CVE-2025-40058

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> iommu/vt-d: Disallow dirty tracking if incoherent page walk<br /> <br /> Dirty page tracking relies on the IOMMU atomically updating the dirty bit<br /> in the paging-structure entry. For this operation to succeed, the paging-<br /> structure memory must be coherent between the IOMMU and the CPU. In<br /> another word, if the iommu page walk is incoherent, dirty page tracking<br /> doesn&amp;#39;t work.<br /> <br /> The Intel VT-d specification, Section 3.10 "Snoop Behavior" states:<br /> <br /> "Remapping hardware encountering the need to atomically update A/EA/D bits<br /> in a paging-structure entry that is not snooped will result in a non-<br /> recoverable fault."<br /> <br /> To prevent an IOMMU from being incorrectly configured for dirty page<br /> tracking when it is operating in an incoherent mode, mark SSADS as<br /> supported only when both ecap_slads and ecap_smpwc are supported.