From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1755500AbcBHQrM (ORCPT <rfc822;w@1wt.eu>);
	Mon, 8 Feb 2016 11:47:12 -0500
Received: from userp1040.oracle.com ([156.151.31.81]:18953 "EHLO
	userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1753316AbcBHQrJ (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Mon, 8 Feb 2016 11:47:09 -0500
Subject: Re: [Xen-devel] [PATCH v2 3/3] paravirt: rename paravirt_enabled to
 paravirt_legacy
To: Borislav Petkov <bp@alien8.de>
References: <CALCETrU3DaqUeo-n2dV_UmeAcTEV2dQRtxyb-atMP6WFDDif3Q@mail.gmail.com>
 <20160206085930.GF25240@wotan.suse.de>
 <CALCETrWSiN+te_0aYH0NH9oBzGALLhKqxkupiGwbAm2GdCNyVQ@mail.gmail.com>
 <20160206220437.GA4435@pd.tnic> <56B8B6BF.6030007@oracle.com>
 <20160208155507.GF28980@pd.tnic> <56B8BCDB.9040701@citrix.com>
 <56B8BE58.6070003@oracle.com> <56B8C1BC.9040603@citrix.com>
 <56B8C2C8.8050406@oracle.com> <20160208163526.GI28980@pd.tnic>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>, X86 ML <x86@kernel.org>,
        david.e.box@intel.com, Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Lv Zheng <lv.zheng@intel.com>, Jan Beulich <JBeulich@suse.com>,
        "H. Peter Anvin" <hpa@zytor.com>, qiuxishi@huawei.com,
        cocci@systeme.lip6.fr, Xen Devel <xen-devel@lists.xensource.com>,
        Joerg Roedel <joro@8bytes.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Robert Moore <robert.moore@intel.com>, Ingo Molnar <mingo@redhat.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Mauro Carvalho Chehab <mchehab@osg.samsung.com>,
        "Luis R. Rodriguez" <mcgrof@suse.com>,
        Rusty Russell <rusty@rustcorp.com.au>,
        Thomas Gleixner <tglx@linutronix.de>, mcb30@ipxe.org,
        Juergen Gross <jgross@suse.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Andy Lutomirski <luto@amacapital.net>,
        "Luis R. Rodriguez" <mcgrof@kernel.org>, long.wanglong@huawei.com,
        Fengguang Wu <fengguang.wu@intel.com>
From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Message-ID: <56B8C52C.1070301@oracle.com>
Date: Mon, 8 Feb 2016 11:41:16 -0500
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101
 Thunderbird/38.5.1
MIME-Version: 1.0
In-Reply-To: <20160208163526.GI28980@pd.tnic>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
X-Source-IP: aserv0021.oracle.com [141.146.126.233]
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org



On 02/08/2016 11:35 AM, Borislav Petkov wrote:
> On Mon, Feb 08, 2016 at 11:31:04AM -0500, Boris Ostrovsky wrote:
>> I think we are OK for PV because this code will be executed after pvops are
>> set and so we will be calling xen_cpuid().
> Not for the early loader - it is too early for pvops then. So you're
> saying something like that won't work?

Keep in mind that Xen PV doesn't go through startup_32|64(). It starts 
at xen_start_kernel (save for a small stub before that), which sets 
pvops.  It "joins" regular/baremetal code in 
i386_start_kernel/x86_64_start_reservation().

-boris