From: linmiaohe <linmiaohe@huawei.com>
To: <pbonzini@redhat.com>, <rkrcmar@redhat.com>,
<sean.j.christopherson@intel.com>, <vkuznets@redhat.com>,
<jmattson@google.com>, <joro@8bytes.org>, <tglx@linutronix.de>,
<mingo@redhat.com>, <bp@alien8.de>, <hpa@zytor.com>
Cc: <linmiaohe@huawei.com>, <kvm@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <x86@kernel.org>
Subject: [PATCH] KVM: x86: small optimization for is_mtrr_mask calculation
Date: Thu, 5 Mar 2020 10:48:55 +0800 [thread overview]
Message-ID: <1583376535-27255-1-git-send-email-linmiaohe@huawei.com> (raw)
From: Miaohe Lin <linmiaohe@huawei.com>
We can get is_mtrr_mask by calculating (msr - 0x200) % 2 directly.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
arch/x86/kvm/mtrr.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/mtrr.c b/arch/x86/kvm/mtrr.c
index 7f0059aa30e1..a98701d9f2bf 100644
--- a/arch/x86/kvm/mtrr.c
+++ b/arch/x86/kvm/mtrr.c
@@ -348,7 +348,7 @@ static void set_var_mtrr_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
int index, is_mtrr_mask;
index = (msr - 0x200) / 2;
- is_mtrr_mask = msr - 0x200 - 2 * index;
+ is_mtrr_mask = (msr - 0x200) % 2;
cur = &mtrr_state->var_ranges[index];
/* remove the entry if it's in the list. */
@@ -424,7 +424,7 @@ int kvm_mtrr_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
int is_mtrr_mask;
index = (msr - 0x200) / 2;
- is_mtrr_mask = msr - 0x200 - 2 * index;
+ is_mtrr_mask = (msr - 0x200) % 2;
if (!is_mtrr_mask)
*pdata = vcpu->arch.mtrr_state.var_ranges[index].base;
else
--
2.19.1
next reply other threads:[~2020-03-05 2:46 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-05 2:48 linmiaohe [this message]
2020-03-05 14:35 ` Paolo Bonzini
2020-03-05 15:10 ` David Laight
2020-03-05 15:25 ` Paolo Bonzini
2020-03-06 2:05 linmiaohe
2020-03-06 2:09 ` hpa
2020-03-06 2:22 linmiaohe
2020-03-06 2:27 ` Wanpeng Li
2020-03-06 2:30 linmiaohe
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