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

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>

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 0ee5f1bd8af2cd031f0898ca4eac468ce2c8718e..b0f901ee63583ffc17389fa61d97e40c6138aae9 100644 (file)
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -2312,8 +2312,9 @@ __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;