[vfio-users] VM Won't boot with 2 PCIE 1x cards installed.

[Laszlo Ersek]

On 09/09/16 03:21, Brett Peckinpaugh wrote:
> I am running Arch Linux, ACS patch on a Skylake system.  I have some
> audio pop and crackle so wanted to try passing a sound card instead of
> routing the audio from my monitor to my speakers.  I purchased an Asus
> Xonar PCI DGX.  Chip is CMI8788.  I can boot the host with it, or my USB
> card.  But not both.  Error I get is as follows.
> 
> Error starting domain: internal error: qemu unexpectedly closed the
> monitor: 2016-09-09T01:17:41.729237Z qemu-system-x86_64: -device
> vfio-pci,host=0e:00.0,id=hostdev3,bus=pci.0,addr=0x6: vfio: Error:
> Failed to setup INTx fd: Device or resource busy
> 2016-09-09T01:17:41.729854Z qemu-system-x86_64: -device
> vfio-pci,host=0e:00.0,id=hostdev3,bus=pci.0,addr=0x6: Device
> initialization failed

http://vfio.blogspot.hu/2014/09/vfio-interrupts-and-how-to-coax-windows.html

    VFIO does also have support for non-PCI-2.3 compliant devices, but
    it requires a much more restricted configuration.  We still need to
    identify when the assigned device is signaling an interrupt, which
    we can only do in a non-device specific way by requiring only a
    single device per interrupt line.  Also when this is the case, we
    can mask the interrupt at the system APIC rather than at the device
    itself.  Therefore we can achieve the same results, but we require
    an exclusive interrupt line for the device, which can often be an
    insurmountable configuration restriction.

    [...]

    If you find that your device supports MSI but it's not being
    enabled, and your guest is Windows, you can follow the steps found
    here to attempt to enable it. [...]

You can also try moving the card(s) to different slots:

    [...] PCI bridges also incorporate a standard swizzle to remap
    interrupt lines between primary and secondary interfaces, so that we
    don't over-use some of the interrupt lines.  Each slot may also have
    different mappings, so INTA on one slot doesn't actually pull the
    same line as INTA on another slot.