[PATCH] drm/xe: Exclude wopcm region from stolen memory on TGL/DG1

[Zhenyu Yang via B4 Relay]

From: Zhenyu Yang <har...@seu.edu.cn>

Top of DSM contains the WOPCM which shouldn't be accessed. Carve it out
from the stolen memory on TGL/DG1 as well.  This fixes excessive ATS faults
on an RPL laptop since v7.2-rc1.

Fixes: 1c76fa517214 ("drm/xe: Convert stolen memory over to ttm_range_manager")
Signed-off-by: Zhenyu Yang <har...@seu.edu.cn>
---
 drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c 
b/drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c
index 5e9070739e65..75f4d064d711 100644
--- a/drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c
+++ b/drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c
@@ -180,12 +180,22 @@ extern struct resource intel_graphics_stolen_res;
 static u64 detect_stolen(struct xe_device *xe, struct xe_ttm_stolen_mgr *mgr)
 {
 #ifdef CONFIG_X86
+       u64 stolen_size, wopcm_size;
+
        /* Map into GGTT */
        mgr->io_base = pci_resource_start(to_pci_dev(xe->drm.dev), 2);
 
        /* Stolen memory is x86 only */
        mgr->stolen_base = intel_graphics_stolen_res.start;
-       return resource_size(&intel_graphics_stolen_res);
+       stolen_size = resource_size(&intel_graphics_stolen_res);
+
+       /* Carve out the top of DSM as it contains the reserved WOPCM region */
+       wopcm_size = get_wopcm_size(xe);
+       if (drm_WARN_ON(&xe->drm, !wopcm_size))
+               return 0;
+
+       xe_assert(xe, stolen_size >= wopcm_size);
+       return stolen_size - wopcm_size;
 #else
        return 0;
 #endif

---
base-commit: db2ddb87143519e20a95aa36c60b36107b736a58
change-id: 20260811-fix-xe-ttm-4a9713d7cca9