lkml.org 
[lkml]   [2006]   [May]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH 17/35] Segment register changes for Xen
* Zachary Amsden (zach@vmware.com) wrote:
> Chris Wright wrote:
> >1. We clear FS/GS before changing TLS entries and switching LDT, as
> >otherwise the hypervisor will fail to restore thread-local values on
> >return to the guest kernel and we take a slow exception path.
>
> >@@ -647,6 +647,8 @@ struct task_struct fastcall * __switch_t
> > */
> > savesegment(fs, prev->fs);
> > savesegment(gs, prev->gs);
> >+ clearsegment(fs);
> >+ clearsegment(gs);
> >
>
> Really not needed. Think about it. You can even speed up Xen.

Please describe how. I'm afraid I'm missing your point, as I don't see
the improvement.

> I'm glad the native operation here is a nop, but it should be
> hypervisor_clearsegment or xen_clearsegment if you really want to keep it.

Yeah, Andi had similar naming concern.
-
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: 2006-05-18 23:25    [W:0.139 / U:19.788 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site