linux-kernel - Re: [stable] [077/103] KVM: x86: Fix SVM VMCB reset

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Date:	Sat, 23 Oct 2010 08:59:10 -0700
From:	Greg KH <greg@...ah.com>
To:	Zachary Amsden <zamsden@...hat.com>
Cc:	Michael Tokarev <mjt@....msk.ru>, mtosatti@...hat.com,
	Greg KH <gregkh@...e.de>, linux-kernel@...r.kernel.org,
	stable@...nel.org, avi@...hat.com, akpm@...ux-foundation.org,
	torvalds@...ux-foundation.org, stable-review@...nel.org,
	alan@...rguk.ukuu.org.uk
Subject: Re: [stable] [077/103] KVM: x86: Fix SVM VMCB reset

On Sat, Oct 23, 2010 at 03:47:30AM -1000, Zachary Amsden wrote:
> On 10/22/2010 11:51 PM, Michael Tokarev wrote:
>> 22.10.2010 22:51, Greg KH wrote:
>>    
>>> 2.6.35-stable review patch.  If anyone has any objections, please let us know.
>>> ------------------
>>>
>>> From: Marcelo Tosatti<mtosatti@...hat.com>
>>>
>>> commit 58877679fd393d3ef71aa383031ac7817561463d upstream.
>>>
>>> On reset, VMCB TSC should be set to zero.  Instead, code was setting
>>> tsc_offset to zero, which passes through the underlying TSC.
>>>      
>> Not an objection, but shouldn't this and subsequent 078 "KVM: x86: Move
>> TSC reset out of vmcb_init" patches be applied to 2.6.32 too?  The same
>> problem exists in 2.6.32, and the two patches allows an smp linux guest
>> to boot in there, or such a guest just hangs at boot.  (078 patch needs
>> to be adjusted a bit for 2.6.32, since the code there is a bit different
>> and it does not apply correctly; but the change is trivial).
>>
>>    
>
> I concur, although it's possible the backport could go even further.  The 
> problem has existed for some time, but only because of recent changes to 
> selection of default clocksource as well as host side changes has it become 
> an issue.

Ok, please work with the KVM maintainers then, as they are the ones who
send -stable patches to me.

thanks,

greg k-h
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