From: Avi Kivity <avi@redhat.com>
To: Zachary Amsden <zamsden@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
Glauber Costa <glommer@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] x86: fix ordering constraints on crX read/writes
Date: Thu, 15 Jul 2010 10:07:51 +0300 [thread overview]
Message-ID: <4C3EB3C7.90108@redhat.com> (raw)
In-Reply-To: <4C3E5637.4010300@redhat.com>
On 07/15/2010 03:28 AM, Zachary Amsden wrote:
>> static inline void native_write_cr2(unsigned long val)
>> {
>> - asm volatile("mov %0,%%cr2": : "r" (val), "m" (__force_order));
>> + asm volatile("mov %1,%%cr2": "+m" (__force_order) : "r" (val) :
>> "memory");
>> }
>
>
> You don't need the memory clobber there. Technically, this should
> never be used, however.
kvm writes cr2 in order to present the correct value to the guest. It
doesn't use native_write_cr2(), however.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
prev parent reply other threads:[~2010-07-15 7:08 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-14 22:12 [PATCH] x86: fix ordering constraints on crX read/writes Jeremy Fitzhardinge
2010-07-15 0:28 ` Zachary Amsden
2010-07-15 0:55 ` Jeremy Fitzhardinge
2010-07-15 1:00 ` Zachary Amsden
2010-07-15 1:29 ` H. Peter Anvin
2010-07-15 14:34 ` Jeremy Fitzhardinge
2010-07-15 18:54 ` H. Peter Anvin
2010-07-15 19:28 ` Jeremy Fitzhardinge
2010-07-15 19:36 ` H. Peter Anvin
2010-07-15 19:57 ` Jeremy Fitzhardinge
2010-07-15 7:07 ` Avi Kivity [this message]
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