Enabling LPUART1 in DomU on Xen Hypervisor (Kernel 4.14, i.MX8QXP)

[subash_p]

Hi

I'm currently working on enabling LPUART1 in a DomU under the Xen hypervisor, using kernel version 4.14. I'm referencing the i.MX8QM DTS structure and created a new DomU DTS file for the i.MX8QXP, but the UART pins seem to be present (I can locate them), but the DomU isn't recognising them properly. I’ve verified that the nodes are defined and passthrough is done correctly, but still no success.

Domu console log:

root@imx8qxpc0mek:~# dmesg | grep serial
[ 0.374744] msm_serial: driver initialized
[ 0.375534] fsl-lpuart 5a070000.serial: could not find pctldev for node /passthrough/iomuxc/imx8qxp-mek/lpuart1grp, deferring probe
[ 0.573884] fsl-lpuart 5a070000.serial: could not find pctldev for node /passthrough/iomuxc/imx8qxp-mek/lpuart1grp, deferring probe
[ 2.180064] systemd[1]: Created slice Slice /system/serial-getty.
root@imx8qxpc0mek:~# find / -name "lpuart1grp"
/sys/firmware/devicetree/base/passthrough/iomuxc/imx8qxp-mek/lpuart1grp

I've attached both Dom0 and DomU DTS files below.

[Bio_TICFSL]

Hello,

Yes this is a limitation of XEN, The DomU does not seen something like IPU and LpUART. The  domain zero, the management or control domain with privileged access to the hardware and device drivers. DomU is an unprivileged domain with no direct access to the hardware or device drivers.

Regards

[subash_p]

Is it possible to passthrough the UART pins from Dom0 to Domu ?