KVM: SVM: work around errata 1218

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According to AMD, the hypervisor may not be able to determine whether a
fault was a GMET fault or an NX fault based on EXITINFO1, and software
"must read the relevant VMCB to determine whether a fault was a GMET
fault or an NX fault".  The APM further details that they meant the
CPL field.

KVM uses the page fault error code to distinguish the causes of a
nested page fault, so recalculate the PFERR_USER_MASK bit of the
vmexit information.  Only do it for fetches and only if GMET is in
use, because KVM does not differentiate based on PFERR_USER_MASK
for other nested NPT page faults.

Tested-by: David Riley <d.riley@proxmox.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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Paolo Bonzini 2026-04-08 11:42:16 -04:00

parent fe080f58de

commit 878fffd76c

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arch/x86/kvm/svm/svm.c

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