drm/xe/migrate: fix offset and len check

Restriction here is pitch of 4bytes to match pixel width (32b), and hw
restriction where src and dst must be aligned to 64bytes. If any of that
is not possible then we need a bounce buffer.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://lore.kernel.org/r/20251022163836.191405-2-matthew.auld@intel.com

Author: matt-auld

drivers/gpu/drm/xe/xe_migrate.c

@@ -1883,7 +1883,7 @@ static struct dma_fence *xe_migrate_vram(struct xe_migrate *m,
 	unsigned long i, j;
 	bool use_pde = xe_migrate_vram_use_pde(sram_addr, len + sram_offset);
 
-	if (drm_WARN_ON(&xe->drm, (len & XE_CACHELINE_MASK) ||
+	if (drm_WARN_ON(&xe->drm, (!IS_ALIGNED(len, pitch)) ||
 			(sram_offset | vram_addr) & XE_CACHELINE_MASK))
 		return ERR_PTR(-EOPNOTSUPP);
 
@@ -2103,8 +2103,9 @@ int xe_migrate_access_memory(struct xe_migrate *m, struct xe_bo *bo,
 	xe_bo_assert_held(bo);
 
 	/* Use bounce buffer for small access and unaligned access */
-	if (!IS_ALIGNED(len, XE_CACHELINE_BYTES) ||
-	    !IS_ALIGNED((unsigned long)buf + offset, XE_CACHELINE_BYTES)) {
+	if (!IS_ALIGNED(len, 4) ||
+	    !IS_ALIGNED(page_offset, XE_CACHELINE_BYTES) ||
+	    !IS_ALIGNED(offset, XE_CACHELINE_BYTES)) {
 		int buf_offset = 0;
 		void *bounce;
 		int err;