Re: [kvm-unit-tests PATCH v2 5/5] powerpc: Check lswx in little-endian mode.

[Thomas Huth <thuth@redhat.com>]

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On 22.03.2016 00:56, David Gibson wrote:
> On Mon, 21 Mar 2016 12:33:34 +0100
> Laurent Vivier <lvivier@redhat.com> wrote:
> 
>> For lswx in little-endian mode, an alignment interrupt occurs.
>>
>> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
>> Reviewed-by: Thomas Huth <thuth@redhat.com>
> 
> I'm not entirely clear here; will the test fail if the alignment
> exception doesn't occur in little endian mode?

I think so, yes.

> The general trend in Power has been for less and less things to trigger
> alignment exceptions, so failing to cause an alignment exception
> shouldn't cause a test failure (as long as the unaligned case is
> correctly processed, of course).

According to the PowerISA 2.07, chapter 6.5.8, lswx should always
trigger an alignment exception in little endian mode. So that's
architected behavior and the test should be OK, as far as I can see...
In case this gets changed with a future CPU, I think the test could be
adapted later, too?

 Thomas



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