From: Roman Kagan <rkagan@virtuozzo.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: <asmetanin@virtuozzo.com>, <kvm@vger.kernel.org>,
"Denis V. Lunev" <den@openvz.org>,
Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH kvm-unit-tests] KVM: x86: add hyperv clock test case
Date: Thu, 28 Jan 2016 21:45:52 +0300 [thread overview]
Message-ID: <20160128184551.GB29344@rkaganb.sw.ru> (raw)
In-Reply-To: <56AA397B.4080209@redhat.com>
On Thu, Jan 28, 2016 at 04:53:31PM +0100, Paolo Bonzini wrote:
> I guess what we can do is to compute the TSC reference page parameters
> as soon as the master clock is activated, and use them instead of
> get_kernel_ns() to compute the reference count MSR (again if the master
> clock is activated). But I'm now a bit wary to enable the hyper-v TSC
> reference page without knowing the effects of a divergence between the
> two mechanisms. Especially if a migration could lead to a switch from
> one to the other and thus to the time going backwards.
IIUC Hyper-V treats the TSC reference page as an alternative an better
way to obtain that very same time reference counter. So no, we may not
allow the two to diverge IMO.
Roman.
next prev parent reply other threads:[~2016-01-28 18:46 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-28 14:04 [PATCH kvm-unit-tests] KVM: x86: add hyperv clock test case Paolo Bonzini
2016-01-28 14:04 ` Paolo Bonzini
2016-01-28 14:25 ` Andrey Smetanin
2016-01-28 14:50 ` Paolo Bonzini
2016-01-28 15:53 ` Paolo Bonzini
2016-01-28 18:45 ` Roman Kagan [this message]
2016-01-28 18:53 ` Roman Kagan
2016-01-28 21:28 ` Paolo Bonzini
2016-01-28 16:22 ` Roman Kagan
2016-02-03 16:37 ` Paolo Bonzini
2016-02-04 9:33 ` Roman Kagan
2016-02-04 10:13 ` Paolo Bonzini
2016-02-04 11:12 ` Roman Kagan
2016-04-21 17:01 ` Roman Kagan
2016-04-22 13:32 ` Roman Kagan
2016-04-22 18:08 ` Paolo Bonzini
2016-04-25 8:47 ` Roman Kagan
2016-04-26 10:34 ` Roman Kagan
2016-05-25 18:33 ` Roman Kagan
2016-05-26 14:47 ` Roman Kagan
2016-05-29 22:34 ` Marcelo Tosatti
2016-02-08 15:18 [PATCH 0/4] kvmclock: improve accuracy Paolo Bonzini
2016-02-08 15:18 ` [PATCH 1/4] KVM: x86: rename argument to kvm_set_tsc_khz Paolo Bonzini
2016-02-11 15:01 ` Marcelo Tosatti
2016-02-08 15:18 ` [PATCH 2/4] KVM: x86: rewrite handling of scaled TSC for kvmclock Paolo Bonzini
2016-02-11 15:23 ` Marcelo Tosatti
2016-02-08 15:18 ` [PATCH 3/4] KVM: x86: pass kvm_get_time_scale arguments in hertz Paolo Bonzini
2016-02-08 15:18 ` [PATCH 4/4] KVM: x86: track actual TSC frequency from the timekeeper struct Paolo Bonzini
2016-02-09 18:41 ` Owen Hofmann
2016-02-10 13:57 ` Paolo Bonzini
2016-02-16 13:48 ` Marcelo Tosatti
2016-02-16 14:25 ` Marcelo Tosatti
2016-02-16 16:59 ` Paolo Bonzini
2016-02-19 14:12 ` Marcelo Tosatti
2016-02-19 15:53 ` Paolo Bonzini
2016-02-16 14:00 ` [PATCH 0/4] kvmclock: improve accuracy Marcelo Tosatti
2016-08-31 14:13 [PATCH kvm-unit-tests] KVM: x86: add hyperv clock test case Roman Kagan
2016-09-01 16:07 ` Paolo Bonzini
2016-09-01 16:07 Paolo Bonzini
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