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=-8.3 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,URIBL_BLOCKED, USER_AGENT_SANE_1 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 9930CC35242 for ; Sat, 25 Jan 2020 09:32:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6BBA32071E for ; Sat, 25 Jan 2020 09:32:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Of2AhvTn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727747AbgAYJcI (ORCPT ); Sat, 25 Jan 2020 04:32:08 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:55996 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725710AbgAYJcI (ORCPT ); Sat, 25 Jan 2020 04:32:08 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579944727; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4aVPwT+ullXbV9ZGelAsF2ZlUzo01e9ol8SPKMVndpw=; b=Of2AhvTnZpik7dhPmb37Ryh2IrPZ2XH6xNPAEgxDeW1jEuVGNdjkuiE6kS6BCmcpmRDQvs xvhvMb9TLArRxFmNf2pnNZM5TYQSe7OjlYt0nkxKhTeuf/MibS26/P3QNmz7KiQKQ/QPvp BZJIk/iPg/CInRAMqoHOoUxjKUoWR+Q= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-415-SfySA-O0PgKGEN1mHH71ZQ-1; Sat, 25 Jan 2020 04:32:05 -0500 X-MC-Unique: SfySA-O0PgKGEN1mHH71ZQ-1 Received: by mail-wm1-f71.google.com with SMTP id g26so401187wmk.6 for ; Sat, 25 Jan 2020 01:32:05 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=4aVPwT+ullXbV9ZGelAsF2ZlUzo01e9ol8SPKMVndpw=; b=kQDJXcRBnDJbNzmwEMHNafIDHTpNhniZQL9d4xG/XYOlQqRi6ClJ7OhV8BLcDTMrsv EYOY0KQz47l107nGhkYoNO1ij6UIFhMnUjb/MKv78LD2hPVRLB0d4G9fQ9P5IAxbqi2m u0KCZHxPFgmXxg6P4VlKxD5MdluVVyBLC1GL4ogx/ZOcpxoM5H+AVmwUl42AgNvJWiSg lLp7fWPCM5HrOTHTP3aqudg4eOidO6AGncplAwwkNFLH+3/Pg+7pOyegiYHlsCSYxs3C 5zNHj/O7d0zi4tvaq2KwXxIXDQpJ1HpoYoftWg5hkpNdk9o5KapMxoSmb7vg4ODX9Mjj 3wVQ== X-Gm-Message-State: APjAAAWC+DWVT33yc+1TM9znzUKAOefWGiS76IxGWPJ98B9+HhUH3PHp rqjsOUtbEAzkvlPZJJFVVX/rf6z76c7noOkC76fMjehievezSmToFgWrz6ww2Q7sj/U/z2r8/7f vonp3/izTwbxKw74/syDCbgTG X-Received: by 2002:a05:6000:11c3:: with SMTP id i3mr9377038wrx.244.1579944724475; Sat, 25 Jan 2020 01:32:04 -0800 (PST) X-Google-Smtp-Source: APXvYqy6XvOgjU6V9Wv3zn93Ex1jpxLzeOnJ89MIAzXJBVajO5ULnjaciehkCA0EPTt32FXxUHMtbg== X-Received: by 2002:a05:6000:11c3:: with SMTP id i3mr9377021wrx.244.1579944724231; Sat, 25 Jan 2020 01:32:04 -0800 (PST) Received: from [192.168.10.150] ([93.56.166.5]) by smtp.gmail.com with ESMTPSA id b67sm10500968wmc.38.2020.01.25.01.32.02 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 25 Jan 2020 01:32:03 -0800 (PST) Subject: Re: [PATCH] KVM: x86: Take a u64 when checking for a valid dr7 value To: Sean Christopherson Cc: Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Krish Sadhukhan , Randy Dunlap References: <20200124230722.8964-1-sean.j.christopherson@intel.com> From: Paolo Bonzini Message-ID: <118ad0a6-b190-80ee-98fa-615466d2bf12@redhat.com> Date: Sat, 25 Jan 2020 10:32:02 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <20200124230722.8964-1-sean.j.christopherson@intel.com> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 25/01/20 00:07, Sean Christopherson wrote: > Take a u64 instead of an unsigned long in kvm_dr7_valid() to fix a build > warning on i386 due to right-shifting a 32-bit value by 32 when checking > for bits being set in dr7[63:32]. > > Alternatively, the warning could be resolved by rewriting the check to > use an i386-friendly method, but taking a u64 fixes another oddity on > 32-bit KVM. Beause KVM implements natural width VMCS fields as u64s to > avoid layout issues between 32-bit and 64-bit, a devious guest can stuff > vmcs12->guest_dr7 with a 64-bit value even when both the guest and host > are 32-bit kernels. KVM eventually drops vmcs12->guest_dr7[63:32] when > propagating vmcs12->guest_dr7 to vmcs02, but ideally KVM would not rely > on that behavior for correctness. > > Cc: Jim Mattson > Cc: Krish Sadhukhan > Fixes: ecb697d10f70 ("KVM: nVMX: Check GUEST_DR7 on vmentry of nested guests") > Reported-by: Randy Dunlap > Signed-off-by: Sean Christopherson > --- > arch/x86/kvm/x86.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h > index 2d2ff855773b..3624665acee4 100644 > --- a/arch/x86/kvm/x86.h > +++ b/arch/x86/kvm/x86.h > @@ -357,7 +357,7 @@ static inline bool kvm_pat_valid(u64 data) > return (data | ((data & 0x0202020202020202ull) << 1)) == data; > } > > -static inline bool kvm_dr7_valid(unsigned long data) > +static inline bool kvm_dr7_valid(u64 data) > { > /* Bits [63:32] are reserved */ > return !(data >> 32); > Queued, thanks. Paolo