[libvirt] More then one pci device possible with libvirt and pci passthrough?

Mark McLoughlin markmc at redhat.com
Mon Jun 29 16:03:07 UTC 2009


Hi Mirko,

On Sun, 2009-06-28 at 17:46 +0200, Mirko Raasch wrote:
> Hi,
> 
> i want to use more then one pci card in my debian guest.
> 
> But when i start the guest, the log says:
> 
>   libvirtd: 15:44:55.459: warning : pciTrySecondaryBusReset:483 : Other
> devices on bus with 0000:05:01.0, not doing bus reset
> 
> With "/usr/bin/qemu-system-x86_64 -m 512 -name test -hda
> /media/vm/test.img -boot c -vnc :2 -k de -pcidevice host=05:01.0
> -pcidevice host=05:02.0 -pcidevice host=05:03.0" there seems to be no
> problems.

I'm afraid this is purely a limitation with the current code in qemu:

    /* For now, we just refuse to do a secondary bus reset                                                                    
     * if there are other devices/functions behind the bus.                                                                   
     * In future, we could allow it so long as those devices                                                                  
     * are not in use by the host or other guests.                                                                            
     */
    if (pciBusContainsOtherDevices(conn, dev)) {
        VIR_WARN("Other devices on bus with %s, not doing bus reset",
                 dev->name);
        return -1;
    }

We also have a bug tracking this issue:

  https://bugzilla.redhat.com/499678

Fixes welcome! :-)

Cheers,
Mark.





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