | 1 + hw/vfio/trace-events | 1 + 4 files changed, 168 insertions(+) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ typedef struct VFIODeviceStatePacket { uint8_t data[0]; } QEMU_PACKED VFIODeviceStatePacket; +/* type safety */ +typedef struct VFIOStateBuffers { + GArray *array; +} VFIOStateBuffers; + +typedef struct VFIOStateBuffer { + bool is_present; + char *data; + size_t len; +} VFIOStateBuffer; + typedef struct VFIOMultifd { + VFIOStateBuffers load_bufs; + QemuCond load_bufs_buffer_ready_cond; + QemuMutex load_bufs_mutex; /* Lock order: this lock -> BQL */ + uint32_t load_buf_idx; + uint32_t load_buf_idx_last; } VFIOMultifd; +static void vfio_state_buffer_clear(gpointer data) +{ + VFIOStateBuffer *lb = data; + + if (!lb->is_present) { + return; + } + + g_clear_pointer(&lb->data, g_free); + lb->is_present = false; +} + +static void vfio_state_buffers_init(VFIOStateBuffers *bufs) +{ + bufs->array = g_array_new(FALSE, TRUE, sizeof(VFIOStateBuffer)); + g_array_set_clear_func(bufs->array, vfio_state_buffer_clear); +} + +static void vfio_state_buffers_destroy(VFIOStateBuffers *bufs) +{ + g_clear_pointer(&bufs->array, g_array_unref); +} + +static void vfio_state_buffers_assert_init(VFIOStateBuffers *bufs) +{ + assert(bufs->array); +} + +static unsigned int vfio_state_buffers_size_get(VFIOStateBuffers *bufs) +{ + return bufs->array->len; +} + +static void vfio_state_buffers_size_set(VFIOStateBuffers *bufs, + unsigned int size) +{ + g_array_set_size(bufs->array, size); +} + +static VFIOStateBuffer *vfio_state_buffers_at(VFIOStateBuffers *bufs, + unsigned int idx) +{ + return &g_array_index(bufs->array, VFIOStateBuffer, idx); +} + +/* called with load_bufs_mutex locked */ +static bool vfio_load_state_buffer_insert(VFIODevice *vbasedev, + VFIODeviceStatePacket *packet, + size_t packet_total_size, + Error **errp) +{ + VFIOMigration *migration = vbasedev->migration; + VFIOMultifd *multifd = migration->multifd; + VFIOStateBuffer *lb; + + vfio_state_buffers_assert_init(&multifd->load_bufs); + if (packet->idx >= vfio_state_buffers_size_get(&multifd->load_bufs)) { + vfio_state_buffers_size_set(&multifd->load_bufs, packet->idx + 1); + } + + lb = vfio_state_buffers_at(&multifd->load_bufs, packet->idx); + if (lb->is_present) { + error_setg(errp, "%s: state buffer %" PRIu32 " already filled", + vbasedev->name, packet->idx); + return false; + } + + assert(packet->idx >= multifd->load_buf_idx); + + lb->data = g_memdup2(&packet->data, packet_total_size - sizeof(*packet)); + lb->len = packet_total_size - sizeof(*packet); + lb->is_present = true; + + return true; +} + +bool vfio_multifd_load_state_buffer(void *opaque, char *data, size_t data_size, + Error **errp) +{ + VFIODevice *vbasedev = opaque; + VFIOMigration *migration = vbasedev->migration; + VFIOMultifd *multifd = migration->multifd; + VFIODeviceStatePacket *packet = (VFIODeviceStatePacket *)data; + + if (!vfio_multifd_transfer_enabled(vbasedev)) { + error_setg(errp, + "%s: got device state packet but not doing multifd transfer", + vbasedev->name); + return false; + } + + assert(multifd); + + if (data_size < sizeof(*packet)) { + error_setg(errp, "%s: packet too short at %zu (min is %zu)", + vbasedev->name, data_size, sizeof(*packet)); + return false; + } + + if (packet->version != VFIO_DEVICE_STATE_PACKET_VER_CURRENT) { + error_setg(errp, "%s: packet has unknown version %" PRIu32, + vbasedev->name, packet->version); + return false; + } + + if (packet->idx == UINT32_MAX) { + error_setg(errp, "%s: packet index is invalid", vbasedev->name); + return false; + } + + trace_vfio_load_state_device_buffer_incoming(vbasedev->name, packet->idx); + + /* + * Holding BQL here would violate the lock order and can cause + * a deadlock once we attempt to lock load_bufs_mutex below. + */ + assert(!bql_locked()); + + WITH_QEMU_LOCK_GUARD(&multifd->load_bufs_mutex) { + /* config state packet should be the last one in the stream */ + if (packet->flags & VFIO_DEVICE_STATE_CONFIG_STATE) { + multifd->load_buf_idx_last = packet->idx; + } + + if (!vfio_load_state_buffer_insert(vbasedev, packet, data_size, + errp)) { + return false; + } + + qemu_cond_signal(&multifd->load_bufs_buffer_ready_cond); + } + + return true; +} + static VFIOMultifd *vfio_multifd_new(void) { VFIOMultifd *multifd = g_new(VFIOMultifd, 1); + vfio_state_buffers_init(&multifd->load_bufs); + + qemu_mutex_init(&multifd->load_bufs_mutex); + + multifd->load_buf_idx = 0; + multifd->load_buf_idx_last = UINT32_MAX; + qemu_cond_init(&multifd->load_bufs_buffer_ready_cond); + return multifd; } static void vfio_multifd_free(VFIOMultifd *multifd) { + vfio_state_buffers_destroy(&multifd->load_bufs); + qemu_cond_destroy(&multifd->load_bufs_buffer_ready_cond); + qemu_mutex_destroy(&multifd->load_bufs_mutex); + g_free(multifd); } diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.h +++ b/hw/vfio/migration-multifd.h @@ -XXX,XX +XXX,XX @@ void vfio_multifd_cleanup(VFIODevice *vbasedev); bool vfio_multifd_transfer_supported(void); bool vfio_multifd_transfer_enabled(VFIODevice *vbasedev); +bool vfio_multifd_load_state_buffer(void *opaque, char *data, size_t data_size, + Error **errp); + #endif diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ static const SaveVMHandlers savevm_vfio_handlers = { .load_setup = vfio_load_setup, .load_cleanup = vfio_load_cleanup, .load_state = vfio_load_state, + .load_state_buffer = vfio_multifd_load_state_buffer, .switchover_ack_needed = vfio_switchover_ack_needed, }; diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/trace-events +++ b/hw/vfio/trace-events @@ -XXX,XX +XXX,XX @@ vfio_load_device_config_state_start(const char *name) " (%s)" vfio_load_device_config_state_end(const char *name) " (%s)" vfio_load_state(const char *name, uint64_t data) " (%s) data 0x%"PRIx64 vfio_load_state_device_data(const char *name, uint64_t data_size, int ret) " (%s) size %"PRIu64" ret %d" +vfio_load_state_device_buffer_incoming(const char *name, uint32_t idx) " (%s) idx %"PRIu32 vfio_migration_realize(const char *name) " (%s)" vfio_migration_set_device_state(const char *name, const char *state) " (%s) state %s" vfio_migration_set_state(const char *name, const char *new_state, const char *recover_state) " (%s) new state %s, recover state %s" From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Add a thread which loads the VFIO device state buffers that were received via multifd. Each VFIO device that has multifd device state transfer enabled has one such thread, which is created using migration core API qemu_loadvm_start_load_thread(). Since it's important to finish loading device state transferred via the main migration channel (via save_live_iterate SaveVMHandler) before starting loading the data asynchronously transferred via multifd the thread doing the actual loading of the multifd transferred data is only started from switchover_start SaveVMHandler. switchover_start handler is called when MIG_CMD_SWITCHOVER_START sub-command of QEMU_VM_COMMAND is received via the main migration channel. This sub-command is only sent after all save_live_iterate data have already been posted so it is safe to commence loading of the multifd-transferred device state upon receiving it - loading of save_live_iterate data happens synchronously in the main migration thread (much like the processing of MIG_CMD_SWITCHOVER_START) so by the time MIG_CMD_SWITCHOVER_START is processed all the proceeding data must have already been loaded. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 226 ++++++++++++++++++++++++++++++++++++ hw/vfio/migration-multifd.h | 2 + hw/vfio/migration.c | 12 ++ hw/vfio/trace-events | 7 ++ 4 files changed, 247 insertions(+) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ typedef struct VFIOStateBuffer { } VFIOStateBuffer; typedef struct VFIOMultifd { + bool load_bufs_thread_running; + bool load_bufs_thread_want_exit; + VFIOStateBuffers load_bufs; QemuCond load_bufs_buffer_ready_cond; + QemuCond load_bufs_thread_finished_cond; QemuMutex load_bufs_mutex; /* Lock order: this lock -> BQL */ uint32_t load_buf_idx; uint32_t load_buf_idx_last; @@ -XXX,XX +XXX,XX @@ bool vfio_multifd_load_state_buffer(void *opaque, char *data, size_t data_size, return true; } +static bool vfio_load_bufs_thread_load_config(VFIODevice *vbasedev, + Error **errp) +{ + error_setg(errp, "not yet there"); + return false; +} + +static VFIOStateBuffer *vfio_load_state_buffer_get(VFIOMultifd *multifd) +{ + VFIOStateBuffer *lb; + unsigned int bufs_len; + + bufs_len = vfio_state_buffers_size_get(&multifd->load_bufs); + if (multifd->load_buf_idx >= bufs_len) { + assert(multifd->load_buf_idx == bufs_len); + return NULL; + } + + lb = vfio_state_buffers_at(&multifd->load_bufs, + multifd->load_buf_idx); + if (!lb->is_present) { + return NULL; + } + + return lb; +} + +static bool vfio_load_state_buffer_write(VFIODevice *vbasedev, + VFIOStateBuffer *lb, + Error **errp) +{ + VFIOMigration *migration = vbasedev->migration; + VFIOMultifd *multifd = migration->multifd; + g_autofree char *buf = NULL; + char *buf_cur; + size_t buf_len; + + if (!lb->len) { + return true; + } + + trace_vfio_load_state_device_buffer_load_start(vbasedev->name, + multifd->load_buf_idx); + + /* lb might become re-allocated when we drop the lock */ + buf = g_steal_pointer(&lb->data); + buf_cur = buf; + buf_len = lb->len; + while (buf_len > 0) { + ssize_t wr_ret; + int errno_save; + + /* + * Loading data to the device takes a while, + * drop the lock during this process. + */ + qemu_mutex_unlock(&multifd->load_bufs_mutex); + wr_ret = write(migration->data_fd, buf_cur, buf_len); + errno_save = errno; + qemu_mutex_lock(&multifd->load_bufs_mutex); + + if (wr_ret < 0) { + error_setg(errp, + "%s: writing state buffer %" PRIu32 " failed: %d", + vbasedev->name, multifd->load_buf_idx, errno_save); + return false; + } + + assert(wr_ret <= buf_len); + buf_len -= wr_ret; + buf_cur += wr_ret; + } + + trace_vfio_load_state_device_buffer_load_end(vbasedev->name, + multifd->load_buf_idx); + + return true; +} + +static bool vfio_load_bufs_thread_want_exit(VFIOMultifd *multifd, + bool *should_quit) +{ + return multifd->load_bufs_thread_want_exit || qatomic_read(should_quit); +} + +/* + * This thread is spawned by vfio_multifd_switchover_start() which gets + * called upon encountering the switchover point marker in main migration + * stream. + * + * It exits after either: + * * completing loading the remaining device state and device config, OR: + * * encountering some error while doing the above, OR: + * * being forcefully aborted by the migration core by it setting should_quit + * or by vfio_load_cleanup_load_bufs_thread() setting + * multifd->load_bufs_thread_want_exit. + */ +static bool vfio_load_bufs_thread(void *opaque, bool *should_quit, Error **errp) +{ + VFIODevice *vbasedev = opaque; + VFIOMigration *migration = vbasedev->migration; + VFIOMultifd *multifd = migration->multifd; + bool ret = false; + + trace_vfio_load_bufs_thread_start(vbasedev->name); + + assert(multifd); + QEMU_LOCK_GUARD(&multifd->load_bufs_mutex); + + assert(multifd->load_bufs_thread_running); + + while (true) { + VFIOStateBuffer *lb; + + /* + * Always check cancellation first after the buffer_ready wait below in + * case that cond was signalled by vfio_load_cleanup_load_bufs_thread(). + */ + if (vfio_load_bufs_thread_want_exit(multifd, should_quit)) { + error_setg(errp, "operation cancelled"); + goto thread_exit; + } + + assert(multifd->load_buf_idx <= multifd->load_buf_idx_last); + + lb = vfio_load_state_buffer_get(multifd); + if (!lb) { + trace_vfio_load_state_device_buffer_starved(vbasedev->name, + multifd->load_buf_idx); + qemu_cond_wait(&multifd->load_bufs_buffer_ready_cond, + &multifd->load_bufs_mutex); + continue; + } + + if (multifd->load_buf_idx == multifd->load_buf_idx_last) { + break; + } + + if (multifd->load_buf_idx == 0) { + trace_vfio_load_state_device_buffer_start(vbasedev->name); + } + + if (!vfio_load_state_buffer_write(vbasedev, lb, errp)) { + goto thread_exit; + } + + if (multifd->load_buf_idx == multifd->load_buf_idx_last - 1) { + trace_vfio_load_state_device_buffer_end(vbasedev->name); + } + + multifd->load_buf_idx++; + } + + if (!vfio_load_bufs_thread_load_config(vbasedev, errp)) { + goto thread_exit; + } + + ret = true; + +thread_exit: + /* + * Notify possibly waiting vfio_load_cleanup_load_bufs_thread() that + * this thread is exiting. + */ + multifd->load_bufs_thread_running = false; + qemu_cond_signal(&multifd->load_bufs_thread_finished_cond); + + trace_vfio_load_bufs_thread_end(vbasedev->name); + + return ret; +} + static VFIOMultifd *vfio_multifd_new(void) { VFIOMultifd *multifd = g_new(VFIOMultifd, 1); @@ -XXX,XX +XXX,XX @@ static VFIOMultifd *vfio_multifd_new(void) multifd->load_buf_idx_last = UINT32_MAX; qemu_cond_init(&multifd->load_bufs_buffer_ready_cond); + multifd->load_bufs_thread_running = false; + multifd->load_bufs_thread_want_exit = false; + qemu_cond_init(&multifd->load_bufs_thread_finished_cond); + return multifd; } +/* + * Terminates vfio_load_bufs_thread by setting + * multifd->load_bufs_thread_want_exit and signalling all the conditions + * the thread could be blocked on. + * + * Waits for the thread to signal that it had finished. + */ +static void vfio_load_cleanup_load_bufs_thread(VFIOMultifd *multifd) +{ + /* The lock order is load_bufs_mutex -> BQL so unlock BQL here first */ + bql_unlock(); + WITH_QEMU_LOCK_GUARD(&multifd->load_bufs_mutex) { + while (multifd->load_bufs_thread_running) { + multifd->load_bufs_thread_want_exit = true; + + qemu_cond_signal(&multifd->load_bufs_buffer_ready_cond); + qemu_cond_wait(&multifd->load_bufs_thread_finished_cond, + &multifd->load_bufs_mutex); + } + } + bql_lock(); +} + static void vfio_multifd_free(VFIOMultifd *multifd) { + vfio_load_cleanup_load_bufs_thread(multifd); + + qemu_cond_destroy(&multifd->load_bufs_thread_finished_cond); vfio_state_buffers_destroy(&multifd->load_bufs); qemu_cond_destroy(&multifd->load_bufs_buffer_ready_cond); qemu_mutex_destroy(&multifd->load_bufs_mutex); @@ -XXX,XX +XXX,XX @@ bool vfio_multifd_setup(VFIODevice *vbasedev, bool alloc_multifd, Error **errp) return true; } + +int vfio_multifd_switchover_start(VFIODevice *vbasedev) +{ + VFIOMigration *migration = vbasedev->migration; + VFIOMultifd *multifd = migration->multifd; + + assert(multifd); + + /* The lock order is load_bufs_mutex -> BQL so unlock BQL here first */ + bql_unlock(); + WITH_QEMU_LOCK_GUARD(&multifd->load_bufs_mutex) { + assert(!multifd->load_bufs_thread_running); + multifd->load_bufs_thread_running = true; + } + bql_lock(); + + qemu_loadvm_start_load_thread(vfio_load_bufs_thread, vbasedev); + + return 0; +} diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.h +++ b/hw/vfio/migration-multifd.h @@ -XXX,XX +XXX,XX @@ bool vfio_multifd_transfer_enabled(VFIODevice *vbasedev); bool vfio_multifd_load_state_buffer(void *opaque, char *data, size_t data_size, Error **errp); +int vfio_multifd_switchover_start(VFIODevice *vbasedev); + #endif diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ static bool vfio_switchover_ack_needed(void *opaque) return vfio_precopy_supported(vbasedev); } +static int vfio_switchover_start(void *opaque) +{ + VFIODevice *vbasedev = opaque; + + if (vfio_multifd_transfer_enabled(vbasedev)) { + return vfio_multifd_switchover_start(vbasedev); + } + + return 0; +} + static const SaveVMHandlers savevm_vfio_handlers = { .save_prepare = vfio_save_prepare, .save_setup = vfio_save_setup, @@ -XXX,XX +XXX,XX @@ static const SaveVMHandlers savevm_vfio_handlers = { .load_state = vfio_load_state, .load_state_buffer = vfio_multifd_load_state_buffer, .switchover_ack_needed = vfio_switchover_ack_needed, + .switchover_start = vfio_switchover_start, }; /* ---------------------------------------------------------------------- */ diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/trace-events +++ b/hw/vfio/trace-events @@ -XXX,XX +XXX,XX @@ vfio_display_edid_update(uint32_t prefx, uint32_t prefy) "%ux%u" vfio_display_edid_write_error(void) "" # migration.c +vfio_load_bufs_thread_start(const char *name) " (%s)" +vfio_load_bufs_thread_end(const char *name) " (%s)" vfio_load_cleanup(const char *name) " (%s)" vfio_load_device_config_state_start(const char *name) " (%s)" vfio_load_device_config_state_end(const char *name) " (%s)" vfio_load_state(const char *name, uint64_t data) " (%s) data 0x%"PRIx64 vfio_load_state_device_data(const char *name, uint64_t data_size, int ret) " (%s) size %"PRIu64" ret %d" vfio_load_state_device_buffer_incoming(const char *name, uint32_t idx) " (%s) idx %"PRIu32 +vfio_load_state_device_buffer_start(const char *name) " (%s)" +vfio_load_state_device_buffer_starved(const char *name, uint32_t idx) " (%s) idx %"PRIu32 +vfio_load_state_device_buffer_load_start(const char *name, uint32_t idx) " (%s) idx %"PRIu32 +vfio_load_state_device_buffer_load_end(const char *name, uint32_t idx) " (%s) idx %"PRIu32 +vfio_load_state_device_buffer_end(const char *name) " (%s)" vfio_migration_realize(const char *name) " (%s)" vfio_migration_set_device_state(const char *name, const char *state) " (%s) state %s" vfio_migration_set_state(const char *name, const char *new_state, const char *recover_state) " (%s) new state %s, recover state %s" From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Automatic memory management helps avoid memory safety issues. Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- migration/qemu-file.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/migration/qemu-file.h b/migration/qemu-file.h index XXXXXXX..XXXXXXX 100644 --- a/migration/qemu-file.h +++ b/migration/qemu-file.h @@ -XXX,XX +XXX,XX @@ QEMUFile *qemu_file_new_input(QIOChannel *ioc); QEMUFile *qemu_file_new_output(QIOChannel *ioc); int qemu_fclose(QEMUFile *f); +G_DEFINE_AUTOPTR_CLEANUP_FUNC(QEMUFile, qemu_fclose) + /* * qemu_file_transferred: * From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Load device config received via multifd using the existing machinery behind vfio_load_device_config_state(). Also, make sure to process the relevant main migration channel flags. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 49 +++++++++++++++++++++++++++++++++-- hw/vfio/migration.c | 9 ++++++- include/hw/vfio/vfio-common.h | 2 ++ 3 files changed, 57 insertions(+), 3 deletions(-) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ #include "qemu/lockable.h" #include "qemu/main-loop.h" #include "qemu/thread.h" +#include "io/channel-buffer.h" #include "migration/qemu-file.h" #include "migration-multifd.h" #include "trace.h" @@ -XXX,XX +XXX,XX @@ bool vfio_multifd_load_state_buffer(void *opaque, char *data, size_t data_size, static bool vfio_load_bufs_thread_load_config(VFIODevice *vbasedev, Error **errp) { - error_setg(errp, "not yet there"); - return false; + VFIOMigration *migration = vbasedev->migration; + VFIOMultifd *multifd = migration->multifd; + VFIOStateBuffer *lb; + g_autoptr(QIOChannelBuffer) bioc = NULL; + g_autoptr(QEMUFile) f_out = NULL, f_in = NULL; + uint64_t mig_header; + int ret; + + assert(multifd->load_buf_idx == multifd->load_buf_idx_last); + lb = vfio_state_buffers_at(&multifd->load_bufs, multifd->load_buf_idx); + assert(lb->is_present); + + bioc = qio_channel_buffer_new(lb->len); + qio_channel_set_name(QIO_CHANNEL(bioc), "vfio-device-config-load"); + + f_out = qemu_file_new_output(QIO_CHANNEL(bioc)); + qemu_put_buffer(f_out, (uint8_t *)lb->data, lb->len); + + ret = qemu_fflush(f_out); + if (ret) { + error_setg(errp, "%s: load config state flush failed: %d", + vbasedev->name, ret); + return false; + } + + qio_channel_io_seek(QIO_CHANNEL(bioc), 0, 0, NULL); + f_in = qemu_file_new_input(QIO_CHANNEL(bioc)); + + mig_header = qemu_get_be64(f_in); + if (mig_header != VFIO_MIG_FLAG_DEV_CONFIG_STATE) { + error_setg(errp, "%s: expected FLAG_DEV_CONFIG_STATE but got %" PRIx64, + vbasedev->name, mig_header); + return false; + } + + bql_lock(); + ret = vfio_load_device_config_state(f_in, vbasedev); + bql_unlock(); + + if (ret < 0) { + error_setg(errp, "%s: vfio_load_device_config_state() failed: %d", + vbasedev->name, ret); + return false; + } + + return true; } static VFIOStateBuffer *vfio_load_state_buffer_get(VFIOMultifd *multifd) diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ static int vfio_save_device_config_state(QEMUFile *f, void *opaque, return ret; } -static int vfio_load_device_config_state(QEMUFile *f, void *opaque) +int vfio_load_device_config_state(QEMUFile *f, void *opaque) { VFIODevice *vbasedev = opaque; uint64_t data; @@ -XXX,XX +XXX,XX @@ static int vfio_load_state(QEMUFile *f, void *opaque, int version_id) switch (data) { case VFIO_MIG_FLAG_DEV_CONFIG_STATE: { + if (vfio_multifd_transfer_enabled(vbasedev)) { + error_report("%s: got DEV_CONFIG_STATE in main migration " + "channel but doing multifd transfer", + vbasedev->name); + return -EINVAL; + } + return vfio_load_device_config_state(f, opaque); } case VFIO_MIG_FLAG_DEV_SETUP_STATE: diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -XXX,XX +XXX,XX @@ void vfio_mig_add_bytes_transferred(unsigned long val); bool vfio_device_state_is_running(VFIODevice *vbasedev); bool vfio_device_state_is_precopy(VFIODevice *vbasedev); +int vfio_load_device_config_state(QEMUFile *f, void *opaque); + #ifdef CONFIG_LINUX int vfio_get_region_info(VFIODevice *vbasedev, int index, struct vfio_region_info **info); From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Implement the multifd device state transfer via additional per-device thread inside save_live_complete_precopy_thread handler. Switch between doing the data transfer in the new handler and doing it in the old save_state handler depending if VFIO multifd transfer is enabled or not. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 142 ++++++++++++++++++++++++++++++++++ hw/vfio/migration-multifd.h | 6 ++ hw/vfio/migration.c | 22 ++++-- hw/vfio/trace-events | 2 + include/hw/vfio/vfio-common.h | 6 ++ 5 files changed, 172 insertions(+), 6 deletions(-) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ bool vfio_multifd_setup(VFIODevice *vbasedev, bool alloc_multifd, Error **errp) return true; } +void vfio_multifd_emit_dummy_eos(VFIODevice *vbasedev, QEMUFile *f) +{ + assert(vfio_multifd_transfer_enabled(vbasedev)); + + /* + * Emit dummy NOP data on the main migration channel since the actual + * device state transfer is done via multifd channels. + */ + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); +} + +static bool +vfio_save_complete_precopy_thread_config_state(VFIODevice *vbasedev, + char *idstr, + uint32_t instance_id, + uint32_t idx, + Error **errp) +{ + g_autoptr(QIOChannelBuffer) bioc = NULL; + g_autoptr(QEMUFile) f = NULL; + int ret; + g_autofree VFIODeviceStatePacket *packet = NULL; + size_t packet_len; + + bioc = qio_channel_buffer_new(0); + qio_channel_set_name(QIO_CHANNEL(bioc), "vfio-device-config-save"); + + f = qemu_file_new_output(QIO_CHANNEL(bioc)); + + if (vfio_save_device_config_state(f, vbasedev, errp)) { + return false; + } + + ret = qemu_fflush(f); + if (ret) { + error_setg(errp, "%s: save config state flush failed: %d", + vbasedev->name, ret); + return false; + } + + packet_len = sizeof(*packet) + bioc->usage; + packet = g_malloc0(packet_len); + packet->version = VFIO_DEVICE_STATE_PACKET_VER_CURRENT; + packet->idx = idx; + packet->flags = VFIO_DEVICE_STATE_CONFIG_STATE; + memcpy(&packet->data, bioc->data, bioc->usage); + + if (!multifd_queue_device_state(idstr, instance_id, + (char *)packet, packet_len)) { + error_setg(errp, "%s: multifd config data queuing failed", + vbasedev->name); + return false; + } + + vfio_mig_add_bytes_transferred(packet_len); + + return true; +} + +/* + * This thread is spawned by the migration core directly via + * .save_live_complete_precopy_thread SaveVMHandler. + * + * It exits after either: + * * completing saving the remaining device state and device config, OR: + * * encountering some error while doing the above, OR: + * * being forcefully aborted by the migration core by + * multifd_device_state_save_thread_should_exit() returning true. + */ +bool +vfio_multifd_save_complete_precopy_thread(SaveLiveCompletePrecopyThreadData *d, + Error **errp) +{ + VFIODevice *vbasedev = d->handler_opaque; + VFIOMigration *migration = vbasedev->migration; + bool ret = false; + g_autofree VFIODeviceStatePacket *packet = NULL; + uint32_t idx; + + if (!vfio_multifd_transfer_enabled(vbasedev)) { + /* Nothing to do, vfio_save_complete_precopy() does the transfer. */ + return true; + } + + trace_vfio_save_complete_precopy_thread_start(vbasedev->name, + d->idstr, d->instance_id); + + /* We reach here with device state STOP or STOP_COPY only */ + if (vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_STOP_COPY, + VFIO_DEVICE_STATE_STOP, errp)) { + goto thread_exit; + } + + packet = g_malloc0(sizeof(*packet) + migration->data_buffer_size); + packet->version = VFIO_DEVICE_STATE_PACKET_VER_CURRENT; + + for (idx = 0; ; idx++) { + ssize_t data_size; + size_t packet_size; + + if (multifd_device_state_save_thread_should_exit()) { + error_setg(errp, "operation cancelled"); + goto thread_exit; + } + + data_size = read(migration->data_fd, &packet->data, + migration->data_buffer_size); + if (data_size < 0) { + error_setg(errp, "%s: reading state buffer %" PRIu32 " failed: %d", + vbasedev->name, idx, errno); + goto thread_exit; + } else if (data_size == 0) { + break; + } + + packet->idx = idx; + packet_size = sizeof(*packet) + data_size; + + if (!multifd_queue_device_state(d->idstr, d->instance_id, + (char *)packet, packet_size)) { + error_setg(errp, "%s: multifd data queuing failed", vbasedev->name); + goto thread_exit; + } + + vfio_mig_add_bytes_transferred(packet_size); + } + + if (!vfio_save_complete_precopy_thread_config_state(vbasedev, + d->idstr, + d->instance_id, + idx, errp)) { + goto thread_exit; + } + + ret = true; + +thread_exit: + trace_vfio_save_complete_precopy_thread_end(vbasedev->name, ret); + + return ret; +} + int vfio_multifd_switchover_start(VFIODevice *vbasedev) { VFIOMigration *migration = vbasedev->migration; diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.h +++ b/hw/vfio/migration-multifd.h @@ -XXX,XX +XXX,XX @@ bool vfio_multifd_transfer_enabled(VFIODevice *vbasedev); bool vfio_multifd_load_state_buffer(void *opaque, char *data, size_t data_size, Error **errp); +void vfio_multifd_emit_dummy_eos(VFIODevice *vbasedev, QEMUFile *f); + +bool +vfio_multifd_save_complete_precopy_thread(SaveLiveCompletePrecopyThreadData *d, + Error **errp); + int vfio_multifd_switchover_start(VFIODevice *vbasedev); #endif diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ static void vfio_migration_set_device_state(VFIODevice *vbasedev, vfio_migration_send_event(vbasedev); } -static int vfio_migration_set_state(VFIODevice *vbasedev, - enum vfio_device_mig_state new_state, - enum vfio_device_mig_state recover_state, - Error **errp) +int vfio_migration_set_state(VFIODevice *vbasedev, + enum vfio_device_mig_state new_state, + enum vfio_device_mig_state recover_state, + Error **errp) { VFIOMigration *migration = vbasedev->migration; uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) + @@ -XXX,XX +XXX,XX @@ static int vfio_load_buffer(QEMUFile *f, VFIODevice *vbasedev, return ret; } -static int vfio_save_device_config_state(QEMUFile *f, void *opaque, - Error **errp) +int vfio_save_device_config_state(QEMUFile *f, void *opaque, Error **errp) { VFIODevice *vbasedev = opaque; int ret; @@ -XXX,XX +XXX,XX @@ static int vfio_save_complete_precopy(QEMUFile *f, void *opaque) int ret; Error *local_err = NULL; + if (vfio_multifd_transfer_enabled(vbasedev)) { + vfio_multifd_emit_dummy_eos(vbasedev, f); + return 0; + } + trace_vfio_save_complete_precopy_start(vbasedev->name); /* We reach here with device state STOP or STOP_COPY only */ @@ -XXX,XX +XXX,XX @@ static void vfio_save_state(QEMUFile *f, void *opaque) Error *local_err = NULL; int ret; + if (vfio_multifd_transfer_enabled(vbasedev)) { + vfio_multifd_emit_dummy_eos(vbasedev, f); + return; + } + ret = vfio_save_device_config_state(f, opaque, &local_err); if (ret) { error_prepend(&local_err, @@ -XXX,XX +XXX,XX @@ static const SaveVMHandlers savevm_vfio_handlers = { .is_active_iterate = vfio_is_active_iterate, .save_live_iterate = vfio_save_iterate, .save_live_complete_precopy = vfio_save_complete_precopy, + .save_live_complete_precopy_thread = vfio_multifd_save_complete_precopy_thread, .save_state = vfio_save_state, .load_setup = vfio_load_setup, .load_cleanup = vfio_load_cleanup, diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/trace-events +++ b/hw/vfio/trace-events @@ -XXX,XX +XXX,XX @@ vfio_save_block_precopy_empty_hit(const char *name) " (%s)" vfio_save_cleanup(const char *name) " (%s)" vfio_save_complete_precopy(const char *name, int ret) " (%s) ret %d" vfio_save_complete_precopy_start(const char *name) " (%s)" +vfio_save_complete_precopy_thread_start(const char *name, const char *idstr, uint32_t instance_id) " (%s) idstr %s instance %"PRIu32 +vfio_save_complete_precopy_thread_end(const char *name, int ret) " (%s) ret %d" vfio_save_device_config_state(const char *name) " (%s)" vfio_save_iterate(const char *name, uint64_t precopy_init_size, uint64_t precopy_dirty_size) " (%s) precopy initial size %"PRIu64" precopy dirty size %"PRIu64 vfio_save_iterate_start(const char *name) " (%s)" diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -XXX,XX +XXX,XX @@ void vfio_mig_add_bytes_transferred(unsigned long val); bool vfio_device_state_is_running(VFIODevice *vbasedev); bool vfio_device_state_is_precopy(VFIODevice *vbasedev); +int vfio_save_device_config_state(QEMUFile *f, void *opaque, Error **errp); int vfio_load_device_config_state(QEMUFile *f, void *opaque); #ifdef CONFIG_LINUX @@ -XXX,XX +XXX,XX @@ struct vfio_info_cap_header * vfio_get_device_info_cap(struct vfio_device_info *info, uint16_t id); struct vfio_info_cap_header * vfio_get_cap(void *ptr, uint32_t cap_offset, uint16_t id); + +int vfio_migration_set_state(VFIODevice *vbasedev, + enum vfio_device_mig_state new_state, + enum vfio_device_mig_state recover_state, + Error **errp); #endif bool vfio_migration_realize(VFIODevice *vbasedev, Error **errp); From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This property allows configuring whether to transfer the particular device state via multifd channels when live migrating that device. It defaults to AUTO, which means that VFIO device state transfer via multifd channels is attempted in configurations that otherwise support it. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 18 +++++++++++++++++- hw/vfio/pci.c | 8 ++++++++ include/hw/vfio/vfio-common.h | 2 ++ 3 files changed, 27 insertions(+), 1 deletion(-) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ bool vfio_multifd_transfer_supported(void) bool vfio_multifd_transfer_enabled(VFIODevice *vbasedev) { - return false; + VFIOMigration *migration = vbasedev->migration; + + return migration->multifd_transfer; } bool vfio_multifd_setup(VFIODevice *vbasedev, bool alloc_multifd, Error **errp) { VFIOMigration *migration = vbasedev->migration; + if (vbasedev->migration_multifd_transfer == ON_OFF_AUTO_AUTO) { + migration->multifd_transfer = vfio_multifd_transfer_supported(); + } else { + migration->multifd_transfer = + vbasedev->migration_multifd_transfer == ON_OFF_AUTO_ON; + } + if (!vfio_multifd_transfer_enabled(vbasedev)) { /* Nothing further to check or do */ return true; } + if (!vfio_multifd_transfer_supported()) { + error_setg(errp, + "%s: Multifd device transfer requested but unsupported in the current config", + vbasedev->name); + return false; + } + if (alloc_multifd) { assert(!migration->multifd); migration->multifd = vfio_multifd_new(); diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -XXX,XX +XXX,XX @@ static const Property vfio_pci_dev_properties[] = { VFIO_FEATURE_ENABLE_IGD_OPREGION_BIT, false), DEFINE_PROP_ON_OFF_AUTO("enable-migration", VFIOPCIDevice, vbasedev.enable_migration, ON_OFF_AUTO_AUTO), + DEFINE_PROP_ON_OFF_AUTO("x-migration-multifd-transfer", VFIOPCIDevice, + vbasedev.migration_multifd_transfer, + ON_OFF_AUTO_AUTO), DEFINE_PROP_BOOL("migration-events", VFIOPCIDevice, vbasedev.migration_events, false), DEFINE_PROP_BOOL("x-no-mmap", VFIOPCIDevice, vbasedev.no_mmap, false), @@ -XXX,XX +XXX,XX @@ static void vfio_pci_dev_class_init(ObjectClass *klass, void *data) pdc->exit = vfio_exitfn; pdc->config_read = vfio_pci_read_config; pdc->config_write = vfio_pci_write_config; + + object_class_property_set_description(klass, /* 10.0 */ + "x-migration-multifd-transfer", + "Transfer this device state via " + "multifd channels when live migrating it"); } static const TypeInfo vfio_pci_dev_info = { diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -XXX,XX +XXX,XX @@ typedef struct VFIOMigration { uint64_t mig_flags; uint64_t precopy_init_size; uint64_t precopy_dirty_size; + bool multifd_transfer; VFIOMultifd *multifd; bool initial_data_sent; @@ -XXX,XX +XXX,XX @@ typedef struct VFIODevice { bool no_mmap; bool ram_block_discard_allowed; OnOffAuto enable_migration; + OnOffAuto migration_multifd_transfer; bool migration_events; VFIODeviceOps *ops; unsigned int num_irqs; From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> DEFINE_PROP_ON_OFF_AUTO() property isn't runtime-mutable so using it would mean that the source VM would need to decide upfront at startup time whether it wants to do a multifd device state transfer at some point. Source VM can run for a long time before being migrated so it is desirable to have a fallback mechanism to the old way of transferring VFIO device state if it turns to be necessary. This brings this property to the same mutability level as ordinary migration parameters, which too can be adjusted at the run time. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 4 ++++ hw/vfio/pci.c | 20 +++++++++++++++++--- 2 files changed, 21 insertions(+), 3 deletions(-) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ bool vfio_multifd_setup(VFIODevice *vbasedev, bool alloc_multifd, Error **errp) { VFIOMigration *migration = vbasedev->migration; + /* + * Make a copy of this setting at the start in case it is changed + * mid-migration. + */ if (vbasedev->migration_multifd_transfer == ON_OFF_AUTO_AUTO) { migration->multifd_transfer = vfio_multifd_transfer_supported(); } else { diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -XXX,XX +XXX,XX @@ static void vfio_instance_init(Object *obj) pci_dev->cap_present |= QEMU_PCI_CAP_EXPRESS; } +static PropertyInfo vfio_pci_migration_multifd_transfer_prop; + static const Property vfio_pci_dev_properties[] = { DEFINE_PROP_PCI_HOST_DEVADDR("host", VFIOPCIDevice, host), DEFINE_PROP_UUID_NODEFAULT("vf-token", VFIOPCIDevice, vf_token), @@ -XXX,XX +XXX,XX @@ static const Property vfio_pci_dev_properties[] = { VFIO_FEATURE_ENABLE_IGD_OPREGION_BIT, false), DEFINE_PROP_ON_OFF_AUTO("enable-migration", VFIOPCIDevice, vbasedev.enable_migration, ON_OFF_AUTO_AUTO), - DEFINE_PROP_ON_OFF_AUTO("x-migration-multifd-transfer", VFIOPCIDevice, - vbasedev.migration_multifd_transfer, - ON_OFF_AUTO_AUTO), + DEFINE_PROP("x-migration-multifd-transfer", VFIOPCIDevice, + vbasedev.migration_multifd_transfer, + vfio_pci_migration_multifd_transfer_prop, OnOffAuto, + .set_default = true, .defval.i = ON_OFF_AUTO_AUTO), DEFINE_PROP_BOOL("migration-events", VFIOPCIDevice, vbasedev.migration_events, false), DEFINE_PROP_BOOL("x-no-mmap", VFIOPCIDevice, vbasedev.no_mmap, false), @@ -XXX,XX +XXX,XX @@ static const TypeInfo vfio_pci_nohotplug_dev_info = { static void register_vfio_pci_dev_type(void) { + /* + * Ordinary ON_OFF_AUTO property isn't runtime-mutable, but source VM can + * run for a long time before being migrated so it is desirable to have a + * fallback mechanism to the old way of transferring VFIO device state if + * it turns to be necessary. + * The following makes this type of property have the same mutability level + * as ordinary migration parameters. + */ + vfio_pci_migration_multifd_transfer_prop = qdev_prop_on_off_auto; + vfio_pci_migration_multifd_transfer_prop.realized_set_allowed = true; + type_register_static(&vfio_pci_dev_info); type_register_static(&vfio_pci_nohotplug_dev_info); } From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Add a hw_compat entry for recently added x-migration-multifd-transfer VFIO property. Reviewed-by: Cédric Le Goater <clg@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/core/machine.c | 1 + 1 file changed, 1 insertion(+) diff --git a/hw/core/machine.c b/hw/core/machine.c index XXXXXXX..XXXXXXX 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -XXX,XX +XXX,XX @@ GlobalProperty hw_compat_9_2[] = { { "virtio-mem-pci", "vectors", "0" }, { "migration", "multifd-clean-tls-termination", "false" }, { "migration", "send-switchover-start", "off"}, + { "vfio-pci", "x-migration-multifd-transfer", "off" }, }; const size_t hw_compat_9_2_len = G_N_ELEMENTS(hw_compat_9_2); From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Allow capping the maximum count of in-flight VFIO device state buffers queued at the destination, otherwise a malicious QEMU source could theoretically cause the target QEMU to allocate unlimited amounts of memory for buffers-in-flight. Since this is not expected to be a realistic threat in most of VFIO live migration use cases and the right value depends on the particular setup disable the limit by default by setting it to UINT64_MAX. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 16 ++++++++++++++++ hw/vfio/pci.c | 9 +++++++++ include/hw/vfio/vfio-common.h | 1 + 3 files changed, 26 insertions(+) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ typedef struct VFIOMultifd { QemuMutex load_bufs_mutex; /* Lock order: this lock -> BQL */ uint32_t load_buf_idx; uint32_t load_buf_idx_last; + uint32_t load_buf_queued_pending_buffers; } VFIOMultifd; static void vfio_state_buffer_clear(gpointer data) @@ -XXX,XX +XXX,XX @@ static bool vfio_load_state_buffer_insert(VFIODevice *vbasedev, assert(packet->idx >= multifd->load_buf_idx); + multifd->load_buf_queued_pending_buffers++; + if (multifd->load_buf_queued_pending_buffers > + vbasedev->migration_max_queued_buffers) { + error_setg(errp, + "%s: queuing state buffer %" PRIu32 + " would exceed the max of %" PRIu64, + vbasedev->name, packet->idx, + vbasedev->migration_max_queued_buffers); + return false; + } + lb->data = g_memdup2(&packet->data, packet_total_size - sizeof(*packet)); lb->len = packet_total_size - sizeof(*packet); lb->is_present = true; @@ -XXX,XX +XXX,XX @@ static bool vfio_load_bufs_thread(void *opaque, bool *should_quit, Error **errp) goto thread_exit; } + assert(multifd->load_buf_queued_pending_buffers > 0); + multifd->load_buf_queued_pending_buffers--; + if (multifd->load_buf_idx == multifd->load_buf_idx_last - 1) { trace_vfio_load_state_device_buffer_end(vbasedev->name); } @@ -XXX,XX +XXX,XX @@ static VFIOMultifd *vfio_multifd_new(void) multifd->load_buf_idx = 0; multifd->load_buf_idx_last = UINT32_MAX; + multifd->load_buf_queued_pending_buffers = 0; qemu_cond_init(&multifd->load_bufs_buffer_ready_cond); multifd->load_bufs_thread_running = false; diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -XXX,XX +XXX,XX @@ static const Property vfio_pci_dev_properties[] = { vbasedev.migration_multifd_transfer, vfio_pci_migration_multifd_transfer_prop, OnOffAuto, .set_default = true, .defval.i = ON_OFF_AUTO_AUTO), + DEFINE_PROP_UINT64("x-migration-max-queued-buffers", VFIOPCIDevice, + vbasedev.migration_max_queued_buffers, UINT64_MAX), DEFINE_PROP_BOOL("migration-events", VFIOPCIDevice, vbasedev.migration_events, false), DEFINE_PROP_BOOL("x-no-mmap", VFIOPCIDevice, vbasedev.no_mmap, false), @@ -XXX,XX +XXX,XX @@ static void vfio_pci_dev_class_init(ObjectClass *klass, void *data) "x-migration-multifd-transfer", "Transfer this device state via " "multifd channels when live migrating it"); + object_class_property_set_description(klass, /* 10.0 */ + "x-migration-max-queued-buffers", + "Maximum count of in-flight VFIO " + "device state buffers queued at the " + "destination when doing live " + "migration of device state via " + "multifd channels"); } static const TypeInfo vfio_pci_dev_info = { diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -XXX,XX +XXX,XX @@ typedef struct VFIODevice { bool ram_block_discard_allowed; OnOffAuto enable_migration; OnOffAuto migration_multifd_transfer; + uint64_t migration_max_queued_buffers; bool migration_events; VFIODeviceOps *ops; unsigned int num_irqs; From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> This property allows configuring whether to start the config load only after all iterables were loaded. Such interlocking is required for ARM64 due to this platform VFIO dependency on interrupt controller being loaded first. The property defaults to AUTO, which means ON for ARM, OFF for other platforms. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- hw/vfio/migration-multifd.c | 91 +++++++++++++++++++++++++++++++++++ hw/vfio/migration-multifd.h | 3 ++ hw/vfio/migration.c | 10 +++- hw/vfio/pci.c | 9 ++++ include/hw/vfio/vfio-common.h | 2 + 5 files changed, 114 insertions(+), 1 deletion(-) diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.c +++ b/hw/vfio/migration-multifd.c @@ -XXX,XX +XXX,XX @@ typedef struct VFIODeviceStatePacket { uint8_t data[0]; } QEMU_PACKED VFIODeviceStatePacket; +bool vfio_load_config_after_iter(VFIODevice *vbasedev) +{ + if (vbasedev->migration_load_config_after_iter == ON_OFF_AUTO_ON) { + return true; + } else if (vbasedev->migration_load_config_after_iter == ON_OFF_AUTO_OFF) { + return false; + } + + assert(vbasedev->migration_load_config_after_iter == ON_OFF_AUTO_AUTO); + + /* + * Starting the config load only after all iterables were loaded is required + * for ARM64 due to this platform VFIO dependency on interrupt controller + * being loaded first. + * + * See commit d329f5032e17 ("vfio: Move the saving of the config space to + * the right place in VFIO migration"). + */ +#if defined(TARGET_ARM) + return true; +#else + return false; +#endif +} + /* type safety */ typedef struct VFIOStateBuffers { GArray *array; @@ -XXX,XX +XXX,XX @@ typedef struct VFIOMultifd { bool load_bufs_thread_running; bool load_bufs_thread_want_exit; + bool load_bufs_iter_done; + QemuCond load_bufs_iter_done_cond; + VFIOStateBuffers load_bufs; QemuCond load_bufs_buffer_ready_cond; QemuCond load_bufs_thread_finished_cond; @@ -XXX,XX +XXX,XX @@ static bool vfio_load_bufs_thread(void *opaque, bool *should_quit, Error **errp) multifd->load_buf_idx++; } + if (vfio_load_config_after_iter(vbasedev)) { + while (!multifd->load_bufs_iter_done) { + qemu_cond_wait(&multifd->load_bufs_iter_done_cond, + &multifd->load_bufs_mutex); + + /* + * Need to re-check cancellation immediately after wait in case + * cond was signalled by vfio_load_cleanup_load_bufs_thread(). + */ + if (vfio_load_bufs_thread_want_exit(multifd, should_quit)) { + error_setg(errp, "operation cancelled"); + goto thread_exit; + } + } + } + if (!vfio_load_bufs_thread_load_config(vbasedev, errp)) { goto thread_exit; } @@ -XXX,XX +XXX,XX @@ thread_exit: return ret; } +int vfio_load_state_config_load_ready(VFIODevice *vbasedev) +{ + VFIOMigration *migration = vbasedev->migration; + VFIOMultifd *multifd = migration->multifd; + int ret = 0; + + if (!vfio_multifd_transfer_enabled(vbasedev)) { + error_report("%s: got DEV_CONFIG_LOAD_READY outside multifd transfer", + vbasedev->name); + return -EINVAL; + } + + if (!vfio_load_config_after_iter(vbasedev)) { + error_report("%s: got DEV_CONFIG_LOAD_READY but was disabled", + vbasedev->name); + return -EINVAL; + } + + assert(multifd); + + /* The lock order is load_bufs_mutex -> BQL so unlock BQL here first */ + bql_unlock(); + WITH_QEMU_LOCK_GUARD(&multifd->load_bufs_mutex) { + if (multifd->load_bufs_iter_done) { + /* Can't print error here as we're outside BQL */ + ret = -EINVAL; + break; + } + + multifd->load_bufs_iter_done = true; + qemu_cond_signal(&multifd->load_bufs_iter_done_cond); + } + bql_lock(); + + if (ret) { + error_report("%s: duplicate DEV_CONFIG_LOAD_READY", + vbasedev->name); + } + + return ret; +} + static VFIOMultifd *vfio_multifd_new(void) { VFIOMultifd *multifd = g_new(VFIOMultifd, 1); @@ -XXX,XX +XXX,XX @@ static VFIOMultifd *vfio_multifd_new(void) multifd->load_buf_queued_pending_buffers = 0; qemu_cond_init(&multifd->load_bufs_buffer_ready_cond); + multifd->load_bufs_iter_done = false; + qemu_cond_init(&multifd->load_bufs_iter_done_cond); + multifd->load_bufs_thread_running = false; multifd->load_bufs_thread_want_exit = false; qemu_cond_init(&multifd->load_bufs_thread_finished_cond); @@ -XXX,XX +XXX,XX @@ static void vfio_load_cleanup_load_bufs_thread(VFIOMultifd *multifd) multifd->load_bufs_thread_want_exit = true; qemu_cond_signal(&multifd->load_bufs_buffer_ready_cond); + qemu_cond_signal(&multifd->load_bufs_iter_done_cond); qemu_cond_wait(&multifd->load_bufs_thread_finished_cond, &multifd->load_bufs_mutex); } @@ -XXX,XX +XXX,XX @@ static void vfio_multifd_free(VFIOMultifd *multifd) vfio_load_cleanup_load_bufs_thread(multifd); qemu_cond_destroy(&multifd->load_bufs_thread_finished_cond); + qemu_cond_destroy(&multifd->load_bufs_iter_done_cond); vfio_state_buffers_destroy(&multifd->load_bufs); qemu_cond_destroy(&multifd->load_bufs_buffer_ready_cond); qemu_mutex_destroy(&multifd->load_bufs_mutex); diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration-multifd.h +++ b/hw/vfio/migration-multifd.h @@ -XXX,XX +XXX,XX @@ void vfio_multifd_cleanup(VFIODevice *vbasedev); bool vfio_multifd_transfer_supported(void); bool vfio_multifd_transfer_enabled(VFIODevice *vbasedev); +bool vfio_load_config_after_iter(VFIODevice *vbasedev); bool vfio_multifd_load_state_buffer(void *opaque, char *data, size_t data_size, Error **errp); +int vfio_load_state_config_load_ready(VFIODevice *vbasedev); + void vfio_multifd_emit_dummy_eos(VFIODevice *vbasedev, QEMUFile *f); bool diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -XXX,XX +XXX,XX @@ static void vfio_save_state(QEMUFile *f, void *opaque) int ret; if (vfio_multifd_transfer_enabled(vbasedev)) { - vfio_multifd_emit_dummy_eos(vbasedev, f); + if (vfio_load_config_after_iter(vbasedev)) { + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_CONFIG_LOAD_READY); + } else { + vfio_multifd_emit_dummy_eos(vbasedev, f); + } return; } @@ -XXX,XX +XXX,XX @@ static int vfio_load_state(QEMUFile *f, void *opaque, int version_id) return ret; } + case VFIO_MIG_FLAG_DEV_CONFIG_LOAD_READY: + { + return vfio_load_state_config_load_ready(vbasedev); + } default: error_report("%s: Unknown tag 0x%"PRIx64, vbasedev->name, data); return -EINVAL; diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index XXXXXXX..XXXXXXX 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -XXX,XX +XXX,XX @@ static const Property vfio_pci_dev_properties[] = { vbasedev.migration_multifd_transfer, vfio_pci_migration_multifd_transfer_prop, OnOffAuto, .set_default = true, .defval.i = ON_OFF_AUTO_AUTO), + DEFINE_PROP_ON_OFF_AUTO("x-migration-load-config-after-iter", VFIOPCIDevice, + vbasedev.migration_load_config_after_iter, + ON_OFF_AUTO_AUTO), DEFINE_PROP_UINT64("x-migration-max-queued-buffers", VFIOPCIDevice, vbasedev.migration_max_queued_buffers, UINT64_MAX), DEFINE_PROP_BOOL("migration-events", VFIOPCIDevice, @@ -XXX,XX +XXX,XX @@ static void vfio_pci_dev_class_init(ObjectClass *klass, void *data) "x-migration-multifd-transfer", "Transfer this device state via " "multifd channels when live migrating it"); + object_class_property_set_description(klass, /* 10.0 */ + "x-migration-load-config-after-iter", + "Start the config load only after " + "all iterables were loaded when doing " + "live migration of device state via " + "multifd channels"); object_class_property_set_description(klass, /* 10.0 */ "x-migration-max-queued-buffers", "Maximum count of in-flight VFIO " diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -XXX,XX +XXX,XX @@ #define VFIO_MIG_FLAG_DEV_SETUP_STATE (0xffffffffef100003ULL) #define VFIO_MIG_FLAG_DEV_DATA_STATE (0xffffffffef100004ULL) #define VFIO_MIG_FLAG_DEV_INIT_DATA_SENT (0xffffffffef100005ULL) +#define VFIO_MIG_FLAG_DEV_CONFIG_LOAD_READY (0xffffffffef100006ULL) enum { VFIO_DEVICE_TYPE_PCI = 0, @@ -XXX,XX +XXX,XX @@ typedef struct VFIODevice { bool ram_block_discard_allowed; OnOffAuto enable_migration; OnOffAuto migration_multifd_transfer; + OnOffAuto migration_load_config_after_iter; uint64_t migration_max_queued_buffers; bool migration_events; VFIODeviceOps *ops; From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> Update the VFIO documentation at docs/devel/migration describing the changes brought by the multifd device state transfer. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- docs/devel/migration/vfio.rst | 79 +++++++++++++++++++++++++++++++---- 1 file changed, 72 insertions(+), 7 deletions(-) diff --git a/docs/devel/migration/vfio.rst b/docs/devel/migration/vfio.rst index XXXXXXX..XXXXXXX 100644 --- a/docs/devel/migration/vfio.rst +++ b/docs/devel/migration/vfio.rst @@ -XXX,XX +XXX,XX @@ VFIO implements the device hooks for the iterative approach as follows: * A ``switchover_ack_needed`` function that checks if the VFIO device uses "switchover-ack" migration capability when this capability is enabled. -* A ``save_state`` function to save the device config space if it is present. +* A ``switchover_start`` function that in the multifd mode starts a thread that + reassembles the multifd received data and loads it in-order into the device. + In the non-multifd mode this function is a NOP. -* A ``save_live_complete_precopy`` function that sets the VFIO device in - _STOP_COPY state and iteratively copies the data for the VFIO device until - the vendor driver indicates that no data remains. +* A ``save_state`` function to save the device config space if it is present + in the non-multifd mode. + In the multifd mode it just emits either a dummy EOS marker or + "all iterables were loaded" flag for configurations that need to defer + loading device config space after them. -* A ``load_state`` function that loads the config section and the data - sections that are generated by the save functions above. +* A ``save_live_complete_precopy`` function that in the non-multifd mode sets + the VFIO device in _STOP_COPY state and iteratively copies the data for the + VFIO device until the vendor driver indicates that no data remains. + In the multifd mode it just emits a dummy EOS marker. + +* A ``save_live_complete_precopy_thread`` function that in the multifd mode + provides thread handler performing multifd device state transfer. + It sets the VFIO device to _STOP_COPY state, iteratively reads the data + from the VFIO device and queues it for multifd transmission until the vendor + driver indicates that no data remains. + After that, it saves the device config space and queues it for multifd + transfer too. + In the non-multifd mode this thread is a NOP. + +* A ``load_state`` function that loads the data sections that are generated + by the main migration channel save functions above. + In the non-multifd mode it also loads the config section, while in the + multifd mode it handles the optional "all iterables were loaded" flag if + it is in use. + +* A ``load_state_buffer`` function that loads the device state and the device + config that arrived via multifd channels. + It's used only in the multifd mode. * ``cleanup`` functions for both save and load that perform any migration related cleanup. @@ -XXX,XX +XXX,XX @@ Live migration save path Then the VFIO device is put in _STOP_COPY state (FINISH_MIGRATE, _ACTIVE, _STOP_COPY) .save_live_complete_precopy() is called for each active device - For the VFIO device, iterate in .save_live_complete_precopy() until + For the VFIO device: in the non-multifd mode iterate in + .save_live_complete_precopy() until pending data is 0 + In the multifd mode this iteration is done in + .save_live_complete_precopy_thread() instead. | (POSTMIGRATE, _COMPLETED, _STOP_COPY) Migraton thread schedules cleanup bottom half and exits @@ -XXX,XX +XXX,XX @@ Live migration resume path (RESTORE_VM, _ACTIVE, _STOP) | For each device, .load_state() is called for that device section data + transmitted via the main migration channel. + For data transmitted via multifd channels .load_state_buffer() is called + instead. (RESTORE_VM, _ACTIVE, _RESUMING) | At the end, .load_cleanup() is called for each device and vCPUs are started @@ -XXX,XX +XXX,XX @@ Postcopy ======== Postcopy migration is currently not supported for VFIO devices. + +Multifd +======= + +Starting from QEMU version 10.0 there's a possibility to transfer VFIO device +_STOP_COPY state via multifd channels. This helps reduce downtime - especially +with multiple VFIO devices or with devices having a large migration state. +As an additional benefit, setting the VFIO device to _STOP_COPY state and +saving its config space is also parallelized (run in a separate thread) in +such migration mode. + +The multifd VFIO device state transfer is controlled by +"x-migration-multifd-transfer" VFIO device property. This property defaults to +AUTO, which means that VFIO device state transfer via multifd channels is +attempted in configurations that otherwise support it. + +Since the target QEMU needs to load device state buffers in-order it needs to +queue incoming buffers until they can be loaded into the device. +This means that a malicious QEMU source could theoretically cause the target +QEMU to allocate unlimited amounts of memory for such buffers-in-flight. + +The "x-migration-max-queued-buffers" property allows capping the maximum count +of these VFIO device state buffers queued at the destination. + +Because a malicious QEMU source causing OOM on the target is not expected to be +a realistic threat in most of VFIO live migration use cases and the right value +depends on the particular setup by default this queued buffers limit is +disabled by setting it to UINT64_MAX. + +Some host platforms (like ARM64) require that VFIO device config is loaded only +after all iterables were loaded. +Such interlocking is controlled by "x-migration-load-config-after-iter" VFIO +device property, which in its default setting (AUTO) does so only on platforms +that actually require it. From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> All callers to migration_incoming_state_destroy() other than postcopy_ram_listen_thread() do this call with BQL held. Since migration_incoming_state_destroy() ultimately calls "load_cleanup" SaveVMHandlers and it will soon call BQL-sensitive code it makes sense to always call that function under BQL rather than to have it deal with both cases (with BQL and without BQL). Add the necessary bql_lock() and bql_unlock() to postcopy_ram_listen_thread(). qemu_loadvm_state_main() in postcopy_ram_listen_thread() could call "load_state" SaveVMHandlers that are expecting BQL to be held. In principle, the only devices that should be arriving on migration channel serviced by postcopy_ram_listen_thread() are those that are postcopiable and whose load handlers are safe to be called without BQL being held. But nothing currently prevents the source from sending data for "unsafe" devices which would cause trouble there. Add a TODO comment there so it's clear that it would be good to improve handling of such (erroneous) case in the future. Acked-by: Peter Xu <peterx@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> --- migration/migration.c | 13 +++++++++++++ migration/savevm.c | 4 ++++ 2 files changed, 17 insertions(+) diff --git a/migration/migration.c b/migration/migration.c index XXXXXXX..XXXXXXX 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -XXX,XX +XXX,XX @@ void migration_incoming_state_destroy(void) struct MigrationIncomingState *mis = migration_incoming_get_current(); multifd_recv_cleanup(); + /* * RAM state cleanup needs to happen after multifd cleanup, because * multifd threads can use some of its states (receivedmap). + * The VFIO load_cleanup() implementation is BQL-sensitive. It requires + * BQL must NOT be taken when recycling load threads, so that it won't + * block the load threads from making progress on address space + * modification operations. + * + * To make it work, we could try to not take BQL for all load_cleanup(), + * or conditionally unlock BQL only if bql_locked() in VFIO. + * + * Since most existing call sites take BQL for load_cleanup(), make + * it simple by taking BQL always as the rule, so that VFIO can unlock + * BQL and retake unconditionally. */ + assert(bql_locked()); qemu_loadvm_state_cleanup(); if (mis->to_src_file) { diff --git a/migration/savevm.c b/migration/savevm.c index XXXXXXX..XXXXXXX 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -XXX,XX +XXX,XX @@ static void *postcopy_ram_listen_thread(void *opaque) * in qemu_file, and thus we must be blocking now. */ qemu_file_set_blocking(f, true); + + /* TODO: sanity check that only postcopiable data will be loaded here */ load_res = qemu_loadvm_state_main(f, mis); /* @@ -XXX,XX +XXX,XX @@ static void *postcopy_ram_listen_thread(void *opaque) * (If something broke then qemu will have to exit anyway since it's * got a bad migration state). */ + bql_lock(); migration_incoming_state_destroy(); + bql_unlock(); rcu_unregister_thread(); mis->have_listen_thread = false;