The current setup of the quarantine page tables assumes that the quarantine domain (dom_io) has been initialized with an address width of DEFAULT_DOMAIN_ADDRESS_WIDTH (48) and hence 4 page table levels. However dom_io being a PV domain gets the AMD-Vi IOMMU page tables levels based on the maximum (hot pluggable) RAM address, and hence on systems with no RAM above the 512GB mark only 3 page-table levels are configured in the IOMMU. On systems without RAM above the 512GB boundary amd_iommu_quarantine_init() will setup page tables for the scratch page with 4 levels, while the IOMMU will be configured to use 3 levels only, resulting in the last page table directory (PDE) effectively becoming a page table entry (PTE), and hence a device in quarantine mode gaining write access to the page destined to be a PDE. Due to this page table level mismatch, the sink page the device gets read/write access to is no longer cleared between device assignment, possibly leading to data leaks.
OS | Version | Architecture | Package | Version | Filename |
---|---|---|---|---|---|
Debian | 12 | all | xen | < 4.17.2+76-ge1f9cb16e2-1~deb12u1 | xen_4.17.2+76-ge1f9cb16e2-1~deb12u1_all.deb |
Debian | 11 | all | xen | <= 4.14.6-1 | xen_4.14.6-1_all.deb |
Debian | 10 | all | xen | <= 4.11.4+107-gef32c7afa2-1 | xen_4.11.4+107-gef32c7afa2-1_all.deb |
Debian | 999 | all | xen | < 4.17.2+76-ge1f9cb16e2-1 | xen_4.17.2+76-ge1f9cb16e2-1_all.deb |
Debian | 13 | all | xen | < 4.17.2+76-ge1f9cb16e2-1 | xen_4.17.2+76-ge1f9cb16e2-1_all.deb |