linux-kernel - Re: [Xen-devel] [PATCH v2 3/3] paravirt: rename paravirt_enabled to paravirt

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Message-ID: <56B8C52C.1070301@oracle.com>
Date:	Mon, 8 Feb 2016 11:41:16 -0500
From:	Boris Ostrovsky <boris.ostrovsky@...cle.com>
To:	Borislav Petkov <bp@...en8.de>
Cc:	Andrew Cooper <andrew.cooper3@...rix.com>, X86 ML <x86@...nel.org>,
	david.e.box@...el.com, Andrey Ryabinin <ryabinin.a.a@...il.com>,
	Lv Zheng <lv.zheng@...el.com>, Jan Beulich <JBeulich@...e.com>,
	"H. Peter Anvin" <hpa@...or.com>, qiuxishi@...wei.com,
	cocci@...teme.lip6.fr, Xen Devel <xen-devel@...ts.xensource.com>,
	Joerg Roedel <joro@...tes.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Robert Moore <robert.moore@...el.com>,
	Ingo Molnar <mingo@...hat.com>,
	Andrey Ryabinin <aryabinin@...tuozzo.com>,
	Mauro Carvalho Chehab <mchehab@....samsung.com>,
	"Luis R. Rodriguez" <mcgrof@...e.com>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Thomas Gleixner <tglx@...utronix.de>, mcb30@...e.org,
	Juergen Gross <jgross@...e.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Andy Lutomirski <luto@...capital.net>,
	"Luis R. Rodriguez" <mcgrof@...nel.org>, long.wanglong@...wei.com,
	Fengguang Wu <fengguang.wu@...el.com>
Subject: Re: [Xen-devel] [PATCH v2 3/3] paravirt: rename paravirt_enabled to
 paravirt_legacy



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