docs: device_model: Updated the serial device doc

As we switched the AArch64 serial device to PL011, we also need to
update the documentation.

Signed-off-by: Henry Wang <Henry.Wang@arm.com>
This commit is contained in:
Henry Wang 2021-03-15 11:10:58 +08:00 committed by Michael
parent 9c3b489f0e
commit 06d83d2eb3

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@ -28,9 +28,13 @@ This document describes the device model supported by `cloud-hypervisor`.
### Serial port
Simple emulation of a serial port by reading and writing to specific port I/O
addresses. Used as the default console for Linux when booting with the option
`console=ttyS0`, the serial port can be very useful to gather early logs from
the operating system booted inside the VM.
addresses. The serial port can be very useful to gather early logs from the
operating system booted inside the VM.
For x86_64, The default serial port is from an emulated 16550A device. It can
be used as the default console for Linux when booting with the option
`console=ttyS0`. For AArch64, the default serial port is from an emulated
PL011 UART device. The related command line for AArch64 is `console=ttyAMA0`.
This device is always built-in, and it is disabled by default. It can be
enabled with the `--serial` option, as long as its parameter is not `off`.