Amazon EC2 bare metal instances have no UART at the legacy I/O port
0x3f8. Their only serial port is a 16550-compatible PCI device (vendor
0x1d0f, device 0x8250) with its registers in the MMIO space of BAR 0.
pci_uart_config() uses the default parameters for a device that is not
in uart_config[], and those only accept an I/O BAR, so "com1=...,pci"
cannot find this device. Add it, with the same layout that Linux uses
(commit 3bfd1300abfe ("serial: 8250_pci: Add Amazon PCI serial device
ID")): one port at the start of BAR 0, 1-byte registers, and the
default 1.8432MHz clock.
Assisted-by: Claude:claude-opus-5-5
Signed-off-by: Benjamin Leggett <benjamin@edera.io>
Acked-by: Jan Beulich <jbeulich@suse.com>
