[PATCH] drm/amdgpu: Pin MMIO/DOORBELL BO's in GTT domain

[Ramesh Errabolu]

MMIO/DOORBELL BOs encode control data and should be pinned in GTT
domain before enabling PCIe connected peer devices in accessing it

Signed-off-by: Ramesh Errabolu <Ramesh.Errabolu at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h    | 25 +++++++++
 .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  | 55 +++++++++++++++++++
 2 files changed, 80 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
index 4c1d6536a7a5..d9a1cfd7876f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
@@ -300,6 +300,31 @@ int amdgpu_amdkfd_gpuvm_import_dmabuf(struct amdgpu_device *adev,
 				      uint64_t va, void *drm_priv,
 				      struct kgd_mem **mem, uint64_t *size,
 				      uint64_t *mmap_offset);
+
+/**
+ * amdgpu_amdkfd_gpuvm_pin_bo() - Pins a BO using following criteria
+ * @bo: Handle of buffer object being pinned
+ * @domain: Domain into which BO should be pinned
+ *
+ *   - USERPTR BOs are UNPINNABLE and will return error
+ *   - All other BO types (GTT, VRAM, MMIO and DOORBELL) will have their
+ *     PIN count incremented. It is valid to PIN a BO multiple times
+ *
+ * Return: ZERO if successful in pinning, Non-Zero in case of error.
+ * Will return -EINVAL if input BO parameter is a USERPTR type.
+ */
+int amdgpu_amdkfd_gpuvm_pin_bo(struct amdgpu_bo *bo, u32 domain);
+
+/**
+ * amdgpu_amdkfd_gpuvm_unpin_bo() - Unpins BO using following criteria
+ * @bo: Handle of buffer object being unpinned
+ *
+ *   - Is a illegal request for USERPTR BOs and is ignored
+ *   - All other BO types (GTT, VRAM, MMIO and DOORBELL) will have their
+ *     PIN count decremented. Calls to UNPIN must balance calls to PIN
+ */
+void amdgpu_amdkfd_gpuvm_unpin_bo(struct amdgpu_bo *bo);
+
 int amdgpu_amdkfd_get_tile_config(struct amdgpu_device *adev,
 				struct tile_config *config);
 void amdgpu_amdkfd_ras_poison_consumption_handler(struct amdgpu_device *adev);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index 4fa814358552..f4ffc41873dd 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -1299,6 +1299,36 @@ static int init_kfd_vm(struct amdgpu_vm *vm, void **process_info,
 	return ret;
 }
 
+int amdgpu_amdkfd_gpuvm_pin_bo(struct amdgpu_bo *bo, u32 domain)
+{
+	int ret = 0;
+
+	ret = amdgpu_bo_reserve(bo, false);
+	if (unlikely(ret))
+		return ret;
+
+	ret = amdgpu_bo_pin_restricted(bo, domain, 0, 0);
+	if (ret)
+		pr_err("Error in Pinning BO to domain: %d\n", domain);
+
+	amdgpu_bo_sync_wait(bo, AMDGPU_FENCE_OWNER_KFD, false);
+	amdgpu_bo_unreserve(bo);
+
+	return ret;
+}
+
+void amdgpu_amdkfd_gpuvm_unpin_bo(struct amdgpu_bo *bo)
+{
+	int ret = 0;
+
+	ret = amdgpu_bo_reserve(bo, false);
+	if (unlikely(ret))
+		return;
+
+	amdgpu_bo_unpin(bo);
+	amdgpu_bo_unreserve(bo);
+}
+
 int amdgpu_amdkfd_gpuvm_acquire_process_vm(struct amdgpu_device *adev,
 					   struct file *filp, u32 pasid,
 					   void **process_info,
@@ -1525,6 +1555,23 @@ int amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu(
 	if (offset)
 		*offset = amdgpu_bo_mmap_offset(bo);
 
+	if (flags & (KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL |
+			KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP)) {
+		ret = amdgpu_amdkfd_bo_validate(bo, AMDGPU_GEM_DOMAIN_GTT, false);
+		if (ret) {
+			pr_err("Validating MMIO/DOORBELL BO during ALLOC FAILED\n");
+			goto err_node_allow;
+		}
+
+		ret = amdgpu_amdkfd_gpuvm_pin_bo(bo, AMDGPU_GEM_DOMAIN_GTT);
+		if (ret) {
+			pr_err("Pinning MMIO/DOORBELL BO during ALLOC FAILED\n");
+			goto err_node_allow;
+		}
+		bo->allowed_domains = AMDGPU_GEM_DOMAIN_GTT;
+		bo->preferred_domains = AMDGPU_GEM_DOMAIN_GTT;
+	}
+
 	return 0;
 
 allocate_init_user_pages_failed:
@@ -1561,6 +1608,14 @@ int amdgpu_amdkfd_gpuvm_free_memory_of_gpu(
 	bool is_imported = false;
 
 	mutex_lock(&mem->lock);
+
+	/* Unpin MMIO/DOORBELL BO's that were pinnned during allocation */
+	if (mem->alloc_flags &
+	    (KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL |
+	     KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP)) {
+		amdgpu_amdkfd_gpuvm_unpin_bo(mem->bo);
+	}
+
 	mapped_to_gpu_memory = mem->mapped_to_gpu_memory;
 	is_imported = mem->is_imported;
 	mutex_unlock(&mem->lock);
-- 
2.31.1