ath11k and vfio-pci support

[James Prestwood]

Hi,

On 1/11/24 6:04 PM, Baochen Qiang wrote:
>
>
> On 1/11/2024 9:38 PM, James Prestwood wrote:
>>
>> On 1/11/24 5:11 AM, Kalle Valo wrote:
>>> James Prestwood <prestwoj at gmail.com> writes:
>>>
>>>> Hi Kalle, Baochen,
>>>>
>>>> On 1/11/24 12:16 AM, Kalle Valo wrote:
>>>>> Baochen Qiang <quic_bqiang at quicinc.com> writes:
>>>>>
>>>>>> On 1/10/2024 10:55 PM, James Prestwood wrote:
>>>>>>> Hi Kalle,
>>>>>>> On 1/10/24 5:49 AM, Kalle Valo wrote:
>>>>>>>> James Prestwood <prestwoj at gmail.com> writes:
>>>>>>>>
>>>>>>>>>> But I have also no idea what is causing this, I guess we are 
>>>>>>>>>> doing
>>>>>>>>>> something wrong with the PCI communication? That reminds me, 
>>>>>>>>>> you could
>>>>>>>>>> try this in case that helps:
>>>>>>>>>>
>>>>>>>>>> https://patchwork.kernel.org/project/linux-wireless/patch/20231212031914.47339-1-imguzh@gmail.com/ 
>>>>>>>>>>
>>>>>>>>> Heh, I saw this pop up a day after I sent this and was 
>>>>>>>>> wondering. Is
>>>>>>>>> this something I'd need on the host kernel, guest, or both?
>>>>>>>> On the guest where ath11k is running. I'm not optimistic that 
>>>>>>>> this would
>>>>>>>> solve your issue, I suspect there can be also other bugs, but 
>>>>>>>> good to
>>>>>>>> know if the patch changes anything.
>>>>>>> Looks the same here, didn't seem to change anything based on the
>>>>>>> kernel logs.
>>>>>>>
>>>>>> Could you try this?
>>>>>>
>>>>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/net/wireless/ath/ath11k/pci.c?id=39564b475ac5a589e6c22c43a08cbd283c295d2c 
>>>>>>
>>>>> This reminds me, I assumed James was testing with ath.git master 
>>>>> branch
>>>>> (which has that commit) but I never checked that. So for testing 
>>>>> please
>>>>> always use the master branch to get the latest and greatest ath11k:
>>>>>
>>>>> https://git.kernel.org/pub/scm/linux/kernel/git/kvalo/ath.git/
>>>>>
>>>>> There's a quite long delay from ath.git to official releases.
>>>> Good to know, and I was not in fact using that branch. Rebuilt from
>>>> ath.git/master but still roughly the same behavior. There does appear
>>>> to be more output now though, specifically a firmware crash:
>>>>
>>>> [    2.281721] ath11k_pci 0000:00:06.0: failed to receive control
>>>> response completion, polling..
>>>> [    2.282101] ip (65) used greatest stack depth: 12464 bytes left
>>>> [    3.306039] ath11k_pci 0000:00:06.0: Service connect timeout
>>>> [    3.307588] ath11k_pci 0000:00:06.0: failed to connect to HTT: -110
>>>> [    3.309286] ath11k_pci 0000:00:06.0: failed to start core: -110
>>>> [    3.519637] ath11k_pci 0000:00:06.0: firmware crashed: 
>>>> MHI_CB_EE_RDDM
>>>> [    3.519678] ath11k_pci 0000:00:06.0: ignore reset dev flags 0x4000
>>>> [    3.627087] ath11k_pci 0000:00:06.0: firmware crashed: 
>>>> MHI_CB_EE_RDDM
>>>> [    3.627129] ath11k_pci 0000:00:06.0: ignore reset dev flags 0x4000
>>>> [   13.802105] ath11k_pci 0000:00:06.0: failed to wait wlan mode
>>>> request (mode 4): -110
>>>> [   13.802175] ath11k_pci 0000:00:06.0: qmi failed to send wlan mode
>>>> off: -110
>>> Ok, that's progress now. Can you try next try the iommu patch[1] we
>>> talked about earlier? It's already in master-pending branch (along with
>>> other pending patches) so you can use that branch if you want.
>>>
>>> [1] 
>>> https://patchwork.kernel.org/project/linux-wireless/patch/20231212031914.47339-1-imguzh@gmail.com/
>>
>> Same result unfortunately, tried both with just [1] applied to 
>> ath.git and at HEAD of master-pending.
>>
>> Thanks,
>>
>> James
> Strange that still fails. Are you now seeing this error in your host 
> or your Qemu? or both?
> Could you share your test steps? And if you can share please be as 
> detailed as possible since I'm not familiar with passing WLAN hardware 
> to a VM using vfio-pci.

Just in Qemu, the hardware works fine on my host machine.

I basically follow this guide to set it up, its written in the context 
of GPUs/libvirt but the host setup is exactly the same. By no means do 
you need to read it all, once you set the vfio-pci.ids and see your 
unclaimed adapter you can stop:

https://wiki.archlinux.org/title/PCI_passthrough_via_OVMF

In short you should be able to set the following host kernel options and 
reboot (assuming your motherboard/hardware is compatible):

intel_iommu=on iommu=pt vfio-pci.ids=17cb:1103

Obviously change the device/vendor IDs to whatever ath11k hw you have. 
Once the host is rebooted you should see your wlan adapter as UNCLAIMED, 
showing the driver in use as vfio-pci. If not, its likely your 
motherboard just isn't compatible, the device has to be in its own IOMMU 
group (you could try switching PCI ports if this is the case).

I then build a "kvm_guest.config" kernel with the driver/firmware for 
ath11k and boot into that with the following Qemu options:

-enable-kvm -device -vfio-pci,host=<PCI address>

If it seems easier you could also utilize IWD's test-runner which 
handles launching the Qemu kernel automatically, detecting any 
vfio-devices and passes them through and mounts some useful host folders 
into the VM. Its actually a very good general purpose tool for kernel 
testing, not just for IWD:

https://git.kernel.org/pub/scm/network/wireless/iwd.git/tree/doc/test-runner.txt

Once set up you can just run test-runner with a few flags and you'll 
boot into a shell:

./tools/test-runner -k <kernel-image> --hw --start /bin/bash

Please reach out if you have questions, thanks for looking into this.