[ovirt-devel] SR-IOV feature

[Itamar Heim]

On 10/05/2014 07:02 AM, Alona Kaplan wrote:
> Hi all,
>
> Currently SR-IOV in oVirt is only supported using vdsm-hook [1].
> This feature will add SR-IOV support to oVirt management system (including migration).
>
> You are more than welcome to review the feature page-
> http://www.ovirt.org/Feature/SR-IOV
>
>
> Thanks,
> Alona.
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>

Glad to see this.

some questions:

> Note: this feature is about exposing a virtualized (or VirtIO) vNic to the guest, and not about exposing the PCI device to it. This restriction is necessary for migration to be supported.

did not understand this sentence - are you hinting to macvtap?

> add/edit profile

so i gather the implementation is at profile level, which is at logical 
network level?
how does this work exactly? can this logical network be vlan tagged or 
must be native? if vlan tagged who does the tagging for the passthrough 
device? (I see later on vf_vlan is one of the parameters to vdsm, just 
wondering how the mapping can be at host level if this is a passthrough 
device)?
is this because the use of virtio (macvtap)?
wouldn't it be better to support both macvtap and passthrough and just 
flag the VM as non migratable in that case?

also (and doesn't have to be in first phase) what happens if i ran out 
of hosts with sr-iov (or they failed) - can i fail back to non 
pcipassthrough profile for backup (policy question at vm level if more 
important to have sr-iov or more important it will run even without it 
since it provides a critical service, with a [scheduling] preference to 
run on sr-iov?
(oh, i see this is in the "futures" section already.


> management, display and migration properties are not relevant for the VFs configuration

just wondering - any technical reason we can't put the management on a 
VF (not saying its a priority to do so)?

> sr-iov host nic management - num of VFs

I assume this is for admin to define a policy on how many VFs to use, 
based on the max as reported by getVdsCaps. worth stating that for clarity.

>  User Experience - Setup networks - Option 1

in the last picture ("Edit VFs networks and labels") - why are there 
labels here together with the networks (if labels appear at the PF level 
in the first dialog)?

iiuc, the option 2 is re-using the setup networks, where the PF will 
just be another physical interface, and networks or labels edited just 
like for regular network interfaces?
(not sure where you are on this, but it sounds more straight 
forward/similar to existing concepts iiuc).

Question: any issues with hot plug/unplug or just expected to work normally?

Thanks,
    Itamar