From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: [RTF] kvm:x86:Fix error checking in the function pf_interception Date: Fri, 7 Aug 2015 09:31:01 +0200 Message-ID: <20150807073101.GT14980@8bytes.org> References: <1438913423-30959-1-git-send-email-xerofoify@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: gleb@kernel.org, pbonzini@redhat.com, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org To: Nicholas Krause Return-path: Content-Disposition: inline In-Reply-To: <1438913423-30959-1-git-send-email-xerofoify@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Thu, Aug 06, 2015 at 10:10:23PM -0400, Nicholas Krause wrote: > This fixes error checking in the function pf_interception by > checking if the call to kvm_mmu_unprotect_page_virt returns > zero to indicate the function has failed internally and if > this occurs we must return immediately to the caller of the > function pf_interception with the return value of zero from > the call to the function kvm_mmu_unprotect_page_virt to indicate > failure to the caller of the function pf_interception. > > Signed-off-by: Nicholas Krause > --- > arch/x86/kvm/svm.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c > index 8e0c084..a57aee1 100644 > --- a/arch/x86/kvm/svm.c > +++ b/arch/x86/kvm/svm.c > @@ -1814,8 +1814,11 @@ static int pf_interception(struct vcpu_svm *svm) > error_code = svm->vmcb->control.exit_info_1; > > trace_kvm_page_fault(fault_address, error_code); > - if (!npt_enabled && kvm_event_needs_reinjection(&svm->vcpu)) > - kvm_mmu_unprotect_page_virt(&svm->vcpu, fault_address); > + if (!npt_enabled && kvm_event_needs_reinjection(&svm->vcpu)) { > + r = kvm_mmu_unprotect_page_virt(&svm->vcpu, fault_address); > + if (!r) > + break; > + } NAK. kvm_mmu_unprotect_page_virt does not return an error but whether it unprotected a page or not. This patch breaks SVM.