Messages in this thread | | | From | Jim Mattson <> | Date | Wed, 8 Jan 2020 09:50:55 -0800 | Subject | Re: [PATCH] KVM: x86/mmu: Fix a benign Bitwise vs. Logical OR mixup |
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On Wed, Jan 8, 2020 at 2:13 AM Vitaly Kuznetsov <vkuznets@redhat.com> wrote: > > Sean Christopherson <sean.j.christopherson@intel.com> writes: > > > Use a Logical OR in __is_rsvd_bits_set() to combine the two reserved bit > > checks, which are obviously intended to be logical statements. Switching > > to a Logical OR is functionally a nop, but allows the compiler to better > > optimize the checks. > > > > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> > > --- > > arch/x86/kvm/mmu/mmu.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > > index 7269130ea5e2..72e845709027 100644 > > --- a/arch/x86/kvm/mmu/mmu.c > > +++ b/arch/x86/kvm/mmu/mmu.c > > @@ -3970,7 +3970,7 @@ __is_rsvd_bits_set(struct rsvd_bits_validate *rsvd_check, u64 pte, int level) > > { > > int bit7 = (pte >> 7) & 1, low6 = pte & 0x3f; > > > > - return (pte & rsvd_check->rsvd_bits_mask[bit7][level-1]) | > > + return (pte & rsvd_check->rsvd_bits_mask[bit7][level-1]) || > > ((rsvd_check->bad_mt_xwr & (1ull << low6)) != 0); > > Redundant parentheses detected!
I think you mean superfluous rather than redundant.
> > } > > Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
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