KVM: x86/mmu: Drop exec/NX check from "page fault can be fast"

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Tweak the "page fault can be fast" logic to explicitly check for !PRESENT
faults in the access tracking case, and drop the exec/NX check that
becomes redundant as a result.  No sane hardware will generate an access
that is both an instruct fetch and a write, i.e. it's a waste of cycles.
If hardware goes off the rails, or KVM runs under a misguided hypervisor,
spuriously running throught fast path is benign (KVM has been uknowingly
being doing exactly that for years).

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220423034752.1161007-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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Sean Christopherson 2022-04-23 03:47:45 +00:00 • committed by Paolo Bonzini

parent 54275f74cf

commit 5c64aba517

1 changed files with 12 additions and 7 deletions

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arch/x86/kvm/mmu/mmu.c

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