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From: Avi Kivity <avi@qumranet.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: kvm-devel@lists.sourceforge.net, qemu-devel@nongnu.org,
	"Maciej W. Rozycki" <macro@linux-mips.org>,
	Glauber Costa <gcosta@redhat.com>
Subject: Re: [PATCH] ignore reads to the EOI register.
Date: Thu, 27 Mar 2008 14:55:39 +0200	[thread overview]
Message-ID: <47EB994B.7080108@qumranet.com> (raw)
In-Reply-To: <87hcesjpqa.fsf@basil.nowhere.org>

Andi Kleen wrote:
> "Maciej W. Rozycki" <macro@linux-mips.org> writes:
>   
>>  Linux performs reads to all registers written including this one 
>> deliberately using an RMW cycle to avoid triggering an erratum in some 
>> early Pentium integrated APICs.  Obviously it does not matter for most of 
>> the world as the workaround is build-time conditional, but you'll get it 
>> if you build a generic "runs everywhere" kernel.
>>     
>
> It would be quite possible to make the cycle conditional on a
> cpufeatures.h quirk flag that is only set on P5. Just would need to
> out of line a few functions to avoid code bloat.
>   

Or, alternatives? xchg vs mov?

-- 
error compiling committee.c: too many arguments to function


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WARNING: multiple messages have this Message-ID (diff)
From: Avi Kivity <avi@qumranet.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: kvm-devel@lists.sourceforge.net, qemu-devel@nongnu.org,
	"Maciej W. Rozycki" <macro@linux-mips.org>,
	Glauber Costa <gcosta@redhat.com>
Subject: [Qemu-devel] Re: [PATCH] ignore reads to the EOI register.
Date: Thu, 27 Mar 2008 14:55:39 +0200	[thread overview]
Message-ID: <47EB994B.7080108@qumranet.com> (raw)
In-Reply-To: <87hcesjpqa.fsf@basil.nowhere.org>

Andi Kleen wrote:
> "Maciej W. Rozycki" <macro@linux-mips.org> writes:
>   
>>  Linux performs reads to all registers written including this one 
>> deliberately using an RMW cycle to avoid triggering an erratum in some 
>> early Pentium integrated APICs.  Obviously it does not matter for most of 
>> the world as the workaround is build-time conditional, but you'll get it 
>> if you build a generic "runs everywhere" kernel.
>>     
>
> It would be quite possible to make the cycle conditional on a
> cpufeatures.h quirk flag that is only set on P5. Just would need to
> out of line a few functions to avoid code bloat.
>   

Or, alternatives? xchg vs mov?

-- 
error compiling committee.c: too many arguments to function

  parent reply	other threads:[~2008-03-27 12:55 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-27  0:57 [PATCH] ignore reads to the EOI register Glauber Costa
2008-03-27  0:57 ` [Qemu-devel] " Glauber Costa
2008-03-27  8:18 ` Avi Kivity
2008-03-27  8:18   ` [Qemu-devel] " Avi Kivity
2008-03-27 11:29   ` Maciej W. Rozycki
2008-03-27 11:29     ` [Qemu-devel] " Maciej W. Rozycki
     [not found]     ` <87hcesjpqa.fsf@basil.nowhere.org>
2008-03-27 12:55       ` Avi Kivity [this message]
2008-03-27 12:55         ` Avi Kivity
2008-03-27 13:36       ` Maciej W. Rozycki
2008-03-27 13:36         ` [Qemu-devel] " Maciej W. Rozycki
2008-03-27 23:39 ` [Qemu-devel] " Aurelien Jarno
2008-03-27 23:39   ` Aurelien Jarno
2008-03-28 12:59   ` Glauber Costa
2008-03-28 12:59     ` Glauber Costa

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