iommu/vt-d: Make kernel parameter igfx_off work with vIOMMU

[ Upstream commit 5daab58043ee2bca861068e2595564828f3bc663 ] The kernel parameter igfx_off is used by users to disable DMA remapping for the Intel integrated graphic device. It was designed for bare metal cases where a dedicated IOMMU is used for graphic. This doesn't apply to virtual IOMMU case where an include-all IOMMU is used. This makes the kernel parameter work with virtual IOMMU as well. Cc: Ashok Raj <[email protected]> Cc: Jacob Pan <[email protected]> Suggested-by: Kevin Tian <[email protected]> Fixes: c0771df ("intel-iommu: Export a flag indicating that the IOMMU is used for iGFX.") Signed-off-by: Lu Baolu <[email protected]> Tested-by: Zhenyu Wang <[email protected]> Signed-off-by: Joerg Roedel <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: John Vincent <[email protected]> Signed-off-by: John Vincent <[email protected]>
ravindu644 · Aug 18, 2024 · 93e6212 · 93e6212
1 parent 0ef021b
commit 93e6212
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
@@ -3361,9 +3361,12 @@ static int __init init_dmars(void)
 		iommu_identity_mapping |= IDENTMAP_ALL;
 
 #ifdef CONFIG_INTEL_IOMMU_BROKEN_GFX_WA
-	iommu_identity_mapping |= IDENTMAP_GFX;
+	dmar_map_gfx = 0;
 #endif
 
+	if (!dmar_map_gfx)
+		iommu_identity_mapping |= IDENTMAP_GFX;
+
 	check_tylersburg_isoch();
 
 	if (iommu_identity_mapping) {