CVE-2021-47035

In the Linux kernel, the following vulnerability has been resolved:

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.