CVE-2026-74439 iommu/vt-d: Clear Present bit before tearing down scalable-mode context entry

In the Linux kernel, the following vulnerability has been resolved: iommu/vt-d: Clear Present bit before tearing down scalable-mode context entry devicepasidtableteardown zeroes the 128-bit scalable-mode context entry with contextclearentry while the Present bit is still set. This creates a windo...