On 2023-10-11 19:36, Xiaogang.Chen wrote:
From: Xiaogang Chen <xiaogang.chen@xxxxxxx>
Since you are the author of this updated patch, you should also add your Signed-off-by below.
This is needed to correctly handle BOs imported into compute VM from gfx. Both kfd and gfx should use same bo_va when map the Bos into same VM, otherwise we may trigger kernel general protection when iterate mappings from bo_va. Signed-off-by: Felix Kuehling <Felix.Kuehling@xxxxxxx> Acked-by: Christian König <christian.koenig@xxxxxxx> Reviewed-by: Ramesh Errabolu <Ramesh.Errabolu@xxxxxxx> Reviewed-By: Xiaogang Chen <Xiaogang.Chen@xxxxxxx> Tested-By: Xiaogang Chen <Xiaogang.Chen@xxxxxxx>
You lost any mention of reference counting from the commit headline and description. I think that's still an important concept that should be mentioned. I'd change the headline to something like this:
drm/amdgpu: Correctly use bo_va->ref_count in compute VMs Regards, Felix
--- drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index a15e59abe70a..c1ec93cc50ae 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -832,6 +832,7 @@ static int kfd_mem_attach(struct amdgpu_device *adev, struct kgd_mem *mem, uint64_t va = mem->va; struct kfd_mem_attachment *attachment[2] = {NULL, NULL}; struct amdgpu_bo *bo[2] = {NULL, NULL}; + struct amdgpu_bo_va *bo_va; bool same_hive = false; int i, ret;@@ -919,7 +920,13 @@ static int kfd_mem_attach(struct amdgpu_device *adev, struct kgd_mem *mem,pr_debug("Unable to reserve BO during memory attach"); goto unwind; } - attachment[i]->bo_va = amdgpu_vm_bo_add(adev, vm, bo[i]); + bo_va = amdgpu_vm_bo_find(vm, bo[i]); + if (!bo_va) + bo_va = amdgpu_vm_bo_add(adev, vm, bo[i]); + else + ++bo_va->ref_count; + attachment[i]->bo_va = bo_va; + amdgpu_bo_unreserve(bo[i]); if (unlikely(!attachment[i]->bo_va)) { ret = -ENOMEM; @@ -943,7 +950,8 @@ static int kfd_mem_attach(struct amdgpu_device *adev, struct kgd_mem *mem, continue; if (attachment[i]->bo_va) { amdgpu_bo_reserve(bo[i], true); - amdgpu_vm_bo_del(adev, attachment[i]->bo_va); + if (--attachment[i]->bo_va->ref_count == 0) + amdgpu_vm_bo_del(adev, attachment[i]->bo_va); amdgpu_bo_unreserve(bo[i]); list_del(&attachment[i]->list); }
