drm/virtio: add in/out fence support for explicit synchronization

When the execbuf call receives an in-fence it will get the dma_fence
related to that fence fd and wait on it before submitting the draw call.

On the out-fence side we get fence returned by the submitted draw call
and attach it to a sync_file and send the sync_file fd to userspace. On
error -1 is returned to userspace.

VIRTGPU_EXECBUF_FENCE_FD_IN & VIRTGPU_EXECBUF_FENCE_FD_OUT
are supported at the simultaneously and can be flagged
for simultaneously.

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Signed-off-by: Robert Foss <robert.foss@collabora.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20181112165157.32765-4-robert.foss@collabora.com
Suggested-by: Rob Herring <robh@kernel.org>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 3d49783..340f251 100644 (file)
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -28,6 +28,7 @@
 #include <drm/drmP.h>
 #include <drm/virtgpu_drm.h>
 #include <drm/ttm/ttm_execbuf_util.h>
+#include <linux/sync_file.h>
 
 #include "virtgpu_drv.h"
 
@@ -105,7 +106,7 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
        struct virtio_gpu_device *vgdev = dev->dev_private;
        struct virtio_gpu_fpriv *vfpriv = drm_file->driver_priv;
        struct drm_gem_object *gobj;
-       struct virtio_gpu_fence *fence;
+       struct virtio_gpu_fence *out_fence;
        struct virtio_gpu_object *qobj;
        int ret;
        uint32_t *bo_handles = NULL;
@@ -114,6 +115,9 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
        struct ttm_validate_buffer *buflist = NULL;
        int i;
        struct ww_acquire_ctx ticket;
+       struct sync_file *sync_file;
+       int in_fence_fd = exbuf->fence_fd;
+       int out_fence_fd = -1;
        void *buf;
 
        if (vgdev->has_virgl_3d == false)
@@ -124,6 +128,33 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
 
        exbuf->fence_fd = -1;
 
+       if (exbuf->flags & VIRTGPU_EXECBUF_FENCE_FD_IN) {
+               struct dma_fence *in_fence;
+
+               in_fence = sync_file_get_fence(in_fence_fd);
+
+               if (!in_fence)
+                       return -EINVAL;
+
+               /*
+                * Wait if the fence is from a foreign context, or if the fence
+                * array contains any fence from a foreign context.
+                */
+               ret = 0;
+               if (!dma_fence_match_context(in_fence, vgdev->fence_drv.context))
+                       ret = dma_fence_wait(in_fence, true);
+
+               dma_fence_put(in_fence);
+               if (ret)
+                       return ret;
+       }
+
+       if (exbuf->flags & VIRTGPU_EXECBUF_FENCE_FD_OUT) {
+               out_fence_fd = get_unused_fd_flags(O_CLOEXEC);
+               if (out_fence_fd < 0)
+                       return out_fence_fd;
+       }
+
        INIT_LIST_HEAD(&validate_list);
        if (exbuf->num_bo_handles) {
 
@@ -133,26 +164,22 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
                                           sizeof(struct ttm_validate_buffer),
                                           GFP_KERNEL | __GFP_ZERO);
                if (!bo_handles || !buflist) {
-                       kvfree(bo_handles);
-                       kvfree(buflist);
-                       return -ENOMEM;
+                       ret = -ENOMEM;
+                       goto out_unused_fd;
                }
 
                user_bo_handles = (void __user *)(uintptr_t)exbuf->bo_handles;
                if (copy_from_user(bo_handles, user_bo_handles,
                                   exbuf->num_bo_handles * sizeof(uint32_t))) {
                        ret = -EFAULT;
-                       kvfree(bo_handles);
-                       kvfree(buflist);
-                       return ret;
+                       goto out_unused_fd;
                }
 
                for (i = 0; i < exbuf->num_bo_handles; i++) {
                        gobj = drm_gem_object_lookup(drm_file, bo_handles[i]);
                        if (!gobj) {
-                               kvfree(bo_handles);
-                               kvfree(buflist);
-                               return -ENOENT;
+                               ret = -ENOENT;
+                               goto out_unused_fd;
                        }
 
                        qobj = gem_to_virtio_gpu_obj(gobj);
@@ -161,6 +188,7 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
                        list_add(&buflist[i].head, &validate_list);
                }
                kvfree(bo_handles);
+               bo_handles = NULL;
        }
 
        ret = virtio_gpu_object_list_validate(&ticket, &validate_list);
@@ -174,28 +202,47 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
                goto out_unresv;
        }
 
-       fence = virtio_gpu_fence_alloc(vgdev);
-       if (!fence) {
-               kfree(buf);
+       out_fence = virtio_gpu_fence_alloc(vgdev);
+       if(!out_fence) {
                ret = -ENOMEM;
-               goto out_unresv;
+               goto out_memdup;
+       }
+
+       if (out_fence_fd >= 0) {
+               sync_file = sync_file_create(&out_fence->f);
+               if (!sync_file) {
+                       dma_fence_put(&out_fence->f);
+                       ret = -ENOMEM;
+                       goto out_memdup;
+               }
+
+               exbuf->fence_fd = out_fence_fd;
+               fd_install(out_fence_fd, sync_file->file);
        }
+
        virtio_gpu_cmd_submit(vgdev, buf, exbuf->size,
-                             vfpriv->ctx_id, &fence);
+                             vfpriv->ctx_id, &out_fence);
 
-       ttm_eu_fence_buffer_objects(&ticket, &validate_list, &fence->f);
+       ttm_eu_fence_buffer_objects(&ticket, &validate_list, &out_fence->f);
 
        /* fence the command bo */
        virtio_gpu_unref_list(&validate_list);
        kvfree(buflist);
-       dma_fence_put(&fence->f);
        return 0;
 
+out_memdup:
+       kfree(buf);
 out_unresv:
        ttm_eu_backoff_reservation(&ticket, &validate_list);
 out_free:
        virtio_gpu_unref_list(&validate_list);
+out_unused_fd:
+       kvfree(bo_handles);
        kvfree(buflist);
+
+       if (out_fence_fd >= 0)
+               put_unused_fd(out_fence_fd);
+
        return ret;
 }
 

diff --git a/include/uapi/drm/virtgpu_drm.h b/include/uapi/drm/virtgpu_drm.h
index 91062f4..f06a789 100644 (file)
--- a/include/uapi/drm/virtgpu_drm.h
+++ b/include/uapi/drm/virtgpu_drm.h
@@ -66,7 +66,7 @@ struct drm_virtgpu_execbuffer {
        __u64 command; /* void* */
        __u64 bo_handles;
        __u32 num_bo_handles;
-       __s32 fence_fd;
+       __s32 fence_fd; /* in/out fence fd (see VIRTGPU_EXECBUF_FENCE_FD_IN/OUT) */
 };
 
 #define VIRTGPU_PARAM_3D_FEATURES 1 /* do we have 3D features in the hw */