topic Re: Virtualization of USB interfaces in i.MX Processors

Virtualization of USB interfaces

david_gounaris — Mon, 08 Mar 2021 10:59:40 GMT

Hello, I have a question regarding virtualization of usbh1 and usbotg1 using Xen on imx8qm.

In the provided device-tree fsl-imx8qm-device.dtsi, the referenced usbphy (usbphy1 and usbphynop2) for the two controllers (usbh1 and usbotg1) share the same clock and power-domain.

Is it possible to use usbh1 in dom0 and usbotg1 in domu?

Could you please provide an example of how this could be done?

Re: Virtualization of USB interfaces

Bio_TICFSL — Tue, 09 Mar 2021 13:54:00 GMT

Hello david,

There are two general methods for passing through individual host devices to a guest. The first is via an emulated USB device controller; the second is PVUSB.

more information: https://wiki.xenproject.org/wiki/Xen_USB_Passthrough

Regards

Re: Virtualization of USB interfaces

david_gounaris — Wed, 10 Mar 2021 10:21:25 GMT

Thank you for your reply.

I have followed the examples in fsl-imx8qm-mek-dom0.dts and fsl-imx8qm-mek-domu.dts to pass-through other devices to domu. This has worked as expected, but not for usbh1 and usbotg1. I think it is a problem that they share the same clock and power-domain. Can you check if possible to split them into the two domains?

I consider Emulated USB and PVUSB as an alternative if the above method is not possible.

Best Regards / David

Re: Virtualization of USB interfaces

Bio_TICFSL — Wed, 10 Mar 2021 14:18:55 GMT

To change the clock in different domain it not possible, sorry.

Regards

Re: Virtualization of USB interfaces

david_gounaris — Tue, 16 Mar 2021 13:17:03 GMT

The response is a bit unclear to me. Is it not possible to share the clock between two domains? Is the preferred method in this case to use pvusb?

Best Regards / David Gounaris