This is on Ubuntu 12.04LTS using KVM. The system has a graphics card which is visible to the hypervisor's kernel shown as follows:
# virsh nodedev-dumpxml pci_0000_21_00_0
<device>
<name>pci_0000_21_00_0</name>
<parent>pci_0000_20_02_0</parent>
<driver>
<name>nvidia</name>
</driver>
<capability type='pci'>
<domain>0</domain>
<bus>33</bus>
<slot>0</slot>
<function>0</function>
<product id='0x0a65'>GT218 [GeForce 210]</product>
<vendor id='0x10de'>NVIDIA Corporation</vendor>
<capability type='virt_functions'>
</capability>
</capability>
</device>
There is also a PCI Function #1 which is the audio portion of the card for which I omitted the dumpxml.
In my domain XML, I have the following:
<hostdev mode='subsystem' type='pci' managed='yes'>
<source>
<address domain='0x0000' bus='0x21' slot='0x00' function='0x0'/>
</source>
<address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0' multifunction='on'/>
</hostdev>
<hostdev mode='subsystem' type='pci' managed='yes'>
<source>
<address domain='0x0000' bus='0x21' slot='0x00' function='0x1'/>
</source>
<address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x1'/>
</hostdev>
Without these hostdev tags my guest VM boots up just fine (it is also an Ubuntu 12.04LTS kernel). When I try to start the VM with them I get:
# virsh nodedev-detach pci_0000_21_00_0
Device pci_0000_21_00_0 detached
# virsh nodedev-detach pci_0000_21_00_1
Device pci_0000_21_00_1 detached
# virsh start testv
error: Failed to start domain testv
error: Unable to read from monitor: Connection reset by peer
Can anyone say what is going wrong?
UPDATE: Being somewhat new to KVM I didn't realize there was a log file available. It says this:
Failed to assign device "hostdev0" : Device or resource busy
*** The driver 'pci-stub' is occupying your device 0000:21:00.0.
***
*** You can try the following commands to free it:
***
*** $ echo "10de 0a65" > /sys/bus/pci/drivers/pci-stub/new_id
*** $ echo "0000:21:00.0" > /sys/bus/pci/drivers/pci-stub/unbind
*** $ echo "0000:21:00.0" > /sys/bus/pci/drivers/pci-stub/bind
*** $ echo "10de 0a65" > /sys/bus/pci/drivers/pci-stub/remove_id
***
kvm: -device pci-assign,host=21:00.0,id=hostdev0,configfd=30,bus=pci.0,multifunction=on,addr=0x4: Device 'pci-assign' could not be initialized
2014-12-17 19:15:52.368+0000: shutting down
So apparently the nodedev-detatch command leaves a stub driver active? Are the suggested commands to be run in the hypervisor or the VM?