drm/xe: Validate preferred system memory placement in xe_svm_range_validate

Ensure preferred system memory placement is checked in
xe_svm_range_validate when dpagemap is NULL. Without this check, a
prefetch to system memory may become a no-op because device memory is
considered a valid placement.

Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Fixes: 238dbc9d9f4a ("drm/xe: Use the vma attibute drm_pagemap to select where to migrate")
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Link: https://patch.msgid.link/20260106213443.1866797-1-matthew.brost@intel.com

diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c
index fa2ee2c08f318e0b2c5e820a0c52e9d0770fb47b..213f0334518a467255930391267c974b7c1fdaf2 100644 (file)
--- a/drivers/gpu/drm/xe/xe_svm.c
+++ b/drivers/gpu/drm/xe/xe_svm.c
@@ -988,6 +988,8 @@ bool xe_svm_range_validate(struct xe_vm *vm,
        ret = (range->tile_present & ~range->tile_invalidated & tile_mask) == tile_mask;
        if (dpagemap)
                ret = ret && xe_svm_range_has_pagemap_locked(range, dpagemap);
+       else
+               ret = ret && !range->base.pages.dpagemap;
 
        xe_svm_notifier_unlock(vm);