Re: [PATCH 05/22] hw/arm: Select VIRTIO_NET for virt machine

[Fabiano Rosas]

Paolo Bonzini <pbonzini@redhat.com> writes:

> On 5/3/23 20:32, Peter Maydell wrote:
>> Do we really want to build a QEMU that then barfs unless
>> you pass -nodefaults, though ? That doesn't seem very useful.
>> Something somewhere ought to be saying "if you want the
>> virt board then you almost certainly want these".
>
> Well, the point is that --without-default-devices is intended to be for 
> people that write their device config by hand.
>

It's a bit hard to maintain the original intention with just
documentation. Couldn't we require that --without-default-devices always
be accompanied by --with-devices? And more to the point of Peter's
question, couldn't we just leave the defaults off unconditionally when
--without-default-devices is passed without --with-devices?

The coupling of -nodefaults with --without-default-devices is a bit
redundant. If we're choosing to not build some devices, then the QEMU
binary should already know that.

Just to be clear, -nodefaults by itself still makes sense because we can
have a simple command line for those using QEMU directly while allowing
the management layer to fine tune the devices.

In the long run, I think we need to add some configure option that gives
us pure allnoconfig so we can have that in the CI and catch these CONFIG
issues before merging. There's no reason to merge a new CONFIG if it
will then be impossible to turn it off.