drm/amdgpu: allow pinning DMA-bufs into VRAM if all importers can do P2P

Try pinning into VRAM to allow P2P with RDMA NICs without ODP
support if all attachments can do P2P. If any attachment can't do
P2P just pin into GTT instead.

Acked-by: Simona Vetter <[email protected]>
Signed-off-by: Christian König <[email protected]>
Signed-off-by: Felix Kuehling <[email protected]>
Reviewed-by: Felix Kuehling <[email protected]>
Tested-by: Pak Nin Lui <[email protected]>
Cc: Simona Vetter <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

Author: ChristianKoenigAMD

drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c

@@ -75,11 +75,25 @@ static int amdgpu_dma_buf_attach(struct dma_buf *dmabuf,
  */
 static int amdgpu_dma_buf_pin(struct dma_buf_attachment *attach)
 {
-	struct drm_gem_object *obj = attach->dmabuf->priv;
-	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
+	struct dma_buf *dmabuf = attach->dmabuf;
+	struct amdgpu_bo *bo = gem_to_amdgpu_bo(dmabuf->priv);
+	u32 domains = bo->preferred_domains;
 
-	/* pin buffer into GTT */
-	return amdgpu_bo_pin(bo, AMDGPU_GEM_DOMAIN_GTT);
+	dma_resv_assert_held(dmabuf->resv);
+
+	/*
+	 * Try pinning into VRAM to allow P2P with RDMA NICs without ODP
+	 * support if all attachments can do P2P. If any attachment can't do
+	 * P2P just pin into GTT instead.
+	 */
+	list_for_each_entry(attach, &dmabuf->attachments, node)
+		if (!attach->peer2peer)
+			domains &= ~AMDGPU_GEM_DOMAIN_VRAM;
+
+	if (domains & AMDGPU_GEM_DOMAIN_VRAM)
+		bo->flags |= AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED;
+
+	return amdgpu_bo_pin(bo, domains);
 }
 
 /**
@@ -134,9 +148,6 @@ static struct sg_table *amdgpu_dma_buf_map(struct dma_buf_attachment *attach,
 		r = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
 		if (r)
 			return ERR_PTR(r);
-
-	} else if (bo->tbo.resource->mem_type != TTM_PL_TT) {
-		return ERR_PTR(-EBUSY);
 	}
 
 	switch (bo->tbo.resource->mem_type) {