Re: [PATCH v6 1/2] libxl: Introduce functions to add and remove USB devices to an HVM guest

[George Dunlap <george.dunlap@eu.citrix.com>]

On 24/04/13 14:51, Ian Campbell wrote:
> On Wed, 2013-04-24 at 14:32 +0100, George Dunlap wrote:
>
>> There's also the translation of "AUTO" protocol into PV or HVM, and
> This made me wonder, how is libxl_device_usb_protocol different from the
> type of the domain? Can you (or is the intention) use PV with an HVM
> domain? I suppose DEVICEMODEL is HVM only?

The intention is to allow HVM guests to use either DEVICEMODEL or PV as 
protocols.

> Is "protocol" really the right word for this? I'd half expect it to mean
> USB 1.0 vs 2.0 vs 3.0. For NICS we call this Enum libxl_nic_type. FWIW

But we're already using 'type' for the device type. :-)

I think for nics it makes sense to call it a 'type', as for NICs we 
refer to the *emulated device* as a NIC, or the PV device as a NIC, 
which is then (virtually) plugged into a bridge somewhere.  But in this 
case I don't think it makes sense, as it's the actual host device you 
care about, and the way the guest talks to it is either via PV or qemu.  
"Protocol" may not be the very best option, but at least it gives you 
the idea of a conduit.

  -George