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

[Jan Kiszka <jan.kiszka@web.de>]

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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

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?

Jan

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


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