From mboxrd@z Thu Jan  1 00:00:00 1970
From: Borislav Petkov <bp@alien8.de>
Subject: Re: [PATCH v2 3/3] paravirt: rename paravirt_enabled to
 paravirt_legacy
Date: Wed, 17 Feb 2016 23:03:04 +0100
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To: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, Andrew Cooper <andrew.cooper3@citrix.com>, David Vrabel <david.vrabel@citrix.com>, Andy Lutomirski <luto@amacapital.net>, Juergen Gross <jgross@suse.com>, Michael Brown <mcb30@ipxe.org>, Thomas Gleixner <tglx@linutronix.de>, Andrey Ryabinin <aryabinin@virtuozzo.com>, Joerg Roedel <joro@8bytes.org>, Robert Moore <robert.moore@intel.com>, Mauro Carvalho Chehab <mchehab@osg.samsung.com>, "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>, Xen Devel <xen-devel@lists.xensource.com>, "H. Peter Anvin" <hpa@zytor.com>, Rusty Russell <rusty@rustcorp.com.au>, Jan Beulich <JBeulich@suse.com>, Lv Zheng <lv.zheng@intel.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, long.wanglong@huawei.com, Fengguang Wu <fengguang.wu@intel.com>, qiuxishi@huawei.comAndrey Ryabinin <ryab>
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On Wed, Feb 17, 2016 at 04:21:56PM -0500, Boris Ostrovsky wrote:
> That's exactly the point: if something is mapped it's an error for a
> non-PV kernel.

How would something be mapped there? __PAGE_OFFSET is
0xffff880000000000.

Or are you thinking about some insanely b0rked kernel code mapping stuff
in there?

> By removing paravirt_enabled() we may miss those errors. Worse, I think we
> may even crash while doing pagetable walk (although it's probably better to
> crash here than to use an unexpected translation in real code somewhere)

Well, if this is the only site which keeps paravirt_enabled() from being
buried, we need to think about a better way to detect a hypervisor.
Maybe we should look at x86_hyper, use CPUID(0x4...) or something else.

What's your preference?

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.