Re: Xen data from meta-virtualization layer

[Michael Walle <michael@xxxxxxxx>]

Hi Julien,

Am 2022-02-05 00:29, schrieb Julien Grall:
[..]
> > But not a very user friendly one, though. I guess the first UART
> > is disabled/removed by Xen? I haven't looked at how it is handled.
> >
> > Can't we search for other uarts with the same interrupt and disable
> > these, too? Maybe conditionally by the SoC compatible?
> The problem sounds quite similar to the one we had on sunxi. Although
> the UART was on the same page rather than sharing interrupts.
>
> Xen has per-platform hook to prevent a device been assigned
> to dom0. For an example, you could look at:
>
> https://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=xen/arch/arm/platforms/sunxi.c
Nice. At least, this is working now ;) I'll send a patch in
the next few days.

I guess it's safe to assume that we can always remove both UARTs
on the LS1028A (probably on most layerscapes). The most common
use case is to use the first UART for Xen. You could run Xen
without console (?), then you'd miss the possibility to map
the DUART. Or there could be a new driver for the LPUART on the
LS1028A. In this case, the DUART wouldn't be used by Xen either.

But I think we should start simple and just remove the DUART
altogether via that hook.

-michael