From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Hildenbrand Subject: Re: [PATCH 2/6] KVM: VMX: cleanup check for invalid EPT violation Date: Thu, 9 Mar 2017 11:43:12 +0100 Message-ID: <5de81ced-c083-25e1-8954-6c232b9a7acd@redhat.com> References: <1488996236-5676-1-git-send-email-pbonzini@redhat.com> <1488996236-5676-3-git-send-email-pbonzini@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: 7bit Cc: bdas@redhat.com, dmatlack@google.com To: Paolo Bonzini , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Return-path: In-Reply-To: <1488996236-5676-3-git-send-email-pbonzini@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Am 08.03.2017 um 19:03 schrieb Paolo Bonzini: > handle_ept_violation is checking for "guest-linear-address invalid" + > "paging-structure walk", which is a sign of a bug in KVM. However, > _all_ EPT violations without a valid guest linear address are paging > structure walks, because those EPT violations happen when loading the > guest PDPTEs. So simplify the check to only look at bit 7 of the > exit qualification. Do we have any define for this magic bit 7? #EPT_EXITQ_GLA_VALID 0x80 > > Signed-off-by: Paolo Bonzini > --- > arch/x86/kvm/vmx.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 89b74d9bc357..cb9034601c7b 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -6232,12 +6232,10 @@ 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) { > + if ((exit_qualification & 0x80) == 0) { > 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), > -- Thanks, David