KVM: x86/mmu: Optimize not-present/MMIO SPTE check in get_mmio_spte()

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Check only the terminal leaf for a "!PRESENT || MMIO" SPTE when looking
for reserved bits on valid, non-MMIO SPTEs.  The get_walk() helpers
terminate their walks if a not-present or MMIO SPTE is encountered, i.e.
the non-terminal SPTEs have already been verified to be regular SPTEs.
This eliminates an extra check-and-branch in a relatively hot loop.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20201218003139.2167891-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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Sean Christopherson 2020-12-17 16:31:39 -08:00 • committed by Paolo Bonzini

parent dde81f9477

commit 9aa418792f

1 changed files with 13 additions and 7 deletions

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arch/x86/kvm/mmu/mmu.c

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