Let's move work management inside the vdpa_sim core.
This way we can easily change how we manage the works, without
having to change the devices each time.
Acked-by: Eugenio Pérez Martin <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
drivers/vdpa/vdpa_sim/vdpa_sim.h | 3 ++-
drivers/vdpa/vdpa_sim/vdpa_sim.c | 17 +++++++++++++++--
drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 6 ++----
drivers/vdpa/vdpa_sim/vdpa_sim_net.c | 6 ++----
4 files changed, 21 insertions(+), 11 deletions(-)
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h
index 144858636c10..acee20faaf6a 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
@@ -45,7 +45,7 @@ struct vdpasim_dev_attr {
u32 ngroups;
u32 nas;
- work_func_t work_fn;
+ void (*work_fn)(struct vdpasim *vdpasim);
void (*get_config)(struct vdpasim *vdpasim, void *config);
void (*set_config)(struct vdpasim *vdpasim, const void *config);
int (*get_stats)(struct vdpasim *vdpasim, u16 idx,
@@ -78,6 +78,7 @@ struct vdpasim {
struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *attr,
const struct vdpa_dev_set_config *config);
+void vdpasim_schedule_work(struct vdpasim *vdpasim);
/* TODO: cross-endian support */
static inline bool vdpasim_is_little_endian(struct vdpasim *vdpasim)
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index 47cdf2a1f5b8..f6329900e61a 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -127,6 +127,13 @@ static void vdpasim_do_reset(struct vdpasim *vdpasim)
static const struct vdpa_config_ops vdpasim_config_ops;
static const struct vdpa_config_ops vdpasim_batch_config_ops;
+static void vdpasim_work_fn(struct work_struct *work)
+{
+ struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
+
+ vdpasim->dev_attr.work_fn(vdpasim);
+}
+
struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
const struct vdpa_dev_set_config *config)
{
@@ -163,7 +170,7 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
vdpasim = vdpa_to_sim(vdpa);
vdpasim->dev_attr = *dev_attr;
- INIT_WORK(&vdpasim->work, dev_attr->work_fn);
+ INIT_WORK(&vdpasim->work, vdpasim_work_fn);
spin_lock_init(&vdpasim->lock);
spin_lock_init(&vdpasim->iommu_lock);
@@ -214,6 +221,12 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
}
EXPORT_SYMBOL_GPL(vdpasim_create);
+void vdpasim_schedule_work(struct vdpasim *vdpasim)
+{
+ schedule_work(&vdpasim->work);
+}
+EXPORT_SYMBOL_GPL(vdpasim_schedule_work);
+
static int vdpasim_set_vq_address(struct vdpa_device *vdpa, u16 idx,
u64 desc_area, u64 driver_area,
u64 device_area)
@@ -248,7 +261,7 @@ static void vdpasim_kick_vq(struct vdpa_device *vdpa, u16 idx)
}
if (vq->ready)
- schedule_work(&vdpasim->work);
+ vdpasim_schedule_work(vdpasim);
}
static void vdpasim_set_vq_cb(struct vdpa_device *vdpa, u16 idx,
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
index 5117959bed8a..eb4897c8541e 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
@@ -11,7 +11,6 @@
#include <linux/module.h>
#include <linux/device.h>
#include <linux/kernel.h>
-#include <linux/sched.h>
#include <linux/blkdev.h>
#include <linux/vringh.h>
#include <linux/vdpa.h>
@@ -286,9 +285,8 @@ static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
return handled;
}
-static void vdpasim_blk_work(struct work_struct *work)
+static void vdpasim_blk_work(struct vdpasim *vdpasim)
{
- struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
bool reschedule = false;
int i;
@@ -326,7 +324,7 @@ static void vdpasim_blk_work(struct work_struct *work)
spin_unlock(&vdpasim->lock);
if (reschedule)
- schedule_work(&vdpasim->work);
+ vdpasim_schedule_work(vdpasim);
}
static void vdpasim_blk_get_config(struct vdpasim *vdpasim, void *config)
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
index 862f405362de..e61a9ecbfafe 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
@@ -11,7 +11,6 @@
#include <linux/module.h>
#include <linux/device.h>
#include <linux/kernel.h>
-#include <linux/sched.h>
#include <linux/etherdevice.h>
#include <linux/vringh.h>
#include <linux/vdpa.h>
@@ -192,9 +191,8 @@ static void vdpasim_handle_cvq(struct vdpasim *vdpasim)
u64_stats_update_end(&net->cq_stats.syncp);
}
-static void vdpasim_net_work(struct work_struct *work)
+static void vdpasim_net_work(struct vdpasim *vdpasim)
{
- struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
struct vdpasim_virtqueue *txq = &vdpasim->vqs[1];
struct vdpasim_virtqueue *rxq = &vdpasim->vqs[0];
struct vdpasim_net *net = sim_to_net(vdpasim);
@@ -260,7 +258,7 @@ static void vdpasim_net_work(struct work_struct *work)
vdpasim_net_complete(rxq, write);
if (tx_pkts > 4) {
- schedule_work(&vdpasim->work);
+ vdpasim_schedule_work(vdpasim);
goto out;
}
}
--
2.39.2
Let's use our own kthread to run device jobs.
This allows us more flexibility, especially we can attach the kthread
to the user address space when vDPA uses user's VA.
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
Notes:
v3:
- fix `dev` not initialized in the error path [Simon Horman]
drivers/vdpa/vdpa_sim/vdpa_sim.h | 3 ++-
drivers/vdpa/vdpa_sim/vdpa_sim.c | 19 +++++++++++++------
2 files changed, 15 insertions(+), 7 deletions(-)
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h
index acee20faaf6a..ce83f9130a5d 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
@@ -57,7 +57,8 @@ struct vdpasim_dev_attr {
struct vdpasim {
struct vdpa_device vdpa;
struct vdpasim_virtqueue *vqs;
- struct work_struct work;
+ struct kthread_worker *worker;
+ struct kthread_work work;
struct vdpasim_dev_attr dev_attr;
/* spinlock to synchronize virtqueue state */
spinlock_t lock;
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index f6329900e61a..1cfa56c52e5a 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -11,8 +11,8 @@
#include <linux/module.h>
#include <linux/device.h>
#include <linux/kernel.h>
+#include <linux/kthread.h>
#include <linux/slab.h>
-#include <linux/sched.h>
#include <linux/dma-map-ops.h>
#include <linux/vringh.h>
#include <linux/vdpa.h>
@@ -127,7 +127,7 @@ static void vdpasim_do_reset(struct vdpasim *vdpasim)
static const struct vdpa_config_ops vdpasim_config_ops;
static const struct vdpa_config_ops vdpasim_batch_config_ops;
-static void vdpasim_work_fn(struct work_struct *work)
+static void vdpasim_work_fn(struct kthread_work *work)
{
struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
@@ -170,11 +170,17 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
vdpasim = vdpa_to_sim(vdpa);
vdpasim->dev_attr = *dev_attr;
- INIT_WORK(&vdpasim->work, vdpasim_work_fn);
+ dev = &vdpasim->vdpa.dev;
+
+ kthread_init_work(&vdpasim->work, vdpasim_work_fn);
+ vdpasim->worker = kthread_create_worker(0, "vDPA sim worker: %s",
+ dev_attr->name);
+ if (IS_ERR(vdpasim->worker))
+ goto err_iommu;
+
spin_lock_init(&vdpasim->lock);
spin_lock_init(&vdpasim->iommu_lock);
- dev = &vdpasim->vdpa.dev;
dev->dma_mask = &dev->coherent_dma_mask;
if (dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64)))
goto err_iommu;
@@ -223,7 +229,7 @@ EXPORT_SYMBOL_GPL(vdpasim_create);
void vdpasim_schedule_work(struct vdpasim *vdpasim)
{
- schedule_work(&vdpasim->work);
+ kthread_queue_work(vdpasim->worker, &vdpasim->work);
}
EXPORT_SYMBOL_GPL(vdpasim_schedule_work);
@@ -623,7 +629,8 @@ static void vdpasim_free(struct vdpa_device *vdpa)
struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
int i;
- cancel_work_sync(&vdpasim->work);
+ kthread_cancel_work_sync(&vdpasim->work);
+ kthread_destroy_worker(vdpasim->worker);
for (i = 0; i < vdpasim->dev_attr.nvqs; i++) {
vringh_kiov_cleanup(&vdpasim->vqs[i].out_iov);
--
2.39.2The spinlock we use to protect the state of the simulator is sometimes
held for a long time (for example, when devices handle requests).
This also prevents us from calling functions that might sleep (such as
kthread_flush_work() in the next patch), and thus having to release
and retake the lock.
For these reasons, let's replace the spinlock with a mutex that gives
us more flexibility.
Suggested-by: Jason Wang <jasowang@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
drivers/vdpa/vdpa_sim/vdpa_sim.h | 4 ++--
drivers/vdpa/vdpa_sim/vdpa_sim.c | 34 ++++++++++++++--------------
drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 4 ++--
drivers/vdpa/vdpa_sim/vdpa_sim_net.c | 4 ++--
4 files changed, 23 insertions(+), 23 deletions(-)
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h
index ce83f9130a5d..4774292fba8c 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
@@ -60,8 +60,8 @@ struct vdpasim {
struct kthread_worker *worker;
struct kthread_work work;
struct vdpasim_dev_attr dev_attr;
- /* spinlock to synchronize virtqueue state */
- spinlock_t lock;
+ /* mutex to synchronize virtqueue state */
+ struct mutex mutex;
/* virtio config according to device type */
void *config;
struct vhost_iotlb *iommu;
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index 1cfa56c52e5a..ab4cfb82c237 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -178,7 +178,7 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
if (IS_ERR(vdpasim->worker))
goto err_iommu;
- spin_lock_init(&vdpasim->lock);
+ mutex_init(&vdpasim->mutex);
spin_lock_init(&vdpasim->iommu_lock);
dev->dma_mask = &dev->coherent_dma_mask;
@@ -286,13 +286,13 @@ static void vdpasim_set_vq_ready(struct vdpa_device *vdpa, u16 idx, bool ready)
struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
bool old_ready;
- spin_lock(&vdpasim->lock);
+ mutex_lock(&vdpasim->mutex);
old_ready = vq->ready;
vq->ready = ready;
if (vq->ready && !old_ready) {
vdpasim_queue_ready(vdpasim, idx);
}
- spin_unlock(&vdpasim->lock);
+ mutex_unlock(&vdpasim->mutex);
}
static bool vdpasim_get_vq_ready(struct vdpa_device *vdpa, u16 idx)
@@ -310,9 +310,9 @@ static int vdpasim_set_vq_state(struct vdpa_device *vdpa, u16 idx,
struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
struct vringh *vrh = &vq->vring;
- spin_lock(&vdpasim->lock);
+ mutex_lock(&vdpasim->mutex);
vrh->last_avail_idx = state->split.avail_index;
- spin_unlock(&vdpasim->lock);
+ mutex_unlock(&vdpasim->mutex);
return 0;
}
@@ -409,9 +409,9 @@ static u8 vdpasim_get_status(struct vdpa_device *vdpa)
struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
u8 status;
- spin_lock(&vdpasim->lock);
+ mutex_lock(&vdpasim->mutex);
status = vdpasim->status;
- spin_unlock(&vdpasim->lock);
+ mutex_unlock(&vdpasim->mutex);
return status;
}
@@ -420,19 +420,19 @@ static void vdpasim_set_status(struct vdpa_device *vdpa, u8 status)
{
struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
- spin_lock(&vdpasim->lock);
+ mutex_lock(&vdpasim->mutex);
vdpasim->status = status;
- spin_unlock(&vdpasim->lock);
+ mutex_unlock(&vdpasim->mutex);
}
static int vdpasim_reset(struct vdpa_device *vdpa)
{
struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
- spin_lock(&vdpasim->lock);
+ mutex_lock(&vdpasim->mutex);
vdpasim->status = 0;
vdpasim_do_reset(vdpasim);
- spin_unlock(&vdpasim->lock);
+ mutex_unlock(&vdpasim->mutex);
return 0;
}
@@ -441,9 +441,9 @@ static int vdpasim_suspend(struct vdpa_device *vdpa)
{
struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
- spin_lock(&vdpasim->lock);
+ mutex_lock(&vdpasim->mutex);
vdpasim->running = false;
- spin_unlock(&vdpasim->lock);
+ mutex_unlock(&vdpasim->mutex);
return 0;
}
@@ -453,7 +453,7 @@ static int vdpasim_resume(struct vdpa_device *vdpa)
struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
int i;
- spin_lock(&vdpasim->lock);
+ mutex_lock(&vdpasim->mutex);
vdpasim->running = true;
if (vdpasim->pending_kick) {
@@ -464,7 +464,7 @@ static int vdpasim_resume(struct vdpa_device *vdpa)
vdpasim->pending_kick = false;
}
- spin_unlock(&vdpasim->lock);
+ mutex_unlock(&vdpasim->mutex);
return 0;
}
@@ -536,14 +536,14 @@ static int vdpasim_set_group_asid(struct vdpa_device *vdpa, unsigned int group,
iommu = &vdpasim->iommu[asid];
- spin_lock(&vdpasim->lock);
+ mutex_lock(&vdpasim->mutex);
for (i = 0; i < vdpasim->dev_attr.nvqs; i++)
if (vdpasim_get_vq_group(vdpa, i) == group)
vringh_set_iotlb(&vdpasim->vqs[i].vring, iommu,
&vdpasim->iommu_lock);
- spin_unlock(&vdpasim->lock);
+ mutex_unlock(&vdpasim->mutex);
return 0;
}
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
index eb4897c8541e..568119e1553f 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
@@ -290,7 +290,7 @@ static void vdpasim_blk_work(struct vdpasim *vdpasim)
bool reschedule = false;
int i;
- spin_lock(&vdpasim->lock);
+ mutex_lock(&vdpasim->mutex);
if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK))
goto out;
@@ -321,7 +321,7 @@ static void vdpasim_blk_work(struct vdpasim *vdpasim)
}
}
out:
- spin_unlock(&vdpasim->lock);
+ mutex_unlock(&vdpasim->mutex);
if (reschedule)
vdpasim_schedule_work(vdpasim);
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
index e61a9ecbfafe..7ab434592bfe 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
@@ -201,7 +201,7 @@ static void vdpasim_net_work(struct vdpasim *vdpasim)
u64 rx_drops = 0, rx_overruns = 0, rx_errors = 0, tx_errors = 0;
int err;
- spin_lock(&vdpasim->lock);
+ mutex_lock(&vdpasim->mutex);
if (!vdpasim->running)
goto out;
@@ -264,7 +264,7 @@ static void vdpasim_net_work(struct vdpasim *vdpasim)
}
out:
- spin_unlock(&vdpasim->lock);
+ mutex_unlock(&vdpasim->mutex);
u64_stats_update_begin(&net->tx_stats.syncp);
net->tx_stats.pkts += tx_pkts;
--
2.39.2The new "use_va" module parameter (default: true) is used in
vdpa_alloc_device() to inform the vDPA framework that the device
supports VA.
vringh is initialized to use VA only when "use_va" is true and the
user's mm has been bound. So, only when the bus supports user VA
(e.g. vhost-vdpa).
vdpasim_mm_work_fn work is used to serialize the binding to a new
address space when the .bind_mm callback is invoked, and unbinding
when the .unbind_mm callback is invoked.
Call mmget_not_zero()/kthread_use_mm() inside the worker function
to pin the address space only as long as needed, following the
documentation of mmget() in include/linux/sched/mm.h:
* Never use this function to pin this address space for an
* unbounded/indefinite amount of time.
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
Notes:
v3:
- called mmget_not_zero() before kthread_use_mm() [Jason]
As the documentation of mmget() in include/linux/sched/mm.h says:
* Never use this function to pin this address space for an
* unbounded/indefinite amount of time.
I moved mmget_not_zero/kthread_use_mm inside the worker function,
this way we pin the address space only as long as needed.
This is similar to what vfio_iommu_type1_dma_rw_chunk() does in
drivers/vfio/vfio_iommu_type1.c
- simplified the mm bind/unbind [Jason]
- renamed vdpasim_worker_change_mm_sync() [Jason]
- fix commit message (s/default: false/default: true)
v2:
- `use_va` set to true by default [Eugenio]
- supported the new unbind_mm callback [Jason]
- removed the unbind_mm call in vdpasim_do_reset() [Jason]
- avoided to release the lock while call kthread_flush_work() since we
are now using a mutex to protect the device state
drivers/vdpa/vdpa_sim/vdpa_sim.h | 1 +
drivers/vdpa/vdpa_sim/vdpa_sim.c | 80 +++++++++++++++++++++++++++++++-
2 files changed, 79 insertions(+), 2 deletions(-)
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h
index 4774292fba8c..3a42887d05d9 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
@@ -59,6 +59,7 @@ struct vdpasim {
struct vdpasim_virtqueue *vqs;
struct kthread_worker *worker;
struct kthread_work work;
+ struct mm_struct *mm_bound;
struct vdpasim_dev_attr dev_attr;
/* mutex to synchronize virtqueue state */
struct mutex mutex;
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index ab4cfb82c237..23c891cdcd54 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -35,10 +35,44 @@ module_param(max_iotlb_entries, int, 0444);
MODULE_PARM_DESC(max_iotlb_entries,
"Maximum number of iotlb entries for each address space. 0 means unlimited. (default: 2048)");
+static bool use_va = true;
+module_param(use_va, bool, 0444);
+MODULE_PARM_DESC(use_va, "Enable/disable the device's ability to use VA");
+
#define VDPASIM_QUEUE_ALIGN PAGE_SIZE
#define VDPASIM_QUEUE_MAX 256
#define VDPASIM_VENDOR_ID 0
+struct vdpasim_mm_work {
+ struct kthread_work work;
+ struct vdpasim *vdpasim;
+ struct mm_struct *mm_to_bind;
+ int ret;
+};
+
+static void vdpasim_mm_work_fn(struct kthread_work *work)
+{
+ struct vdpasim_mm_work *mm_work =
+ container_of(work, struct vdpasim_mm_work, work);
+ struct vdpasim *vdpasim = mm_work->vdpasim;
+
+ mm_work->ret = 0;
+
+ //TODO: should we attach the cgroup of the mm owner?
+ vdpasim->mm_bound = mm_work->mm_to_bind;
+}
+
+static void vdpasim_worker_change_mm_sync(struct vdpasim *vdpasim,
+ struct vdpasim_mm_work *mm_work)
+{
+ struct kthread_work *work = &mm_work->work;
+
+ kthread_init_work(work, vdpasim_mm_work_fn);
+ kthread_queue_work(vdpasim->worker, work);
+
+ kthread_flush_work(work);
+}
+
static struct vdpasim *vdpa_to_sim(struct vdpa_device *vdpa)
{
return container_of(vdpa, struct vdpasim, vdpa);
@@ -59,8 +93,10 @@ static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx)
{
struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
uint16_t last_avail_idx = vq->vring.last_avail_idx;
+ bool va_enabled = use_va && vdpasim->mm_bound;
- vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true, false,
+ vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true,
+ va_enabled,
(struct vring_desc *)(uintptr_t)vq->desc_addr,
(struct vring_avail *)
(uintptr_t)vq->driver_addr,
@@ -130,8 +166,20 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops;
static void vdpasim_work_fn(struct kthread_work *work)
{
struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
+ struct mm_struct *mm = vdpasim->mm_bound;
+
+ if (mm) {
+ if (!mmget_not_zero(mm))
+ return;
+ kthread_use_mm(mm);
+ }
vdpasim->dev_attr.work_fn(vdpasim);
+
+ if (mm) {
+ kthread_unuse_mm(mm);
+ mmput(mm);
+ }
}
struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
@@ -162,7 +210,7 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
vdpa = __vdpa_alloc_device(NULL, ops,
dev_attr->ngroups, dev_attr->nas,
dev_attr->alloc_size,
- dev_attr->name, false);
+ dev_attr->name, use_va);
if (IS_ERR(vdpa)) {
ret = PTR_ERR(vdpa);
goto err_alloc;
@@ -582,6 +630,30 @@ static int vdpasim_set_map(struct vdpa_device *vdpa, unsigned int asid,
return ret;
}
+static int vdpasim_bind_mm(struct vdpa_device *vdpa, struct mm_struct *mm)
+{
+ struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
+ struct vdpasim_mm_work mm_work;
+
+ mm_work.vdpasim = vdpasim;
+ mm_work.mm_to_bind = mm;
+
+ vdpasim_worker_change_mm_sync(vdpasim, &mm_work);
+
+ return mm_work.ret;
+}
+
+static void vdpasim_unbind_mm(struct vdpa_device *vdpa)
+{
+ struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
+ struct vdpasim_mm_work mm_work;
+
+ mm_work.vdpasim = vdpasim;
+ mm_work.mm_to_bind = NULL;
+
+ vdpasim_worker_change_mm_sync(vdpasim, &mm_work);
+}
+
static int vdpasim_dma_map(struct vdpa_device *vdpa, unsigned int asid,
u64 iova, u64 size,
u64 pa, u32 perm, void *opaque)
@@ -678,6 +750,8 @@ static const struct vdpa_config_ops vdpasim_config_ops = {
.set_group_asid = vdpasim_set_group_asid,
.dma_map = vdpasim_dma_map,
.dma_unmap = vdpasim_dma_unmap,
+ .bind_mm = vdpasim_bind_mm,
+ .unbind_mm = vdpasim_unbind_mm,
.free = vdpasim_free,
};
@@ -712,6 +786,8 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops = {
.get_iova_range = vdpasim_get_iova_range,
.set_group_asid = vdpasim_set_group_asid,
.set_map = vdpasim_set_map,
+ .bind_mm = vdpasim_bind_mm,
+ .unbind_mm = vdpasim_unbind_mm,
.free = vdpasim_free,
};
--
2.39.2
在 2023/3/21 23:48, Stefano Garzarella 写道:
> The new "use_va" module parameter (default: true) is used in
> vdpa_alloc_device() to inform the vDPA framework that the device
> supports VA.
>
> vringh is initialized to use VA only when "use_va" is true and the
> user's mm has been bound. So, only when the bus supports user VA
> (e.g. vhost-vdpa).
>
> vdpasim_mm_work_fn work is used to serialize the binding to a new
> address space when the .bind_mm callback is invoked, and unbinding
> when the .unbind_mm callback is invoked.
>
> Call mmget_not_zero()/kthread_use_mm() inside the worker function
> to pin the address space only as long as needed, following the
> documentation of mmget() in include/linux/sched/mm.h:
>
> * Never use this function to pin this address space for an
> * unbounded/indefinite amount of time.
>
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> ---
>
> Notes:
> v3:
> - called mmget_not_zero() before kthread_use_mm() [Jason]
> As the documentation of mmget() in include/linux/sched/mm.h says:
>
> * Never use this function to pin this address space for an
> * unbounded/indefinite amount of time.
>
> I moved mmget_not_zero/kthread_use_mm inside the worker function,
> this way we pin the address space only as long as needed.
> This is similar to what vfio_iommu_type1_dma_rw_chunk() does in
> drivers/vfio/vfio_iommu_type1.c
> - simplified the mm bind/unbind [Jason]
> - renamed vdpasim_worker_change_mm_sync() [Jason]
> - fix commit message (s/default: false/default: true)
> v2:
> - `use_va` set to true by default [Eugenio]
> - supported the new unbind_mm callback [Jason]
> - removed the unbind_mm call in vdpasim_do_reset() [Jason]
> - avoided to release the lock while call kthread_flush_work() since we
> are now using a mutex to protect the device state
>
> drivers/vdpa/vdpa_sim/vdpa_sim.h | 1 +
> drivers/vdpa/vdpa_sim/vdpa_sim.c | 80 +++++++++++++++++++++++++++++++-
> 2 files changed, 79 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h
> index 4774292fba8c..3a42887d05d9 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
> @@ -59,6 +59,7 @@ struct vdpasim {
> struct vdpasim_virtqueue *vqs;
> struct kthread_worker *worker;
> struct kthread_work work;
> + struct mm_struct *mm_bound;
> struct vdpasim_dev_attr dev_attr;
> /* mutex to synchronize virtqueue state */
> struct mutex mutex;
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> index ab4cfb82c237..23c891cdcd54 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> @@ -35,10 +35,44 @@ module_param(max_iotlb_entries, int, 0444);
> MODULE_PARM_DESC(max_iotlb_entries,
> "Maximum number of iotlb entries for each address space. 0 means unlimited. (default: 2048)");
>
> +static bool use_va = true;
> +module_param(use_va, bool, 0444);
> +MODULE_PARM_DESC(use_va, "Enable/disable the device's ability to use VA");
> +
> #define VDPASIM_QUEUE_ALIGN PAGE_SIZE
> #define VDPASIM_QUEUE_MAX 256
> #define VDPASIM_VENDOR_ID 0
>
> +struct vdpasim_mm_work {
> + struct kthread_work work;
> + struct vdpasim *vdpasim;
> + struct mm_struct *mm_to_bind;
> + int ret;
> +};
> +
> +static void vdpasim_mm_work_fn(struct kthread_work *work)
> +{
> + struct vdpasim_mm_work *mm_work =
> + container_of(work, struct vdpasim_mm_work, work);
> + struct vdpasim *vdpasim = mm_work->vdpasim;
> +
> + mm_work->ret = 0;
> +
> + //TODO: should we attach the cgroup of the mm owner?
> + vdpasim->mm_bound = mm_work->mm_to_bind;
> +}
> +
> +static void vdpasim_worker_change_mm_sync(struct vdpasim *vdpasim,
> + struct vdpasim_mm_work *mm_work)
> +{
> + struct kthread_work *work = &mm_work->work;
> +
> + kthread_init_work(work, vdpasim_mm_work_fn);
> + kthread_queue_work(vdpasim->worker, work);
> +
> + kthread_flush_work(work);
> +}
> +
> static struct vdpasim *vdpa_to_sim(struct vdpa_device *vdpa)
> {
> return container_of(vdpa, struct vdpasim, vdpa);
> @@ -59,8 +93,10 @@ static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx)
> {
> struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
> uint16_t last_avail_idx = vq->vring.last_avail_idx;
> + bool va_enabled = use_va && vdpasim->mm_bound;
>
> - vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true, false,
> + vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true,
> + va_enabled,
> (struct vring_desc *)(uintptr_t)vq->desc_addr,
> (struct vring_avail *)
> (uintptr_t)vq->driver_addr,
> @@ -130,8 +166,20 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops;
> static void vdpasim_work_fn(struct kthread_work *work)
> {
> struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
> + struct mm_struct *mm = vdpasim->mm_bound;
> +
> + if (mm) {
> + if (!mmget_not_zero(mm))
> + return;
Do we need to check use_va here.
Other than this
Acked-by: Jason Wang <jasowang@redhat.com>
Thanks
> + kthread_use_mm(mm);
> + }
>
> vdpasim->dev_attr.work_fn(vdpasim);
> +
> + if (mm) {
> + kthread_unuse_mm(mm);
> + mmput(mm);
> + }
> }
>
> struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
> @@ -162,7 +210,7 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
> vdpa = __vdpa_alloc_device(NULL, ops,
> dev_attr->ngroups, dev_attr->nas,
> dev_attr->alloc_size,
> - dev_attr->name, false);
> + dev_attr->name, use_va);
> if (IS_ERR(vdpa)) {
> ret = PTR_ERR(vdpa);
> goto err_alloc;
> @@ -582,6 +630,30 @@ static int vdpasim_set_map(struct vdpa_device *vdpa, unsigned int asid,
> return ret;
> }
>
> +static int vdpasim_bind_mm(struct vdpa_device *vdpa, struct mm_struct *mm)
> +{
> + struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
> + struct vdpasim_mm_work mm_work;
> +
> + mm_work.vdpasim = vdpasim;
> + mm_work.mm_to_bind = mm;
> +
> + vdpasim_worker_change_mm_sync(vdpasim, &mm_work);
> +
> + return mm_work.ret;
> +}
> +
> +static void vdpasim_unbind_mm(struct vdpa_device *vdpa)
> +{
> + struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
> + struct vdpasim_mm_work mm_work;
> +
> + mm_work.vdpasim = vdpasim;
> + mm_work.mm_to_bind = NULL;
> +
> + vdpasim_worker_change_mm_sync(vdpasim, &mm_work);
> +}
> +
> static int vdpasim_dma_map(struct vdpa_device *vdpa, unsigned int asid,
> u64 iova, u64 size,
> u64 pa, u32 perm, void *opaque)
> @@ -678,6 +750,8 @@ static const struct vdpa_config_ops vdpasim_config_ops = {
> .set_group_asid = vdpasim_set_group_asid,
> .dma_map = vdpasim_dma_map,
> .dma_unmap = vdpasim_dma_unmap,
> + .bind_mm = vdpasim_bind_mm,
> + .unbind_mm = vdpasim_unbind_mm,
> .free = vdpasim_free,
> };
>
> @@ -712,6 +786,8 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops = {
> .get_iova_range = vdpasim_get_iova_range,
> .set_group_asid = vdpasim_set_group_asid,
> .set_map = vdpasim_set_map,
> + .bind_mm = vdpasim_bind_mm,
> + .unbind_mm = vdpasim_unbind_mm,
> .free = vdpasim_free,
> };
>
On Fri, Mar 24, 2023 at 11:49:32AM +0800, Jason Wang wrote:
>
>在 2023/3/21 23:48, Stefano Garzarella 写道:
>>The new "use_va" module parameter (default: true) is used in
>>vdpa_alloc_device() to inform the vDPA framework that the device
>>supports VA.
>>
>>vringh is initialized to use VA only when "use_va" is true and the
>>user's mm has been bound. So, only when the bus supports user VA
>>(e.g. vhost-vdpa).
>>
>>vdpasim_mm_work_fn work is used to serialize the binding to a new
>>address space when the .bind_mm callback is invoked, and unbinding
>>when the .unbind_mm callback is invoked.
>>
>>Call mmget_not_zero()/kthread_use_mm() inside the worker function
>>to pin the address space only as long as needed, following the
>>documentation of mmget() in include/linux/sched/mm.h:
>>
>> * Never use this function to pin this address space for an
>> * unbounded/indefinite amount of time.
>>
>>Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
>>---
>>
>>Notes:
>> v3:
>> - called mmget_not_zero() before kthread_use_mm() [Jason]
>> As the documentation of mmget() in include/linux/sched/mm.h says:
>> * Never use this function to pin this address space for an
>> * unbounded/indefinite amount of time.
>> I moved mmget_not_zero/kthread_use_mm inside the worker function,
>> this way we pin the address space only as long as needed.
>> This is similar to what vfio_iommu_type1_dma_rw_chunk() does in
>> drivers/vfio/vfio_iommu_type1.c
>> - simplified the mm bind/unbind [Jason]
>> - renamed vdpasim_worker_change_mm_sync() [Jason]
>> - fix commit message (s/default: false/default: true)
>> v2:
>> - `use_va` set to true by default [Eugenio]
>> - supported the new unbind_mm callback [Jason]
>> - removed the unbind_mm call in vdpasim_do_reset() [Jason]
>> - avoided to release the lock while call kthread_flush_work() since we
>> are now using a mutex to protect the device state
>>
>> drivers/vdpa/vdpa_sim/vdpa_sim.h | 1 +
>> drivers/vdpa/vdpa_sim/vdpa_sim.c | 80 +++++++++++++++++++++++++++++++-
>> 2 files changed, 79 insertions(+), 2 deletions(-)
>>
>>diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h
>>index 4774292fba8c..3a42887d05d9 100644
>>--- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
>>+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
>>@@ -59,6 +59,7 @@ struct vdpasim {
>> struct vdpasim_virtqueue *vqs;
>> struct kthread_worker *worker;
>> struct kthread_work work;
>>+ struct mm_struct *mm_bound;
>> struct vdpasim_dev_attr dev_attr;
>> /* mutex to synchronize virtqueue state */
>> struct mutex mutex;
>>diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>>index ab4cfb82c237..23c891cdcd54 100644
>>--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
>>+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>>@@ -35,10 +35,44 @@ module_param(max_iotlb_entries, int, 0444);
>> MODULE_PARM_DESC(max_iotlb_entries,
>> "Maximum number of iotlb entries for each address space. 0 means unlimited. (default: 2048)");
>>+static bool use_va = true;
>>+module_param(use_va, bool, 0444);
>>+MODULE_PARM_DESC(use_va, "Enable/disable the device's ability to use VA");
>>+
>> #define VDPASIM_QUEUE_ALIGN PAGE_SIZE
>> #define VDPASIM_QUEUE_MAX 256
>> #define VDPASIM_VENDOR_ID 0
>>+struct vdpasim_mm_work {
>>+ struct kthread_work work;
>>+ struct vdpasim *vdpasim;
>>+ struct mm_struct *mm_to_bind;
>>+ int ret;
>>+};
>>+
>>+static void vdpasim_mm_work_fn(struct kthread_work *work)
>>+{
>>+ struct vdpasim_mm_work *mm_work =
>>+ container_of(work, struct vdpasim_mm_work, work);
>>+ struct vdpasim *vdpasim = mm_work->vdpasim;
>>+
>>+ mm_work->ret = 0;
>>+
>>+ //TODO: should we attach the cgroup of the mm owner?
>>+ vdpasim->mm_bound = mm_work->mm_to_bind;
>>+}
>>+
>>+static void vdpasim_worker_change_mm_sync(struct vdpasim *vdpasim,
>>+ struct vdpasim_mm_work *mm_work)
>>+{
>>+ struct kthread_work *work = &mm_work->work;
>>+
>>+ kthread_init_work(work, vdpasim_mm_work_fn);
>>+ kthread_queue_work(vdpasim->worker, work);
>>+
>>+ kthread_flush_work(work);
>>+}
>>+
>> static struct vdpasim *vdpa_to_sim(struct vdpa_device *vdpa)
>> {
>> return container_of(vdpa, struct vdpasim, vdpa);
>>@@ -59,8 +93,10 @@ static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx)
>> {
>> struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
>> uint16_t last_avail_idx = vq->vring.last_avail_idx;
>>+ bool va_enabled = use_va && vdpasim->mm_bound;
>>- vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true, false,
>>+ vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true,
>>+ va_enabled,
>> (struct vring_desc *)(uintptr_t)vq->desc_addr,
>> (struct vring_avail *)
>> (uintptr_t)vq->driver_addr,
>>@@ -130,8 +166,20 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops;
>> static void vdpasim_work_fn(struct kthread_work *work)
>> {
>> struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
>>+ struct mm_struct *mm = vdpasim->mm_bound;
>>+
>>+ if (mm) {
>>+ if (!mmget_not_zero(mm))
>>+ return;
>
>
>Do we need to check use_va here.
Yep, right!
>
>Other than this
>
>Acked-by: Jason Wang <jasowang@redhat.com>
Thanks for the reviews,
Stefano
On Tue, Mar 21, 2023 at 11:48 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
>
> The new "use_va" module parameter (default: true) is used in
> vdpa_alloc_device() to inform the vDPA framework that the device
> supports VA.
>
> vringh is initialized to use VA only when "use_va" is true and the
> user's mm has been bound. So, only when the bus supports user VA
> (e.g. vhost-vdpa).
>
> vdpasim_mm_work_fn work is used to serialize the binding to a new
> address space when the .bind_mm callback is invoked, and unbinding
> when the .unbind_mm callback is invoked.
>
> Call mmget_not_zero()/kthread_use_mm() inside the worker function
> to pin the address space only as long as needed, following the
> documentation of mmget() in include/linux/sched/mm.h:
>
> * Never use this function to pin this address space for an
> * unbounded/indefinite amount of time.
I wonder if everything would be simplified if we just allow the parent
to advertise whether or not it requires the address space.
Then when vhost-vDPA probes the device it can simply advertise
use_work as true so vhost core can use get_task_mm() in this case?
Thanks
>
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> ---
>
> Notes:
> v3:
> - called mmget_not_zero() before kthread_use_mm() [Jason]
> As the documentation of mmget() in include/linux/sched/mm.h says:
>
> * Never use this function to pin this address space for an
> * unbounded/indefinite amount of time.
>
> I moved mmget_not_zero/kthread_use_mm inside the worker function,
> this way we pin the address space only as long as needed.
> This is similar to what vfio_iommu_type1_dma_rw_chunk() does in
> drivers/vfio/vfio_iommu_type1.c
> - simplified the mm bind/unbind [Jason]
> - renamed vdpasim_worker_change_mm_sync() [Jason]
> - fix commit message (s/default: false/default: true)
> v2:
> - `use_va` set to true by default [Eugenio]
> - supported the new unbind_mm callback [Jason]
> - removed the unbind_mm call in vdpasim_do_reset() [Jason]
> - avoided to release the lock while call kthread_flush_work() since we
> are now using a mutex to protect the device state
>
> drivers/vdpa/vdpa_sim/vdpa_sim.h | 1 +
> drivers/vdpa/vdpa_sim/vdpa_sim.c | 80 +++++++++++++++++++++++++++++++-
> 2 files changed, 79 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h
> index 4774292fba8c..3a42887d05d9 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
> @@ -59,6 +59,7 @@ struct vdpasim {
> struct vdpasim_virtqueue *vqs;
> struct kthread_worker *worker;
> struct kthread_work work;
> + struct mm_struct *mm_bound;
> struct vdpasim_dev_attr dev_attr;
> /* mutex to synchronize virtqueue state */
> struct mutex mutex;
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> index ab4cfb82c237..23c891cdcd54 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> @@ -35,10 +35,44 @@ module_param(max_iotlb_entries, int, 0444);
> MODULE_PARM_DESC(max_iotlb_entries,
> "Maximum number of iotlb entries for each address space. 0 means unlimited. (default: 2048)");
>
> +static bool use_va = true;
> +module_param(use_va, bool, 0444);
> +MODULE_PARM_DESC(use_va, "Enable/disable the device's ability to use VA");
> +
> #define VDPASIM_QUEUE_ALIGN PAGE_SIZE
> #define VDPASIM_QUEUE_MAX 256
> #define VDPASIM_VENDOR_ID 0
>
> +struct vdpasim_mm_work {
> + struct kthread_work work;
> + struct vdpasim *vdpasim;
> + struct mm_struct *mm_to_bind;
> + int ret;
> +};
> +
> +static void vdpasim_mm_work_fn(struct kthread_work *work)
> +{
> + struct vdpasim_mm_work *mm_work =
> + container_of(work, struct vdpasim_mm_work, work);
> + struct vdpasim *vdpasim = mm_work->vdpasim;
> +
> + mm_work->ret = 0;
> +
> + //TODO: should we attach the cgroup of the mm owner?
> + vdpasim->mm_bound = mm_work->mm_to_bind;
> +}
> +
> +static void vdpasim_worker_change_mm_sync(struct vdpasim *vdpasim,
> + struct vdpasim_mm_work *mm_work)
> +{
> + struct kthread_work *work = &mm_work->work;
> +
> + kthread_init_work(work, vdpasim_mm_work_fn);
> + kthread_queue_work(vdpasim->worker, work);
> +
> + kthread_flush_work(work);
> +}
> +
> static struct vdpasim *vdpa_to_sim(struct vdpa_device *vdpa)
> {
> return container_of(vdpa, struct vdpasim, vdpa);
> @@ -59,8 +93,10 @@ static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx)
> {
> struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
> uint16_t last_avail_idx = vq->vring.last_avail_idx;
> + bool va_enabled = use_va && vdpasim->mm_bound;
>
> - vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true, false,
> + vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true,
> + va_enabled,
> (struct vring_desc *)(uintptr_t)vq->desc_addr,
> (struct vring_avail *)
> (uintptr_t)vq->driver_addr,
> @@ -130,8 +166,20 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops;
> static void vdpasim_work_fn(struct kthread_work *work)
> {
> struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
> + struct mm_struct *mm = vdpasim->mm_bound;
> +
> + if (mm) {
> + if (!mmget_not_zero(mm))
> + return;
> + kthread_use_mm(mm);
> + }
>
> vdpasim->dev_attr.work_fn(vdpasim);
> +
> + if (mm) {
> + kthread_unuse_mm(mm);
> + mmput(mm);
> + }
> }
>
> struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
> @@ -162,7 +210,7 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
> vdpa = __vdpa_alloc_device(NULL, ops,
> dev_attr->ngroups, dev_attr->nas,
> dev_attr->alloc_size,
> - dev_attr->name, false);
> + dev_attr->name, use_va);
> if (IS_ERR(vdpa)) {
> ret = PTR_ERR(vdpa);
> goto err_alloc;
> @@ -582,6 +630,30 @@ static int vdpasim_set_map(struct vdpa_device *vdpa, unsigned int asid,
> return ret;
> }
>
> +static int vdpasim_bind_mm(struct vdpa_device *vdpa, struct mm_struct *mm)
> +{
> + struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
> + struct vdpasim_mm_work mm_work;
> +
> + mm_work.vdpasim = vdpasim;
> + mm_work.mm_to_bind = mm;
> +
> + vdpasim_worker_change_mm_sync(vdpasim, &mm_work);
> +
> + return mm_work.ret;
> +}
> +
> +static void vdpasim_unbind_mm(struct vdpa_device *vdpa)
> +{
> + struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
> + struct vdpasim_mm_work mm_work;
> +
> + mm_work.vdpasim = vdpasim;
> + mm_work.mm_to_bind = NULL;
> +
> + vdpasim_worker_change_mm_sync(vdpasim, &mm_work);
> +}
> +
> static int vdpasim_dma_map(struct vdpa_device *vdpa, unsigned int asid,
> u64 iova, u64 size,
> u64 pa, u32 perm, void *opaque)
> @@ -678,6 +750,8 @@ static const struct vdpa_config_ops vdpasim_config_ops = {
> .set_group_asid = vdpasim_set_group_asid,
> .dma_map = vdpasim_dma_map,
> .dma_unmap = vdpasim_dma_unmap,
> + .bind_mm = vdpasim_bind_mm,
> + .unbind_mm = vdpasim_unbind_mm,
> .free = vdpasim_free,
> };
>
> @@ -712,6 +786,8 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops = {
> .get_iova_range = vdpasim_get_iova_range,
> .set_group_asid = vdpasim_set_group_asid,
> .set_map = vdpasim_set_map,
> + .bind_mm = vdpasim_bind_mm,
> + .unbind_mm = vdpasim_unbind_mm,
> .free = vdpasim_free,
> };
>
> --
> 2.39.2
>
On Thu, Mar 23, 2023 at 11:42:07AM +0800, Jason Wang wrote: >On Tue, Mar 21, 2023 at 11:48 PM Stefano Garzarella <sgarzare@redhat.com> wrote: >> >> The new "use_va" module parameter (default: true) is used in >> vdpa_alloc_device() to inform the vDPA framework that the device >> supports VA. >> >> vringh is initialized to use VA only when "use_va" is true and the >> user's mm has been bound. So, only when the bus supports user VA >> (e.g. vhost-vdpa). >> >> vdpasim_mm_work_fn work is used to serialize the binding to a new >> address space when the .bind_mm callback is invoked, and unbinding >> when the .unbind_mm callback is invoked. >> >> Call mmget_not_zero()/kthread_use_mm() inside the worker function >> to pin the address space only as long as needed, following the >> documentation of mmget() in include/linux/sched/mm.h: >> >> * Never use this function to pin this address space for an >> * unbounded/indefinite amount of time. > >I wonder if everything would be simplified if we just allow the parent >to advertise whether or not it requires the address space. > >Then when vhost-vDPA probes the device it can simply advertise >use_work as true so vhost core can use get_task_mm() in this case? IIUC set user_worker to true, it also creates the kthread in the vhost core (but we can add another variable to avoid this). My biggest concern is the comment in include/linux/sched/mm.h. get_task_mm() uses mmget(), but in the documentation they advise against pinning the address space indefinitely, so I preferred in keeping mmgrab() in the vhost core, then call mmget_not_zero() in the worker only when it is running. In the future maybe mm will be used differently from parent if somehow it is supported by iommu, so I would leave it to the parent to handle this. Thanks, Stefano
On Thu, Mar 23, 2023 at 5:50 PM Stefano Garzarella <sgarzare@redhat.com> wrote: > > On Thu, Mar 23, 2023 at 11:42:07AM +0800, Jason Wang wrote: > >On Tue, Mar 21, 2023 at 11:48 PM Stefano Garzarella <sgarzare@redhat.com> wrote: > >> > >> The new "use_va" module parameter (default: true) is used in > >> vdpa_alloc_device() to inform the vDPA framework that the device > >> supports VA. > >> > >> vringh is initialized to use VA only when "use_va" is true and the > >> user's mm has been bound. So, only when the bus supports user VA > >> (e.g. vhost-vdpa). > >> > >> vdpasim_mm_work_fn work is used to serialize the binding to a new > >> address space when the .bind_mm callback is invoked, and unbinding > >> when the .unbind_mm callback is invoked. > >> > >> Call mmget_not_zero()/kthread_use_mm() inside the worker function > >> to pin the address space only as long as needed, following the > >> documentation of mmget() in include/linux/sched/mm.h: > >> > >> * Never use this function to pin this address space for an > >> * unbounded/indefinite amount of time. > > > >I wonder if everything would be simplified if we just allow the parent > >to advertise whether or not it requires the address space. > > > >Then when vhost-vDPA probes the device it can simply advertise > >use_work as true so vhost core can use get_task_mm() in this case? > > IIUC set user_worker to true, it also creates the kthread in the vhost > core (but we can add another variable to avoid this). > > My biggest concern is the comment in include/linux/sched/mm.h. > get_task_mm() uses mmget(), but in the documentation they advise against > pinning the address space indefinitely, so I preferred in keeping > mmgrab() in the vhost core, then call mmget_not_zero() in the worker > only when it is running. Ok. > > In the future maybe mm will be used differently from parent if somehow > it is supported by iommu, so I would leave it to the parent to handle > this. This should be possible, I was told by Intel that their IOMMU can access the process page table for shared virtual memory. Thanks > > Thanks, > Stefano >
On Fri, Mar 24, 2023 at 10:54:39AM +0800, Jason Wang wrote: >On Thu, Mar 23, 2023 at 5:50 PM Stefano Garzarella <sgarzare@redhat.com> wrote: >> >> On Thu, Mar 23, 2023 at 11:42:07AM +0800, Jason Wang wrote: >> >On Tue, Mar 21, 2023 at 11:48 PM Stefano Garzarella <sgarzare@redhat.com> wrote: >> >> >> >> The new "use_va" module parameter (default: true) is used in >> >> vdpa_alloc_device() to inform the vDPA framework that the device >> >> supports VA. >> >> >> >> vringh is initialized to use VA only when "use_va" is true and the >> >> user's mm has been bound. So, only when the bus supports user VA >> >> (e.g. vhost-vdpa). >> >> >> >> vdpasim_mm_work_fn work is used to serialize the binding to a new >> >> address space when the .bind_mm callback is invoked, and unbinding >> >> when the .unbind_mm callback is invoked. >> >> >> >> Call mmget_not_zero()/kthread_use_mm() inside the worker function >> >> to pin the address space only as long as needed, following the >> >> documentation of mmget() in include/linux/sched/mm.h: >> >> >> >> * Never use this function to pin this address space for an >> >> * unbounded/indefinite amount of time. >> > >> >I wonder if everything would be simplified if we just allow the parent >> >to advertise whether or not it requires the address space. >> > >> >Then when vhost-vDPA probes the device it can simply advertise >> >use_work as true so vhost core can use get_task_mm() in this case? >> >> IIUC set user_worker to true, it also creates the kthread in the vhost >> core (but we can add another variable to avoid this). >> >> My biggest concern is the comment in include/linux/sched/mm.h. >> get_task_mm() uses mmget(), but in the documentation they advise against >> pinning the address space indefinitely, so I preferred in keeping >> mmgrab() in the vhost core, then call mmget_not_zero() in the worker >> only when it is running. > >Ok. > >> >> In the future maybe mm will be used differently from parent if somehow >> it is supported by iommu, so I would leave it to the parent to handle >> this. > >This should be possible, I was told by Intel that their IOMMU can >access the process page table for shared virtual memory. Cool, we should investigate this. Do you have any pointers to their documentation? Thanks, Stefano
On Fri, Mar 24, 2023 at 10:43 PM Stefano Garzarella <sgarzare@redhat.com> wrote: > > On Fri, Mar 24, 2023 at 10:54:39AM +0800, Jason Wang wrote: > >On Thu, Mar 23, 2023 at 5:50 PM Stefano Garzarella <sgarzare@redhat.com> wrote: > >> > >> On Thu, Mar 23, 2023 at 11:42:07AM +0800, Jason Wang wrote: > >> >On Tue, Mar 21, 2023 at 11:48 PM Stefano Garzarella <sgarzare@redhat.com> wrote: > >> >> > >> >> The new "use_va" module parameter (default: true) is used in > >> >> vdpa_alloc_device() to inform the vDPA framework that the device > >> >> supports VA. > >> >> > >> >> vringh is initialized to use VA only when "use_va" is true and the > >> >> user's mm has been bound. So, only when the bus supports user VA > >> >> (e.g. vhost-vdpa). > >> >> > >> >> vdpasim_mm_work_fn work is used to serialize the binding to a new > >> >> address space when the .bind_mm callback is invoked, and unbinding > >> >> when the .unbind_mm callback is invoked. > >> >> > >> >> Call mmget_not_zero()/kthread_use_mm() inside the worker function > >> >> to pin the address space only as long as needed, following the > >> >> documentation of mmget() in include/linux/sched/mm.h: > >> >> > >> >> * Never use this function to pin this address space for an > >> >> * unbounded/indefinite amount of time. > >> > > >> >I wonder if everything would be simplified if we just allow the parent > >> >to advertise whether or not it requires the address space. > >> > > >> >Then when vhost-vDPA probes the device it can simply advertise > >> >use_work as true so vhost core can use get_task_mm() in this case? > >> > >> IIUC set user_worker to true, it also creates the kthread in the vhost > >> core (but we can add another variable to avoid this). > >> > >> My biggest concern is the comment in include/linux/sched/mm.h. > >> get_task_mm() uses mmget(), but in the documentation they advise against > >> pinning the address space indefinitely, so I preferred in keeping > >> mmgrab() in the vhost core, then call mmget_not_zero() in the worker > >> only when it is running. > > > >Ok. > > > >> > >> In the future maybe mm will be used differently from parent if somehow > >> it is supported by iommu, so I would leave it to the parent to handle > >> this. > > > >This should be possible, I was told by Intel that their IOMMU can > >access the process page table for shared virtual memory. > > Cool, we should investigate this. Do you have any pointers to their > documentation? The vtd-spec I think. Thanks > > Thanks, > Stefano >
On Thu, Mar 23, 2023 at 10:50:06AM +0100, Stefano Garzarella wrote: > On Thu, Mar 23, 2023 at 11:42:07AM +0800, Jason Wang wrote: > > On Tue, Mar 21, 2023 at 11:48 PM Stefano Garzarella <sgarzare@redhat.com> wrote: > > > > > > The new "use_va" module parameter (default: true) is used in > > > vdpa_alloc_device() to inform the vDPA framework that the device > > > supports VA. > > > > > > vringh is initialized to use VA only when "use_va" is true and the > > > user's mm has been bound. So, only when the bus supports user VA > > > (e.g. vhost-vdpa). > > > > > > vdpasim_mm_work_fn work is used to serialize the binding to a new > > > address space when the .bind_mm callback is invoked, and unbinding > > > when the .unbind_mm callback is invoked. > > > > > > Call mmget_not_zero()/kthread_use_mm() inside the worker function > > > to pin the address space only as long as needed, following the > > > documentation of mmget() in include/linux/sched/mm.h: > > > > > > * Never use this function to pin this address space for an > > > * unbounded/indefinite amount of time. > > > > I wonder if everything would be simplified if we just allow the parent > > to advertise whether or not it requires the address space. > > > > Then when vhost-vDPA probes the device it can simply advertise > > use_work as true so vhost core can use get_task_mm() in this case? > > IIUC set user_worker to true, it also creates the kthread in the vhost > core (but we can add another variable to avoid this). > > My biggest concern is the comment in include/linux/sched/mm.h. > get_task_mm() uses mmget(), but in the documentation they advise against > pinning the address space indefinitely, so I preferred in keeping > mmgrab() in the vhost core, then call mmget_not_zero() in the worker > only when it is running. > > In the future maybe mm will be used differently from parent if somehow > it is supported by iommu, so I would leave it to the parent to handle > this. > > Thanks, > Stefano I think iommufd is supposed to handle all this detail, yes.
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