Re: Intel QAT 8970 accel card on ARM Ampere Server

[Patrick Robb <probb@iol.unh.edu>]

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On Mon, Oct 9, 2023 at 11:56 PM Dharmik Jayesh Thakkar <
DharmikJayesh.Thakkar@arm.com> wrote:

> Hi Patrick,
>
>
>
> Can you provide the grub settings? Is iommu.passthrough=1 included?
>

Sure. I'm not sure if you just wanted the kernel cmdline options or the
whole grub config, but I assume you just meant kernel cmdline. Let me know
if you meant more.

GRUB_CMDLINE_LINUX_DEFAULT="default_hugepagesz=1G hugepagesz=1G
hugepages=32 iommu=pt intel_iommu=on isolcpus=39-79 nohz_full=39-79
rcu_nocbs=39-79 processor.max_cstate=1 intel_pstate=disable
console=ttyS0,115200 console=tty0"

But, iommu.passthrough=1 is not included, so I can add that if we need to.
Do you know that this won't have any bad implications for the (intel,
nvidia, broadcom) NICs which we test on this server?


>
>
> Also, is qat_c62xvf loaded as well?
>
qat_c62xvf is built in to the kernel also.


>
>

>
> Finally, a few guidelines on the vfio driver:
>
> At times, we need to configure the vfio driver.
>
> On kernel vers. 5.9+ we need to load the vfio-pci driver with the
> additional parameter *disable_denylist=1*
>
> Unload the vfio-pci driver if it is already loaded so that we can reload
> it with the correct parameters :
> *sudo modprobe -r vfio_iommu_type1; sudo modprobe -r vfio_pci; sudo
> modprobe -r vfio_virqfd; sudo modprobe -r vfio*
>
> If you can't unload the vfio driver because it's been built into the
> kernel, you'll have to find another way to change VFIO parameters, or to
> rebuild your kernel with VFIO_PCI set as a module. Failing to do that, you
> might encounter issues later on when you try to bind the VFs to VFIO.
>
> Load the vfio-pci driver and bind it to QAT VFs device ids:
> *sudo modprobe vfio-pci disable_denylist=1 enable_sriov=1
> vfio-pci.ids=8086:37c9*
>
> Enable no-iommu-mode:
> *echo "1" | sudo tee
> /sys/module/vfio/parameters/enable_unsafe_noiommu_mode*
>
>  /sys/module/vfio/parameter is missing ?
>
> If /sys/module/vfio/parameters does not exist, you might be missing the
> kernel module VFIO_NOIOMMU
>
>
>
> *Automatically set VFIO params on boot*
>
> It's possible to set these parameters automatically on boot by creating a
> */etc/modprobe.d/vfio-pci.conf *file with the parameters :
> *cat /etc/modprobe.d/vfio-pci.conf*
> *options vfio enable_unsafe_noiommu_mode=1*
> *options vfio-pci disable_denylist=1 enable_sriov=1 vfio-pci.ids=8086:37c9*
>
>
>
> We haven’t encountered this issue in the past, so just making sure the
> configuration is correct. I don’t think having the driver static/loadable
> should make a difference, I will try with building statically on my setup.
>
>
>
> Thank you!
>
>
> Okay, this should be fine. Like I said, we are also running tests on NICs
on this server. So, in our Jenkinsfiles scripts for running the testing, I
will add a preliminary step only for QAT tests which runs:
*sudo modprobe -r vfio_iommu_type1; sudo modprobe -r vfio_pci; sudo
modprobe -r vfio_virqfd; sudo modprobe -r vfio*
*sudo modprobe vfio-pci disable_denylist=1 enable_sriov=1
vfio-pci.ids=8086:37c9*
*echo "1" | sudo tee /sys/module/vfio/parameters/enable_unsafe_noiommu_mode*
(then run QAT tests)

And if running on NICs, have a preliminary step which runs
*sudo modprobe -r vfio_iommu_type1; sudo modprobe -r vfio_pci; sudo
modprobe -r vfio_virqfd; sudo modprobe -r vfio*
*sudo modprobe vfio*

David does this also sound reasonable to you, per your comment about
isolating this setting to QAT card testing?

Dharmik if this all sounds okay and you can confirm the iommu.passthrough
change is fine, I will proceed. Thank you for providing the assistance.

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