WiFi card PCI-passthrough assistance

Software & Operating Systems Linux
,
1

I’m trying to pass through a WiFi card to a KVM-based host as-follows in the template:

    <hostdev mode='subsystem' type='pci' managed='yes'>
      <source>
        <address domain='0x0000' bus='0x00' slot='0x08' function='0x0'/>
      </source>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
    </hostdev>

Here’s the lspci -k output for this device:

08:00.0 Network controller: Qualcomm Atheros AR93xx Wireless Network Adapter (rev 01)
        Subsystem: Qualcomm Atheros AR93xx Wireless Network Adapter
        Kernel driver in use: vfio-pci
        Kernel modules: ath9k

And the group information on my physical host:

$ find /sys/kernel/iommu_groups/ -type l
/sys/kernel/iommu_groups/7/devices/0000:00:18.3
/sys/kernel/iommu_groups/7/devices/0000:00:18.1
/sys/kernel/iommu_groups/7/devices/0000:00:18.6
/sys/kernel/iommu_groups/7/devices/0000:00:18.4
/sys/kernel/iommu_groups/7/devices/0000:00:18.2
/sys/kernel/iommu_groups/7/devices/0000:00:18.0
/sys/kernel/iommu_groups/7/devices/0000:00:18.7
/sys/kernel/iommu_groups/7/devices/0000:00:18.5
/sys/kernel/iommu_groups/5/devices/0000:00:08.0
/sys/kernel/iommu_groups/5/devices/0000:12:00.2
/sys/kernel/iommu_groups/5/devices/0000:12:00.0
/sys/kernel/iommu_groups/5/devices/0000:00:08.1
/sys/kernel/iommu_groups/5/devices/0000:12:00.3
/sys/kernel/iommu_groups/3/devices/0000:00:04.0
/sys/kernel/iommu_groups/1/devices/0000:00:02.0
/sys/kernel/iommu_groups/6/devices/0000:00:14.3
/sys/kernel/iommu_groups/6/devices/0000:00:14.0
/sys/kernel/iommu_groups/4/devices/0000:00:07.0
/sys/kernel/iommu_groups/4/devices/0000:11:00.2
/sys/kernel/iommu_groups/4/devices/0000:11:00.0
/sys/kernel/iommu_groups/4/devices/0000:00:07.1
/sys/kernel/iommu_groups/4/devices/0000:11:00.3
/sys/kernel/iommu_groups/2/devices/0000:00:03.1
/sys/kernel/iommu_groups/2/devices/0000:0a:00.2
/sys/kernel/iommu_groups/2/devices/0000:0a:00.0
/sys/kernel/iommu_groups/2/devices/0000:00:03.0
/sys/kernel/iommu_groups/2/devices/0000:0a:00.3
/sys/kernel/iommu_groups/2/devices/0000:0a:00.1
/sys/kernel/iommu_groups/0/devices/0000:03:00.0
/sys/kernel/iommu_groups/0/devices/0000:04:06.0
/sys/kernel/iommu_groups/0/devices/0000:09:00.0
/sys/kernel/iommu_groups/0/devices/0000:00:01.0
/sys/kernel/iommu_groups/0/devices/0000:08:00.0 < My card
/sys/kernel/iommu_groups/0/devices/0000:01:00.0
/sys/kernel/iommu_groups/0/devices/0000:09:00.3
/sys/kernel/iommu_groups/0/devices/0000:03:00.1
/sys/kernel/iommu_groups/0/devices/0000:09:00.1
/sys/kernel/iommu_groups/0/devices/0000:00:01.3
/sys/kernel/iommu_groups/0/devices/0000:04:01.0
/sys/kernel/iommu_groups/0/devices/0000:00:01.1
/sys/kernel/iommu_groups/0/devices/0000:04:04.0
/sys/kernel/iommu_groups/0/devices/0000:05:00.0
/sys/kernel/iommu_groups/0/devices/0000:04:07.0
/sys/kernel/iommu_groups/0/devices/0000:04:00.0
/sys/kernel/iommu_groups/0/devices/0000:03:00.2
/sys/kernel/iommu_groups/0/devices/0000:09:00.2

When I try to start the domain:

$ virsh start home-assistant
error: Failed to start domain home-assistant
error: internal error: qemu unexpectedly closed the monitor: 2019-11-19T18:50:24.521776Z qemu-system-x86_64: warning: host doesn't support requested feature: CPUID.01H:ECX.vmx [bit 5]
2019-11-19T18:50:24.533638Z qemu-system-x86_64: -device vfio-pci,host=00:08.0,id=hostdev0,bus=pci.0,addr=0x7: vfio error: 0000:00:08.0: group 5 is not viable
Please ensure all devices within the iommu_group are bound to their vfio bus driver.

It seems this card is a member of IOMMU group 0? Is there a way to change this?

2

There’s various kernel parameters (and the ACS patch) that affect iommu groups, but they have side effects.

Might be easier to grab a $10 USB WiFi adapter, and pass it through to your guest.

1 Like
3

Not a bad suggestion at all, I may actually have one laying around (perhaps plugged into an old Pi) - thanks!

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