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From: Paolo Bonzini <pbonzini@redhat.com>
To: Nadav Amit <nadav.amit@gmail.com>, fenghua.yu@intel.com
Cc: kvm list <kvm@vger.kernel.org>, Eduardo Habkost <ehabkost@redhat.com>
Subject: Re: KVM causes #GP on XRSTORS
Date: Fri, 21 Nov 2014 15:46:55 +0100	[thread overview]
Message-ID: <546F505F.9080309@redhat.com> (raw)
In-Reply-To: <AA52FB0B-FB19-4DC0-964B-2984040B15A6@gmail.com>



On 20/11/2014 17:34, Nadav Amit wrote:
> Fenghua,
> 
> I got KVM (v3.17) crashing on a machine that supports XRSTORS - It appears to get a #GP when it is trying to load the guest FPU.
> One reason for the #GP is that XCOMP_BV[63] is zeroed on the guest_fpu, but I am not sure it is the only problem.
> Was KVM ever tested with XRSTORS?

What is the content of the CPUID[EAX=13,ECX=0] and CPUID[EAX=13,ECX=1]
leaves on the host?

Fenghua, which processors have XSAVEC, which have XGETBV with ECX=1, and
which have XSAVES?  We need to expose this in QEMU, for which I can send
a patch later today or next week (CCing Eduardo for this).

We will also have to uncompact the XSAVE area either in KVM_GET_XSAVE or
in QEMU.  It's probably not hard to do it in the kernel.

Paolo

  parent reply	other threads:[~2014-11-21 14:47 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-20 16:34 KVM causes #GP on XRSTORS Nadav Amit
2014-11-20 22:18 ` Yu, Fenghua
2014-11-21  0:10 ` Wanpeng Li
2014-11-21  1:09   ` Nadav Amit
2014-11-21 14:46 ` Paolo Bonzini [this message]
2014-11-21 18:34   ` Paolo Bonzini
2014-11-24  2:05   ` Wanpeng Li
2014-11-25 18:41   ` Eduardo Habkost

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