From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yu Zhang Subject: Re: [PATCH v1 1/4] KVM: MMU: check guest CR3 reserved bits based on its physical address width. Date: Mon, 14 Aug 2017 19:39:01 +0800 Message-ID: <93d301f3-7fdc-866c-a140-4afe0c0a8dab@linux.intel.com> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org, rkrcmar@redhat.com, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, xiaoguangrong@tencent.com, joro@8bytes.org To: Paolo Bonzini , kvm@vger.kernel.org Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org 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; >> >