From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1175DECDFB1 for ; Sun, 15 Jul 2018 16:06:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B6571208E7 for ; Sun, 15 Jul 2018 16:06:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B6571208E7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726907AbeGOQ3W (ORCPT ); Sun, 15 Jul 2018 12:29:22 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:50378 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726638AbeGOQ3W (ORCPT ); Sun, 15 Jul 2018 12:29:22 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 66A6A4005F6C; Sun, 15 Jul 2018 16:05:56 +0000 (UTC) Received: from [10.36.116.39] (ovpn-116-39.ams2.redhat.com [10.36.116.39]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E5FF7215688A; Sun, 15 Jul 2018 16:05:54 +0000 (UTC) Subject: Re: [PATCH 2/2] KVM: X86: Fix loss of CR3_PCID_INVD bit when guest writes CR3 To: Wanpeng Li , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Junaid Shahid References: <1526181854-3631-1-git-send-email-wanpengli@tencent.com> From: Paolo Bonzini Openpgp: preference=signencrypt Autocrypt: addr=pbonzini@redhat.com; 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Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <1526181854-3631-1-git-send-email-wanpengli@tencent.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Sun, 15 Jul 2018 16:05:56 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Sun, 15 Jul 2018 16:05:56 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'pbonzini@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13/05/2018 05:24, Wanpeng Li wrote: > From: Wanpeng Li > > SDM volume 3, section 4.10.4: > > * MOV to CR3. The behavior of the instruction depends on the value of CR4.PCIDE: > — If CR4.PCIDE = 1 and bit 63 of the instruction’s source operand is 1, the > instruction is not required to invalidate any TLB entries or entries in > paging-structure caches. > > The CR3_PCID_INVD bit should not be removed if CR4.PCIDE = 1 when guest writes > CR3, this patch fixes it. > > Cc: Paolo Bonzini > Cc: Radim Krčmář > Cc: Junaid Shahid > Signed-off-by: Wanpeng Li > --- > arch/x86/kvm/x86.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 9a90668..438f140 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -849,11 +849,13 @@ EXPORT_SYMBOL_GPL(kvm_set_cr4); > > int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) > { > + unsigned long cr3_check = cr3; > + > #ifdef CONFIG_X86_64 > bool pcid_enabled = kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE); > > if (pcid_enabled) > - cr3 &= ~CR3_PCID_INVD; > + cr3_check &= ~CR3_PCID_INVD; > #endif > > if (cr3 == kvm_read_cr3(vcpu) && !pdptrs_changed(vcpu)) { > @@ -863,7 +865,7 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) > } > > if (is_long_mode(vcpu) && > - (cr3 & rsvd_bits(cpuid_maxphyaddr(vcpu), 63))) > + (cr3_check & rsvd_bits(cpuid_maxphyaddr(vcpu), 63))) > return 1; > else if (is_pae(vcpu) && is_paging(vcpu) && > !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) > Note that bit 63 is never written into CR3, and is always zero when read. Paolo