iommu/vt-d: Enhance capability check for nested parent domain allocation

This adds the scalable mode check before allocating the nested parent domain as checking nested capability is not enough. User may turn off scalable mode which also means no nested support even if the hardware supports it. Fixes: c97d1b2 ("iommu/vt-d: Add domain_alloc_user op") Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Yi Liu <[email protected]> Reviewed-by: Lu Baolu <[email protected]> Reviewed-by: Kevin Tian <[email protected]> Signed-off-by: Jason Gunthorpe <[email protected]>
niw · Oct 26, 2023 · a2cdecd · a2cdecd
1 parent 55a0165
commit a2cdecd
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Showing 2 changed files with 3 additions and 1 deletion.
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
@@ -4095,7 +4095,7 @@ intel_iommu_domain_alloc_user(struct device *dev, u32 flags,
 	if (!iommu)
 		return ERR_PTR(-ENODEV);
 
-	if ((flags & IOMMU_HWPT_ALLOC_NEST_PARENT) && !ecap_nest(iommu->ecap))
+	if ((flags & IOMMU_HWPT_ALLOC_NEST_PARENT) && !nested_supported(iommu))
 		return ERR_PTR(-EOPNOTSUPP);
 
 	dirty_tracking = (flags & IOMMU_HWPT_ALLOC_DIRTY_TRACKING);

diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
@@ -544,6 +544,8 @@ enum {
 				 ecap_pasid((iommu)->ecap))
 #define ssads_supported(iommu) (sm_supported(iommu) &&                 \
 				ecap_slads((iommu)->ecap))
+#define nested_supported(iommu)	(sm_supported(iommu) &&			\
+				 ecap_nest((iommu)->ecap))
 
 struct pasid_entry;
 struct pasid_state_entry;