From: Weidong Han <weidong.han@intel.com>
To: Keir Fraser <keir.fraser@eu.citrix.com>
Cc: Tim Deegan <Tim.Deegan@eu.citrix.com>,
Xen-devel <xen-devel@lists.xensource.com>,
Jan Beulich <JBeulich@novell.com>
Subject: Re: [PATCH 0/3 v2] XSAVE/XRSTOR fixes and enhancements
Date: Wed, 01 Sep 2010 16:26:50 +0800 [thread overview]
Message-ID: <4C7E0E4A.9040104@intel.com> (raw)
In-Reply-To: <C8A3C8D6.219F6%keir.fraser@eu.citrix.com>
Keir Fraser wrote:
> On 01/09/2010 08:56, "Weidong Han" <weidong.han@intel.com> wrote:
>
>
>>> Well that's how it was explained to me at the time. Was that in fact wrong
>>> and we are already broken for save/restore for some subtle unexplained
>>> reason?
>>>
>>>
>> When XSAVE is enabled, it saves states to xsave_area in struct hvm_vcpu.
>> But hvm_save_cpu_ctxt and hvm_load_cpu_ctxt don't save/restore FPU/SSE
>> from xsave_area. So FPU/SSE states are incorrect after guest save/restore.
>>
>
> Ignoring AVX, that needs fixing in 4.0 branch. The state needs pulling out
> of the xsave area and into the existing hvm_hw_cpu structure. Or, we disable
> xsave by default on 4.0.x branch. What do you think?
>
>
I prefer to disable it by default on 4.0 branch now. After finish guest save/restore with XSAVE/XRSTOR in xen-unstable, we can port code to 4.0 branch and enable it again.
Regards,
Weidong
next prev parent reply other threads:[~2010-09-01 8:26 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-31 14:52 [PATCH 0/3 v2] XSAVE/XRSTOR fixes and enhancements Han, Weidong
2010-08-31 14:56 ` Tim Deegan
2010-09-01 1:17 ` Weidong Han
2010-08-31 14:57 ` Keir Fraser
2010-09-01 1:53 ` Weidong Han
2010-09-01 7:26 ` Keir Fraser
2010-09-01 7:39 ` Keir Fraser
2010-09-01 7:56 ` Weidong Han
2010-09-01 8:09 ` Keir Fraser
2010-09-01 8:26 ` Weidong Han [this message]
2010-09-01 7:45 ` Weidong Han
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