This is a note to let you know that I've just added the patch titled
drm/virtio: Conditionally allocate virtio_gpu_fence
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-virtio-conditionally-allocate-virtio_gpu_fence.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 70d1ace56db6c79d39dbe9c0d5244452b67e2fde Mon Sep 17 00:00:00 2001
From: Gurchetan Singh <gurchetansingh@xxxxxxxxxxxx>
Date: Fri, 7 Jul 2023 14:31:24 -0700
Subject: drm/virtio: Conditionally allocate virtio_gpu_fence
From: Gurchetan Singh <gurchetansingh@xxxxxxxxxxxx>
commit 70d1ace56db6c79d39dbe9c0d5244452b67e2fde upstream.
We don't want to create a fence for every command submission. It's
only necessary when userspace provides a waitable token for submission.
This could be:
1) bo_handles, to be used with VIRTGPU_WAIT
2) out_fence_fd, to be used with dma_fence apis
3) a ring_idx provided with VIRTGPU_CONTEXT_PARAM_POLL_RINGS_MASK
+ DRM event API
4) syncobjs in the future
The use case for just submitting a command to the host, and expecting
no response. For example, gfxstream has GFXSTREAM_CONTEXT_PING that
just wakes up the host side worker threads. There's also
CROSS_DOMAIN_CMD_SEND which just sends data to the Wayland server.
This prevents the need to signal the automatically created
virtio_gpu_fence.
In addition, VIRTGPU_EXECBUF_RING_IDX is checked when creating a
DRM event object. VIRTGPU_CONTEXT_PARAM_POLL_RINGS_MASK is
already defined in terms of per-context rings. It was theoretically
possible to create a DRM event on the global timeline (ring_idx == 0),
if the context enabled DRM event polling. However, that wouldn't
work and userspace (Sommelier). Explicitly disallow it for
clarity.
Signed-off-by: Gurchetan Singh <gurchetansingh@xxxxxxxxxxxx>
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
Tested-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx> # edited coding style
Link: https://patchwork.freedesktop.org/patch/msgid/20230707213124.494-1-gurchetansingh@xxxxxxxxxxxx
Signed-off-by: Alyssa Ross <hi@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/virtio/virtgpu_ioctl.c | 30 ++++++++++++++++++------------
1 file changed, 18 insertions(+), 12 deletions(-)
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -43,13 +43,9 @@ static int virtio_gpu_fence_event_create
struct virtio_gpu_fence *fence,
uint32_t ring_idx)
{
- struct virtio_gpu_fpriv *vfpriv = file->driver_priv;
struct virtio_gpu_fence_event *e = NULL;
int ret;
- if (!(vfpriv->ring_idx_mask & BIT_ULL(ring_idx)))
- return 0;
-
e = kzalloc(sizeof(*e), GFP_KERNEL);
if (!e)
return -ENOMEM;
@@ -121,6 +117,7 @@ static int virtio_gpu_execbuffer_ioctl(s
struct virtio_gpu_device *vgdev = dev->dev_private;
struct virtio_gpu_fpriv *vfpriv = file->driver_priv;
struct virtio_gpu_fence *out_fence;
+ bool drm_fence_event;
int ret;
uint32_t *bo_handles = NULL;
void __user *user_bo_handles = NULL;
@@ -216,15 +213,24 @@ static int virtio_gpu_execbuffer_ioctl(s
goto out_memdup;
}
- out_fence = virtio_gpu_fence_alloc(vgdev, fence_ctx, ring_idx);
- if(!out_fence) {
- ret = -ENOMEM;
- goto out_unresv;
- }
+ if ((exbuf->flags & VIRTGPU_EXECBUF_RING_IDX) &&
+ (vfpriv->ring_idx_mask & BIT_ULL(ring_idx)))
+ drm_fence_event = true;
+ else
+ drm_fence_event = false;
+
+ if ((exbuf->flags & VIRTGPU_EXECBUF_FENCE_FD_OUT) ||
+ exbuf->num_bo_handles ||
+ drm_fence_event)
+ out_fence = virtio_gpu_fence_alloc(vgdev, fence_ctx, ring_idx);
+ else
+ out_fence = NULL;
- ret = virtio_gpu_fence_event_create(dev, file, out_fence, ring_idx);
- if (ret)
- goto out_unresv;
+ if (drm_fence_event) {
+ ret = virtio_gpu_fence_event_create(dev, file, out_fence, ring_idx);
+ if (ret)
+ goto out_unresv;
+ }
if (out_fence_fd >= 0) {
sync_file = sync_file_create(&out_fence->f);
Patches currently in stable-queue which might be from gurchetansingh@xxxxxxxxxxxx are
queue-6.1/drm-virtio-conditionally-allocate-virtio_gpu_fence.patch
