Re: [Qemu-devel] [PATCH 0/3] build configuration query tool and conditional (qemu-io)test skip

["Daniel P. Berrange" <berrange@redhat.com>]

On Fri, Jul 21, 2017 at 01:33:25PM +0100, Stefan Hajnoczi wrote:
> On Thu, Jul 20, 2017 at 11:47:27PM -0400, Cleber Rosa wrote:
> > This is a follow up to a previous discussion about reported failures when
> > running some qemu-iotests.  Turns out the failures were due to missing
> > libraries, which in turn, reflected on the host build configuration.
> > 
> > This series introduces a tool that can check both host and target level
> > build configurations.  On top of that, it adds a function to to be used
> > on qemu-iotests.  Finally, as an example, it sets a test to be skipped
> > if the required feature is not enable on the host build configuration.
> > 
> > Cleber Rosa (3):
> >   scripts: introduce buildconf.py
> >   qemu-iotests: add _require_feature() function
> >   qemu-iotests: require CONFIG_LINUX_AIO for test 087
> > 
> >  scripts/buildconf.py         | 278 +++++++++++++++++++++++++++++++++++++++++++
> >  tests/qemu-iotests/087       |   1 +
> >  tests/qemu-iotests/check     |   2 +
> >  tests/qemu-iotests/common.rc |   7 ++
> >  4 files changed, 288 insertions(+)
> > 
> 
> It should be possible to run iotests against any
> qemu/qemu-img/qemu-io/qemu-nbd binaries - even if no build root is
> available.

For sake of argument, two options for non-buildroot scenario

 - assume all features are present, so we're no worse than we are today.
 - install config.h (or same data in a structured format) to
   /usr/share/qemu so its available for query

Downside of 2 of course is that other non-iotests apps might start
to depend on it

> How about invoking qemu-img and tools to determine their capabilities?
> 
> At the beginning of ./check, query the qemu/qemu-img/qemu-io/qemu-nbd
> binaries for specific features.  This produces a set of available
> features and tests can say:
> 
>   _supported_feature aio_native
> 
> This feature can be checked by opening an image file:
> 
>   qemu-io --format raw --nocache --native-aio --cmd quit test.img

I think this is useful as a general approach, because there are bound
to be a number of features which are available at compile time, but
cannot actually be used at runtime. eg not every filesystem supports
O_DIRECT, even if we've built support for it.

Regards,
Daniel
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