Re: [Xen-devel] regression from c/s 22071:c5aed2e049bc (ept: Put locks around ept_get_entry) ?

[Keir Fraser <keir@xxxxxxx>]

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