linux-kernel - [PATCH v2 2/2] KVM: x86: use x86_get

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Message-Id: <20211201024650.88254-3-pizhenwei@bytedance.com>
Date:   Wed,  1 Dec 2021 10:46:50 +0800
From:   zhenwei pi <pizhenwei@...edance.com>
To:     tglx@...utronix.de, pbonzini@...hat.com
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org, x86@...nel.org,
        zhenwei pi <pizhenwei@...edance.com>
Subject: [PATCH v2 2/2] KVM: x86: use x86_get_freq to get freq for kvmclock

If the host side supports APERF&MPERF feature, the guest side may get
mismatched frequency.

KVM uses x86_get_cpufreq_khz() to get the same frequency for guest side.

Signed-off-by: zhenwei pi <pizhenwei@...edance.com>
---
 arch/x86/kvm/x86.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5a403d92833f..125ed3c8b21a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8305,10 +8305,8 @@ static void tsc_khz_changed(void *data)
 
 	if (data)
 		khz = freq->new;
-	else if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC))
-		khz = cpufreq_quick_get(raw_smp_processor_id());
 	if (!khz)
-		khz = tsc_khz;
+		khz = x86_get_cpufreq_khz(raw_smp_processor_id());
 	__this_cpu_write(cpu_tsc_khz, khz);
 }
 
-- 
2.25.1