Re: [PATCH] drm/virtio: kick vq outside of the vq lock

> @@ -291,11 +291,9 @@ static int virtio_gpu_queue_ctrl_buffer_locked(struct > virtio_gpu_device *vgdev, > trace_virtio_gpu_cmd_queue(vq, > (struct virtio_gpu_ctrl_hdr *)vbuf->buf); > > - virtqueue_kick(vq); > + ret =

[PATCH] drm/virtio: kick vq outside of the vq lock

Replace virtqueue_kick by virtqueue_kick_prepare, which requires serialization, and virtqueue_notify, which does not. Repurpose the return values to indicate whether the vq should be notified. This fixes a bad spinlock contention when the host is qemu. When the guest calls virtqueue_notify, the

[PATCH] drm/virtio: kick vq outside of the vq lock

Replace virtqueue_kick by virtqueue_kick_prepare, which requires serialization, and virtqueue_notify, which does not. Repurpose the return values to indicate whether the vq should be notified. This fixes a lock contention with qemu host. When the guest calls vibad rtqueue_notify, the qemu vcpu