Re: [Qemu-devel] [PATCH v2 4/7] scripts/qemu.py: set predefined machine type based on arch

[Eduardo Habkost]

On Wed, Oct 10, 2018 at 08:35:38AM -0400, Cleber Rosa wrote:
> 
> 
> On 10/10/18 7:00 AM, Philippe Mathieu-Daudé wrote:
> > On 10/10/2018 01:26, Cleber Rosa wrote:
> >> Some targets require a machine type to be set, as there's no default
> >> (aarch64 is one example).  To give a consistent interface to users of
> >> this API, this changes set_machine() so that a predefined default can
> >> be used, if one is not given.  The approach used is exactly the same
> >> with the console device type.
> >>
> >> Also, even when there's a default machine type, for some purposes,
> >> testing included, it's better if outside code is explicit about the
> >> machine type, instead of relying on whatever is set internally.
> >>
> >> Signed-off-by: Cleber Rosa <address@hidden>
> >> ---
> >>  scripts/qemu.py | 22 +++++++++++++++++++++-
> >>  1 file changed, 21 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/scripts/qemu.py b/scripts/qemu.py
> >> index d9e24a0c1a..fca9b76990 100644
> >> --- a/scripts/qemu.py
> >> +++ b/scripts/qemu.py
> >> @@ -36,6 +36,15 @@ CONSOLE_DEV_TYPES = {
> >>      r'^s390-ccw-virtio.*': 'sclpconsole',
> >>      }
> >>  
> >> +#: Maps archictures to the preferred machine type
> >> +MACHINE_TYPES = {
> >> +    r'^aarch64$': 'virt',
> >> +    r'^ppc$': 'g3beige',
> >> +    r'^ppc64$': 'pseries',
> >> +    r'^s390x$': 's390-ccw-virtio',
> >> +    r'^x86_64$': 'q35',
> > 
> > Why choose Q35 rather than PC (the default)?
> > 
> > I was wondering about how to generate variants/machines.json but this is
> > definitively something we want to do via a QMP query.
> > 
> > Eduardo what do you think?
> > 
> 
> It was motivated by Eduardo's initiative to make q35 the default "across
> the board".  He can confirm and give more details.

Making Q35 the default on applications using QEMU and libvirt is
something I'd like to happen.  But I think the simplest way to do
that is to change the QEMU default.  This way you won't need this
table on qemu.py: you can just use the default provided by QEMU.

-- 
Eduardo