[Qemu-discuss] Can QEMU -M virt on arm / aarch64 have multiple serial TTYs like such as PL011 ttyAMA0 and ttyAMA1?

[Ciro Santilli]

https://unix.stackexchange.com/questions/479085/can-qemu-m-virt-on-arm-aarch64-have-multiple-serial-ttys-like-such-as-pl011-t

I was playing around with TTYs, and for `qemu-system-x86_64 -M pc`,
whenever I pass the `-serial` option it crates a new TTY and I can
attach a serial like `ttyS0` and `ttyS1` to it from Linux.

For ARM however, I can't get past the first `ttyAMA0`. If I add
`-serial`, it does not show on `info qtree` and the kernel boot
messages only find one:

    9000000.pl011: ttyAMA0 at MMIO 0x9000000 (irq = 54, base_baud = 0)
is a PL011 rev1

Is it possible, and if not, is there a specific design reason for that?

I'm on QEMU v3.0.0. From the source it does not seem possible:
https://github.com/qemu/qemu/blob/v3.0.0/hw/arm/virt.c#L138 as there
is only one UART in the memory map:

    [VIRT_GIC_REDIST] =         { 0x080A0000, 0x00F60000 },
    [VIRT_UART] =               { 0x09000000, 0x00001000 },
    [VIRT_RTC] =                { 0x09010000, 0x00001000 },

I'm doing this because I'm trying to see if connecting from a
different serial will make KGDB work. On x86_64 I can connect to
`ttyS0`, but I thought it was worth giving this a try on ARM. See
also: 
https://stackoverflow.com/questions/22004616/how-to-debug-the-linux-kernel-with-qemu-and-kgdb/44197715#44197715