[PATCH v1] drm/virtio: Reset device before deleting virtqueues on freeze

[PATCH v1] drm/virtio: Reset device before deleting virtqueues on freeze

[Yuho Choi]

virtgpu_freeze() waits for the control and cursor queues to drain and
then deletes the virtqueues, but nothing tells the device to stop first.
del_vqs() frees the vring backing, but does not provide a generic device
quiesce operation. In particular, modern virtio-pci keeps enabled queues
active until the device is reset, so the device is left DRIVER_OK with
its queues pointing at memory that has been freed and may be reused while
the guest is suspended. virtio_device_restore() only resets the device
later, on resume.

Reset the device before deleting the virtqueues, the way
virtio_gpu_deinit() already does on removal.

Fixes: cad6a879a7fb ("drm/virtio: Freeze and restore hooks to support suspend and resume")
Cc: stable@vger.kernel.org
Signed-off-by: Yuho Choi <oss.patchbox@gmail.com>
---
 drivers/gpu/drm/virtio/virtgpu_drv.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c
index 2aaa7cb08085..52c174f9bff7 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.c
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.c
@@ -225,6 +225,7 @@ static int virtgpu_freeze(struct virtio_device *vdev)
 		goto err_resume;
 	}
 
+	virtio_reset_device(vdev);
 	vdev->config->del_vqs(vdev);
 
 	return 0;
-- 
2.43.0

Re: [PATCH v1] drm/virtio: Reset device before deleting virtqueues on freeze

[sashiko-bot]

> virtgpu_freeze() waits for the control and cursor queues to drain and
> then deletes the virtqueues, but nothing tells the device to stop first.
> del_vqs() frees the vring backing, but does not provide a generic device
> quiesce operation. In particular, modern virtio-pci keeps enabled queues
> active until the device is reset, so the device is left DRIVER_OK with
> its queues pointing at memory that has been freed and may be reused while
> the guest is suspended. virtio_device_restore() only resets the device
> later, on resume.
> 
> Reset the device before deleting the virtqueues, the way
> virtio_gpu_deinit() already does on removal.
> 
> Fixes: cad6a879a7fb ("drm/virtio: Freeze and restore hooks to support suspend and resume")
> Cc: stable@vger.kernel.org
> Signed-off-by: Yuho Choi <oss.patchbox@gmail.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260926202040.1313385-1-oss.patchbox@gmail.com?part=1