description: PCI devices with RMRRs not deassigned correctly Certain PCI devices in a system might be assigned Reserved Memory Regions (specified via Reserved Memory Region Reporting, "RMRR"). These are typically used for platform tasks such as legacy USB emulation. If such a device is passed through to a guest, then on guest shutdown the device is not properly deassigned. The IOMMU configuration for these devices which are not properly deassigned ends up pointing to a freed data structure, including the IO Pagetables. Subsequent DMA or interrupts from the device will have unpredictable behaviour, ranging from IOMMU faults to memory corruption.
problem types: unknown
affected:
{
product: xen
vendor: Xen
versions:
lessThan: 4.12, status: unknown, version: unspecified, versionType: custom
lessThan: unspecified, status: affected, version: 4.12.x, versionType: custom
lessThan: unspecified, status: unaffected, version: next of xen-unstable, versionType: custom
}
metrics:
other: [
content: {'description': {'description_data': [{'lang': 'eng', 'value': 'Administrators of guests which have been assigned RMRR-using PCI\ndevices can cause denial of service and other problems, possibly\nincluding escalation of privilege.'}]}}
type: unknown
]