WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] regression from c/s 22071:c5aed2e049bc (ept: Put locks a

To: Jan Beulich <JBeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] regression from c/s 22071:c5aed2e049bc (ept: Put locks around ept_get_entry) ?
From: Keir Fraser <keir@xxxxxxx>
Date: Thu, 16 Dec 2010 17:03:11 +0000
Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>, Christoph Egger <Christoph.Egger@xxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Thu, 16 Dec 2010 09:05:09 -0800
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:sender:user-agent:date :subject:from:to:cc:message-id:thread-topic:thread-index:in-reply-to :mime-version:content-type:content-transfer-encoding; bh=+WvhZPLbPmD7zmxLFnDkZepP24+ivDbnWihLDHdJme8=; b=Zq7KBFDYy5CcnMULHDEy6FihoyXGfcLPvf0WiPS6DXzSd/bBnb0vU95OXRC70mOHkU SWZucp9AyHNFa2Oni9l3SLCJsUk8WDZN4rhD3u/kgxW40xItf+8gx3Q21qER7xaQg7dz gMsQXA1uZ0PhQfrkpqGao5Ke+Wk9KjYFn57Vs=
Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:user-agent:date:subject:from:to:cc:message-id:thread-topic :thread-index:in-reply-to:mime-version:content-type :content-transfer-encoding; b=m8KzPpuTs+c2Xyj8tlwlbEENv4fEOVIFpTOcaBDCSorM+IX0aadILKoUjihbkcUEjq GYMqBRH26F/ajn9bzRwpUYdGTHmjcVkj6OwQ6b8G6INi071eHQ8vcBb5AFUplUxBvvIK cKI+hacajUdKAygnnET0Sv4jQxcTV9JpPKkXY=
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <4D0A516B0200007800028755@xxxxxxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcudQx57xcyHiSTYCk6266TOuiPtnA==
Thread-topic: [Xen-devel] regression from c/s 22071:c5aed2e049bc (ept: Put locks around ept_get_entry) ?
User-agent: Microsoft-Entourage/12.27.0.100910
On 16/12/2010 16:50, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote:

>>>> On 16.12.10 at 17:42, Keir Fraser <keir@xxxxxxx> wrote:
>> The issue is not one of serialisation or code ordering. It is one of
>> memory-access atomicity. Thus it seems to me that volatile is the correct
> 
> Indeed, I agree.
> 
>> approach therefore. Perhaps *(volatile type *)px = x or, really, even better
>> I should define some {read,write}_atomic{8,16,32,64} accessor functions
>> which use inline asm to absolutely definitely emit a single atomic 'mov'
>> instruction.
>> 
>> Make sense?
> 
> Yes.

Excellent. I will lay groundwork and fix pte_{read,write}_atomic directly in
-unstable and -4.0-testing. I will then post a proposed fix for EPT to the
list. I don't know that code so well and I may not otherwise catch all
places that require use of the new accessor macros.

 -- Keir

> Jan
> 



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>