From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: KVM causes #GP on XRSTORS Date: Fri, 21 Nov 2014 15:46:55 +0100 Message-ID: <546F505F.9080309@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Cc: kvm list , Eduardo Habkost To: Nadav Amit , fenghua.yu@intel.com Return-path: Received: from mail-wi0-f181.google.com ([209.85.212.181]:62722 "EHLO mail-wi0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754269AbaKUOrG (ORCPT ); Fri, 21 Nov 2014 09:47:06 -0500 Received: by mail-wi0-f181.google.com with SMTP id r20so9052481wiv.14 for ; Fri, 21 Nov 2014 06:47:00 -0800 (PST) In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: 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