Re: [PATCH kvm-unit-tests 4/4] x86/taskswitch_vm86: Task switches into/out of VM86

[Kevin Wolf <kwolf@redhat.com>]

Am 23.01.2012 17:42, schrieb Gleb Natapov:
> On Mon, Jan 23, 2012 at 05:32:59PM +0100, Kevin Wolf wrote:
>> Am 23.01.2012 17:22, schrieb Gleb Natapov:
>>> On Mon, Jan 23, 2012 at 05:20:22PM +0100, Kevin Wolf wrote:
>>>> Am 23.01.2012 17:10, schrieb Gleb Natapov:
>>>>> On Mon, Jan 23, 2012 at 05:07:13PM +0100, Kevin Wolf wrote:
>>>>>> This adds a test case that jumps into VM86 by iret-ing to a TSS and back
>>>>>> to Protected Mode using a task gate in the IDT.
>>>>>>
>>>>> Can you add the test case to taskswitch2.c?
>>>>
>>> Running one test to check all aspects of taskswitch emulation.
>>
>> (We all know that top-posting is disliked, but middle-posting looks even
>> crazier!)
>>
> Inserting replies 

Very true!

> at random places is a new cool thing!
> 
>> Does having one test provide any value in and of itself? It's just an
>> implementation detail of the test suite. When testing the KVM patches I
>> ran all three test cases with './run_tests.sh -g task', which is
>> hopefully easy enough.
>>
> I think it does. I do not have to use external script to combine tests
> on the same topic or even remember that such script exists. We do not
> create separate tests to test each instruction emulation either. And I
> usually run qemu not on the same machine I compile it on, so I need
> special tricks to make those test script work. Of course if putting this
> code into existing test file is hard separate test is OK, but is this
> really the case here?

I haven't really checked whether they interfere. I guess I would have to
move the GDT indexes for my manually created TSSes and I would have to
hope that nobody else needs the memory I'm overwriting with the real
mode code (there doesn't seem to be memory management for < 1 MB).

Should taskswitch.c and taskswitch2.c be merged as well then? Or is
there a reason why they must stay separate? One file or three files
makes sense to me for three tests, but two not so much.

Kevin