[PATCH 1/6] drm/amdgpu: Generalize KFD dmabuf import

[Errabolu, Ramesh]

[AMD Official Use Only - General]

A minor comment, unrelated to the patch. The comments are inline.

Regards,
Ramesh

-----Original Message-----
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of Felix Kuehling
Sent: Thursday, January 12, 2023 7:02 AM
To: amd-gfx at lists.freedesktop.org; dri-devel at lists.freedesktop.org
Cc: Chen, Xiaogang <Xiaogang.Chen at amd.com>; Koenig, Christian <Christian.Koenig at amd.com>
Subject: [PATCH 1/6] drm/amdgpu: Generalize KFD dmabuf import

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Use proper amdgpu_gem_prime_import function to handle all kinds of imports. Remember the dmabuf reference to enable proper multi-GPU attachment to multiple VMs without erroneously re-exporting the underlying BO multiple times.

Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
---
 .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  | 38 ++++++++++---------
 1 file changed, 21 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index 6f236ded5f12..e13c3493b786 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -2209,30 +2209,27 @@ int amdgpu_amdkfd_gpuvm_import_dmabuf(struct amdgpu_device *adev,
        struct amdgpu_bo *bo;
        int ret;

-       if (dma_buf->ops != &amdgpu_dmabuf_ops)
-               /* Can't handle non-graphics buffers */
-               return -EINVAL;
-
-       obj = dma_buf->priv;
-       if (drm_to_adev(obj->dev) != adev)
-               /* Can't handle buffers from other devices */
-               return -EINVAL;
+       obj = amdgpu_gem_prime_import(adev_to_drm(adev), dma_buf);
+       if (IS_ERR(obj))
+               return PTR_ERR(obj);

        bo = gem_to_amdgpu_bo(obj);
        if (!(bo->preferred_domains & (AMDGPU_GEM_DOMAIN_VRAM |
-                                   AMDGPU_GEM_DOMAIN_GTT)))
+                                   AMDGPU_GEM_DOMAIN_GTT))) {
                /* Only VRAM and GTT BOs are supported */
-               return -EINVAL;
+               ret = -EINVAL;
+               goto err_put_obj;
+       }

        *mem = kzalloc(sizeof(struct kgd_mem), GFP_KERNEL);
-       if (!*mem)
-               return -ENOMEM;
+       if (!*mem) {
+               ret = -ENOMEM;
+               goto err_put_obj;
+       }

        ret = drm_vma_node_allow(&obj->vma_node, drm_priv);
-       if (ret) {
-               kfree(*mem);
-               return ret;
-       }
+       if (ret)
+               goto err_free_mem;

        if (size)
                *size = amdgpu_bo_size(bo); @@ -2249,7 +2246,8 @@ int amdgpu_amdkfd_gpuvm_import_dmabuf(struct amdgpu_device *adev,
                | KFD_IOC_ALLOC_MEM_FLAGS_WRITABLE
                | KFD_IOC_ALLOC_MEM_FLAGS_EXECUTABLE;
Ramesh: Is it correct to assign WRITE & EXECUTABLE permissions to alloc_flags variable.

-       drm_gem_object_get(&bo->tbo.base);
+       get_dma_buf(dma_buf);
+       (*mem)->dmabuf = dma_buf;
        (*mem)->bo = bo;
        (*mem)->va = va;
        (*mem)->domain = (bo->preferred_domains & AMDGPU_GEM_DOMAIN_VRAM) ?
@@ -2261,6 +2259,12 @@ int amdgpu_amdkfd_gpuvm_import_dmabuf(struct amdgpu_device *adev,
        (*mem)->is_imported = true;

        return 0;
+
+err_free_mem:
+       kfree(*mem);
+err_put_obj:
+       drm_gem_object_put(obj);
+       return ret;
 }

 /* Evict a userptr BO by stopping the queues if necessary
--
2.34.1