[vfio-users] Cannot get vfio-pci to work

[Alex Williamson]

[cc +vfio-users]

On Thu, 16 Aug 2018 19:50:04 +0200
Jes Urup <jes at urup.me> wrote:

> I still get the same error.
> But i managed to get this from dmesg:
> https://paste.pound-python.org/show/lZ7ZsSrZn7pmfekxI6hU/
> Could it be bacause of grsec/pax ?

Potentially, I don't have any experience with either of those.  Can
they be disabled for testing?  Looking at the QEMU code, the "no such
host device" is well before you'd get the permission denied error I
mention below, this is simply trying to stat the
directory /sys/bus/pci/devices/0000:04:00.0.  So probably likely that
you're running in a security environment that isn't letting QEMU do
what it needs to do for device assignment.  Thanks,

Alex

> 2018-08-16 19:05 GMT+02:00 Alex Williamson <alex.williamson at redhat.com>:
> 
> > [cc +vfio-users]
> >
> > On Thu, 16 Aug 2018 18:39:18 +0200
> > Jes Urup <jes at urup.me> wrote:
> >  
> > > Okay, i thought that i should add a network card to the vm and select the
> > > physical nic.
> > > So i now tried to add the physical nic from "PCI Host Device", but i then
> > > get this error when i try to start it: 0000:04:00.0: no such host device:
> > > Permission denied.
> > > Hope you can help with that error or guide me to where i can get help  
> > with  
> > > that.
> > > And thanks for your quick replies!  
> >
> > The board is sufficiently old that perhaps the processor is missing or
> > has broken and disabled interrupt remapping, in which case dmesg would
> > be telling you:
> >
> >         No interrupt remapping support.  Use the module param
> >         "allow_unsafe_interrupts" to enable VFIO IOMMU support on this
> >         platform
> >
> > This puts your system at risk of a malicious guest trying to exploit
> > interrupts via DMA.  If you opt-in to this risk, then update your
> > modprobe.d with:
> >
> > options vfio_iommu_type1 allow_unsafe_interrupts=1
> >
> > Thanks,
> > Alex
> >  
> 
> 
>