Re: [Qemu-devel] [PATCH RFC] hw/pc: set q35 as the default x86 machine

[Eduardo Habkost <ehabkost@redhat.com>]

On Mon, Jun 04, 2018 at 04:38:22AM +0300, Michael S. Tsirkin wrote:
> On Sun, Jun 03, 2018 at 12:27:49PM +0300, Marcel Apfelbaum wrote:
> > Moving to QEMU 3.0 seems like a good opportunity for such a change.
> > 
> > I440FX is really old and does not support modern features like IOMMU.
> > Q35's SATA emulation is faster than pc's IDE, native PCI express hotplug
> > is cleaner than ACPI based one and so on...
> > 
> > Also the libvirt guys added very good support for the Q35 machine (thanks!).
> > 
> > Management software should always specify the machine type and for the
> > current setups, adding '-machine pc' to the command line is not such a
> > big deal.
> > 
> > In time the pc machine will fade out and we will probably stop adding
> > new versions at some point.
> > 
> > Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
> 
> For command line users, I think changing the default isn't nice.
> 
> Yes it's easy to add -machine pc but there's no documentation
> that tells you to do so. Add to that shortcuts like -cdrom
> stop working, hotplug needs extra bridges to work, and one
> can see that while management tool users benefit from q35,
> command line users will suffer.
> 
> Can't we add a tag for management without changing the command line
> default? How about "management-default"? "recommended"? "latest"?

We could add new aliases if they are useful for management
software, but we would need a well-defined use case and set of
requirements+expectations for the new alias.

-- 
Eduardo