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From: Alexey Makhalov <amakhalov@vmware.com>
To: <linux-kernel@vger.kernel.org>,
	<virtualization@lists.linux-foundation.org>, <hpa@zytor.com>,
	<bp@alien8.de>, <mingo@redhat.com>, <tglx@linutronix.de>,
	<pv-drivers@vmware.com>, <sdeep@vmware.com>
Cc: Alexey Makhalov <amakhalov@vmware.com>
Subject: [PATCH] x86/vmware: avoid TSC recalibration
Date: Mon, 4 Jan 2021 16:47:52 -0800	[thread overview]
Message-ID: <20210105004752.131069-1-amakhalov@vmware.com> (raw)

When TSC frequency is known (retrieved from hypervisor), we should skip
TSC refined calibration by setting X86_FEATURE_TSC_KNOWN_FREQ.

Signed-off-by: Alexey Makhalov <amakhalov@vmware.com>
---
 arch/x86/kernel/cpu/vmware.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index c6ede3b3d302..83164110ccc5 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -378,6 +378,8 @@ static void __init vmware_set_capabilities(void)
 {
 	setup_force_cpu_cap(X86_FEATURE_CONSTANT_TSC);
 	setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
+	if (vmware_tsc_khz)
+		setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
 	if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMCALL)
 		setup_force_cpu_cap(X86_FEATURE_VMCALL);
 	else if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMMCALL)
-- 
2.11.0


WARNING: multiple messages have this Message-ID (diff)
From: Alexey Makhalov <amakhalov@vmware.com>
To: <linux-kernel@vger.kernel.org>,
	<virtualization@lists.linux-foundation.org>, <hpa@zytor.com>,
	<bp@alien8.de>,  <mingo@redhat.com>, <tglx@linutronix.de>,
	<pv-drivers@vmware.com>, <sdeep@vmware.com>
Cc: Alexey Makhalov <amakhalov@vmware.com>
Subject: [PATCH] x86/vmware: avoid TSC recalibration
Date: Mon, 4 Jan 2021 16:47:52 -0800	[thread overview]
Message-ID: <20210105004752.131069-1-amakhalov@vmware.com> (raw)

When TSC frequency is known (retrieved from hypervisor), we should skip
TSC refined calibration by setting X86_FEATURE_TSC_KNOWN_FREQ.

Signed-off-by: Alexey Makhalov <amakhalov@vmware.com>
---
 arch/x86/kernel/cpu/vmware.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index c6ede3b3d302..83164110ccc5 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -378,6 +378,8 @@ static void __init vmware_set_capabilities(void)
 {
 	setup_force_cpu_cap(X86_FEATURE_CONSTANT_TSC);
 	setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
+	if (vmware_tsc_khz)
+		setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
 	if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMCALL)
 		setup_force_cpu_cap(X86_FEATURE_VMCALL);
 	else if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMMCALL)
-- 
2.11.0

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Virtualization@lists.linux-foundation.org
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             reply	other threads:[~2021-01-05  1:05 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-05  0:47 Alexey Makhalov [this message]
2021-01-05  0:47 ` [PATCH] x86/vmware: avoid TSC recalibration Alexey Makhalov
2021-01-05 13:06 ` Vitaly Kuznetsov
2021-01-05 13:06   ` Vitaly Kuznetsov
2021-03-15 22:24   ` Alexey Makhalov
2021-03-15 22:24     ` Alexey Makhalov
2021-03-28 19:14 ` [tip: x86/vmware] x86/vmware: Avoid TSC recalibration when frequency is known tip-bot2 for Alexey Makhalov

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