From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] KVM: x86/mmu: Fix a benign Bitwise vs. Logical OR mixup
Date: Tue, 7 Jan 2020 16:18:59 -0800 [thread overview]
Message-ID: <20200108001859.25254-1-sean.j.christopherson@intel.com> (raw)
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);
}
--
2.24.1
next reply other threads:[~2020-01-08 0:19 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-08 0:18 Sean Christopherson [this message]
2020-01-08 10:13 ` [PATCH] KVM: x86/mmu: Fix a benign Bitwise vs. Logical OR mixup Vitaly Kuznetsov
2020-01-08 17:50 ` Jim Mattson
2020-01-09 14:13 ` David Laight
2020-01-09 15:26 ` Arvind Sankar
2020-01-09 16:36 ` Sean Christopherson
2020-01-09 17:24 ` Sean Christopherson
2020-01-15 18:20 ` Paolo Bonzini
2020-01-08 8:37 linmiaohe
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