KVM: x86/mmu: Remove redundant is_tdp_mmu_enabled check

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This check is redundant because the root shadow page will only be a TDP
MMU page if is_tdp_mmu_enabled() returns true, and is_tdp_mmu_enabled()
never changes for the lifetime of a VM.

It's possible that this check was added for performance reasons but it
is unlikely that it is useful in practice since to_shadow_page() is
cheap. That being said, this patch also caches the return value of
is_tdp_mmu_root() in direct_page_fault() since there's no reason to
duplicate the call so many times, so performance is not a concern.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20210617231948.2591431-3-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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This commit is contained in:

David Matlack 2021-06-17 23:19:46 +00:00 • committed by Paolo Bonzini

parent aa23c0ad14

commit 0b873fd7fb

2 changed files with 7 additions and 8 deletions

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11

arch/x86/kvm/mmu/mmu.c

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4

arch/x86/kvm/mmu/tdp_mmu.h

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