drm/virtio: implement context init: add virtio_gpu_fence_event

Similar to DRM_VMW_EVENT_FENCE_SIGNALED.  Sends a pollable event
to the DRM file descriptor when a fence on a specific ring is
signaled.

One difference is the event is not exposed via the UAPI -- this is
because host responses are on a shared memory buffer of type
BLOB_MEM_GUEST [this is the common way to receive responses with
virtgpu].  As such, there is no context specific read(..)
implementation either -- just a poll(..) implementation.

Signed-off-by: Gurchetan Singh <gurchetansingh@chromium.org>
Acked-by: Nicholas Verne <nverne@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20210921232024.817-12-gurchetansingh@chromium.org
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index cb60d52c2bd1..e0265fe74aa5 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -138,11 +138,18 @@ 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;
+};
+
 struct virtio_gpu_fence {
 	struct dma_fence f;
 	uint32_t ring_idx;
 	uint64_t fence_id;
 	bool emit_fence_info;
+	struct virtio_gpu_fence_event *e;
 	struct virtio_gpu_fence_driver *drv;
 	struct list_head node;
 };