iommu/arm-smmu-v3: Fix pgsize_bit for sva domains

commit 12f7802
Author: Balbir Singh <[email protected]>
Date: Sat Apr 12 10:23:54 2025 +1000

    iommu/arm-smmu-v3: Fix pgsize_bit for sva domains

    UBSan caught a bug with IOMMU SVA domains, where the reported exponent
    value in __arm_smmu_tlb_inv_range() was >= 64.
    __arm_smmu_tlb_inv_range() uses the domain's pgsize_bitmap to compute
    the number of pages to invalidate and the invalidation range. Currently
    arm_smmu_sva_domain_alloc() does not setup the iommu domain's
    pgsize_bitmap. This leads to __ffs() on the value returning 64 and that
    leads to undefined behaviour w.r.t. shift operations

    Fix this by initializing the iommu_domain's pgsize_bitmap to PAGE_SIZE.
    Effectively the code needs to use the smallest page size for
    invalidation

    Cc: [email protected]
    Fixes: eb6c976 ("iommu/arm-smmu-v3: Avoid constructing invalid range commands")
    Suggested-by: Jason Gunthorpe <[email protected]>
    Signed-off-by: Balbir Singh <[email protected]>

    Cc: Jean-Philippe Brucker <[email protected]>
    Cc: Will Deacon <[email protected]>
    Cc: Robin Murphy <[email protected]>
    Cc: Joerg Roedel <[email protected]>
    Cc: Jason Gunthorpe <[email protected]>
    Reviewed-by: Jason Gunthorpe <[email protected]>
    Link: https://lore.kernel.org/r/[email protected]
    Signed-off-by: Will Deacon <[email protected]>

(cherry picked from commit 12f7802)
Signed-off-by: Jerry Snitselaar <[email protected]>
Upstream-Status: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
JIRA: https://issues.redhat.com/browse/RHEL-89891
JIRA: https://issues.redhat.com/browse/RHEL-92494

Author: snits

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c

@@ -411,6 +411,12 @@ struct iommu_domain *arm_smmu_sva_domain_alloc(struct device *dev,
 		return ERR_CAST(smmu_domain);
 	smmu_domain->domain.type = IOMMU_DOMAIN_SVA;
 	smmu_domain->domain.ops = &arm_smmu_sva_domain_ops;
+
+	/*
+	 * Choose page_size as the leaf page size for invalidation when
+	 * ARM_SMMU_FEAT_RANGE_INV is present
+	 */
+	smmu_domain->domain.pgsize_bitmap = PAGE_SIZE;
 	smmu_domain->smmu = smmu;
 
 	ret = xa_alloc(&arm_smmu_asid_xa, &asid, smmu_domain,