From patchwork Fri Jul 10 12:01:33 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 6765421 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 173AA9F2F0 for ; Fri, 10 Jul 2015 12:01:45 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 3764220681 for ; Fri, 10 Jul 2015 12:01:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4A74320651 for ; Fri, 10 Jul 2015 12:01:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754796AbbGJMBk (ORCPT ); Fri, 10 Jul 2015 08:01:40 -0400 Received: from mail-wi0-f176.google.com ([209.85.212.176]:36818 "EHLO mail-wi0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754633AbbGJMBi (ORCPT ); Fri, 10 Jul 2015 08:01:38 -0400 Received: by widjy10 with SMTP id jy10so13552264wid.1; Fri, 10 Jul 2015 05:01:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id; bh=zUayFyotyzUHPoSTODpX8GVyHHTtat76bxcW0lz8paA=; b=RLatAyovQ46xj9S678xjnzluf1yqCe0qepK2fxKfPq2Dc3AiP771zP+pq8IUe2KSAc uzUC2DhFdbACEfBk58uVG/kDUJNl8XKgctOz396xiv1IT6H3KLsrzZ1ibpJzvP9lB0x1 +0dPwjjH4IMetIIW8HLYZSgjIs905SsjVZbbBWR94//hJVBJmPv/PixJJiAIP1gWYjhS mDvKXfahP/s5mXFaI2nftdai8MdBjFoYZ6IQoX75Qu9SBSLG74oljcx9Rg08PCGFyM+E 7TKMC1DkXw89D/Ss901b1dU+uj8PpiyllC0vC+XmE3BC75Z0U8eJl/q0y2ZrFct13Xau RQRA== X-Received: by 10.180.85.194 with SMTP id j2mr5515566wiz.11.1436529697539; Fri, 10 Jul 2015 05:01:37 -0700 (PDT) Received: from 640k.lan (dynamic-adsl-94-39-132-37.clienti.tiscali.it. [94.39.132.37]) by smtp.gmail.com with ESMTPSA id ft5sm2637199wib.4.2015.07.10.05.01.35 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 10 Jul 2015 05:01:36 -0700 (PDT) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: guangrong.xiao@linux.intel.com, joerg.roedel@suse.de Subject: [PATCH] KVM: svm: remove KVM_QUIRK_CD_NW_CLEARED quirk Date: Fri, 10 Jul 2015 14:01:33 +0200 Message-Id: <1436529693-9743-1-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.8.3.1 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-7.4 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We can disable CD unconditionally when there is no assigned device. KVM now forces guest PAT to all-writeback in that case, so it makes sense to also force CR0.CD=0. When there are assigned devices, emulate cache-disabled operation through the page tables. This behavior is consistent with VMX, where CD/NW are not touched by vmentry/vmexit. Note that buggy firmware that does not clear CD/NW is _seriously_ old: SeaBIOS for example has been doing it since October 2008. Signed-off-by: Paolo Bonzini Reviewed-by: Joerg Roedel Reviewed-by: Xiao Guangrong --- arch/x86/kvm/svm.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index bbc678a66b18..9b1513065a6a 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1173,6 +1173,9 @@ static u64 svm_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio) if (!is_mmio && !kvm_arch_has_assigned_device(vcpu->kvm)) return 0; + if (kvm_read_cr0(vcpu) & X86_CR0_CD) + return _PAGE_NOCACHE; + mtrr = kvm_mtrr_get_guest_memory_type(vcpu, gfn); return mtrr2protval[mtrr]; } @@ -1667,13 +1670,10 @@ static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) if (!vcpu->fpu_active) cr0 |= X86_CR0_TS; - /* - * re-enable caching here because the QEMU bios - * does not do it - this results in some delay at - * reboot - */ - if (!(vcpu->kvm->arch.disabled_quirks & KVM_QUIRK_CD_NW_CLEARED)) - cr0 &= ~(X86_CR0_CD | X86_CR0_NW); + + /* These are emulated via page tables. */ + cr0 &= ~(X86_CR0_CD | X86_CR0_NW); + svm->vmcb->save.cr0 = cr0; mark_dirty(svm->vmcb, VMCB_CR); update_cr0_intercept(svm);