Re: [Qemu-devel] change x86 default machine type to Q35?

[Thomas Huth]

 Hi,

On 05.07.2017 08:57, Chao Peng wrote:
> 
> Q35 has been in QEMU for quite a while. Compared to the current default
> i440FX, Q35 is probably not that mature and not widely used, however in
> some case, Q35 has advantages, for example, in supporting new features.
> For instance, we have some features require PCI-e support which is only
> available on Q35 and some others need it for EFI support. It is of
> course not necessary to change it as the default but if more and more
> features have dependencies on Q35 because of requiring much more modern
> features then I think it may be worth to do so. In such case we can have
> more people to use it and find problems we may know or not know.

Yes, IMHO at one point in time, we should switch the default machine
type to q35. The i440FX is really quite old...

> There are certainly some drawbacks:
> -        Compatibility: current code or script may need adjustment

That might be a real concern ... so I think a good point in time to
switch to the q35 machine type would be when we switch to the next major
version number of QEMU, i.e. when we switch to version 3.0. If the users
see a new major version number, they might be more willing to accept
such major changes (yeah, I know, we've discussed in the past that
version numbers are just numbers ... but still, there is some kind of
psychological aspect to this, too, I think)

> -        Quality: we may suffer more bugs on Q35

I hope that the q35 machine will become mature soon once it has been
made the default machine.

 Thomas