[RFC PATCH 1/3] drm/amdgpu: Add vm->notifier_lock

[Felix Kuehling]

This points to a mutex to serialize with MMU notifiers during page table
updates. For graphics contexts, the notifier lock is per adev. For compute
contexts the lock is per process.

Signed-off-by: Felix Kuehling <felix.kuehl...@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 3 +++
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c           | 1 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h           | 3 +++
 3 files changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index b15091d8310d..7aaa844a8284 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -1325,9 +1325,12 @@ static int init_kfd_vm(struct amdgpu_vm *vm, void 
**process_info,
 
                *process_info = info;
                *ef = dma_fence_get(&info->eviction_fence->base);
+       } else {
+               info = *process_info;
        }
 
        vm->process_info = *process_info;
+       vm->notifier_lock = &info->notifier_lock;
 
        /* Validate page directory and attach eviction fence */
        ret = amdgpu_bo_reserve(vm->root.bo, true);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index dc379dc22c77..a04f7aef4ca9 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -2075,6 +2075,7 @@ int amdgpu_vm_init(struct amdgpu_device *adev, struct 
amdgpu_vm *vm)
 
        mutex_init(&vm->eviction_lock);
        vm->evicting = false;
+       vm->notifier_lock = &adev->notifier_lock;
 
        r = amdgpu_vm_pt_create(adev, vm, adev->vm_manager.root_level,
                                false, &root);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
index 094bb4807303..07af80df812b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
@@ -251,6 +251,9 @@ struct amdgpu_vm {
        bool                    evicting;
        unsigned int            saved_flags;
 
+       /* Pointer to notifier lock used when updating PTEs */
+       struct mutex            *notifier_lock;
+
        /* Lock to protect vm_bo add/del/move on all lists of vm */
        spinlock_t              status_lock;
 
-- 
2.32.0