[CI 42/44] drm/xe/svm: Determine a vma is backed by device memory

[Oak Zeng <oak.zeng@intel.com>]

With system allocator, a userptr can now be back by device
memory also. Introduce a helper function xe_vma_is_devmem
to determine whether a range of vma is backed by device memory.

Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Brian Welty <brian.welty@intel.com>
Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Signed-off-by: Oak Zeng <oak.zeng@intel.com>
---
 drivers/gpu/drm/xe/xe_pt.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_pt.c b/drivers/gpu/drm/xe/xe_pt.c
index 3c89a32741f5..a576d5cb7727 100644
--- a/drivers/gpu/drm/xe/xe_pt.c
+++ b/drivers/gpu/drm/xe/xe_pt.c
@@ -3,6 +3,7 @@
  * Copyright © 2022 Intel Corporation
  */
 
+#include <linux/hmm.h>
 #include "xe_pt.h"
 
 #include "regs/xe_gtt_defs.h"
@@ -578,6 +579,29 @@ static const struct xe_pt_walk_ops xe_pt_stage_bind_ops = {
 	.pt_entry = xe_pt_stage_bind_entry,
 };
 
+static bool xe_vma_is_devmem(struct xe_vma *vma, u64 start)
+{
+	struct xe_bo *bo = xe_vma_bo(vma);
+
+	if (xe_vma_is_userptr(vma)) {
+		struct xe_userptr_vma *uvma = to_userptr_vma(vma);
+		struct drm_hmmptr *hmmptr = &uvma->userptr.hmmptr;
+		u64 offset = start - xe_vma_start(vma);
+		u64 page_idx = offset >> PAGE_SHIFT;
+		u64 hmm_pfn = hmmptr->pfn[page_idx];
+		struct page *page = hmm_pfn_to_page(hmm_pfn);
+
+		/**
+		 * FIXME: Assume there is no mixture system memory and device
+		 * memory placement in the [start, end) range of vma. We might
+		 * need to relook at this in the future.
+		 */
+		return is_device_private_page(page);
+	}
+
+	return bo && (xe_bo_is_vram(bo) || xe_bo_is_stolen_devmem(bo));
+}
+
 /**
  * xe_pt_stage_bind() - Build a disconnected page-table tree for a given address
  * range.
@@ -604,8 +628,7 @@ xe_pt_stage_bind(struct xe_tile *tile, struct xe_vma *vma, u64 start, u64 end,
 {
 	struct xe_device *xe = tile_to_xe(tile);
 	struct xe_bo *bo = xe_vma_bo(vma);
-	bool is_devmem = !xe_vma_is_userptr(vma) && bo &&
-		(xe_bo_is_vram(bo) || xe_bo_is_stolen_devmem(bo));
+	bool is_devmem = xe_vma_is_devmem(vma, start);
 	struct xe_res_cursor curs;
 	struct xe_pt_stage_bind_walk xe_walk = {
 		.base = {
-- 
2.26.3