Re: [Qemu-devel] Re: virtio-serial: An interface for host-guest communication

[Anthony Liguori <anthony@codemonkey.ws>]

Gerd Hoffmann wrote:
> Ok, lets rip out the in-kernel ioapic code then.  It can (and has 
> been) done in userspace.

The justification is performance although that's not really true anymore 
post TPR optimization.

But FWIW, I opposed both the in-kernel apic and the in-kernel pit when 
they were introduced.  If nothing else, I'm at least consistent :-)

> The daemon increases the possibility of userspace bugs.

How?

> Seriously:  Attaching a name tag to virtio-serial devices and have 
> them exposed via sysfs is probably *much* less code than a vmchannel 
> daemon.

I strongly doubt that.

>> If we really want
>> vmchannel to be used by application developers, then we really need a
>> libvmchannel.
>
> We need a sane solution developed and merged and not a new idea each 
> week.

There is nothing sane about vmchannel.  It's just an attempt to bypass 
QEMU which is going to introduce all sorts of complexities wrt 
migration, guest compatibility, etc.

However, as I've mentioned repeatedly, the reason I won't merge 
virtio-serial is that it duplicates functionality with virtio-console.  
If the two are converged, I'm happy to merge it.  I'm not opposed to 
having more functionality.

I think it's the wrong solution for the use-case, and I always have, but 
that's independent of my willingness to merge it.

Regards,

Anthony Liguori