From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932846AbcBCXSJ (ORCPT ); Wed, 3 Feb 2016 18:18:09 -0500 Received: from mail-pf0-f178.google.com ([209.85.192.178]:34694 "EHLO mail-pf0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932214AbcBCXSG convert rfc822-to-8bit (ORCPT ); Wed, 3 Feb 2016 18:18:06 -0500 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 9.2 \(3112\)) Subject: Re: [PATCH 1/2] KVM: x86: fix ordering of cr0 initialization code in vmx_cpu_reset From: Nadav Amit In-Reply-To: <1454539876-8310-1-git-send-email-brogers@suse.com> Date: Wed, 3 Feb 2016 15:18:03 -0800 Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, jan.kiszka@siemens.com, Nadav Amit Content-Transfer-Encoding: 8BIT Message-Id: References: <1454539876-8310-1-git-send-email-brogers@suse.com> To: Bruce Rogers X-Mailer: Apple Mail (2.3112) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Oops. Anyhow, I see my patch has done a similar change in init_vmcb() , so you may want to revert it as well. Nadav Bruce Rogers wrote: > Commit d28bc9dd25ce reversed the order of two lines which initialize cr0, > allowing the current (old) cr0 value to mess up vcpu initialization. > This was observed in the checks for cr0 X86_CR0_WP bit in the context of > kvm_mmu_reset_context(). Besides, setting vcpu->arch.cr0 after vmx_set_cr0() > is completely redundant. Change the order back to ensure proper vcpu > intiialization. > > Signed-off-by: Bruce Rogers > --- > arch/x86/kvm/vmx.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index e2951b6..21507b4 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -4993,8 +4993,8 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) > vmcs_write16(VIRTUAL_PROCESSOR_ID, vmx->vpid); > > cr0 = X86_CR0_NW | X86_CR0_CD | X86_CR0_ET; > - vmx_set_cr0(vcpu, cr0); /* enter rmode */ > vmx->vcpu.arch.cr0 = cr0; > + vmx_set_cr0(vcpu, cr0); /* enter rmode */ > vmx_set_cr4(vcpu, 0); > vmx_set_efer(vcpu, 0); > vmx_fpu_activate(vcpu); > -- > 1.9.0