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Set up and start the Fuchsia emulator (FEMU)

This document describes how to set up and run the Fuchsia emulator (FEMU), including networking and GPU support setup.

Prerequisites

To run FEMU, you must have:

Building Fuchsia for FEMU

Before you can use FEMU, you need to build Fuchsia using fx set, specifying a qemu board and supported product. This example uses qemu-x64 for the board and workstation for the product:

fx set workstation.qemu-x64 --release [--with=...]
fx build

Configure network

For Fuchsia's ephemeral software to work with FEMU, you need to configure an IPv6 network.

Linux

To enable networking in FEMU using tap networking, run the following commands:

sudo ip tuntap add dev qemu mode tap user $USER
sudo ip link set qemu up

macOS

User Networking (SLIRP) is the default networking set up for FEMU on macOS. This networking set up does not support Fuchsia device discovery.

Start FEMU

The most common way to run FEMU is with networking enabled, using the following commands.

Linux

To support device discovery without access to external networks.

fx vdl start -N

To get access to external networks:

fx vdl start -N -u FUCHSIA_ROOT/scripts/start-unsecure-internet.sh

Once you run the command, a separate window opens with the title "Fuchsia Emulator". After the Fuchsia emulator launches successfully, the terminal starts with the SSH console. You can run shell commands in this window, just like you would on a Fuchsia device.

macOS

On macOS, Fuchsia device discovery does not work. However, you can still use fx tools such as fx ssh.

fx vdl start

From the output, take note of the instruction on running fx set-device, you will need it for the steps below.

Run fx set-device to specify the launched Fuchsia emulator SSH port. For SSH_PORT, use the value that the fx vdl start --host-gpu command outputted.

fx set-device 127.0.0.1:SSH_PORT

Additional FEMU options

Input options

By default FEMU uses multi-touch input. You can add the argument --pointing-device mouse for mouse cursor input instead.

fx vdl start --pointing-device mouse

Run FEMU without GUI support

If you don't need graphics or working under the remote workflow, you can run FEMU in headless mode:

fx vdl start --headless

Specify GPU used by FEMU

By default, FEMU launcher uses software rendering using SwiftShader. To force FEMU to use a specific graphics emulation method, use the parameters --host-gpu or --software-gpu to the fx vdl start command.

These are the valid commands and options:

GPU Emulation method Explanation fx vdl start flag
Hardware (host GPU) Uses the host machine’s GPU directly to perform GPU processing. fx vdl start --host-gpu
Software (host CPU) Uses the host machine’s CPU to simulate GPU processing. fx vdl start --software-gpu

Supported hardware for graphics acceleration

FEMU currently supports a limited set of GPUs on macOS and Linux for hardware graphics acceleration. FEMU uses a software renderer fallback for unsupported GPUs.

Operating System GPU Manufacturer OS / Driver Version
Linux Nvidia Quadro Nvidia Linux Drivers 440.100+
macOS Intel HD Graphics macOS version 10.15+
macOS AMD Radeon Pro macOS version 10.15+

Exit FEMU

To exit FEMU, run dm poweroff in the FEMU terminal.

Next steps