[libvirt] [Engine-devel] Supporting native USB in oVirt

[Oved Ourfalli]

Rephrasing my question a bit, to make it more clear.
We are now working on adding the support for native USB devices on oVirt.

This requires adding composite PCI devices to a VM (details below), requiring specific set of restrictions on the addresses of these devices, and the connections between them.
Is it possible to add such a composite set of devices to a VM while using automatic address assignment, as we do today on the other PCI devices?

More details below...

Thank you,
Oved

----- Original Message -----
> From: "Hans de Goede" <hdegoede at redhat.com>
> To: "Oved Ourfalli" <ovedo at redhat.com>
> Cc: "engine-devel" <engine-devel at ovirt.org>, libvirt-list at redhat.com
> Sent: Thursday, May 10, 2012 11:32:15 AM
> Subject: Re: [Engine-devel] [libvirt]Supporting native USB in oVirt
> 
> Hi Oved,
> 
> I think it will help if you can re-formulate things into
> a question for the libvirt developers. e.g. something along
> the lines of: "is it possible to add composite PCI devices
> to a vm while using automatic address assignment" ?
> 
> Regards,
> 
> Hans
> 
> 
> On 05/09/2012 03:46 PM, Oved Ourfalli wrote:
> > Hey,
> >
> > We are now working on adding the support for native USB devices on
> > oVirt, and we have some difficulties.
> > Please see the details/discussion below.
> >
> > Thank you for your help,
> > Oved
> >
> > ----- Forwarded Message -----
> > From: "Itamar Heim"<iheim at redhat.com>
> > To: "Michal Privoznik"<mprivozn at redhat.com>
> > Cc: "Oved Ourfalli"<ovedo at redhat.com>, "Dave
> > Allan"<dallan at redhat.com>, "Jiri Denemark"<jdenemar at redhat.com>,
> > "Igor Lvovsky"<ilvovsky at redhat.com>, "Eli
> > Mesika"<emesika at redhat.com>, "Hans de Goede"<hdegoede at redhat.com>,
> > "Dan Kenigsberg"<danken at redhat.com>, "Andrew
> > Cathrow"<acathrow at redhat.com>
> > Sent: Wednesday, May 9, 2012 1:18:40 PM
> > Subject: Re: Supporting native USB in oVirt
> >
> > On 05/09/2012 01:12 PM, Michal Privoznik wrote:
> >> On 08.05.2012 09:19, Oved Ourfalli wrote:
> >>> Hi,
> >>>
> >>> We are now working on adding the support for native USB devices
> >>> on oVirt.
> >>> As far as we understand, in order to use it we need to pass the
> >>> following devices with the following restrictions (according to
> >>> the EHCI spec):
> >>> 1. EHCI USB controller - with the highest function number, #7.
> >>>
> >>> devices='{type:controller,device:usb,model:ich9-ehci1,address:{type:pci,domain:0x0000,bus:0x00,slot:0x04,function:0x7}}'
> >>>
> >>> 2. 3 UHCI USB controllers, on the same bus and PCI slot as the
> >>> EHCI controller. Set the multifunction bit to on, on the
> >>> controller with function #0.
> >>>
> >>> devices='{type:controller,device:usb,model:ich9-uhci1,master:{startport:0},address:{type:pci,domain:0x0000,bus:0x00,slot:0x04,function:0x0,multifunction:on}}'
> >>> devices='{type:controller,device:usb,model:ich9-uhci2,master:{startport:2},address:{type:pci,domain:0x0000,bus:0x00,slot:0x04,function:0x1}}'
> >>> devices='{type:controller,device:usb,model:ich9-uhci3,master:{startport:4},address:{type:pci,domain:0x0000,bus:0x00,slot:0x04,function:0x2}}'
> >>>
> >>> 3. USB redirect devices (according to the needed number of USB
> >>> slots, maximum 6) on the same bus, each one having a different
> >>> port.
> >>>
> >>> devices='{type:redir,device:spicevmc,bus:usb,address:{type:usb,bus:0,port:1}}'
> >>> devices='{type:redir,device:spicevmc,bus:usb,address:{type:usb,bus:0,port:2}}'
> >>> devices='{type:redir,device:spicevmc,bus:usb,address:{type:usb,bus:0,port:3}}'
> >>> devices='{type:redir,device:spicevmc,bus:usb,address:{type:usb,bus:0,port:4}}'
> >>> devices='{type:redir,device:spicevmc,bus:usb,address:{type:usb,bus:0,port:5}}'
> >>> devices='{type:redir,device:spicevmc,bus:usb,address:{type:usb,bus:0,port:6}}'
> >>>
> >>> 4. If we want more than 6 USB slots, we need to have 2 EHCI
> >>> controllers, and 6 UHCI controllers, that are consistent with
> >>> the restrictions above, on different bus.
> >>> (we need them to be on different bus, since the connection
> >>> between the redirect devices and the controllers is the bus).
> >>>
> >>> According to Hans (cc-ed), if we let libvirt pick its own
> >>> addresses, it will put each controller of the composite USB
> >>> controller device on its own pci slot, which is a violation of
> >>> the EHCI spec.
> >>
> >>>
> >>> The problem is that the oVirt engine is not aware of addresses.
> >>> They aren't managed by it.
> >>> They are chosen automatically by libvirt, returned to the engine,
> >>> and they saved in the engine database in order to provide the
> >>> ability to retain the same PCI addresses after VM restart.
> >>>
> >>> So, in order to support the EHCI spec, oVirt will have to be
> >>> aware of addresses, manage them (allocate them, check for
> >>> collisions, update on every libvirt change regarding that,
> >>> etc...). Obviously, it doesn't feel right, and in fact it is
> >>> also not feasible, to manage these addresses in the oVirt
> >>> domain.
> >>>
> >>> Is all the above correct, or are we missing something?
> >>> If so, can you address the issues above, and provide the ability
> >>> to manage these devices in libvirt?
> >>
> >> Let's have this conversation upstream (libvirt-list at redhat.com).
> >> Many
> >> developers are there so if there's anything libvirt can do, we
> >> should
> >> agree on concept there.
> >
> > --
> > libvir-list mailing list
> > libvir-list at redhat.com
> > https://www.redhat.com/mailman/listinfo/libvir-list
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