From mboxrd@z Thu Jan  1 00:00:00 1970
From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: Re: [Xen-devel] [PATCH v2 3/3] paravirt: rename paravirt_enabled to
 paravirt_legacy
Date: Mon, 8 Feb 2016 11:41:16 -0500
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To: Borislav Petkov <bp@alien8.de>
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.wan
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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