From: Avi Kivity <avi@argo.co.il>
To: Ingo Molnar <mingo@elte.hu>
Cc: Avi Kivity <avi@qumranet.com>,
kvm-devel <kvm-devel@lists.sourceforge.net>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [kvm-devel] Guest kernel hangs in smp kvm for older kernels prior to tsc sync cleanup
Date: Wed, 19 Dec 2007 16:27:19 +0200 [thread overview]
Message-ID: <47692A47.4040803@argo.co.il> (raw)
In-Reply-To: <20071219140624.GF21282@elte.hu>
Ingo Molnar wrote:
> * Avi Kivity <avi@qumranet.com> wrote:
>
>
>> Avi Kivity wrote:
>>
>>> Testing shows wrmsr and rdtsc function normally.
>>>
>>> I'll try pinning the vcpus to cpus and see if that helps.
>>>
>>>
>> It does.
>>
>
> do we let the guest read the physical CPU's TSC? That would be trouble.
>
>
vmx (and svm) allow us to add an offset to the physical tsc. We set it
on startup to -tsc (so that an rdtsc on boot would return 0), and
massage it on vcpu migration so that guest rdtsc is monotonic.
The net effect is that tsc on a vcpu can experience large forward jumps
and changes in rate, but no negative jumps.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2007-12-19 14:27 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-18 17:20 Avi Kivity
2007-12-18 22:19 ` Ingo Molnar
2007-12-19 6:33 ` Avi Kivity
2007-12-19 11:19 ` [kvm-devel] " Avi Kivity
2007-12-19 11:39 ` Avi Kivity
2007-12-19 14:06 ` Ingo Molnar
2007-12-19 14:27 ` Avi Kivity [this message]
2007-12-19 15:32 ` Glauber de Oliveira Costa
2007-12-19 15:41 ` Avi Kivity
2007-12-20 10:34 ` Glauber de Oliveira Costa
2007-12-19 16:55 ` Amit Shah
2007-12-19 17:04 ` [kvm-devel] Guest kernel hangs in smp kvm for older kernelsprior " Dor Laor
2007-12-19 17:09 ` Avi Kivity
2007-12-19 14:53 ` [kvm-devel] Guest kernel hangs in smp kvm for older kernels prior " Avi Kivity
2007-12-19 15:09 ` Ingo Molnar
2007-12-19 15:21 ` Avi Kivity
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