[PATCH 71/95] drm/amdgpu: Pin page tables in NPA VMs

From: Felix Kuehling <[email protected]>

With latest POR, remote importers aren't guaranteed to support
instruction replay-on-fault. Therefore, we cannot support unpinned
exports or unpinned page-tables in the exporter mappings into NPA space.

Signed-off-by: Felix Kuehling <[email protected]>
Reviewed-by: Mukul Joshi <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ualink.c |  4 +--
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c     | 40 ++++++++++++++++++++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h     |  3 ++
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c  | 25 +++++++++++++-
 4 files changed, 69 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ualink.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ualink.c
index 68faf2a30e0a1..f45edc882b2f2 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ualink.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ualink.c
@@ -3397,8 +3397,8 @@ int amdgpu_ualink_manager_start(struct amdgpu_device *adev)
 	if (r)
 		goto out;
 
-	/* For using CPU for page table updates. */
-	r = amdgpu_vm_make_compute(adev, &adev->ualink.npa_vm);
+	/* For pinning page tables and using CPU for page table updates. */
+	r = amdgpu_vm_make_npa(adev, &adev->ualink.npa_vm);
 	if (r)
 		goto uninit_vm;
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 8f8fecb9738ba..a7981aab0a329 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -2748,6 +2748,46 @@ int amdgpu_vm_make_compute(struct amdgpu_device *adev, struct amdgpu_vm *vm)
 	return r;
 }
 
+/**
+ * amdgpu_vm_make_npa - Turn a GFX VM into an NPA VM
+ *
+ * @adev: amdgpu_device pointer
+ * @vm: requested vm
+ *
+ * This only works on GFX VMs that don't have any BOs added and no
+ * page tables allocated yet.
+ *
+ * Changes the following VM parameters:
+ * - use_cpu_for_update
+ * - pins page tables
+ * - initializes PTEs to no-retry encoding
+ *
+ * Reinitializes the page directory to reflect the changed ATS
+ * setting.
+ *
+ * Returns:
+ * 0 for success, -errno for errors.
+ */
+int amdgpu_vm_make_npa(struct amdgpu_device *adev, struct amdgpu_vm *vm)
+{
+	int r = amdgpu_vm_make_compute(adev, vm);
+
+	if (r)
+		return r;
+	vm->is_npa = true;
+	r = amdgpu_bo_reserve(vm->root.bo, false);
+	if (r)
+		return r;
+	r = amdgpu_bo_pin(vm->root.bo, AMDGPU_GEM_DOMAIN_VRAM);
+	amdgpu_bo_unreserve(vm->root.bo);
+	if (r)
+		return r;
+
+	vm->is_npa = true;
+
+	return 0;
+}
+
 static int amdgpu_vm_stats_is_zero(struct amdgpu_vm *vm)
 {
 	for (int i = 0; i < __AMDGPU_PL_NUM; ++i) {
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
index 9dd7a17731f2e..defabb0a7b030 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
@@ -443,6 +443,8 @@ struct amdgpu_vm {
 	struct ttm_lru_bulk_move lru_bulk_move;
 	/* Flag to indicate if VM is used for compute */
 	bool			is_compute_context;
+	/* Flag to indicate that page tables are for NPA mappings */
+	bool			is_npa;
 	/* Flag to indicate if VM needs a TLB fence (KFD or KGD) */
 	bool			need_tlb_fence;
 
@@ -503,6 +505,7 @@ void amdgpu_vm_manager_fini(struct amdgpu_device *adev);
 long amdgpu_vm_wait_idle(struct amdgpu_vm *vm, long timeout);
 int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm, int32_t xcp_id);
 int amdgpu_vm_make_compute(struct amdgpu_device *adev, struct amdgpu_vm *vm);
+int amdgpu_vm_make_npa(struct amdgpu_device *adev, struct amdgpu_vm *vm);
 void amdgpu_vm_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm);
 int amdgpu_vm_lock_pd(struct amdgpu_vm *vm, struct drm_exec *exec,
 		      unsigned int num_fences);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
index e43a60d098082..ff69a3c828de3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
@@ -444,6 +444,7 @@ int amdgpu_vm_pt_create(struct amdgpu_device *adev, struct amdgpu_vm *vm,
 {
 	struct amdgpu_bo_param bp;
 	unsigned int num_entries;
+	int r;
 
 	memset(&bp, 0, sizeof(bp));
 
@@ -476,7 +477,24 @@ int amdgpu_vm_pt_create(struct amdgpu_device *adev, struct amdgpu_vm *vm,
 	if (vm->root.bo)
 		bp.resv = vm->root.bo->tbo.base.resv;
 
-	return amdgpu_bo_create_vm(adev, &bp, vmbo);
+	r = amdgpu_bo_create_vm(adev, &bp, vmbo);
+	if (r)
+		return r;
+
+	/* Assumes that reservation is shared with the VM root and that the
+	 * reservation is locked
+	 */
+	if (vm->root.bo && vm->is_npa) {
+		struct amdgpu_bo *pt_bo = &(*vmbo)->bo;
+
+		r = amdgpu_bo_pin(pt_bo, AMDGPU_GEM_DOMAIN_VRAM);
+		if (r) {
+			amdgpu_bo_unref(&pt_bo);
+			return r;
+		}
+	}
+
+	return 0;
 }
 
 /**
@@ -526,6 +544,8 @@ static int amdgpu_vm_pt_alloc(struct amdgpu_device *adev,
 	return 0;
 
 error_free_pt:
+	if (vm->is_npa)
+		amdgpu_bo_unpin(pt_bo);
 	amdgpu_bo_unref(&pt_bo);
 	return r;
 }
@@ -540,6 +560,9 @@ static void amdgpu_vm_pt_free(struct amdgpu_vm_bo_base *entry)
 	if (!entry->bo)
 		return;
 
+	if (entry->vm->is_npa)
+		amdgpu_bo_unpin(entry->bo);
+
 	amdgpu_vm_update_stats(entry, entry->bo->tbo.resource, -1);
 	entry->bo->vm_bo = NULL;
 	ttm_bo_set_bulk_move(&entry->bo->tbo, NULL);
-- 
2.55.0