Re: [Qemu-discuss] Accessing both uart of machine -virt (aarch64)

[Vincent]

Great ! I didn't understand the doc correctly and now it works fine !

Thank you very much,
V.

2017-06-12 20:38 GMT+02:00 Peter Maydell <address@hidden>:

> On 12 June 2017 at 16:58, Vincent <address@hidden> wrote:
> > Hi !
> > I'm trying to test a bare metal aarch64 OS using qemu 'virt' machine.
> > So far I'm only running the EL3 part of the OS.
> > I am using the following command line to start qemu:
> >
> > qemu-system-aarch64 -machine virt,secure=on -cpu cortex-a57 \
> >     -smp 1 -m 4096 -kernel my_kernel.elf -serial stdio
> >
> > When I access the VIRT_UART device, I can see my prints on the standard
> > output of my console, but if I access the VIRT_SECURE_UART, I don't see
> > anything.
>
> You need another -serial option to say where it should go
> (I think by default it will go to a tab in the graphics window).
>
> > Can I redirect both uart to the same output (stdio) ?
>
> Only by using the 'multiplexer' which is the thing that lets
> you use C-a c and so on to switch between multiple outputs on
> the same stdio (usually used for monitor and serial). You won't
> see the output from both at once, but you can flip between them
> with C-a c. This is documented in the manual:
> https://qemu.weilnetz.de/doc/qemu-doc.html#Character-device-options
>
> but roughly speaking you would want
>   -chardev stdio,mux=on,id=char0 \
>   -serial chardev:char0 \
>   -serial chardev:char0
>
> to just mux the two serial outputs. Alternatively you can direct
> the second serial to a TCP port or wherever else is convenient.
>
> thanks
> -- PMM
>