[libvirt-users] Trouble passing PCI device in isolated IOMMU group

[Laine Stump]

On 07/27/2018 11:51 AM, Quincy Wofford wrote:
> I'm attempting PCI-passthrough from host to guest on an HP ProLiant
> 380P, which has an outdated BIOS (2014), but it does support VT-d. I'm
> running CentOS 7, kernel 3.10.0-862.9.1.el7.x86_64.
> 
> I have an Intel 82580 NIC installed with 4 ports. Each of these ports is
> in its own IOMMU group (I enabled SR-IOV at the BIOS, which might be the
> reason they show up separately)
> 
>  After detaching and adding a 'hostdev' device with the appropriate pci
> address, I attempt to start my VM. I get " failed to set iommu for
> container: Operation not permitted". As recommended here
> (http://vfio.blogspot.com/2014/08/vfiovga-faq.html) I parsed dmesg in an
> attempt to find:
> 
> -------------------
> No interrupt remapping support. Use the module param
> "allow_unsafe_interrupts" to enable VFIO IOMMU support on this platform
> -------------------
> ...but nothing similar exists in my logs.
> 
> Since this device is showing up in its own IOMMU group, I assume ACS
> override won't get me any further. In any case, it is not an option for
> me to leave ACS override on. I can turn it on for testing, the server is
> not currently in production.
> 
> Any idea why this could be failing?

If you haven't yet found a solution to this problem, I would recommend
sending your question either to vfio-users at redhat.com, or asking in the
#vfio-users channel on  irc.freenode.net