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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: akataria@vmware.com
Cc: Ingo Molnar <mingo@elte.hu>, "H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>,
	the arch/x86 maintainers <x86@kernel.org>,
	"avi@redhat.com" <avi@redhat.com>,
	Rusty Russell <rusty@rustcorp.com.au>,
	Zach Amsden <zach@vmware.com>, Daniel Hecht <dhecht@vmware.com>,
	"Jun.Nakajima@Intel.Com" <Jun.Nakajima@Intel.Com>,
	Tim Deegan <Tim.Deegan@citrix.com>
Subject: Re: Use CPUID to communicate with the hypervisor.
Date: Sat, 27 Sep 2008 22:01:01 -0700	[thread overview]
Message-ID: <48DF0F8D.3070302@goop.org> (raw)
In-Reply-To: <1222485079.23825.13.camel@alok-dev1>

Alok Kataria wrote:
>> I think there's a move towards doing a scan for a signature, such as
>> checking every 16 leaves after 0x40000000 for "a while" looking for
>> interesting signatures, so that a hypervisor can support multiple ABIs
>> at once.  Given this, it would be better to define a "Generic Hypervisor
>> ABI" signature, and put all the related leaves together.
>>     
>
> Hmm interesting, do you have any pointers to this ?
>   

No.  I think I saw a passing reference from Tim Deegan to it, but I
couldn't find it again when I looked.

> As far as live migration, for full-virt, we think that it should happen
> invisibly to the guest.  So even if we move to a host with different TSC
> frequency it should be the job of the hypervisor to still emulate the
> old frequency. 
>   

Can the tsc be emulated without a performance hit, or does it trap into
the hypervisor?

    J

  parent reply	other threads:[~2008-09-28  5:01 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-09-26 23:46 Use CPUID to communicate with the hypervisor Alok Kataria
2008-09-27  0:09 ` H. Peter Anvin
2008-09-27  0:30   ` Alok Kataria
2008-09-27  0:32     ` H. Peter Anvin
2008-09-27  0:59       ` Nakajima, Jun
2008-09-27  1:55         ` H. Peter Anvin
2008-09-27  4:52           ` Nakajima, Jun
2008-09-29 20:56   ` Karel Zak
2008-09-27  1:02 ` Jeremy Fitzhardinge
2008-09-27  1:28   ` H. Peter Anvin
2008-09-27  3:11   ` Alok Kataria
2008-09-27  4:20     ` H. Peter Anvin
2008-09-27  5:37       ` Alok Kataria
2008-09-28  5:01     ` Jeremy Fitzhardinge [this message]
2008-09-29  9:28       ` Tim Deegan
2008-09-29  9:44         ` Avi Kivity
2008-09-29  6:55 ` Gleb Natapov
2008-09-29  7:37   ` Avi Kivity
2008-09-29  9:08     ` Bernd Eckenfels
2008-09-29  9:33       ` Gleb Natapov
2008-09-29 15:32     ` Nakajima, Jun
2008-09-30  9:16       ` Avi Kivity
2008-09-29  8:24 ` Gerd Hoffmann
2008-09-29 17:55   ` Alok Kataria
2008-09-29 17:58     ` H. Peter Anvin
2008-09-29 18:46     ` Gerd Hoffmann
2008-09-29 19:38       ` Alok Kataria
2008-09-29 20:31         ` H. Peter Anvin
2008-09-29 20:55         ` Nakajima, Jun
2008-09-29 21:07           ` H. Peter Anvin
2008-09-29 21:28             ` Jeremy Fitzhardinge
2008-09-29 21:49               ` H. Peter Anvin
2008-09-29 23:20               ` Zachary Amsden
2008-09-30  0:33                 ` H. Peter Anvin
2008-09-30  0:12               ` Alok Kataria
2008-09-30  0:31                 ` H. Peter Anvin
2008-09-30  0:56                   ` Nakajima, Jun
2008-09-30  0:58                     ` H. Peter Anvin
2008-09-30  1:14                       ` Nakajima, Jun
2008-09-30  2:21                         ` H. Peter Anvin
2008-09-30  3:14                           ` Nakajima, Jun
2008-09-30  3:48                             ` H. Peter Anvin
2008-09-29 22:46         ` Gerd Hoffmann
2008-09-30  0:33           ` Alok Kataria
2008-09-30  8:11             ` Gerd Hoffmann
2008-09-30 16:42               ` Zachary Amsden
2008-10-02 11:52                 ` Avi Kivity
2008-10-01  4:35               ` [Hypervisors] TSC frequency change Alok Kataria
2008-10-01  9:47                 ` Gerd Hoffmann

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