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

[Quincy Wofford]

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which has an outdated BIOS (2014), but it does support VT-d. I'm running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?

[Laine Stump]

Post by Quincy Wofford
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380P, which has an outdated BIOS (2014), but it does support VT-d. I'm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
-------------------
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-***@redhat.com, or asking in the
#vfio-users channel on irc.freenode.net

[Quincy Wofford]

Thanks for the tip!

Post by Laine Stump

Post by Quincy Wofford
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
-------------------
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
#vfio-users channel on irc.freenode.net