On 08/07/19 18:04, Daniel P. Berrangé wrote: > The downside of using the bus daemon is that we have to spawn a new > instance of dbus-daemon for every QEMU VM that's running on the host, > which is yet more memory overhead for each VM & another process to > manage, and yet another thing to go wrong. > > QEMU already has a direct UNIX socket connection to the helper > processes in question. I'd much rather we just had another direct > UNIX socket connection to that helper, using D-Bus peer-to-peer. > The benefit of debugging doesn't feel compelling enough to justify > running an extra daemon for each VM.
Would it be possible to make QEMU the broker? That is, how hard would it be to embed a minimal DBus broker (which only takes care of connecting servers and clients---stuff like launching servers would be completely out of scope)? Would it for example make sense to split the bus handling part of dbus-broker into a library that QEMU could reuse? (And if we plan to do this, should QEMU use sd-bus instead of gdbus?) In QOM that would be something like -object dbus-connection,id=client1,chardev=...,addr=foo # p2p -object dbus-vmstate,connection=client1 # the interface -object dbus-connection,id=client1,addr=foo # via external daemon -object dbus-vmstate,client=client1 # the interface -object dbus-session,id=session1,chardev=... -object dbus-connection,id=client1,session=session1,addr=foo # via internal daemon -object dbus-vmstate,client=client1 # the interface Paolo
