From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: KVM: MMU: bail out pagewalk on kvm_read_guest error Date: Thu, 14 Jan 2010 17:41:27 -0200 Message-ID: <20100114194127.GA3968@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm To: Avi Kivity Return-path: Received: from mx1.redhat.com ([209.132.183.28]:59423 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757520Ab0ANTlj (ORCPT ); Thu, 14 Jan 2010 14:41:39 -0500 Received: from int-mx05.intmail.prod.int.phx2.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.18]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o0EJfc4b031996 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 14 Jan 2010 14:41:39 -0500 Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: Exit the guest pagetable walk loop if reading gpte failed. Otherwise its possible to enter an endless loop processing the previous present pte. Cc: stable@kernel.org Signed-off-by: Marcelo Tosatti diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 58a0f1e..ede2131 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -150,7 +150,9 @@ walk: walker->table_gfn[walker->level - 1] = table_gfn; walker->pte_gpa[walker->level - 1] = pte_gpa; - kvm_read_guest(vcpu->kvm, pte_gpa, &pte, sizeof(pte)); + if (kvm_read_guest(vcpu->kvm, pte_gpa, &pte, sizeof(pte))) + goto not_present; + trace_kvm_mmu_paging_element(pte, walker->level); if (!is_present_gpte(pte))