[PATCH 08/22] drm/xe/svm: Add helper to invalidate svm range from GPU

[Oak Zeng <oak.zeng@xxxxxxxxx>]

A svm subsystem friendly function is added for svm range invalidation
purpose. svm subsystem doesn't maintain xe_vma, so a temporary xe_vma
is used to call function xe_vma_invalidate_vma

Not sure whether this works or not. Will have to test. if a temporary
vma doesn't work, we will have to call the zap_pte/tlb_inv functions
directly.

Signed-off-by: Oak Zeng <oak.zeng@xxxxxxxxx>
Cc: Niranjana Vishwanathapura <niranjana.vishwanathapura@xxxxxxxxx>
Cc: Matthew Brost <matthew.brost@xxxxxxxxx>
Cc: Thomas Hellström <thomas.hellstrom@xxxxxxxxx>
Cc: Brian Welty <brian.welty@xxxxxxxxx>
---
 drivers/gpu/drm/xe/xe_pt.c | 33 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/xe/xe_pt.h |  1 +
 2 files changed, 34 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_pt.c b/drivers/gpu/drm/xe/xe_pt.c
index 65cfac88ab2f..9805b402ebca 100644
--- a/drivers/gpu/drm/xe/xe_pt.c
+++ b/drivers/gpu/drm/xe/xe_pt.c
@@ -1748,3 +1748,36 @@ int xe_bind_svm_range(struct xe_vm *vm, struct xe_tile *tile,
 	dma_fence_put(fence);
 	return ret;
 }
+
+/**
+ * xe_invalidate_svm_range() - a helper to invalidate a svm address range
+ *
+ * @vm: The vm that the address range belongs to
+ * @start: start of the virtual address range
+ * @size: size of the virtual address range
+ *
+ * This is a helper function supposed to be used by svm subsystem.
+ * svm subsystem doesn't maintain xe_vma, so we create a temporary
+ * xe_vma structure so we can reuse xe_vm_invalidate_vma().
+ */
+void xe_invalidate_svm_range(struct xe_vm *vm, u64 start, u64 size)
+{
+	struct xe_vma vma = {
+		.gpuva = {
+			.va = {
+				.addr = start,
+				.range = size,
+			},
+			.vm = &vm->gpuvm,
+		},
+		/** invalidate from all tiles
+		 *  FIXME: We used temporary vma in xe_bind_svm_range, so
+		 *  we lost track of which tile we are bound to. Does
+		 *  setting tile_present to all tiles cause a problem
+		 *  in xe_vm_invalidate_vma()?
+		 */
+		.tile_present = BIT(vm->xe->info.tile_count) - 1,
+	};
+
+	xe_vm_invalidate_vma(&vma);
+}
diff --git a/drivers/gpu/drm/xe/xe_pt.h b/drivers/gpu/drm/xe/xe_pt.h
index 775d08707466..42d495997635 100644
--- a/drivers/gpu/drm/xe/xe_pt.h
+++ b/drivers/gpu/drm/xe/xe_pt.h
@@ -49,4 +49,5 @@ bool xe_pt_zap_ptes(struct xe_tile *tile, struct xe_vma *vma);
 
 int xe_bind_svm_range(struct xe_vm *vm, struct xe_tile *tile,
 			struct hmm_range *range, u64 flags);
+void xe_invalidate_svm_range(struct xe_vm *vm, u64 start, u64 size);
 #endif
-- 
2.26.3