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

[lonthn@163.com]

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