From: Jason Wang <jasowang@redhat.com>
To: Stefano Garzarella <sgarzare@redhat.com>,
virtualization@lists.linux-foundation.org
Cc: kvm@vger.kernel.org, stefanha@redhat.com,
linux-kernel@vger.kernel.org, eperezma@redhat.com,
"Michael S. Tsirkin" <mst@redhat.com>,
Andrey Zhadchenko <andrey.zhadchenko@virtuozzo.com>,
netdev@vger.kernel.org
Subject: Re: [PATCH v3 8/8] vdpa_sim: add support for user VA
Date: Fri, 24 Mar 2023 11:49:32 +0800 [thread overview]
Message-ID: <78c7511a-deab-7e95-fde1-5317a568cf97@redhat.com> (raw)
In-Reply-To: <20230321154804.184577-4-sgarzare@redhat.com>
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,
> };
>
next prev parent reply other threads:[~2023-03-24 3:50 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-21 15:42 [PATCH v3 0/8] vdpa_sim: add support for user VA Stefano Garzarella
2023-03-21 15:42 ` [PATCH v3 1/8] vdpa: add bind_mm/unbind_mm callbacks Stefano Garzarella
2023-03-23 2:58 ` Jason Wang
2023-03-21 15:42 ` [PATCH v3 2/8] vhost-vdpa: use bind_mm/unbind_mm device callbacks Stefano Garzarella
2023-03-23 3:01 ` Jason Wang
2023-03-23 9:38 ` Stefano Garzarella
2023-03-21 15:42 ` [PATCH v3 3/8] vringh: replace kmap_atomic() with kmap_local_page() Stefano Garzarella
2023-03-22 10:37 ` Fabio M. De Francesco
2023-03-23 3:02 ` Jason Wang
2023-03-21 15:42 ` [PATCH v3 4/8] vringh: support VA with iotlb Stefano Garzarella
2023-03-23 3:36 ` Jason Wang
2023-03-23 10:37 ` Stefano Garzarella
2023-03-23 8:09 ` Eugenio Perez Martin
2023-03-23 10:46 ` Stefano Garzarella
2023-03-23 14:43 ` Eugenio Perez Martin
2023-03-24 14:39 ` Stefano Garzarella
2023-03-21 15:48 ` [PATCH v3 5/8] vdpa_sim: make devices agnostic for work management Stefano Garzarella
2023-03-21 15:48 ` [PATCH v3 6/8] vdpa_sim: use kthread worker Stefano Garzarella
2023-03-21 15:48 ` [PATCH v3 7/8] vdpa_sim: replace the spinlock with a mutex to protect the state Stefano Garzarella
2023-03-21 15:48 ` [PATCH v3 8/8] vdpa_sim: add support for user VA Stefano Garzarella
2023-03-23 3:42 ` Jason Wang
2023-03-23 9:50 ` Stefano Garzarella
2023-03-23 11:44 ` Michael S. Tsirkin
2023-03-24 2:54 ` Jason Wang
2023-03-24 14:43 ` Stefano Garzarella
2023-03-27 3:12 ` Jason Wang
2023-03-24 3:49 ` Jason Wang [this message]
2023-03-24 14:46 ` Stefano Garzarella
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