[PATCH 3/3] drm/virtio: Implement device_attach

[Julia Zhang <julia.zhang@amd.com>]

As vram objects may be imported by other gpu drivers, peer2peer flag
should be checked in dma_buf_ops->attach(). This reimplement virtio gpu
dma_buf_ops->attach by adding a device_attach() function for virtio gpu.
This function will get pci_p2pdma_distance and check attach->peer2peer
before calling drm_gem_map_attach().

Signed-off-by: Julia Zhang <julia.zhang@amd.com>
---
 drivers/gpu/drm/virtio/virtgpu_prime.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_prime.c b/drivers/gpu/drm/virtio/virtgpu_prime.c
index 4960620eba02..4f6bce79e10e 100644
--- a/drivers/gpu/drm/virtio/virtgpu_prime.c
+++ b/drivers/gpu/drm/virtio/virtgpu_prime.c
@@ -116,6 +116,18 @@ static int virtgpu_get_p2pdma_distance(struct dma_buf *dma_buf,
 	return 0;
 }
 
+static int virtgpu_gem_device_attach(struct dma_buf *dma_buf,
+				     struct dma_buf_attachment *attach)
+{
+	int ret = virtgpu_get_p2pdma_distance(dma_buf, attach);
+	if (ret)
+		return ret;
+	if (!attach->peer2peer)
+		return -EBUSY;
+
+	return drm_gem_map_attach(dma_buf, attach);
+}
+
 static const struct virtio_dma_buf_ops virtgpu_dmabuf_ops =  {
 	.ops = {
 		.cache_sgt_mapping = true,
@@ -128,7 +140,7 @@ static const struct virtio_dma_buf_ops virtgpu_dmabuf_ops =  {
 		.vmap = drm_gem_dmabuf_vmap,
 		.vunmap = drm_gem_dmabuf_vunmap,
 	},
-	.device_attach = drm_gem_map_attach,
+	.device_attach = virtgpu_gem_device_attach,
 	.get_uuid = virtgpu_virtio_get_uuid,
 };
 
-- 
2.34.1