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From: Alexey Makhalov <amakhalov@vmware.com>
To: <corbet@lwn.net>, <akataria@vmware.com>, <tglx@linutronix.de>,
	<mingo@redhat.com>, <hpa@zytor.com>, <x86@kernel.org>
Cc: <linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<virtualization@lists.linux-foundation.org>,
	<pv-drivers@vmware.com>, Alexey Makhalov <amakhalov@vmware.com>
Subject: [PATCH v3 1/3] x86/vmware: Use tsc_khz value for calibrate_cpu()
Date: Fri, 28 Oct 2016 00:54:30 -0700	[thread overview]
Message-ID: <20161028075432.90579-2-amakhalov@vmware.com> (raw)
In-Reply-To: <20161028075432.90579-1-amakhalov@vmware.com>

Commit aa297292d708 ("x86/tsc: Enumerate SKL cpu_khz and tsc_khz via
CPUID") separated the calibration mechanisms for cpu_khz and tsc_khz.

Since the vmware hypervisor provides a constant frequency TSC to the guest,
this change can lead to divergence between the tsc and the cpu frequency
after vmotion, which might confuse the user.

Solve this by overriding the x86 platform cpu calibration callback with the
vmware specific tsc calibration function.

Signed-off-by: Alexey Makhalov <amakhalov@vmware.com>
Acked-by: Alok N Kataria <akataria@vmware.com>
---
 arch/x86/kernel/cpu/vmware.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 4e34da4b..480790f 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -83,6 +83,7 @@ static void __init vmware_platform_setup(void)
 
 		vmware_tsc_khz = tsc_khz;
 		x86_platform.calibrate_tsc = vmware_get_tsc_khz;
+		x86_platform.calibrate_cpu = vmware_get_tsc_khz;
 
 #ifdef CONFIG_X86_LOCAL_APIC
 		/* Skip lapic calibration since we know the bus frequency. */
-- 
2.10.1

  reply	other threads:[~2016-10-28  7:55 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-26  5:20 [PATCH 0/3] x86/vmware guest improvements Alexey Makhalov
2016-10-26  5:20 ` [PATCH 1/3] x86/vmware: Use tsc_khz value for calibrate_cpu() Alexey Makhalov
2016-10-26  5:26 ` [PATCH 2/3] x86/vmware: Add basic paravirt ops support Alexey Makhalov
2016-10-26 20:47   ` Tim Mann
2016-10-26 20:47     ` Thomas Gleixner
2016-10-27 19:44       ` [RESEND PATCH 1/3] x86/vmware: Use tsc_khz value for calibrate_cpu() Alexey Makhalov
2016-10-27 19:44         ` [RESEND PATCH 2/3] x86/vmware: Add basic paravirt ops support Alexey Makhalov
2016-10-27 19:44         ` [RESEND PATCH 3/3] x86/vmware: Add paravirt sched clock Alexey Makhalov
2016-10-27 22:10           ` Thomas Gleixner
2016-10-27 21:44         ` [RESEND PATCH 1/3] x86/vmware: Use tsc_khz value for calibrate_cpu() Thomas Gleixner
2016-10-28  7:54           ` [PATCH v3 0/3] x86/vmware guest improvements Alexey Makhalov
2016-10-28  7:54             ` Alexey Makhalov [this message]
2016-10-31  1:17               ` [tip:x86/platform] x86/vmware: Use tsc_khz value for calibrate_cpu() tip-bot for Alexey Makhalov
2016-10-28  7:54             ` [PATCH v3 2/3] x86/vmware: Add basic paravirt ops support Alexey Makhalov
2016-10-31  1:17               ` [tip:x86/platform] " tip-bot for Alexey Makhalov
2016-10-28  7:54             ` [PATCH v3 3/3] x86/vmware: Add paravirt sched clock Alexey Makhalov
2016-10-31  1:18               ` [tip:x86/platform] " tip-bot for Alexey Makhalov
2016-10-26  5:26 ` [PATCH 3/3] " Alexey Makhalov
2016-10-26 10:18   ` Thomas Gleixner
2016-10-26 16:51     ` [PATCH v2 " Alexey Makhalov

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