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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 60713C2D0DB for ; Mon, 27 Jan 2020 18:12:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 41B3522527 for ; Mon, 27 Jan 2020 18:12:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726145AbgA0SM5 (ORCPT ); Mon, 27 Jan 2020 13:12:57 -0500 Received: from mga03.intel.com ([134.134.136.65]:33692 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725828AbgA0SM5 (ORCPT ); Mon, 27 Jan 2020 13:12:57 -0500 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Jan 2020 10:12:56 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,370,1574150400"; d="scan'208";a="221811110" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.202]) by orsmga008.jf.intel.com with ESMTP; 27 Jan 2020 10:12:56 -0800 Date: Mon, 27 Jan 2020 10:12:56 -0800 From: Sean Christopherson To: Dan Carpenter Cc: pbonzini@redhat.com, kvm@vger.kernel.org Subject: Re: [bug report] KVM: x86: avoid incorrect writes to host MSR_IA32_SPEC_CTRL Message-ID: <20200127181255.GA2523@linux.intel.com> References: <20200127060305.jlq5uv6tu67tsbv4@kili.mountain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200127060305.jlq5uv6tu67tsbv4@kili.mountain> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Mon, Jan 27, 2020 at 09:04:22AM +0300, Dan Carpenter wrote: > Hello Paolo Bonzini, > > The patch e71ae535bc24: "KVM: x86: avoid incorrect writes to host > MSR_IA32_SPEC_CTRL" from Jan 20, 2020, leads to the following static > checker warning: > > arch/x86/kvm/vmx/vmx.c:2001 vmx_set_msr() > warn: maybe use && instead of & > > arch/x86/kvm/vmx/vmx.c > 1994 vmx->msr_ia32_umwait_control = data; > 1995 break; > 1996 case MSR_IA32_SPEC_CTRL: > 1997 if (!msr_info->host_initiated && > 1998 !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL)) > 1999 return 1; > 2000 > 2001 if (data & ~kvm_spec_ctrl_valid_bits(vcpu)) > ^^^^^^^^^^^^^^^^^^^^^^^^^ > > This seems wrong. kvm_spec_ctrl_valid_bits() returns a bool so this > is either 0xffffffff or 0xfffffffe. data is a u64. > > 2002 return 1; > 2003 > 2004 vmx->spec_ctrl = data; > 2005 if (!data) > 2006 break; > 2007 > 2008 /* > 2009 * For non-nested: Paolo already had to put on the cone of shame for this one :-) https://lkml.kernel.org/r/6b725990-f0c2-6577-be7e-44e101e540b5@redhat.com