From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:38518 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753583AbcEBNpw (ORCPT ); Mon, 2 May 2016 09:45:52 -0400 Date: Mon, 2 May 2016 15:45:46 +0200 From: Radim =?utf-8?B?S3LEjW3DocWZ?= To: Bruce Rogers Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, namit@cs.technion.ac.il, stable@vger.kernel.org Subject: Re: [PATCH v2] KVM: x86: fix ordering of cr0 initialization code in vmx_cpu_reset Message-ID: <20160502134546.GA24741@potion> References: <1461876561-31889-1-git-send-email-brogers@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1461876561-31889-1-git-send-email-brogers@suse.com> Sender: stable-owner@vger.kernel.org List-ID: 2016-04-28 14:49-0600, Bruce Rogers: > 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 > initialization. > > The combination of booting with ovmf firmware when guest vcpus > 1 and kvm's > ept=N option being set results in a VM-entry failure. This patch fixes that. > > Fixes: d28bc9dd25ce ("KVM: x86: INIT and reset sequences are different") > Cc: stable@vger.kernel.org > Signed-off-by: Bruce Rogers > --- Queued, thanks. > 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 ee1c8a9..ab4a387 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -5046,8 +5046,8 @@ 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 > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html