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RE: [Xen-devel] Task Switching and Xen-SVM

To: "Petersson, Mats" <Mats.Petersson@xxxxxxx>, "Vivek Mohan" <vivek.mt@xxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] Task Switching and Xen-SVM
From: "Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx>
Date: Fri, 27 Oct 2006 10:07:03 +0100
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Thread-topic: [Xen-devel] Task Switching and Xen-SVM
> Do you actually know of any (32-bit) OS that uses task switching? 

It's often used in double fault, NMI and MCA handlers, all of which are
typically fatal.

It would still be good to have them implemented to get a decent oops
message out though.

Ian 

> In my
> experience, it's horribly slow (because it generally saves/restores
more
> of the context than is necessary). Of course, in 64-bit mode it's not
> even allowed, all task-management features have been removed... I'm
> saying 32-bit OS, since there's probably some 16-bit OS's out there
that
> do use task-switching, but those OS's are not able to run on current
Xen
> anyways, since Xen in it's current form is very poor at supporting
> segments with base != 0 in protected mode. So far I've only seen a few
> rare reports of anyone actually wishing to run a 16-bit OS...
> 
> --
> Mats
> >
> > Thanks,
> > Vivek
> >
> > _______________________________________________
> > 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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