From: Andi Kleen <andi@firstfloor.org>
To: Avi Kivity <avi@qumranet.com>
Cc: Agner Fog <agner@agner.org>,
Arjan van de Ven <arjan@infradead.org>,
"H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org
Subject: Re: ABI change for device drivers using future AVX instruction set
Date: Sun, 29 Jun 2008 15:23:17 +0200 [thread overview]
Message-ID: <48678CC5.5080504@firstfloor.org> (raw)
In-Reply-To: <48678BBF.80707@qumranet.com>
Avi Kivity wrote:
> Andi Kleen wrote:
>>>>> We could change kernel_fpu_begin() not to disable
>>>>> preemption, but instead set a task flag. When we get the "no device"
>>>>> fault, if the flag is set, save the fpu state into the kernel fpu save
>>>>> area
>>>> What kernel fpu save area do you mean?
>>>>
>>> A new one, of course.
>>>
>>>
>>
>> With that we would be eventually in the mess Agner talked about.
>>
>>
>
> If you use xsave, I don't see how this is different to the user fpu save
> area.
For once there's no clear error handling path for allocation failures
on the (arbitarily sized) xsave state. On user code that can be barely
tolerated, but for the kernel it would be deadly.
-Andi
next prev parent reply other threads:[~2008-06-29 13:23 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-25 15:32 ABI change for device drivers using future AVX instruction set Agner Fog
2008-06-25 16:22 ` Arjan van de Ven
2008-06-25 19:54 ` Agner Fog
2008-06-25 20:09 ` Arjan van de Ven
2008-06-26 1:11 ` H. Peter Anvin
2008-06-27 11:31 ` Agner Fog
2008-06-27 14:22 ` Arjan van de Ven
2008-06-28 8:05 ` Agner Fog
2008-06-28 8:10 ` David Miller
2008-06-28 11:47 ` Andi Kleen
2008-06-28 15:09 ` Agner Fog
2008-06-28 15:44 ` Helge Hafting
2008-06-28 20:02 ` Andi Kleen
2008-06-29 11:33 ` Avi Kivity
2008-06-29 12:21 ` Andi Kleen
2008-06-29 12:31 ` Avi Kivity
2008-06-29 13:07 ` Andi Kleen
2008-06-29 13:18 ` Avi Kivity
2008-06-29 13:23 ` Andi Kleen [this message]
2008-06-29 13:29 ` Avi Kivity
2008-06-29 22:08 ` H. Peter Anvin
2008-06-29 12:29 ` Alan Cox
2008-07-01 15:30 ` Arjan van de Ven
2008-06-25 20:14 ` Alan Cox
2008-06-26 14:01 ` Andi Kleen
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