A virtual machine in Uvmm is configured with a device tree that contains information about the VMs resources, memory layout, virtual CPUs and peripheral devices.

Uvmm_dtg is a tool to generate such a device tree at runtime according to its command line.

Usage in L4Re

Example lua script for Ned:

-- Create DS holding device tree
local dt = L4.Env.user_factory:create(L4.Proto.Dataspace, 4 * 1024):m("rw");

-- Start the generator
L4.default_loader:start(
{
  caps = { dt = dt },
}, "rom/uvmm_dtg dt"):wait();

-- Start uvmm
vmm.start_vm
{
 ...
 ext_caps = { dt = dt },
 fdt = "dt",
 ...
}

Please notice the :wait() when starting uvmm_dtg. This makes Ned pause until uvmm_dtg has exited and put the device tree into the dataspace such that Uvmm can commence.

Usage

uvmm_dtg [OPTION]... <file>|--

-- print to stdout
file

On L4Re, the string given as <file> is interpreted as a named capability which needs to be backed by a sufficiently large Dataspace. On Linux, a file with the given name is created. In both cases, uvmm_dtg will output into the named file.

Options

-h

Show help.
--arch <target architecture>

Select the target architecture. Valid options are x86, x86_64, arm32, arm64, mips32 and mips64.
--format <format>

Select the output format. Available formats are: txt: The device tree will be printed as plain text (dts). bin: The device tree will be output as binary (dtb).
--mem-base <membase>

Configure the start of the memory distribution. membase can be defined in both decimal and hex notations. uvmm_dtg rounds the given base up to the platforms page size.

This value can be overridden by memory devices with fixed addresses.
--device <devicename:[Option1,Option2=value,Option3=value,...]>

This configures a device.

To get a list of supported devices, use --device help.

To get help for a specific device, use --device devicename:help.