Re: [rtw89] PCI Passthrough Issue: rtl8852be on ARM VM (Ubuntu host/OpenWrt guest)

[lonthn <lonthn@163.com>]

At 2025-06-12 15:38:09, lonthn@163.com wrote:
>Thanks for your quick response.
>
>> This looks like interoperability problem of 36-bit DMA.
>> If you have below commit in your guest OS:
>> 1fd4b3fe52ef ("wifi: rtw89: pci: support 36-bit PCI DMA address")
>> 
>> Please also have below commit to rollback 32-bit DMA.
>> aa70ff0945fe ("wifi: rtw89: pci: early chips only enable 36-bit DMA on specific PCI hosts")
>> 
>> With the latest kernel, you can just comment code as below to use 32-bit DMA.
>
>I tried it and found that it still doesn't work
>
>> I have not ever tried passthrough, so I'm not sure if it can work.
>> Can I know how different the passthrough is?
>
>You can refer to this: https://docs.kernel.org/driver-api/vfio.html
>
>> Does rtl8852be work on host OS?
>
>I'm trying, but when I load the 8852be driver, strangely, I get nothing. 
>$> dmesg |grep 8852be
>no message!
>$> lsmod |grep rtw
>rtw_8852be             16384  0
>rtw_8852b             352256  1 rtw_8852be
>rtw89pci               61440  1 rtw_8852be
>rtw89core             569344  2 rtw89pci,rtw_8852b
>It looks like my device is not detected

I've confirmed that the host system is working