Re: [PATCH RESEND v7 9/9] tests/qtest: Fix tests when no KVM or TCG are present

[Fabiano Rosas <farosas@suse.de>]

Juan Quintela <quintela@redhat.com> writes:

> Fabiano Rosas <farosas@suse.de> wrote:
>> It is possible to have a build with both TCG and KVM disabled due to
>> Xen requiring the i386 and x86_64 binaries to be present in an aarch64
>> host.
>
> Ouch.
>
> Just curious: why are they needed?
>

From https://wiki.xenproject.org/wiki/QEMU_Upstream:

  Why is qemu-system-i386 used even on x86_64 and even non-x86?
  
  QEMU in a Xen system only provides device model (DM) emulation and not
  any CPU instruction emulation, so the nominal arch doesn't actually
  matter and Xen builds i386 everywhere as a basically arbitrary choice.
  
  It happens that the Xen DM part of QEMU is quite closely tied to the x86
  scaffolding for various historical reasons, so we end up using
  qemu-system-i386 even e.g. on ARM!  There is no practical difference
  between qemu-system-i386 and qemu-system-x86_64, they should be
  interchangeable. However only qemu-system-i386 is regularly tested by
  Xen Project (via osstest).

>>
>> If we build with --disable-tcg on the aarch64 host, we will end-up
>> with a QEMU binary (x86) that does not support TCG nor KVM.
>>
>> Fix tests that crash or hang in the above scenario. Do not include any
>> test cases if TCG and KVM are missing.
>>
>> Signed-off-by: Fabiano Rosas <farosas@suse.de>
>> ---
>> This currently affects Arm, but will also affect x86 after the xenpvh
>> series gets merged. This patch fixes both scenarios.
>
> Reviewed-by: Juan Quintela <quintela@redhat.com>

Thanks!