Re: [PATCH v5 08/12] drm/virtio: rework virtio_gpu_execbuffer_ioctl fencing

From: Chia-I Wu
Date: Sun Jun 30 2019 - 14:31:04 EST

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(pressed Send too early)

On Sun, Jun 30, 2019 at 11:20 AM Chia-I Wu <olvaffe@xxxxxxxxx> wrote:
>
> On Fri, Jun 28, 2019 at 5:13 AM Gerd Hoffmann <kraxel@xxxxxxxxxx> wrote:
> >
> > Use gem reservation helpers and direct reservation_object_* calls
> > instead of ttm.
> >
> > v5: fix fencing (Chia-I Wu).
> > v3: Also attach the array of gem objects to the virtio command buffer,
> > so we can drop the object references in the completion callback. Needed
> > because ttm fence helpers grab a reference for us, but gem helpers
> > don't.
> There are other places
There are other places where a vbuffer uses objects, such as in
transfers. Do we need to make sure the objects are alive in those
places?

> >
> > Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> > Acked-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> > ---
> > drivers/gpu/drm/virtio/virtgpu_drv.h | 6 ++-
> > drivers/gpu/drm/virtio/virtgpu_ioctl.c | 62 +++++++++++---------------
> > drivers/gpu/drm/virtio/virtgpu_vq.c | 17 ++++---
> > 3 files changed, 43 insertions(+), 42 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
> > index 98d646789d23..356d27132388 100644
> > --- a/drivers/gpu/drm/virtio/virtgpu_drv.h
> > +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
> > @@ -120,9 +120,9 @@ struct virtio_gpu_vbuffer {
> >
> > char *resp_buf;
> > int resp_size;
> > -
> > virtio_gpu_resp_cb resp_cb;
> >
> > + struct virtio_gpu_object_array *objs;
> > struct list_head list;
> > };
> >
> > @@ -311,7 +311,9 @@ void virtio_gpu_cmd_context_detach_resource(struct virtio_gpu_device *vgdev,
> > uint32_t resource_id);
> > void virtio_gpu_cmd_submit(struct virtio_gpu_device *vgdev,
> > void *data, uint32_t data_size,
> > - uint32_t ctx_id, struct virtio_gpu_fence *fence);
> > + uint32_t ctx_id,
> > + struct virtio_gpu_object_array *objs,
> > + struct virtio_gpu_fence *fence);
> > void virtio_gpu_cmd_transfer_from_host_3d(struct virtio_gpu_device *vgdev,
> > uint32_t resource_id, uint32_t ctx_id,
> > uint64_t offset, uint32_t level,
> > diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> > index 0caff3fa623e..ae6830aa38c9 100644
> > --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> > +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> > @@ -105,14 +105,11 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
> > struct drm_virtgpu_execbuffer *exbuf = data;
> > struct virtio_gpu_device *vgdev = dev->dev_private;
> > struct virtio_gpu_fpriv *vfpriv = drm_file->driver_priv;
> > - struct drm_gem_object *gobj;
> > struct virtio_gpu_fence *out_fence;
> > - struct virtio_gpu_object *qobj;
> > int ret;
> > uint32_t *bo_handles = NULL;
> > void __user *user_bo_handles = NULL;
> > - struct list_head validate_list;
> > - struct ttm_validate_buffer *buflist = NULL;
> > + struct virtio_gpu_object_array *buflist = NULL;
> > int i;
> > struct ww_acquire_ctx ticket;
> > struct sync_file *sync_file;
> > @@ -155,15 +152,10 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
> > return out_fence_fd;
> > }
> >
> > - INIT_LIST_HEAD(&validate_list);
> > if (exbuf->num_bo_handles) {
> > -
> > bo_handles = kvmalloc_array(exbuf->num_bo_handles,
> > - sizeof(uint32_t), GFP_KERNEL);
> > - buflist = kvmalloc_array(exbuf->num_bo_handles,
> > - sizeof(struct ttm_validate_buffer),
> > - GFP_KERNEL | __GFP_ZERO);
> > - if (!bo_handles || !buflist) {
> > + sizeof(uint32_t), GFP_KERNEL);
> > + if (!bo_handles) {
> > ret = -ENOMEM;
> > goto out_unused_fd;
> > }
> > @@ -175,25 +167,22 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
> > goto out_unused_fd;
> > }
> >
> > - for (i = 0; i < exbuf->num_bo_handles; i++) {
> > - gobj = drm_gem_object_lookup(drm_file, bo_handles[i]);
> > - if (!gobj) {
> > - ret = -ENOENT;
> > - goto out_unused_fd;
> > - }
> > -
> > - qobj = gem_to_virtio_gpu_obj(gobj);
> > - buflist[i].bo = &qobj->tbo;
> > -
> > - list_add(&buflist[i].head, &validate_list);
> > + buflist = virtio_gpu_array_from_handles(drm_file, bo_handles,
> > + exbuf->num_bo_handles);
> > + if (!buflist) {
> > + ret = -ENOENT;
> > + goto out_unused_fd;
> > }
> > kvfree(bo_handles);
> > bo_handles = NULL;
> > }
> >
> > - ret = virtio_gpu_object_list_validate(&ticket, &validate_list);
> > - if (ret)
> > - goto out_free;
> > + if (buflist) {
> > + ret = drm_gem_lock_reservations(buflist->objs, buflist->nents,
> > + &ticket);
> > + if (ret)
> > + goto out_unused_fd;
> > + }
> >
> > buf = memdup_user(u64_to_user_ptr(exbuf->command), exbuf->size);
> > if (IS_ERR(buf)) {
> > @@ -219,25 +208,28 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
> > fd_install(out_fence_fd, sync_file->file);
> > }
> >
> > + if (buflist)
> > + for (i = 0; i < exbuf->num_bo_handles; i++)
> > + reservation_object_add_excl_fence(buflist->objs[i]->resv,
> > + &out_fence->f);
> > +
> Another module can see the semi-initialized fence after this. We
> should move this after virtio_gpu_cmd_submit.
>
> > virtio_gpu_cmd_submit(vgdev, buf, exbuf->size,
> > - vfpriv->ctx_id, out_fence);
> > + vfpriv->ctx_id, buflist, out_fence);
> >
> > - ttm_eu_fence_buffer_objects(&ticket, &validate_list, &out_fence->f);
> > -
> > - /* fence the command bo */
> > - virtio_gpu_unref_list(&validate_list);
> > - kvfree(buflist);
> > + if (buflist)
> > + drm_gem_unlock_reservations(buflist->objs, buflist->nents,
> > + &ticket);
> When virtio_gpu_cmd_submit progresses really fast, buflist might have
> been freed.
>
> > return 0;
> >
> > out_memdup:
> > kfree(buf);
> > out_unresv:
> > - ttm_eu_backoff_reservation(&ticket, &validate_list);
> > -out_free:
> > - virtio_gpu_unref_list(&validate_list);
> > + if (buflist)
> > + drm_gem_unlock_reservations(buflist->objs, buflist->nents, &ticket);
> > out_unused_fd:
> > kvfree(bo_handles);
> > - kvfree(buflist);
> > + if (buflist)
> > + virtio_gpu_array_put_free(buflist);
> >
> > if (out_fence_fd >= 0)
> > put_unused_fd(out_fence_fd);
> > diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
> > index 6c1a90717535..0c87c3e086f8 100644
> > --- a/drivers/gpu/drm/virtio/virtgpu_vq.c
> > +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
> > @@ -191,7 +191,7 @@ void virtio_gpu_dequeue_ctrl_func(struct work_struct *work)
> > } while (!virtqueue_enable_cb(vgdev->ctrlq.vq));
> > spin_unlock(&vgdev->ctrlq.qlock);
> >
> > - list_for_each_entry_safe(entry, tmp, &reclaim_list, list) {
> > + list_for_each_entry(entry, &reclaim_list, list) {
> > resp = (struct virtio_gpu_ctrl_hdr *)entry->resp_buf;
> >
> > trace_virtio_gpu_cmd_response(vgdev->ctrlq.vq, resp);
> > @@ -218,14 +218,18 @@ void virtio_gpu_dequeue_ctrl_func(struct work_struct *work)
> > }
> > if (entry->resp_cb)
> > entry->resp_cb(vgdev, entry);
> > -
> > - list_del(&entry->list);
> > - free_vbuf(vgdev, entry);
> > }
> > wake_up(&vgdev->ctrlq.ack_queue);
> >
> > if (fence_id)
> > virtio_gpu_fence_event_process(vgdev, fence_id);
> > +
> > + list_for_each_entry_safe(entry, tmp, &reclaim_list, list) {
> > + if (entry->objs)
> > + virtio_gpu_array_put_free(entry->objs);
> > + list_del(&entry->list);
> > + free_vbuf(vgdev, entry);
> > + }
> > }
> >
> > void virtio_gpu_dequeue_cursor_func(struct work_struct *work)
> > @@ -939,7 +943,9 @@ void virtio_gpu_cmd_transfer_from_host_3d(struct virtio_gpu_device *vgdev,
> >
> > void virtio_gpu_cmd_submit(struct virtio_gpu_device *vgdev,
> > void *data, uint32_t data_size,
> > - uint32_t ctx_id, struct virtio_gpu_fence *fence)
> > + uint32_t ctx_id,
> > + struct virtio_gpu_object_array *objs,
> > + struct virtio_gpu_fence *fence)
> > {
> > struct virtio_gpu_cmd_submit *cmd_p;
> > struct virtio_gpu_vbuffer *vbuf;
> > @@ -949,6 +955,7 @@ void virtio_gpu_cmd_submit(struct virtio_gpu_device *vgdev,
> >
> > vbuf->data_buf = data;
> > vbuf->data_size = data_size;
> > + vbuf->objs = objs;
> >
> > cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_SUBMIT_3D);
> > cmd_p->hdr.ctx_id = cpu_to_le32(ctx_id);
> > --
> > 2.18.1
> >

Next message: Chia-I Wu: "Re: [PATCH v4 11/12] drm/virtio: switch from ttm to gem shmem helpers"
Previous message: Chia-I Wu: "Re: [PATCH v5 09/12] drm/virtio: rework virtio_gpu_object_create fencing"
In reply to: Chia-I Wu: "Re: [PATCH v5 08/12] drm/virtio: rework virtio_gpu_execbuffer_ioctl fencing"
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