KVM: x86/mmu: use kvm_page_format to test SPTEs

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is_access_allowed(), and is_executable_pte() within it, are effectively a
special version of permission_fault() that only supports a subset of roles.
In particular it does not allow SMEP, SMAP and PKE; while SMAP and PKE are
not a problem (they are not supported by EPT/NPT and is_access_allowed() is
only used for either EPT/NPT or CR0.PG=0), lack of ring-0 execution checks
support means that KVM can only use MBEC and GMET with shadow paging.

Replace is_access_allowed() with a modified version of permission_fault(),
looking at the same bitmasks but using the struct kvm_mmu's fmt member;
the new version supports MBEC/GMET for free, just by virtue of filling
in the ACC_* masks from the SPTE.

This prepares for a possible future where TDP entries could have XS!=XU,
for example as part of implementing Hyper-V VSM natively inside KVM.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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Paolo Bonzini 2026-03-03 21:34:46 +01:00

parent 6bb13c2eb7

commit 216b1a47e8

3 changed files with 47 additions and 25 deletions

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18

arch/x86/kvm/mmu/mmu.c

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51

arch/x86/kvm/mmu/spte.h

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3

arch/x86/kvm/mmu/tdp_mmu.c

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