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=-6.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 B880EC67839 for ; Fri, 14 Dec 2018 11:00:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 739B02080F for ; Fri, 14 Dec 2018 11:00:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 739B02080F 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 S1729505AbeLNLAQ (ORCPT ); Fri, 14 Dec 2018 06:00:16 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41152 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726670AbeLNLAP (ORCPT ); Fri, 14 Dec 2018 06:00:15 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0381987622; Fri, 14 Dec 2018 11:00:15 +0000 (UTC) Received: from [10.36.112.72] (ovpn-112-72.ams2.redhat.com [10.36.112.72]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4458F5D6B3; Fri, 14 Dec 2018 11:00:09 +0000 (UTC) Subject: Re: [PATCH V2 1/2] KVM/VMX: Check ept_pointer before flushing ept tlb To: lantianyu1986@gmail.com Cc: Lan Tianyu , rkrcmar@redhat.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, michael.h.kelley@microsoft.com, kys@microsoft.com, vkuznets@redhat.com References: <20181206073437.1995-1-Tianyu.Lan@microsoft.com> From: Paolo Bonzini Openpgp: preference=signencrypt Autocrypt: addr=pbonzini@redhat.com; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 MIME-Version: 1.0 In-Reply-To: <20181206073437.1995-1-Tianyu.Lan@microsoft.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Fri, 14 Dec 2018 11:00:15 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/12/18 08:34, lantianyu1986@gmail.com wrote: > From: Lan Tianyu > > This patch is to initialize ept_pointer to INVALID_PAGE and check it > before flushing ept tlb. If ept_pointer is invalid, bypass the flush > request. > > Signed-off-by: Lan Tianyu Can you explain better *why* this patch is needed? Also, should vmx->ept_pointer be cleared at reset time, rather than vCPU creation? Thanks, Paolo > --- > arch/x86/kvm/vmx.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index c379d0bfdcba..6577ec8cbb0f 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -1582,11 +1582,18 @@ static int vmx_hv_remote_flush_tlb(struct kvm *kvm) > /* > * FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE hypercall needs the address of the > * base of EPT PML4 table, strip off EPT configuration information. > + * If ept_pointer is invalid pointer, bypass the flush request. > */ > if (to_kvm_vmx(kvm)->ept_pointers_match != EPT_POINTERS_MATCH) { > - kvm_for_each_vcpu(i, vcpu, kvm) > + kvm_for_each_vcpu(i, vcpu, kvm) { > + u64 ept_pointer = to_vmx(vcpu)->ept_pointer; > + > + if (!VALID_PAGE(ept_pointer)) > + continue; > + > ret |= hyperv_flush_guest_mapping( > - to_vmx(kvm_get_vcpu(kvm, i))->ept_pointer & PAGE_MASK); > + ept_pointer & PAGE_MASK); > + } > } else { > ret = hyperv_flush_guest_mapping( > to_vmx(kvm_get_vcpu(kvm, 0))->ept_pointer & PAGE_MASK); > @@ -11614,6 +11621,8 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id) > vmx->pi_desc.nv = POSTED_INTR_VECTOR; > vmx->pi_desc.sn = 1; > > + vmx->ept_pointer = INVALID_PAGE; > + > return &vmx->vcpu; > > free_vmcs: >