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authorStefano Garzarella <sgarzare@redhat.com>2023-04-04 16:17:34 +0300
committerMichael S. Tsirkin <mst@redhat.com>2023-04-21 10:02:34 +0300
commit4bb94d2de2fa90aa8d4e1ce940b1b2f7708cf141 (patch)
tree23241f38a4a66e0505def34c6e633a308456d844 /drivers/vdpa
parentd7621c28fca1c16f9e94245479792024a5676c50 (diff)
downloadlinux-4bb94d2de2fa90aa8d4e1ce940b1b2f7708cf141.tar.xz
vdpa_sim: add support for user VA
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. Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Message-Id: <20230404131734.45943-1-sgarzare@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/vdpa')
-rw-r--r--drivers/vdpa/vdpa_sim/vdpa_sim.c97
-rw-r--r--drivers/vdpa/vdpa_sim/vdpa_sim.h1
2 files changed, 90 insertions, 8 deletions
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index 2b2e439a66f7..2c706bb18897 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);
@@ -59,13 +93,20 @@ 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;
-
- vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true,
- (struct vring_desc *)(uintptr_t)vq->desc_addr,
- (struct vring_avail *)
- (uintptr_t)vq->driver_addr,
- (struct vring_used *)
- (uintptr_t)vq->device_addr);
+ struct vring_desc *desc = (struct vring_desc *)
+ (uintptr_t)vq->desc_addr;
+ struct vring_avail *avail = (struct vring_avail *)
+ (uintptr_t)vq->driver_addr;
+ struct vring_used *used = (struct vring_used *)
+ (uintptr_t)vq->device_addr;
+
+ if (use_va && vdpasim->mm_bound) {
+ vringh_init_iotlb_va(&vq->vring, vdpasim->features, vq->num,
+ true, desc, avail, used);
+ } else {
+ vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num,
+ true, desc, avail, used);
+ }
vq->vring.last_avail_idx = last_avail_idx;
@@ -130,8 +171,20 @@ 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 (use_va && mm) {
+ if (!mmget_not_zero(mm))
+ return;
+ kthread_use_mm(mm);
+ }
vdpasim->dev_attr.work_fn(vdpasim);
+
+ if (use_va && mm) {
+ kthread_unuse_mm(mm);
+ mmput(mm);
+ }
}
struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
@@ -162,7 +215,7 @@ 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 +635,30 @@ err:
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 +755,8 @@ 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 +791,8 @@ 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,
};
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;