[PATCH v9 08/18] drm/virtio: rework virtio_gpu_execbuffer_ioctl fencing

From: Gerd Hoffmann
Date: Thu Aug 29 2019 - 06:34:14 EST


Rework fencing workflow, starting with virtio_gpu_execbuffer_ioctl.
Stop using ttm helpers, use the virtio_gpu_array_* helpers (which work
on the reservation objects directly) instead.

Also store the object array in struct virtio_gpu_vbuffer, so we
explicitly keep a reference of all buffers used instead of depending
on ttm_bo_put() checking whenever the object is actually idle before
releasing it.

New workflow:

(1) All gem objects needed by a command are added to a
virtio_gpu_object_array.
(2) All reservation objects will be locked (virtio_gpu_array_lock_resv).
(3) virtio_gpu_fence_emit() completes fence initialization.
(4) fence gets added to the objects, reservation objects are unlocked
(virtio_gpu_array_add_fence, virtio_gpu_array_unlock_resv).
(5) virtio command is submitted to the host.
(6) The completion callback (virtio_gpu_dequeue_ctrl_func)
will drop object references and free virtio_gpu_object_array.

v6: rewrite most of the patch.

Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
---
drivers/gpu/drm/virtio/virtgpu_drv.h | 6 ++-
drivers/gpu/drm/virtio/virtgpu_ioctl.c | 56 +++++++++-----------------
drivers/gpu/drm/virtio/virtgpu_vq.c | 21 +++++++---
3 files changed, 38 insertions(+), 45 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index b6bd2b1141fb..f4f843aec18a 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -121,9 +121,9 @@ 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;
};

@@ -318,7 +318,9 @@ 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 7f1775b9449e..61b1b55ec508 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -107,16 +107,11 @@ 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;
- int i;
- struct ww_acquire_ctx ticket;
+ struct virtio_gpu_object_array *buflist = NULL;
struct sync_file *sync_file;
int in_fence_fd = exbuf->fence_fd;
int out_fence_fd = -1;
@@ -157,15 +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;
}
@@ -177,25 +167,21 @@ 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 = virtio_gpu_array_lock_resv(buflist);
+ if (ret)
+ goto out_unused_fd;
+ }

buf = memdup_user(u64_to_user_ptr(exbuf->command), exbuf->size);
if (IS_ERR(buf)) {
@@ -222,24 +208,18 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
}

virtio_gpu_cmd_submit(vgdev, buf, exbuf->size,
- vfpriv->ctx_id, 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);
+ vfpriv->ctx_id, buflist, out_fence);
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)
+ virtio_gpu_array_unlock_resv(buflist);
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 e41c96143342..5137dcf11d31 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -192,7 +192,7 @@ 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);
@@ -219,14 +219,18 @@ 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)
@@ -337,6 +341,10 @@ static void virtio_gpu_queue_fenced_ctrl_buffer(struct virtio_gpu_device *vgdev,

if (fence)
virtio_gpu_fence_emit(vgdev, hdr, fence);
+ if (vbuf->objs) {
+ virtio_gpu_array_add_fence(vbuf->objs, &fence->f);
+ virtio_gpu_array_unlock_resv(vbuf->objs);
+ }
notify = virtio_gpu_queue_ctrl_buffer_locked(vgdev, vbuf);
spin_unlock(&vgdev->ctrlq.qlock);
if (notify)
@@ -940,7 +948,9 @@ 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;
@@ -950,6 +960,7 @@ 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