[PATCH v13 3/4] drm/amdgpu: Add mapping info option for GEM_OP ioctl

[David Francis]

Add new GEM_OP_IOCTL option GET_MAPPING_INFO, which
returns a list of mappings associated with a given bo, along with
their positions and offsets.

Signed-off-by: David Francis <David.Francis at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 84 +++++++++++++++++++++++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h  |  5 ++
 include/uapi/drm/amdgpu_drm.h           | 18 ++++++
 3 files changed, 107 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index 8b44d10a8b57..23a0545a0400 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -948,6 +948,86 @@ int amdgpu_gem_va_ioctl(struct drm_device *dev, void *data,
 	return r;
 }
 
+/**
+ * amdgpu_gem_list_mappings - get information about a buffer's mappings
+ *
+ * @gobj: gem object
+ * @args: gem_op arguments
+ * @fpriv: drm file pointer
+ *
+ * num_entries is set as an input to the size of the user-allocated array of
+ * drm_amdgpu_gem_vm_bucket stored at args->value.
+ * num_entries is sent back as output as the number of mappings the bo has.
+ * If that number is larger than the size of the array, the ioctl must
+ * be retried.
+ *
+ * Returns:
+ * 0 for success, -errno for errors.
+ */
+static int amdgpu_gem_list_mappings(struct drm_gem_object *gobj, struct amdgpu_fpriv *fpriv,
+					  struct drm_amdgpu_gem_op *args)
+{
+	struct amdgpu_vm *avm = &fpriv->vm;
+	struct amdgpu_bo *bo = gem_to_amdgpu_bo(gobj);
+	struct amdgpu_bo_va *bo_va = amdgpu_vm_bo_find(avm, bo);
+	struct drm_amdgpu_gem_vm_bucket *vm_buckets;
+	struct amdgpu_bo_va_mapping *mapping;
+	struct drm_exec exec;
+	int num_mappings = 0;
+	int ret;
+
+	vm_buckets = kvcalloc(args->num_entries, sizeof(*vm_buckets), GFP_KERNEL);
+	if (!vm_buckets)
+		return -ENOMEM;
+
+	drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT |
+			  DRM_EXEC_IGNORE_DUPLICATES, 0);
+	drm_exec_until_all_locked(&exec) {
+		if (gobj) {
+			ret = drm_exec_lock_obj(&exec, gobj);
+			drm_exec_retry_on_contention(&exec);
+			if (ret)
+				goto unlock_exec;
+		}
+
+		ret = amdgpu_vm_lock_pd(&fpriv->vm, &exec, 0);
+		drm_exec_retry_on_contention(&exec);
+		if (ret)
+			goto unlock_exec;
+	}
+
+	amdgpu_vm_bo_va_for_each_valid_mapping(bo_va, mapping) {
+		if (num_mappings < args->num_entries) {
+			vm_buckets[num_mappings].start = mapping->start;
+			vm_buckets[num_mappings].last = mapping->last;
+			vm_buckets[num_mappings].offset = mapping->offset;
+			vm_buckets[num_mappings].flags = mapping->flags;
+		}
+		num_mappings += 1;
+	}
+
+	amdgpu_vm_bo_va_for_each_invalid_mapping(bo_va, mapping) {
+		if (num_mappings < args->num_entries) {
+			vm_buckets[num_mappings].start = mapping->start;
+			vm_buckets[num_mappings].last = mapping->last;
+			vm_buckets[num_mappings].offset = mapping->offset;
+			vm_buckets[num_mappings].flags = mapping->flags;
+		}
+		num_mappings += 1;
+	}
+
+	if (num_mappings > 0 && num_mappings <= args->num_entries)
+		ret = copy_to_user(u64_to_user_ptr(args->value), vm_buckets, num_mappings * sizeof(*vm_buckets));
+
+	args->num_entries = num_mappings;
+
+unlock_exec:
+	drm_exec_fini(&exec);
+	kvfree(vm_buckets);
+
+	return ret;
+}
+
 int amdgpu_gem_op_ioctl(struct drm_device *dev, void *data,
 			struct drm_file *filp)
 {
@@ -1014,6 +1094,10 @@ int amdgpu_gem_op_ioctl(struct drm_device *dev, void *data,
 
 		amdgpu_bo_unreserve(robj);
 		break;
+	case AMDGPU_GEM_OP_GET_MAPPING_INFO:
+		amdgpu_bo_unreserve(robj);
+		r = amdgpu_gem_list_mappings(gobj, filp->driver_priv, args);
+		break;
 	default:
 		amdgpu_bo_unreserve(robj);
 		r = -EINVAL;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
index f9549f6b3d1f..5a63ae490b0e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
@@ -668,4 +668,9 @@ void amdgpu_vm_tlb_fence_create(struct amdgpu_device *adev,
 				 struct amdgpu_vm *vm,
 				 struct dma_fence **fence);
 
+#define amdgpu_vm_bo_va_for_each_valid_mapping(bo_va, mapping) \
+		list_for_each_entry(mapping, &bo_va->valids, list)
+#define amdgpu_vm_bo_va_for_each_invalid_mapping(bo_va, mapping) \
+		list_for_each_entry(mapping, &bo_va->invalids, list)
+
 #endif
diff --git a/include/uapi/drm/amdgpu_drm.h b/include/uapi/drm/amdgpu_drm.h
index 59b423883e91..7072959103e6 100644
--- a/include/uapi/drm/amdgpu_drm.h
+++ b/include/uapi/drm/amdgpu_drm.h
@@ -802,6 +802,21 @@ union drm_amdgpu_wait_fences {
 
 #define AMDGPU_GEM_OP_GET_GEM_CREATE_INFO	0
 #define AMDGPU_GEM_OP_SET_PLACEMENT		1
+#define AMDGPU_GEM_OP_GET_MAPPING_INFO		2
+
+struct drm_amdgpu_gem_vm_bucket {
+	/* Start of mapping (in number of pages) */
+	__u64 start;
+
+	/* End of mapping (in number of pages) */
+	__u64 last;
+
+	/* Mapping offset */
+	__u64 offset;
+
+	/* flags needed to recreate mapping */
+	__u64 flags;
+};
 
 /* Sets or returns a value associated with a buffer. */
 struct drm_amdgpu_gem_op {
@@ -811,6 +826,9 @@ struct drm_amdgpu_gem_op {
 	__u32	op;
 	/** Input or return value */
 	__u64	value;
+	/** For MAPPING_INFO op: number of mappings (in/out) */
+	__u32	num_entries;
+	__u32	padding;
 };
 
 #define AMDGPU_GEM_LIST_HANDLES_FLAG_IS_IMPORT	(1 << 0)
-- 
2.34.1