Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755144Ab3JRARN (ORCPT ); Thu, 17 Oct 2013 20:17:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33182 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755036Ab3JRARM (ORCPT ); Thu, 17 Oct 2013 20:17:12 -0400 Date: Thu, 17 Oct 2013 21:04:21 -0300 From: Marcelo Tosatti To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, gleb@redhat.com, agraf@suse.de, chao.zhou@intel.com, magnus@boden.cx, kvm@vger.kernel.org Subject: Re: [PATCH 2/2] KVM: x86: fix KVM_SET_XCRS loop Message-ID: <20131018000421.GA6793@amt.cnet> References: <1382021447-20216-1-git-send-email-pbonzini@redhat.com> <1382021447-20216-3-git-send-email-pbonzini@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1382021447-20216-3-git-send-email-pbonzini@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1445 Lines: 39 On Thu, Oct 17, 2013 at 04:50:47PM +0200, Paolo Bonzini wrote: > The loop was always using 0 as the index. This means that > any rubbish after the first element of the array went undetected. > It seems reasonable to assume that no KVM userspace did that. It is not a typo, look at __kvm_set_xcr when setting guest_xcrs->xcrs[i].value, with i != 0. The code is not prepared to deal with XCR != 0 (because its not implemented in hw). > Signed-off-by: Paolo Bonzini > --- > arch/x86/kvm/x86.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index f4e1391..f91dff2 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -3062,9 +3062,9 @@ static int kvm_vcpu_ioctl_x86_set_xcrs(struct kvm_vcpu *vcpu, > > for (i = 0; i < guest_xcrs->nr_xcrs; i++) > /* Only support XCR0 currently */ > - if (guest_xcrs->xcrs[0].xcr == XCR_XFEATURE_ENABLED_MASK) { > + if (guest_xcrs->xcrs[i].xcr == XCR_XFEATURE_ENABLED_MASK) { > r = __kvm_set_xcr(vcpu, XCR_XFEATURE_ENABLED_MASK, > - guest_xcrs->xcrs[0].value); > + guest_xcrs->xcrs[i].value); > break; > } > if (r) > -- > 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/