lkml.org 
[lkml]   [2005]   [Aug]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 8/14] i386 / Add a per cpu gdt accessor
Zwane Mwaikambo wrote:

>On Wed, 10 Aug 2005 zach@vmware.com wrote:
>
>
>
>>Add an accessor function for getting the per-CPU gdt. Callee must already
>>have the CPU.
>>
>>
>
>This one seems superfluous to me, does accessing it indirectly generate
>better code too?
>
>

Thanks for the feedback. I believe the binary compilation is the same.
It is superfluous in the sense that there is not yet a real use for it,
but it is needed for later developement.

Xen requires page isolation of system data structures that could be used
to override privilege. Since they do not shadow the GDT, they require
the GDT to be write protected. A side effect of that is that the GDT
must be moved to an isolated page. Thus, the accessors to allow
transparently moving the GDT for a paravirtual build. There is
deliberately no effect on the standard build.

Zach

P.S. Sorry I got your mail address wrong earlier. I mistyped it from
the update to the CREDITS patch.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-08-11 07:56    [from the cache]
©2003-2011 Jasper Spaans. Advertise on this site