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 CEAD5C433E0 for ; Sat, 23 May 2020 16:15:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A78F82087E for ; Sat, 23 May 2020 16:15:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="hRh/Cn5n" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728141AbgEWQPb (ORCPT ); Sat, 23 May 2020 12:15:31 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:59981 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2387867AbgEWQPb (ORCPT ); Sat, 23 May 2020 12:15:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1590250530; 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=HFg02eb4YubKQIu550jTk5UUZALiVej3kr4L4u3iifQ=; b=hRh/Cn5nZVa4qrPZ8NTS7gKrk4lgtdo4R2EmxsRvC4MNZbClYFqXfYztsScxSIEjPN1Jvl Pq/sV0YYtXJYXY1A+7tXXAp3mzRCEV2Bz4RSgHTJbpsm8PtHQBW9g/LX1Zq0+M0W4qsUtA DgKWJuTJ/ij9+eas/9aeAFYJtojqDHc= 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-19-0ITODA4gNVadJer3b5CRCw-1; Sat, 23 May 2020 12:15:28 -0400 X-MC-Unique: 0ITODA4gNVadJer3b5CRCw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 810B18005AA; Sat, 23 May 2020 16:15:26 +0000 (UTC) Received: from starship.f32vm (unknown [10.35.206.21]) by smtp.corp.redhat.com (Postfix) with ESMTP id 01ACC600E5; Sat, 23 May 2020 16:15:15 +0000 (UTC) From: Maxim Levitsky To: kvm@vger.kernel.org Cc: Paolo Bonzini , "H. Peter Anvin" , Tao Xu , Sean Christopherson , Jim Mattson , linux-kernel@vger.kernel.org, Joerg Roedel , x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)), Wanpeng Li , Ingo Molnar , Thomas Gleixner , Borislav Petkov , Vitaly Kuznetsov , Jingqi Liu , Maxim Levitsky Subject: [PATCH 2/2] kvm/x86: don't expose MSR_IA32_UMWAIT_CONTROL unconditionally Date: Sat, 23 May 2020 19:14:55 +0300 Message-Id: <20200523161455.3940-3-mlevitsk@redhat.com> In-Reply-To: <20200523161455.3940-1-mlevitsk@redhat.com> References: <20200523161455.3940-1-mlevitsk@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@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 b226fb8abe41b..4752293312947 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5316,6 +5316,10 @@ static void kvm_init_msr_list(void) 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; + break; default: break; } -- 2.26.2