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

[Peter Maydell <peter.maydell@linaro.org>]

On 23 October 2017 at 13:27, Jason A. Donenfeld <Jason@zx2c4.com> wrote:
> The QEMU man page says:
>
>        -serial dev
>            This option can be used several times to
>            simulate up to 4 serial ports.
>
> However, the ARM virt machine erroneously only provides 1 serial port.
> This patch fixes it by populating 4 of them.
>
> But, unfortunately, this patch doesn't actually work. Sending it to the
> list as inspiration for somebody on the ARM team who might be able to do
> this more properly.

This is really the documentation being wrong -- that is actually
a PC specific thing. In QEMU generally, -serial can be used
for as many serial ports as the machine model provides, up
to a maximum of four.

Why do you want more than one serial port in the virt board?
If there's a good reason we can add more, but mostly I only
expected that one would be needed, for the console.
(If you're using the TrustZone/EL3 support then there's
a second UART for the Secure world.)

thanks
-- PMM