Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752760AbbGICfl (ORCPT ); Wed, 8 Jul 2015 22:35:41 -0400 Received: from mga11.intel.com ([192.55.52.93]:32907 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751622AbbGICfd (ORCPT ); Wed, 8 Jul 2015 22:35:33 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,436,1432623600"; d="scan'208";a="743385921" Message-ID: <559DDCD0.2090502@linux.intel.com> Date: Thu, 09 Jul 2015 10:30:40 +0800 From: Xiao Guangrong User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Paolo Bonzini , linux-kernel@vger.kernel.org, kvm@vger.kernel.org CC: jroedel@suse.de, alex.williamson@redhat.com, ogerlitz@mellanox.com, amirv@mellanox.com Subject: Re: [PATCH 2/4] KVM: SVM: use NPT page attributes References: <1436276739-50326-1-git-send-email-pbonzini@redhat.com> <1436276739-50326-3-git-send-email-pbonzini@redhat.com> <559CBC4E.2090004@linux.intel.com> <559D0754.6030009@redhat.com> In-Reply-To: <559D0754.6030009@redhat.com> 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: 2171 Lines: 58 On 07/08/2015 07:19 PM, Paolo Bonzini wrote: > > > On 08/07/2015 07:59, Xiao Guangrong wrote: >> >> >> On 07/07/2015 09:45 PM, Paolo Bonzini wrote: >>> Right now, NPT page attributes are not used, and the final page >>> attribute depends solely on gPAT (which however is not synced >>> correctly), the guest MTRRs and the guest page attributes. >>> >>> However, we can do better by mimicking what is done for VMX. >>> In the absence of PCI passthrough, the guest PAT can be ignored >>> and the page attributes can be just WB. If passthrough is being >>> used, instead, keep respecting the guest PAT, and emulate the guest >>> MTRRs through the PAT field of the nested page tables. >>> >>> The only snag is that WP memory cannot be emulated correctly, >>> because Linux's default PAT setting only includes the other types. >>> >>> Signed-off-by: Paolo Bonzini >>> --- >>> arch/x86/kvm/svm.c | 47 ++++++++++++++++++++++++++++++++++++++++++----- >>> 1 file changed, 42 insertions(+), 5 deletions(-) >>> >>> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c >>> index 602b974a60a6..0f125c1860ec 100644 >>> --- a/arch/x86/kvm/svm.c >>> +++ b/arch/x86/kvm/svm.c >>> @@ -1085,6 +1085,47 @@ static u64 svm_compute_tsc_offset(struct >>> kvm_vcpu *vcpu, u64 target_tsc) >>> return target_tsc - tsc; >>> } >>> >>> +static void svm_set_guest_pat(struct vcpu_svm *svm, u64 *g_pat) >>> +{ >>> + struct kvm_vcpu *vcpu = &svm->vcpu; >>> + >>> + /* Unlike Intel, AMD takes the guest's CR0.CD into account. >> >> I noticed this code in svm_set_cr0(): >> >> if (!(vcpu->kvm->arch.disabled_quirks & KVM_QUIRK_CD_NW_CLEARED)) >> cr0 &= ~(X86_CR0_CD | X86_CR0_NW); >> >> gCR0.CD is hidden to CPU if KVM_QUIRK_CD_NW_CLEARED is not set and looks >> like >> it is the normal case after grepping Qemu code. >> How about this one? I still do not know how SVM properly emulates CR0.CD? :( -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/