Re: [PATCH 4/4] Fix task switching.

[Gleb Natapov <gleb@redhat.com>]

On Mon, Mar 30, 2009 at 06:35:05PM +0200, Jan Kiszka wrote:
> Gleb Natapov wrote:
> > On Mon, Mar 30, 2009 at 06:04:45PM +0200, Jan Kiszka wrote:
> >> Gleb Natapov wrote:
> >>> The patch fixes two problems with task switching.
> >>> 1. Back link is written to a wrong TSS.
> >>> 2. Instruction emulation is not needed if the reason for task switch
> >>>    is a task gate in IDT and access to it is caused by an external even.
> >>>
> >>> 2 is currently solved only for VMX since there is not reliable way to
> >>> skip an instruction in SVM. We should emulate it instead.
> >> Does this series fix all issues Bernhard, Thomas and Julian stumbled over?
> >>
> > Haven't tried. I wrote my own tests for task switching. How can I check it?
> > 
> 
> There is a test case attached to Julian's sourceforge-reported bug:
> 
> https://sourceforge.net/tracker/?func=detail&atid=893831&aid=2681442&group_id=180599
> 
I'll try that.

> And I guess Thomas or Bernhard will be happy to give it a try, too... :)
> 
> There was one issue, the IRQ injection bug [1] which was related to IRQ
> tasks IIRC. Thomas and I finally suspected after a private chat that
> there is actually a different reason behind it, something like
> interrupt.pending should be cleared when the injection took place via an
> (emulated) task switch. Any news on this, Thomas?
> 
If this is the case then the patch series should fix it.

> Jan
> 
> [1] http://permalink.gmane.org/gmane.comp.emulators.kvm.devel/29288
> 


--
			Gleb.