iommu/vt-d: Remove WO permissions on second-level paging entries

commit eea53c5816889ee8b64544fa2e9311a81184ff9c upstream.

When the first level page table is used for IOVA translation, it only
supports Read-Only and Read-Write permissions. The Write-Only permission
is not supported as the PRESENT bit (implying Read permission) should
always set. When using second level, we still give separate permissions
that allows WriteOnly which seems inconsistent and awkward. We want to
have consistent behavior. After moving to 1st level, we don't want things
to work sometimes, and break if we use 2nd level for the same mappings.
Hence remove this configuration.

Suggested-by: Ashok Raj <ashok.raj@intel.com>
Fixes: b802d070a52a1 ("iommu/vt-d: Use iova over first level")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20210320025415.641201-3-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 649f43e0497c8fc13d1b34855658680a9f16ea65..eececdeaa40f98e101e9091d2fc2a7b3710f5f6b 100644 (file)
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -2362,8 +2362,9 @@ static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn,
                return -EINVAL;
 
        attr = prot & (DMA_PTE_READ | DMA_PTE_WRITE | DMA_PTE_SNP);
+       attr |= DMA_FL_PTE_PRESENT;
        if (domain_use_first_level(domain)) {
-               attr |= DMA_FL_PTE_PRESENT | DMA_FL_PTE_XD | DMA_FL_PTE_US;
+               attr |= DMA_FL_PTE_XD | DMA_FL_PTE_US;
 
                if (domain->domain.type == IOMMU_DOMAIN_DMA) {
                        attr |= DMA_FL_PTE_ACCESS;