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From: Avi Kivity <avi@redhat.com>
To: "Cui, Dexuan" <dexuan.cui@intel.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"Yang, Sheng" <sheng.yang@intel.com>
Subject: Re: [PATCH 1/1] KVM: X86: add the support of XSAVE/XRSTOR to guest
Date: Thu, 06 May 2010 22:49:09 +0300	[thread overview]
Message-ID: <4BE31D35.7050802@redhat.com> (raw)
In-Reply-To: <4BE31C43.9060506@redhat.com>

On 05/06/2010 10:45 PM, Avi Kivity wrote:
>
> All those control registers are annoying, we have cr1 and cr5-cr7 
> free, cr9-cr15 on x86_64, infinite msr space, and now we have XCRs.  
> Great.
>
> Looking forward to YCR0.
>

I think I see the reason - xgetbv is unprivileged, so applications can 
see what the OS supports instead of looking at cpuid and hoping.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.


      reply	other threads:[~2010-05-06 19:49 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-29  5:22 [PATCH 1/1] KVM: X86: add the support of XSAVE/XRSTOR to guest Dexuan Cui
2010-05-02 14:13 ` Avi Kivity
2010-05-06  4:23   ` Cui, Dexuan
2010-05-06  8:14     ` Avi Kivity
2010-05-06 14:20       ` Cui, Dexuan
2010-05-06 19:45         ` Avi Kivity
2010-05-06 19:49           ` Avi Kivity [this message]

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