[libvirt] [PATCH v4 0/5] PCI hostdev partial assignment support

[Cole Robinson]

On 12/16/19 8:36 AM, Daniel Henrique Barboza wrote:
> changes from version 3 [1]:
> - removed last 2 patches that made function 0 of 
> PCI multifunction devices mandatory
> - new patch: news.xml update
> - changed 'since' version to 6.0.0 in patch 4
> - unassigned hostdevs are now getting qemu aliases
> 
> [1] https://www.redhat.com/archives/libvir-list/2019-November/msg01263.html
> 
> Daniel Henrique Barboza (5):
>   Introducing new address type='unassigned' for PCI hostdevs
>   qemu: handle unassigned PCI hostdevs in command line
>   virhostdev.c: check all IOMMU devs in virHostdevPreparePCIDevices
>   formatdomain.html.in: document <address type='unassigned'/>
>   news.xml: add address type='unassigned' entry
> 

Codewise it looks fine now. But I'm looking more closely at patch #3 and
realizing that it can explicitly reject a previously accepted VM config.
And indeed, now that I give it a test with my GPU passthrough setup, it
is rejecting my previosly working config.

error: Requested operation is not valid: All devices of the same IOMMU
group 1 of the PCI device 0000:01:00.0 must belong to domain win10

I've attached the nodedev XML for the three devices with iommuGroup 1.
Only the two nvidia devices are assigned to my VM, but not the PCIe
controller device.

Is the libvirt heuristic missing something? Or is this acting as expected?

I didn't quite gather that this is a change to reject previously
accepted configurations, so I will defer to Laine and Alex as to whether
this should be committed.

- Cole
-------------- next part --------------
<device>
  <name>pci_0000_00_01_0</name>
  <path>/sys/devices/pci0000:00/0000:00:01.0</path>
  <parent>computer</parent>
  <driver>
    <name>pcieport</name>
  </driver>
  <capability type='pci'>
    <class>0x060400</class>
    <domain>0</domain>
    <bus>0</bus>
    <slot>1</slot>
    <function>0</function>
    <product id='0x1901'>Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor PCIe Controller (x16)</product>
    <vendor id='0x8086'>Intel Corporation</vendor>
    <capability type='pci-bridge'/>
    <iommuGroup number='1'>
      <address domain='0x0000' bus='0x00' slot='0x01' function='0x0'/>
      <address domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
      <address domain='0x0000' bus='0x01' slot='0x00' function='0x1'/>
    </iommuGroup>
    <pci-express>
      <link validity='cap' port='2' speed='8' width='16'/>
      <link validity='sta' speed='8' width='16'/>
    </pci-express>
  </capability>
</device>

<device>
  <name>pci_0000_01_00_0</name>
  <path>/sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0</path>
  <parent>pci_0000_00_01_0</parent>
  <driver>
    <name>vfio-pci</name>
  </driver>
  <capability type='pci'>
    <class>0x030000</class>
    <domain>0</domain>
    <bus>1</bus>
    <slot>0</slot>
    <function>0</function>
    <product id='0x1c82'>GP107 [GeForce GTX 1050 Ti]</product>
    <vendor id='0x10de'>NVIDIA Corporation</vendor>
    <iommuGroup number='1'>
      <address domain='0x0000' bus='0x00' slot='0x01' function='0x0'/>
      <address domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
      <address domain='0x0000' bus='0x01' slot='0x00' function='0x1'/>
    </iommuGroup>
    <pci-express>
      <link validity='cap' port='0' speed='8' width='16'/>
      <link validity='sta' speed='8' width='16'/>
    </pci-express>
  </capability>
</device>

<device>
  <name>pci_0000_01_00_1</name>
  <path>/sys/devices/pci0000:00/0000:00:01.0/0000:01:00.1</path>
  <parent>pci_0000_00_01_0</parent>
  <driver>
    <name>vfio-pci</name>
  </driver>
  <capability type='pci'>
    <class>0x040300</class>
    <domain>0</domain>
    <bus>1</bus>
    <slot>0</slot>
    <function>1</function>
    <product id='0x0fb9'>GP107GL High Definition Audio Controller</product>
    <vendor id='0x10de'>NVIDIA Corporation</vendor>
    <iommuGroup number='1'>
      <address domain='0x0000' bus='0x00' slot='0x01' function='0x0'/>
      <address domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
      <address domain='0x0000' bus='0x01' slot='0x00' function='0x1'/>
    </iommuGroup>
    <pci-express>
      <link validity='cap' port='0' speed='8' width='16'/>
      <link validity='sta' speed='8' width='16'/>
    </pci-express>
  </capability>
</device>