linux-kernel - Re: Is: x86: mm: Fix vmalloc_fault oops during lazy MMU updates Was: Re: [PATCH] mm/x86: Flush lazy MMU when DEBUG

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Message-ID: <512F84AC.503@zytor.com>
Date:	Thu, 28 Feb 2013 08:24:12 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Borislav Petkov <bp@...en8.de>,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Greg KH <gregkh@...uxfoundation.org>, mingo@...hat.com,
	tglx@...utronix.de, xen-devel@...ts.xen.org,
	linux-kernel@...r.kernel.org, samu.kallio@...rdeencloud.com,
	kraman@...hat.com, jwboyer@...hat.com
Subject: Re: Is: x86: mm: Fix vmalloc_fault oops during lazy MMU updates Was:
 Re: [PATCH] mm/x86: Flush lazy MMU when DEBUG_PAGEALLOC is set

On 02/28/2013 08:22 AM, Borislav Petkov wrote:
> On Thu, Feb 28, 2013 at 11:20:20AM -0500, Boris Ostrovsky wrote:
>> On 02/28/2013 11:10 AM, Borislav Petkov wrote:
>>> On Thu, Feb 28, 2013 at 07:53:44AM -0800, H. Peter Anvin wrote:
>>>> At the very least we should have an early filter for the **COMMON!**
>>>> case that we are not on a PV platform.
>>> ... or, patch it out with the alternatives on baremetal, as Steven
>>> suggested.
>>>
>> I think making a check for paravirt_enabled() is safe enough. I'll
>> send a patch shortly.
> 
> Why not make it absolutely for free?

That makes more sense, I think... although of course, there is a cost in
complexity.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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