QEMU usage

Build and configure

You can build an image for QEMU just as you would for all other platforms supported by Clea OS.

When running the build configurator for a QEMU machine, a specific menu appears: QEMU runtime configuration.

This menu contains configuration parameters that will be used to populate the qemuboot.conf and local.qemuboot.conf files (see Support).

A few examples:

Parameter	Description
Memory (MiB)	Amount of available RAM in MiB. Optionally, a suffix of "M" or "G" can be used to signify a value in megabytes or gigabytes respectively.
Number of CPUs	Number of CPU cores inside the QEMU guest, each mapped to a thread on the host.
CPU	QEMU CPU, e.g., -cpu cortex-a72

Use the <Help> button in menuconfig to see a detailed description of each parameter. Many of these parameters map directly to a QEMU command line argument, so also see the QEMU manpage for information.

When in doubt, it is recommended to leave these options unset (they will be set to a valid default value automatically).

Running

See runqemu --help for information on runqemu command line arguments such as nographic and slirp.

With Yocto SDK

You can run an instance of QEMU from an environemnt that provides the bitbake command, i.e.:

• the build environment created by the project setup script seco-setup.sh;
• the Yocto SDK.

runqemu nographic slirp

This will:

• automatically locate the files in tmp/deploy/images/<machine>/;
• nographic disables video output; (optional, you can omit it when using the SDK);
• slirp sets up network in a way that doesn't require root privileges.

With native QEMU

To run an instance of QEMU in an environment without bitbake support, you need to:

• install a suitable QEMU distribution for your host and target systems at /usr prefix;
• copy or cd to the deploy directory tmp/deploy/images/<machine>/.

Then you can issue the command:

# Launch runqemu from current directory
PATH="$PWD:$PATH" ./runqemu seco-clea-os-image-qemuarm-rootfs.local.qemuboot.conf nographic slirp

Replace seco-clea-os-image-qemuarm-rootfs.local.qemuboot.conf with the correct name of the .local.qemuboot.conf file.

The PATH="$PWD:$PATH" assignment is necessary because runqemu needs to locate its Python dependencies in the current directory.

Graphics

To enable video output, omit nographic.

This will spawn a new window and render the guest video output in it.

In this mode, the serial output is hidden by default. Pass serialstdio to keep the serial output enabled:

# With SDK
runqemu slirp serialstdio

# Native QEMU
PATH="$PWD:$PATH" ./runqemu seco-clea-os-image-qemuarm-rootfs.local.qemuboot.conf slirp serialstdio