Commit 7e78781d authored by Gurchetan Singh's avatar Gurchetan Singh Committed by Gerd Hoffmann
Browse files

drm/virtgpu api: define a dummy fence signaled event 



The current virtgpu implementation of poll(..) drops events
when VIRTGPU_CONTEXT_PARAM_POLL_RINGS_MASK is enabled (otherwise
it's like a normal DRM driver).

This is because paravirtualized userspaces receives responses in a
buffer of type BLOB_MEM_GUEST, not by read(..).

To be in line with other DRM drivers and avoid specialized behavior,
it is possible to define a dummy event for virtgpu.  Paravirtualized
userspace will now have to call read(..) on the DRM fd to receive the
dummy event.

Fixes: b1079043 ("drm/virtgpu api: create context init feature")
Reported-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: default avatarGurchetan Singh <gurchetansingh@chromium.org>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20211122232210.602-2-gurchetansingh@google.com


Signed-off-by: default avatarGerd Hoffmann <kraxel@redhat.com>
parent e048834c

drivers/gpu/drm/virtio/virtgpu_drv.h

+0 −1
Original line number Diff line number Diff line
@@ -138,7 +138,6 @@ struct virtio_gpu_fence_driver { 
	spinlock_t       lock;

};



#define VIRTGPU_EVENT_FENCE_SIGNALED_INTERNAL 0x10000000

struct virtio_gpu_fence_event {

	struct drm_pending_event base;

	struct drm_event event;

drivers/gpu/drm/virtio/virtgpu_ioctl.c

+1 −1
Original line number Diff line number Diff line
@@ -54,7 +54,7 @@ static int virtio_gpu_fence_event_create(struct drm_device *dev, 
	if (!e)

		return -ENOMEM;



	e->event.type = VIRTGPU_EVENT_FENCE_SIGNALED_INTERNAL;

	e->event.type = VIRTGPU_EVENT_FENCE_SIGNALED;

	e->event.length = sizeof(e->event);



	ret = drm_event_reserve_init(dev, file, &e->base, &e->event);

include/uapi/drm/virtgpu_drm.h

+7 −0
Original line number Diff line number Diff line
@@ -196,6 +196,13 @@ struct drm_virtgpu_context_init { 
	__u64 ctx_set_params;

};



/*

 * Event code that's given when VIRTGPU_CONTEXT_PARAM_POLL_RINGS_MASK is in

 * effect.  The event size is sizeof(drm_event), since there is no additional

 * payload.

 */

#define VIRTGPU_EVENT_FENCE_SIGNALED 0x90000000



#define DRM_IOCTL_VIRTGPU_MAP \

	DRM_IOWR(DRM_COMMAND_BASE + DRM_VIRTGPU_MAP, struct drm_virtgpu_map)