[PATCH AUTOSEL 6.14 15/34] drm/amdgpu: allow pinning DMA-bufs into VRAM if all importers can do P2P

Sasha Levin
2025-04-14T13:26:49Z

From: Christian König <christian.koenig@amd.com>

[ Upstream commit f5e7fabd1f5c65b2e077efcdb118cfa67eae7311 ]

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 <simona.vetter@ffwll.ch>
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Felix Kuehling <felix.kuehling@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Tested-by: Pak Nin Lui <pak.lui@amd.com>
Cc: Simona Vetter <simona.vetter@ffwll.ch>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c | 25 +++++++++++++++------
1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
index 9f627caedc3f6..ee47f239c8c12 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
+++ b/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) {
--
2.39.5