[PATCH] Find bo_va before create it when map bo into compute VM

[Xiaogang . Chen]

From: Xiaogang Chen <xiaogang.c...@amd.com>

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.kuehl...@amd.com>
Acked-by: Christian König <christian.koe...@amd.com>
Reviewed-by: Ramesh Errabolu <ramesh.errab...@amd.com>
Reviewed-By: Xiaogang Chen <xiaogang.c...@amd.com>
Tested-By: Xiaogang Chen <xiaogang.c...@amd.com>
---
 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);
                }
-- 
2.25.1