Re: [PATCH V7 6/7] xl: add usb-assignable-list command

[Juergen Gross <jgross@suse.com>]

On 10/07/2015 04:35 PM, George Dunlap wrote:
> On Wed, Oct 7, 2015 at 3:26 PM, Juergen Gross <jgross@suse.com> wrote:
>> On 10/07/2015 04:05 PM, Ian Campbell wrote:
>>>
>>> On Wed, 2015-10-07 at 15:54 +0200, Juergen Gross wrote:
>>>
>>>> Hmm, technically all unassigned USB-devices are usable from Dom0. So why
>>>> not list them there.
>>>
>>>
>>> I think you'd at least want to distinguish USB devices available to dom0
>>> as
>>> via a PCI host controller from those which are available via pvusb.
>>
>>
>> Yeah, the non-pvusb devices should be listed as "assignable" if they
>> are handled by a driver domain.
>>
>>> This also doesn't quite work when driver domains are in the picture.
>>
>>
>> --host does?
>>
>> TBH: driver domains seem to be a reason to not support the --host
>> option. So the options are --all or no special option. I'm still
>> fine with both.
>
> I think the idea is that --host doesn't pretend to.  But yes, if we
> made it clear which devices were *assigned* to dom0 from another VM,
> and which were *available from* dom0 to be assigned, then actually
> that could be extended at some point in the future to include devices
> available *from* driver domains.
>
> Alternately, perhaps we should just have
> # xl usb-available [domain]

Would work for me.

Wait, wasn't there a similar command suggested? Something like
"xl usb-assignable-list"? ;-)

> Which will tell you the usb devices available to be assigned from that
> domain; or all available usb devices from all driver domains.  And of
> course for the time being it only works on domain 0, but future
> functionality could implement it for driver domains as well.
>
>> BTW: Do Xen concepts allow to assign a USB-device via pvUSB from a
>> driver domain to Dom0?
>
> Sure, why not?

With driver domains the picture is becoming more complicated.

The main question now is: What is the real purpose of "xl usb-list"?
Should it list the devices which are assigned to a domain, or should it
list the devices which are usable by a domain (probably attributed
whether the device is assignable to other domains)?

I think I'll always use the --all option in case this variant will be
chosen.


Juergen