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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,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 80A80C433E1 for ; Wed, 20 May 2020 16:07:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4EF0B206F1 for ; Wed, 20 May 2020 16:07:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="VxKH4Rx4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726831AbgETQHy (ORCPT ); Wed, 20 May 2020 12:07:54 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:40039 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726775AbgETQHv (ORCPT ); Wed, 20 May 2020 12:07:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589990870; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Cf3WukEsfySNhoecA6qrczHdfhodkstmNrTwpvxGHuU=; b=VxKH4Rx4o3Y99ZH48wRWYyQD2eSMf0ZWmrZXoNSXuzh9n87eza/27Ez8XXXfKXJ67sr0US KrcaO3ZtoGELqGa8KdXU2GcHBC/lCtARAtrhgSStp09JnO/cIUS+a6vInCXHkuzD2YAKoy G8laCcPLK7bfs1oM9kIytsMEKgysx2g= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-211-cTF6r1KZPZueAKuP9-4BHw-1; Wed, 20 May 2020 12:07:48 -0400 X-MC-Unique: cTF6r1KZPZueAKuP9-4BHw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4E9F8800053; Wed, 20 May 2020 16:07:47 +0000 (UTC) Received: from starship.fedora32vm (unknown [10.35.207.28]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3E1BA341FD; Wed, 20 May 2020 16:07:46 +0000 (UTC) From: Maxim Levitsky To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Maxim Levitsky Subject: [PATCH 2/2] kvm/x86: don't expose MSR_IA32_UMWAIT_CONTROL unconditionally Date: Wed, 20 May 2020 19:07:40 +0300 Message-Id: <20200520160740.6144-3-mlevitsk@redhat.com> In-Reply-To: <20200520160740.6144-1-mlevitsk@redhat.com> References: <20200520160740.6144-1-mlevitsk@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This msr is only available when the host supports WAITPKG feature. This breaks a nested guest, if the L1 hypervisor is set to ignore unknown msrs, because the only other safety check that the kernel does is that it attempts to read the msr and rejects it if it gets an exception. Fixes: 6e3ba4abce KVM: vmx: Emulate MSR IA32_UMWAIT_CONTROL Signed-off-by: Maxim Levitsky --- arch/x86/kvm/x86.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index fe3a24fd6b263..9c507b32b1b77 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5314,6 +5314,10 @@ static void kvm_init_msr_list(void) if (msrs_to_save_all[i] - MSR_ARCH_PERFMON_EVENTSEL0 >= min(INTEL_PMC_MAX_GENERIC, x86_pmu.num_counters_gp)) continue; + break; + case MSR_IA32_UMWAIT_CONTROL: + if (!kvm_cpu_cap_has(X86_FEATURE_WAITPKG)) + continue; default: break; } -- 2.26.2