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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 6677BC4646D for ; Wed, 8 Aug 2018 15:57:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2A37F21473 for ; Wed, 8 Aug 2018 15:57:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2A37F21473 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 S1729218AbeHHSQb (ORCPT ); Wed, 8 Aug 2018 14:16:31 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:32828 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727760AbeHHSQb (ORCPT ); Wed, 8 Aug 2018 14:16:31 -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 E0DA340216E7; Wed, 8 Aug 2018 15:56:13 +0000 (UTC) Received: from vitty.brq.redhat.com (unknown [10.43.2.155]) by smtp.corp.redhat.com (Postfix) with ESMTP id BFEBC21568A3; Wed, 8 Aug 2018 15:56:11 +0000 (UTC) From: Vitaly Kuznetsov To: kvm@vger.kernel.org Cc: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Roman Kagan , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , "Michael Kelley (EOSG)" , Mohammed Gamal , Cathy Avery , linux-kernel@vger.kernel.org, Jim Mattson , Liran Alon Subject: [PATCH v4 07/12] x86/kvm/hyperv: don't clear VP assist pages on init Date: Wed, 8 Aug 2018 17:55:47 +0200 Message-Id: <20180808155552.4836-8-vkuznets@redhat.com> In-Reply-To: <20180808155552.4836-1-vkuznets@redhat.com> References: <20180808155552.4836-1-vkuznets@redhat.com> 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 [10.11.55.5]); Wed, 08 Aug 2018 15:56:13 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Wed, 08 Aug 2018 15:56:13 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'vkuznets@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org VP assist pages may hold valuable data which needs to be preserved across migration. Clean PV EOI portion of the data on init, the guest is responsible for making sure there's no garbage in the rest. This will be used for nVMX migration, eVMCS address needs to be preserved. Signed-off-by: Vitaly Kuznetsov --- arch/x86/kvm/hyperv.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index b1655d01c368..ae3e2e0de680 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1080,7 +1080,13 @@ static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host) addr = kvm_vcpu_gfn_to_hva(vcpu, gfn); if (kvm_is_error_hva(addr)) return 1; - if (__clear_user((void __user *)addr, PAGE_SIZE)) + + /* + * Clear apic_assist portion of f(struct hv_vp_assist_page + * only, there can be valuable data in the rest which needs + * to be preserved e.g. on migration. + */ + if (__clear_user((void __user *)addr, sizeof(u32))) return 1; hv->hv_vapic = data; kvm_vcpu_mark_page_dirty(vcpu, gfn); -- 2.14.4