Description
certain VT-d IOMMUs may not work in shared page table mode For efficiency reasons, address translation control structures (page tables) may (and, on suitable hardware, by default will) be shared between CPUs, for second-level translation (EPT), and IOMMUs. These page tables are presently set up to always be 4 levels deep. However, an IOMMU may require the use of just 3 page table levels. In such a configuration the lop level table needs to be stripped before inserting the root table's address into the hardware pagetable base register. When sharing page tables, Xen erroneously skipped this stripping. Consequently, the guest is able to write to leaf page table entries.
Published: 2021-11-21
Score: 8.8 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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Tracking

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Advisories
Source ID Title
EUVD EUVD EUVD-2021-15367 certain VT-d IOMMUs may not work in shared page table mode For efficiency reasons, address translation control structures (page tables) may (and, on suitable hardware, by default will) be shared between CPUs, for second-level translation (EPT), and IOMMUs. These page tables are presently set up to always be 4 levels deep. However, an IOMMU may require the use of just 3 page table levels. In such a configuration the lop level table needs to be stripped before inserting the root table's address into the hardware pagetable base register. When sharing page tables, Xen erroneously skipped this stripping. Consequently, the guest is able to write to leaf page table entries.
History

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cve-icon MITRE

Status: PUBLISHED

Assigner: XEN

Published:

Updated: 2024-08-03T21:47:33.159Z

Reserved: 2021-03-18T00:00:00.000Z

Link: CVE-2021-28710

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2021-11-21T15:15:07.597

Modified: 2024-11-21T06:00:11.550

Link: CVE-2021-28710

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses