linux-kernel - Re: KVM causes #GP on XRSTORS

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <20141124020553.GA27849@kernel>
Date:	Mon, 24 Nov 2014 10:05:53 +0800
From:	Wanpeng Li <wanpeng.li@...ux.intel.com>
To:	Paolo Bonzini <pbonzini@...hat.com>
Cc:	Nadav Amit <nadav.amit@...il.com>, fenghua.yu@...el.com,
	kvm list <kvm@...r.kernel.org>,
	Eduardo Habkost <ehabkost@...hat.com>,
	linux-kernel@...r.kernel.org
Subject: Re: KVM causes #GP on XRSTORS

Hi Paolo,
On Fri, Nov 21, 2014 at 03:46:55PM +0100, Paolo Bonzini wrote:
>
>
>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

Skylake-client supports XSAVES.

>a patch later today or next week (CCing Eduardo for this).

Actually I do the xsaves work in kvm/qemu recently and the patches are
complete, I will start to test it before send out.

Regards,
Wanpeng Li 

>
>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
>--
>To unsubscribe from this list: send the line "unsubscribe kvm" in
>the body of a message to majordomo@...r.kernel.org
>More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/