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=-7.0 required=3.0 tests=INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 59983C43387 for ; Fri, 21 Dec 2018 10:06:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 019AE21919 for ; Fri, 21 Dec 2018 10:06:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389311AbeLUKG4 (ORCPT ); Fri, 21 Dec 2018 05:06:56 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37392 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731648AbeLUKG4 (ORCPT ); Fri, 21 Dec 2018 05:06:56 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1C1688E67A; Fri, 21 Dec 2018 10:06:56 +0000 (UTC) Received: from vitty.brq.redhat.com.redhat.com (unknown [10.43.2.155]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 295D517D4D; Fri, 21 Dec 2018 10:06:54 +0000 (UTC) From: Vitaly Kuznetsov To: Radim =?utf-8?B?S3LEjW3DocWZ?= Cc: kvm@vger.kernel.org, Paolo Bonzini , linux-kernel@vger.kernel.org, Tom Lendacky , Joerg Roedel , x86@kernel.org Subject: Re: [PATCH] KVM: x86: svm: report MSR_IA32_MCG_EXT_CTL as unsupported In-Reply-To: <20181220200630.GC25497@flask> References: <20181219110613.24459-1-vkuznets@redhat.com> <20181220200630.GC25497@flask> Date: Fri, 21 Dec 2018 11:06:52 +0100 Message-ID: <8736qrw5vn.fsf@vitty.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Fri, 21 Dec 2018 10:06:56 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Radim Krčmář writes: > 2018-12-19 12:06+0100, Vitaly Kuznetsov: >> AMD doesn't seem to implement MSR_IA32_MCG_EXT_CTL and svm code in kvm >> knows nothing about it, however, this MSR is among emulated_msrs and >> thus returned with KVM_GET_MSR_INDEX_LIST. The consequent KVM_GET_MSRS, >> of course, fails. >> >> Report the MSR as unsupported to not confuse userspace. >> >> Signed-off-by: Vitaly Kuznetsov >> --- >> arch/x86/kvm/svm.c | 7 +++++++ >> 1 file changed, 7 insertions(+) >> >> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c >> index 2acb42b74a51..dfdf7d0b7f88 100644 >> --- a/arch/x86/kvm/svm.c >> +++ b/arch/x86/kvm/svm.c >> @@ -5845,6 +5845,13 @@ static bool svm_cpu_has_accelerated_tpr(void) >> >> static bool svm_has_emulated_msr(int index) >> { >> + switch (index) { >> + case MSR_IA32_MCG_EXT_CTL: >> + return false; >> + default: >> + break; > > Queued, thanks. > > Btw, I would prefer this without the > > default: break; > > as I don't think we'll ever add something there. "640K ought to be enough for anybody" :-) But in case you commit it as return index != MSR_IA32_MCG_EXT_CTL; I won't object. Thanks, -- Vitaly