[libvirt] [RFC] Add iommu group commands

[Li Zhang]

Hi,

Currently, we need to assign the iommu group to guests manually.
It needs to know the groups information.
I think we can add some iommu group commands to provide users
groups information.

I can think of these commands as the following:

#virsh group-list  <--active>
   * list all the groups in the system with VFIO
   * --active: list the active groups which have been used by guests.

#virsh group-devs  <groupnum>
   * list the devices in the group.
   *If groupnum is not specified, it will list every groups' devices.

# virsh group-dumpxml <groupnum>
   * dump the group's xml configuration.
     dumxml file for example:
     <iommuGroup number='1'>
       <address domain='0x0001' bus='0x40' slot='0x00' function='0x0'/>
       <address domain='0x0001' bus='0x40' slot='0x00' function='0x1'/>
     </iommuGroup>

This information can also be got by #nodedev-dumpxml <device>
But users still can't know all the groups and the devices in the group 
directly.

Any suggestions?

I want to add iommu symbol to the commands name, but it's too long.


Thanks
Li Zhang