From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com>
Implement the multifd device state transfer via additional per-device
thread spawned from save_live_complete_precopy_begin 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.c | 207 ++++++++++++++++++++++++++++++++++
hw/vfio/trace-events | 3 +
include/hw/vfio/vfio-common.h | 9 ++
3 files changed, 219 insertions(+)
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 719e36800ab5..28a835f8a945 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -643,6 +643,16 @@ static int vfio_save_setup(QEMUFile *f, void *opaque, Error **errp)
uint64_t stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE;
int ret;
+ /* Make a copy of this setting at the start in case it is changed mid-migration */
+ migration->multifd_transfer = vbasedev->migration_multifd_transfer;
+
+ if (migration->multifd_transfer && !migration_has_device_state_support()) {
+ error_setg(errp,
+ "%s: Multifd device transfer requested but unsupported in the current config",
+ vbasedev->name);
+ return -EINVAL;
+ }
+
qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
vfio_query_stop_copy_size(vbasedev, &stop_copy_size);
@@ -692,6 +702,8 @@ static int vfio_save_setup(QEMUFile *f, void *opaque, Error **errp)
return ret;
}
+static void vfio_save_complete_precopy_async_thread_thread_terminate(VFIODevice *vbasedev);
+
static void vfio_save_cleanup(void *opaque)
{
VFIODevice *vbasedev = opaque;
@@ -699,6 +711,8 @@ static void vfio_save_cleanup(void *opaque)
Error *local_err = NULL;
int ret;
+ vfio_save_complete_precopy_async_thread_thread_terminate(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.
@@ -712,6 +726,7 @@ static void vfio_save_cleanup(void *opaque)
}
}
+ g_clear_pointer(&migration->idstr, g_free);
g_free(migration->data_buffer);
migration->data_buffer = NULL;
migration->precopy_init_size = 0;
@@ -823,10 +838,17 @@ static int vfio_save_iterate(QEMUFile *f, void *opaque)
static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
{
VFIODevice *vbasedev = opaque;
+ VFIOMigration *migration = vbasedev->migration;
ssize_t data_size;
int ret;
Error *local_err = NULL;
+ if (migration->multifd_transfer) {
+ /* Emit dummy NOP data */
+ qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
+ return 0;
+ }
+
trace_vfio_save_complete_precopy_started(vbasedev->name);
/* We reach here with device state STOP or STOP_COPY only */
@@ -852,12 +874,188 @@ static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
return ret;
}
+static int vfio_save_complete_precopy_async_thread_config_state(VFIODevice *vbasedev, uint32_t idx)
+{
+ VFIOMigration *migration = vbasedev->migration;
+ g_autoptr(QIOChannelBuffer) bioc = NULL;
+ 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));
+
+ ret = vfio_save_device_config_state(f, vbasedev, NULL);
+ if (ret) {
+ return ret;
+ }
+
+ ret = qemu_fflush(f);
+ if (ret) {
+ goto ret_close_file;
+ }
+
+ packet_len = sizeof(*packet) + bioc->usage;
+ packet = g_malloc0(packet_len);
+ packet->idx = idx;
+ packet->flags = VFIO_DEVICE_STATE_CONFIG_STATE;
+ memcpy(&packet->data, bioc->data, bioc->usage);
+
+ ret = multifd_queue_device_state(migration->idstr, migration->instance_id,
+ (char *)packet, packet_len);
+
+ bytes_transferred += packet_len;
+
+ret_close_file:
+ g_clear_pointer(&f, qemu_fclose);
+ return ret;
+}
+
+static void *vfio_save_complete_precopy_async_thread(void *opaque)
+{
+ VFIODevice *vbasedev = opaque;
+ VFIOMigration *migration = vbasedev->migration;
+ int *ret = &migration->save_complete_precopy_thread_ret;
+ g_autofree VFIODeviceStatePacket *packet = NULL;
+ uint32_t idx;
+
+ /* We reach here with device state STOP or STOP_COPY only */
+ *ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_STOP_COPY,
+ VFIO_DEVICE_STATE_STOP, NULL);
+ if (*ret) {
+ return NULL;
+ }
+
+ packet = g_malloc0(sizeof(*packet) + migration->data_buffer_size);
+
+ for (idx = 0; ; idx++) {
+ ssize_t data_size;
+ size_t packet_size;
+
+ data_size = read(migration->data_fd, &packet->data,
+ migration->data_buffer_size);
+ if (data_size < 0) {
+ if (errno != ENOMSG) {
+ *ret = -errno;
+ return NULL;
+ }
+
+ /*
+ * Pre-copy emptied all the device state for now. For more information,
+ * please refer to the Linux kernel VFIO uAPI.
+ */
+ data_size = 0;
+ }
+
+ if (data_size == 0)
+ break;
+
+ packet->idx = idx;
+ packet_size = sizeof(*packet) + data_size;
+
+ *ret = multifd_queue_device_state(migration->idstr, migration->instance_id,
+ (char *)packet, packet_size);
+ if (*ret) {
+ return NULL;
+ }
+
+ bytes_transferred += packet_size;
+ }
+
+ *ret = vfio_save_complete_precopy_async_thread_config_state(vbasedev, idx);
+ if (*ret) {
+ return NULL;
+ }
+
+ trace_vfio_save_complete_precopy_async_finished(vbasedev->name);
+
+ return NULL;
+}
+
+static int vfio_save_complete_precopy_begin(QEMUFile *f,
+ char *idstr, uint32_t instance_id,
+ void *opaque)
+{
+ VFIODevice *vbasedev = opaque;
+ VFIOMigration *migration = vbasedev->migration;
+ int ret;
+
+ migration->save_complete_precopy_thread_ret = 0;
+
+ if (!migration->multifd_transfer) {
+ /* Emit dummy NOP data */
+ qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
+ return 0;
+ }
+
+ qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE_COMPLETE);
+ qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
+
+ ret = qemu_fflush(f);
+ if (ret) {
+ return ret;
+ }
+
+ assert(!migration->save_complete_precopy_thread_started);
+
+ assert(!migration->idstr);
+ migration->idstr = g_strdup(idstr);
+ migration->instance_id = instance_id;
+
+ qemu_thread_create(&migration->save_complete_precopy_thread,
+ "vfio-save_complete_precopy",
+ vfio_save_complete_precopy_async_thread,
+ opaque, QEMU_THREAD_JOINABLE);
+
+ migration->save_complete_precopy_thread_started = true;
+
+ trace_vfio_save_complete_precopy_async_started(vbasedev->name, idstr, instance_id);
+
+ return 0;
+}
+
+static void vfio_save_complete_precopy_async_thread_thread_terminate(VFIODevice *vbasedev)
+{
+ VFIOMigration *migration = vbasedev->migration;
+
+ if (!migration->save_complete_precopy_thread_started) {
+ return;
+ }
+
+ qemu_thread_join(&migration->save_complete_precopy_thread);
+
+ migration->save_complete_precopy_thread_started = false;
+
+ trace_vfio_save_complete_precopy_async_joined(vbasedev->name,
+ migration->save_complete_precopy_thread_ret);
+}
+
+static int vfio_save_complete_precopy_end(QEMUFile *f, void *opaque)
+{
+ VFIODevice *vbasedev = opaque;
+ VFIOMigration *migration = vbasedev->migration;
+
+ vfio_save_complete_precopy_async_thread_thread_terminate(vbasedev);
+
+ return migration->save_complete_precopy_thread_ret;
+}
+
static void vfio_save_state(QEMUFile *f, void *opaque)
{
VFIODevice *vbasedev = opaque;
+ VFIOMigration *migration = vbasedev->migration;
Error *local_err = NULL;
int ret;
+ if (migration->multifd_transfer) {
+ /* Emit dummy NOP data */
+ qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
+ return;
+ }
+
ret = vfio_save_device_config_state(f, opaque, &local_err);
if (ret) {
error_prepend(&local_err,
@@ -1106,6 +1304,8 @@ static const SaveVMHandlers savevm_vfio_handlers = {
.state_pending_exact = vfio_state_pending_exact,
.is_active_iterate = vfio_is_active_iterate,
.save_live_iterate = vfio_save_iterate,
+ .save_live_complete_precopy_begin = vfio_save_complete_precopy_begin,
+ .save_live_complete_precopy_end = vfio_save_complete_precopy_end,
.save_live_complete_precopy = vfio_save_complete_precopy,
.save_state = vfio_save_state,
.load_setup = vfio_load_setup,
@@ -1127,6 +1327,10 @@ static void vfio_vmstate_change_prepare(void *opaque, bool running,
Error *local_err = NULL;
int ret;
+ if (running) {
+ vfio_save_complete_precopy_async_thread_thread_terminate(vbasedev);
+ }
+
new_state = migration->device_state == VFIO_DEVICE_STATE_PRE_COPY ?
VFIO_DEVICE_STATE_PRE_COPY_P2P :
VFIO_DEVICE_STATE_RUNNING_P2P;
@@ -1153,6 +1357,9 @@ static void vfio_vmstate_change(void *opaque, bool running, RunState state)
int ret;
if (running) {
+ /* In case "prepare" callback wasn't registered */
+ vfio_save_complete_precopy_async_thread_thread_terminate(vbasedev);
+
new_state = VFIO_DEVICE_STATE_RUNNING;
} else {
new_state =
diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index 7f224e4d240f..569bb02434f1 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -166,6 +166,9 @@ vfio_save_block(const char *name, int data_size) " (%s) data_size %d"
vfio_save_cleanup(const char *name) " (%s)"
vfio_save_complete_precopy(const char *name, int ret) " (%s) ret %d"
vfio_save_complete_precopy_started(const char *name) " (%s)"
+vfio_save_complete_precopy_async_started(const char *name, const char *idstr, uint32_t instance_id) " (%s) idstr %s instance %"PRIu32
+vfio_save_complete_precopy_async_finished(const char *name) " (%s)"
+vfio_save_complete_precopy_async_joined(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 0x%"PRIx64" precopy dirty size 0x%"PRIx64
vfio_save_iterate_started(const char *name) " (%s)"
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index bc85891d8fff..2d76d3fc8bba 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -70,16 +70,25 @@ typedef struct VFIOMigration {
uint64_t mig_flags;
uint64_t precopy_init_size;
uint64_t precopy_dirty_size;
+ bool multifd_transfer;
bool initial_data_sent;
bool save_iterate_run;
bool save_iterate_empty_hit;
+
+ QemuThread save_complete_precopy_thread;
+ int save_complete_precopy_thread_ret;
+ bool save_complete_precopy_thread_started;
+
QemuThread load_bufs_thread;
Error *load_bufs_thread_errp;
bool load_bufs_thread_started;
bool load_bufs_thread_finished;
bool load_bufs_thread_want_exit;
+ char *idstr;
+ uint32_t instance_id;
+
GArray *load_bufs;
bool load_bufs_device_ready;
QemuCond load_bufs_device_ready_cond;© 2016 - 2024 Red Hat, Inc.