Re: [RFC 0/3] Introduce a new Qemu machine for RISC-V

[Peter Maydell]

On Wed, 18 May 2022 at 09:25, Daniel P. Berrangé <berrange@redhat.com> wrote:
> The fact that RISC-V ecosystem is so young & has relatively few
> users, and even fewer expecting  long term stability, is precisely
> why we should just modify the existing 'virt' machine now rather
> than introducing a new 'virt-pcie'. We can afford to have the
> limited incompatibility in the short term given the small userbase.
> We went through this same exercise with aarch64 virt machine and
> despite the short term disruption, it was a good success IMHO to
> get it switched from MMIO to PCI, instead of having two machines
> in parallel long term.

The aarch64 virt board does still carry around the mmio devices,
though...it's just that we have pci as well now.

Personally I don't think that switching to a new machine type
is likely to help escape from the "bloat" problem, which arises
from two conflicting desires:

 (1) people want this kind of board to be nice and small and
     simple, with a minimal set of devices
 (2) everybody has their own "but this specific one device is
     really important and it should be in the minimal set"
     (watchdog? acpi? ability to power the machine on and off?
     second UART? i2c? etc etc etc)

So either your 'minimal' board is only serving a small subset
of the users who want a minimal board; or else it's not as
minimal as any of them would like; or else it acquires a
growing set of -machine options to turn various devices on
and off...

-- PMM