Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753219AbdHNMBW (ORCPT ); Mon, 14 Aug 2017 08:01:22 -0400 Received: from mga06.intel.com ([134.134.136.31]:53012 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752870AbdHNMBU (ORCPT ); Mon, 14 Aug 2017 08:01:20 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.41,373,1498546800"; d="scan'208";a="299859041" Subject: Re: [PATCH v1 1/4] KVM: MMU: check guest CR3 reserved bits based on its physical address width. To: Paolo Bonzini , kvm@vger.kernel.org References: <1502544906-1108-1-git-send-email-yu.c.zhang@linux.intel.com> <1502544906-1108-2-git-send-email-yu.c.zhang@linux.intel.com> Cc: linux-kernel@vger.kernel.org, rkrcmar@redhat.com, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, xiaoguangrong@tencent.com, joro@8bytes.org From: Yu Zhang Message-ID: <93d301f3-7fdc-866c-a140-4afe0c0a8dab@linux.intel.com> Date: Mon, 14 Aug 2017 19:39:01 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1217 Lines: 46 On 8/14/2017 3:36 PM, Paolo Bonzini wrote: > On 12/08/2017 15:35, Yu Zhang wrote: >> + ctxt->ops->get_cpuid(ctxt, &eax, NULL, NULL, NULL); >> + maxphyaddr = eax * 0xff; > This is "&", not "*". You can also use rsvd_bits here. Oops. Sorry for the typo. :-) >> + rsvd = (~((1UL << maxphyaddr) - 1)) & >> + ~CR3_PCID_INVD; >> + } >> >> if (new_val & rsvd) >> return emulate_gp(ctxt, 0); >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> index e40a779..d9100c4 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -813,10 +813,10 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) >> return 0; >> } >> >> - if (is_long_mode(vcpu)) { >> - if (cr3 & CR3_L_MODE_RESERVED_BITS) >> - return 1; >> - } else if (is_pae(vcpu) && is_paging(vcpu) && >> + if (is_long_mode(vcpu) && >> + (cr3 & rsvd_bits(cpuid_maxphyaddr(vcpu), 63))) >> + return 1; > 62 is a little better, since 63 is the PCID invalidate bit. Got it. Both kvm_set_cr3() and check_cr_write() should use rsvd_bits(maxphyaddr, 62) . Thanks Yu > Paolo > >> + else if (is_pae(vcpu) && is_paging(vcpu) && >> !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) >> return 1; >> >