Re: Redesign of QEMU startup & initial configuration

[Paolo Bonzini]

On 12/13/21 19:53, Daniel P. Berrangé wrote:
> > Adding vhost-user backends and helper processes means one of two things:
> > either you are not going to support hotplug, or you are going to redo
> > libvirtd with a QMP-based RPC.
>
> If it were possible to keep auto-spawning of helpers at the high level
> that feels cleaner, so that the low level only has to worry about a
> single way of doing things. If that is too hard for hotplug though,
> so be it, leave auto-spawning in the low level.

OTOH, autospawning in the low-level saves hotplugging but it kills 
sandboxing; the seccomp filter prohibits forking.

The libvirt model is the only good one once you care about separation of 
privilege.  The idea of moving large parts of libvirt's domain driver 
into a new QEMU-level binary was floated around in the past by Andrea 
Bolognani, and I don't dislike it; but I don't believe anybody will have 
time to actually realize it, much less to bring it to feature parity.

Paolo