Re: [Qemu-devel] [Qemu-arm] [PATCH] hw/arm/virt: support 4 serial ports

["Jason A. Donenfeld" <Jason@zx2c4.com>]

On Thu, Oct 26, 2017 at 4:36 PM, Peter Maydell <peter.maydell@linaro.org> wrote:
> This has *never* been guaranteed or indeed true. It's just happened
> to be true for the x86 PC machine and perhaps for some others that
> you've been using. For instance, the MIPS boston board only has
> one uart. highbank has one. integratorcp has 2. The microblaze
> boards only have one uart. And so on. In cases where we're
> modelling real hardware, if the real board only has one UART
> then we're only going to provide one UART, so in some cases you
> just have to deal with that and have some way in your communication
> protocol to multiplex across a single communications channel.

Interesting. Malta provides quite a few, which is what I'm using on
MIPS, so I guess I've benefited from the uniformity. Since the ARM
virt machine is virtual, it seems like it'd be worthwhile to make it
broadly useful, and adding a few more serial outputs is basically
free.

Right now on build.wireguard.com, I'm just using this horrendous patch
that hopefully hurts to look at: https://א.cc/iKBdlvI3/patch (since I
only need 2). The goal would be for everything else to remain the same
in the deployment, but to not have to use that patch.


>> Could we just do the simple patch of adding four pl011s in there?
>
> I'm still thinking about this. (You definitely can't have four,
> though, because we already have 2 in the trustzone-enabled
> config, so we can only add another 2.)

The trustzone one could be the 5th? Since it's only useful for trustzone.