From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Andi Kleen <ak@muc.de>
Cc: virtualization@lists.osdl.org, Andrew Morton <akpm@osdl.org>,
Chris Wright <chrisw@sous-sol.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/4] x86 paravirt_ops: create no_paravirt.h for native ops
Date: Sun, 06 Aug 2006 22:43:49 -0700 [thread overview]
Message-ID: <44D6D315.2030907@goop.org> (raw)
In-Reply-To: <200608070730.17813.ak@muc.de>
Andi Kleen wrote:
>> +/* Stop speculative execution */
>> +static inline void sync_core(void)
>> +{
>> + unsigned int eax = 1, ebx, ecx, edx;
>> + __cpuid(&eax, &ebx, &ecx, &edx);
>> +}
>>
>
> Actually I don't think this one should be para virtualized at all.
> I don't see any reason at all why a hypervisor should trap it and it
> is very time critical. I would recommend you move it back into the
> normal files without hooks.
>
When VT/AMDV is enabled, cpuid could cause a vm exit, so it would be
nice to use one of the other serializing instructions in this case. For
the default implementation, it should probably be an explicit
asm("cpuid") to make it clear that we don't want any paravirtualized cpuid.
J
next prev parent reply other threads:[~2006-08-07 5:43 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-08-07 4:43 [PATCH 1/4] x86 paravirt_ops: create no_paravirt.h for native ops Rusty Russell
2006-08-07 4:45 ` [PATCH 2/4] x86 paravirt_ops: paravirt_desc.h for native descriptor ops Rusty Russell
2006-08-07 4:47 ` [PATCH 3/4] x86 paravirt_ops: implementation of paravirt_ops Rusty Russell
2006-08-07 4:48 ` [PATCH 4/4] x86 paravirt_ops: binary patching infrastructure Rusty Russell
2006-08-07 5:14 ` Rusty Russell
2006-08-07 5:38 ` Andi Kleen
2006-08-07 5:56 ` Jeremy Fitzhardinge
2006-08-07 5:39 ` [PATCH 3/4] x86 paravirt_ops: implementation of paravirt_ops Andi Kleen
2006-08-07 5:56 ` Jeremy Fitzhardinge
2006-08-07 6:13 ` Rusty Russell
2006-08-07 6:20 ` Andi Kleen
2006-08-07 7:27 ` Rusty Russell
2006-08-07 5:40 ` [PATCH 2/4] x86 paravirt_ops: paravirt_desc.h for native descriptor ops Andi Kleen
2006-08-07 7:50 ` Rusty Russell
2006-08-07 8:53 ` Andi Kleen
2006-08-07 17:19 ` Dave Jones
2006-08-07 5:22 ` [PATCH 1/4] x86 paravirt_ops: create no_paravirt.h for native ops Jeremy Fitzhardinge
2006-08-07 5:30 ` Andi Kleen
2006-08-07 5:43 ` Jeremy Fitzhardinge [this message]
2006-08-07 6:02 ` Andi Kleen
2006-08-07 6:23 ` Jeremy Fitzhardinge
2006-08-07 6:03 ` Rusty Russell
2006-08-07 6:16 ` Andi Kleen
2006-08-07 6:04 ` Rusty Russell
2006-08-07 6:17 ` Andi Kleen
2006-08-07 6:27 ` Muli Ben-Yehuda
2006-08-07 7:34 ` Jan Engelhardt
2006-08-07 8:40 ` Muli Ben-Yehuda
2006-08-07 17:54 ` Jan Engelhardt
2006-08-07 20:51 ` Zachary Amsden
2006-08-08 1:59 ` Andi Kleen
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