Re: [patch] i386: remove IOPL check on task switch

[Zachary Amsden]

Chuck Ebbert wrote:
> In-Reply-To: <454B850C.3050402@xxxxxxxxxx>
>
> On Fri, 03 Nov 2006 10:06:04 -0800, Zachary Amsden wrote:
>
>   
> > Chuck Ebbert wrote:
> >     
> > > IOPL is implicitly saved and restored on task switch,
> > > so explicit check is no longer needed.
> > >       
> > Nack.  This is used for paravirt-ops kernels that use IOPL'd userspace.  
> >     
>
> How does that work?  In the stock kernel, anything done by
> the call to set_iopl_mask() (that was removed by the patch)
> will be nullified by the 'popfl' at the end of the switch_to()
> macro.
>   

Who put a popfl back in switch_to?  I took it out some time ago.  It 
should not be there.  The only reason for it was to stop IOPL leaking 
from one process to another from a sleep during a sysenter based system 
call.

Zach
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