# Arm Server Base System Architecture Reference board (`sbsa-ref`)

While the virt board is a generic board platform that doesn’t match any real hardware the sbsa-ref board intends to look like real hardware. The Server Base System Architecture <https://developer.arm.com/documentation/den0029/latest> defines a minimum base line of hardware support and importantly how the firmware reports that to any operating system. It is a static system that reports a very minimal DT to the firmware for non-discoverable information about components affected by the qemu command line (i.e. cpus and memory). As a result it must have a firmware specifically built to expect a certain hardware layout (as you would in a real machine).

It is intended to be a machine for developing firmware and testing standards compliance with operating systems.

## Supported devices

The sbsa-ref board supports:

> - A configurable number of AArch64 CPUs

> - GIC version 3

> - System bus AHCI controller

> - System bus EHCI controller

> - CDROM and hard disc on AHCI bus

> - E1000E ethernet card on PCIe bus

> - VGA display adaptor on PCIe bus

> - A generic SBSA watchdog device