Re: arm: kvm-selftest

Christoffer Dall
2013-07-31T22:36:57Z

On Wed, Jul 31, 2013 at 06:21:37PM -0400, Andrew Jones wrote:
> Hi Christoffer,
>
> I'm just confirming that I found the right repo/branch for the
> most recent kvmarm unit tests. I'm looking at
>
> github.com/virtualopensystems/linux-kvm-arm kvm-selftest
>
> with last commit
>
> commit b5aec35ee58c6b2d726a3e2fb56ec0e6e89976e0
> Author: Christoffer Dall <cdall@cs.columbia.edu>
> Date: Fri Feb 15 18:37:24 2013 -0500
>
> WIP: These settings are useful for some more profiling
>
> This really needs to be cleaned up and stuff, but the whole
> testing here has bit-rotted and should be picked up by someone.
>
> I know....
>
> Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>
>
> If this is the most recent branch, then I guess I'll volunteer
> myself to be the someone to pick it up and see about integrating
> it into kvm-unit-tests.
>
Hi Drew,

Yes, this is the right repo and the latest commit. You may in fact
benefit from looking at a slightly earlier state of the repo which may
be a bit more clean. There may also be some newer commits in some
*-selftest*-named branches in https://github.com/columbia/linux-kvm-arm.
At least, at some point I added a test that measures IPI cost similarly
to what was done on x86.

Note that the simple VMEXIT count probably doesn't work out-of-the-box,
because reading the cycle counter on ARM requires access to the PMU
registers, which are current trapped and RAZ. I haven't looked closely
at the provisions in the ARM ARM and the TRMs to see if there's some way
we can allow the guest access to these. Otherwise a PV interface may be
necessary. Will Deacon can probably help us answer these questions.

-Christoffer