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[oss-security] Re: Xen Security Advisory 378 v3 (CVE-2021-28694,CVE-2021-28695,CVE-2021-28696) - IOMMU page mapping issues on x86
On Wed, Sep 1, 2021 at 5:34 AM Xen.org security team <security AT xen.org> wrote:
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> Xen Security Advisory CVE-2021-28694,CVE-2021-28695,CVE-2021-28696 / XSA-378
> version 3
> IOMMU page mapping issues on x86
> UPDATES IN VERSION 3
> Warn about dom0=pvh breakage in Resolution section.
> ISSUE DESCRIPTION
> Both AMD and Intel allow ACPI tables to specify regions of memory
> which should be left untranslated, which typically means these
> addresses should pass the translation phase unaltered. While these
> are typically device specific ACPI properties, they can also be
> specified to apply to a range of devices, or even all devices.
> On all systems with such regions Xen failed to prevent guests from
> undoing/replacing such mappings (CVE-2021-28694).
Is there a way to identify if a system's ACPI tables have untranslated
regions? Does it show up in xen or linux dmesg or can it be
identified in sysfs?