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Re: [Xen-devel] BSS region in xen_in_range is incorrect

To: "Han, Weidong" <weidong.han@xxxxxxxxx>, Jan Beulich <JBeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] BSS region in xen_in_range is incorrect
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Thu, 22 Apr 2010 17:44:57 +0100
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I've fixed this as xen-unstable:21225.

 -- Keir

On 22/04/2010 11:57, "Keir Fraser" <keir.fraser@xxxxxxxxxxxxx> wrote:

> Allocate the static buffer in initdata, and always require to dynamically
> allocate a replacement buffer during Xen boot. The latter allocation should
> surely succeed since it happens so early.
> 
> Goodness knows why I applied that patch so late during 4.0.0 release cycle.
> 
>  -- Keir
> 
> On 22/04/2010 10:35, "Han, Weidong" <weidong.han@xxxxxxxxx> wrote:
> 
>> In c/s 21038, console_init_postirq frees default static ring buffer if a
>> dynamic one was obtained. This makes dom0 can use the default static ring
>> buffer which is in BSS region, but xen_in_range didn't remove the region from
>> BSS region which won't be mapped in VT-d page table, so it causes problems
>> when a device DMAs to that region. To fix this issue, 1) remove the freed
>> region from BSS region in xen_in_range; 2) don't free default static ring
>> buffer. Method 1) can fix it cleanly, but maybe need many changes. Method 2)
>> is simple, but it wastes some resources.
>> 
>> Keir / Jan, what's your opinion?
>> 
>> Regards,
>> Weidong
>> 
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>> http://lists.xensource.com/xen-devel
> 
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel



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