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 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 51F38FA374E for ; Thu, 13 Sep 2018 17:35:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6DFCF2177C for ; Thu, 13 Sep 2018 17:05:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6DFCF2177C 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 S1728462AbeIMWQI (ORCPT ); Thu, 13 Sep 2018 18:16:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47112 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727082AbeIMWQH (ORCPT ); Thu, 13 Sep 2018 18:16:07 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7FA543082B71; Thu, 13 Sep 2018 17:05:45 +0000 (UTC) Received: from vitty.brq.redhat.com (unknown [10.43.2.155]) by smtp.corp.redhat.com (Postfix) with ESMTP id 26AA0608E0; Thu, 13 Sep 2018 17:05:42 +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)" , Jim Mattson , Liran Alon , linux-kernel@vger.kernel.org Subject: [PATCH v5 07/12] x86/kvm/hyperv: don't clear VP assist pages on init Date: Thu, 13 Sep 2018 19:05:17 +0200 Message-Id: <20180913170522.24876-8-vkuznets@redhat.com> In-Reply-To: <20180913170522.24876-1-vkuznets@redhat.com> References: <20180913170522.24876-1-vkuznets@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Thu, 13 Sep 2018 17:05:45 +0000 (UTC) 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