From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Hildenbrand Subject: Re: [PATCH 2/6] KVM: VMX: remove bogus check for invalid EPT violation Date: Mon, 3 Apr 2017 13:17:02 +0200 Message-ID: <1e1fbaf4-8ef3-a049-0611-fe810ee1c501@redhat.com> References: <1490867732-16743-1-git-send-email-pbonzini@redhat.com> <1490867732-16743-3-git-send-email-pbonzini@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit To: Paolo Bonzini , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:34724 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751460AbdDCLRI (ORCPT ); Mon, 3 Apr 2017 07:17:08 -0400 In-Reply-To: <1490867732-16743-3-git-send-email-pbonzini@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 30.03.2017 11:55, Paolo Bonzini wrote: > handle_ept_violation is checking for "guest-linear-address invalid" + > "not a paging-structure walk". However, _all_ EPT violations without > a valid guest linear address are paging structure walks, because those > EPT violations happen when loading the guest PDPTEs. > > Therefore, the check can never be true, and even if it were, KVM doesn't > care about the guest linear address; it only uses the guest *physical* > address VMCS field. So, remove the check altogether. > > Signed-off-by: Paolo Bonzini > --- > arch/x86/kvm/vmx.c | 14 -------------- > 1 file changed, 14 deletions(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 0e61b9226bf2..1c372600a962 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -6208,23 +6208,9 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu) > unsigned long exit_qualification; > gpa_t gpa; > u32 error_code; > - int gla_validity; > > exit_qualification = vmcs_readl(EXIT_QUALIFICATION); > > - gla_validity = (exit_qualification >> 7) & 0x3; > - if (gla_validity == 0x2) { > - printk(KERN_ERR "EPT: Handling EPT violation failed!\n"); > - printk(KERN_ERR "EPT: GPA: 0x%lx, GVA: 0x%lx\n", > - (long unsigned int)vmcs_read64(GUEST_PHYSICAL_ADDRESS), > - vmcs_readl(GUEST_LINEAR_ADDRESS)); > - printk(KERN_ERR "EPT: Exit qualification is 0x%lx\n", > - (long unsigned int)exit_qualification); > - vcpu->run->exit_reason = KVM_EXIT_UNKNOWN; > - vcpu->run->hw.hardware_exit_reason = EXIT_REASON_EPT_VIOLATION; > - return 0; > - } > - > /* > * EPT violation happened while executing iret from NMI, > * "blocked by NMI" bit has to be set before next VM entry. > Reviewed-by: David Hildenbrand -- Thanks, David