From 3d1784f73dfb8a2646321f3997d82aafca961c0b Mon Sep 17 00:00:00 2001
From: Gurchetan Singh <gurchetansingh@chromium.org>
Date: Mon, 22 Nov 2021 15:22:09 -0800
Subject: drm/virtgpu api: define a dummy fence signaled event
Git-commit: 7e78781df491e4beb475bac22e6c44236a5002d7
Patch-mainline: v5.16-rc4
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
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: b10790434cf2 ("drm/virtgpu api: create context init feature")
Reported-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Gurchetan Singh <gurchetansingh@chromium.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20211122232210.602-2-gurchetansingh@google.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/virtio/virtgpu_drv.h | 1 -
drivers/gpu/drm/virtio/virtgpu_ioctl.c | 2 +-
include/uapi/drm/virtgpu_drm.h | 7 +++++++
3 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index e0265fe74aa5..0a194aaad419 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -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;
diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 5618a1d5879c..3607646d3229 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -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);
diff --git a/include/uapi/drm/virtgpu_drm.h b/include/uapi/drm/virtgpu_drm.h
index a13e20cc66b4..0512fde5e697 100644
--- a/include/uapi/drm/virtgpu_drm.h
+++ b/include/uapi/drm/virtgpu_drm.h
@@ -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)
--
2.38.1