[dpdk-dev] unable to bind to vfio-pci

[Dybkowski, AdamX]

Hi.

> -----Original Message-----
> From: dev <dev-bounces at dpdk.org> On Behalf Of Sarosh Arif
> Sent: Thursday, 17 September, 2020 08:53
> To: dev at dpdk.org
> Subject: [dpdk-dev] unable to bind to vfio-pci
> 
> I have been trying to bind to vfio-pci using usertools/dpdk-devbind.py but
> am unable to do so. The reason behind this is that I am unable to write in
> /sys/bus/pci/drivers/vfio-pci/bind. Upon searching solutions I tried a couple
> of things such as setting iommu=pt and intel_iommu=on and ensured vt-d is
> enabled.

[Adam] First thing: to check if VT-d is enabled in Linux, you can read MSR 0x3a register. Its lowest bit set will show VT-d works:

(optionally on Ubuntu: apt-get install msr-tools)
modprobe msr
rdmsr 0x3a
3 or 5 -> OK

Other possible way to check for VT-d (IOMMU) working is to view the booting log (dmesg):

dmesg | grep DMAR
"DMAR: IOMMU enabled" -> OK

Both of these should be met in order to use vfio-pci in the next step.

> Along with this I have made sure that the vfio-pci module is correctly loaded.
> I have also tried
> 
> chmod 666 /sys/bus/pci/drivers/vfio-pci/bind
> 
> So that I have permissions to write in this file.
> 
> The error I get when I use usertools/dpdk-devbind.py to bind is this:
> Error: bind failed for 0000:b7:00.1 - Cannot bind to driver vfio-pci
> 
> The details of 0000:b7:00.1 are as follows:
> Ethernet Connection X722 for 10GBASE-T 37d2' if=eno6 drv=i40e
> 
> I have also unbinded The pci bridge to which 0000:b7:00.1 was connected.
> 
> What more can be done to resolve this?
> 
> Regards,
> Sarosh Arif

Adam Dybkowski