0339c2a86f
We should at least document what this machine is about. Reviewed-by: Graeme Gregory <graeme@nuviainc.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-id: 20201104165254.24822-1-alex.bennee@linaro.org Cc: Leif Lindholm <leif@nuviainc.com> Cc: Shashi Mallela <shashi.mallela@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> [PMM: fixed filename mismatch] Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
105 lines
3.7 KiB
ReStructuredText
105 lines
3.7 KiB
ReStructuredText
.. _ARM-System-emulator:
|
|
|
|
Arm System emulator
|
|
-------------------
|
|
|
|
QEMU can emulate both 32-bit and 64-bit Arm CPUs. Use the
|
|
``qemu-system-aarch64`` executable to simulate a 64-bit Arm machine.
|
|
You can use either ``qemu-system-arm`` or ``qemu-system-aarch64``
|
|
to simulate a 32-bit Arm machine: in general, command lines that
|
|
work for ``qemu-system-arm`` will behave the same when used with
|
|
``qemu-system-aarch64``.
|
|
|
|
QEMU has generally good support for Arm guests. It has support for
|
|
nearly fifty different machines. The reason we support so many is that
|
|
Arm hardware is much more widely varying than x86 hardware. Arm CPUs
|
|
are generally built into "system-on-chip" (SoC) designs created by
|
|
many different companies with different devices, and these SoCs are
|
|
then built into machines which can vary still further even if they use
|
|
the same SoC. Even with fifty boards QEMU does not cover more than a
|
|
small fraction of the Arm hardware ecosystem.
|
|
|
|
The situation for 64-bit Arm is fairly similar, except that we don't
|
|
implement so many different machines.
|
|
|
|
As well as the more common "A-profile" CPUs (which have MMUs and will
|
|
run Linux) QEMU also supports "M-profile" CPUs such as the Cortex-M0,
|
|
Cortex-M4 and Cortex-M33 (which are microcontrollers used in very
|
|
embedded boards). For most boards the CPU type is fixed (matching what
|
|
the hardware has), so typically you don't need to specify the CPU type
|
|
by hand, except for special cases like the ``virt`` board.
|
|
|
|
Choosing a board model
|
|
======================
|
|
|
|
For QEMU's Arm system emulation, you must specify which board
|
|
model you want to use with the ``-M`` or ``--machine`` option;
|
|
there is no default.
|
|
|
|
Because Arm systems differ so much and in fundamental ways, typically
|
|
operating system or firmware images intended to run on one machine
|
|
will not run at all on any other. This is often surprising for new
|
|
users who are used to the x86 world where every system looks like a
|
|
standard PC. (Once the kernel has booted, most userspace software
|
|
cares much less about the detail of the hardware.)
|
|
|
|
If you already have a system image or a kernel that works on hardware
|
|
and you want to boot with QEMU, check whether QEMU lists that machine
|
|
in its ``-machine help`` output. If it is listed, then you can probably
|
|
use that board model. If it is not listed, then unfortunately your image
|
|
will almost certainly not boot on QEMU. (You might be able to
|
|
extract the filesystem and use that with a different kernel which
|
|
boots on a system that QEMU does emulate.)
|
|
|
|
If you don't care about reproducing the idiosyncrasies of a particular
|
|
bit of hardware, such as small amount of RAM, no PCI or other hard
|
|
disk, etc., and just want to run Linux, the best option is to use the
|
|
``virt`` board. This is a platform which doesn't correspond to any
|
|
real hardware and is designed for use in virtual machines. You'll
|
|
need to compile Linux with a suitable configuration for running on
|
|
the ``virt`` board. ``virt`` supports PCI, virtio, recent CPUs and
|
|
large amounts of RAM. It also supports 64-bit CPUs.
|
|
|
|
Board-specific documentation
|
|
============================
|
|
|
|
Unfortunately many of the Arm boards QEMU supports are currently
|
|
undocumented; you can get a complete list by running
|
|
``qemu-system-aarch64 --machine help``.
|
|
|
|
..
|
|
This table of contents should be kept sorted alphabetically
|
|
by the title text of each file, which isn't the same ordering
|
|
as an alphabetical sort by filename.
|
|
|
|
.. toctree::
|
|
:maxdepth: 1
|
|
|
|
arm/integratorcp
|
|
arm/mps2
|
|
arm/musca
|
|
arm/realview
|
|
arm/sbsa
|
|
arm/versatile
|
|
arm/vexpress
|
|
arm/aspeed
|
|
arm/digic
|
|
arm/musicpal
|
|
arm/gumstix
|
|
arm/nseries
|
|
arm/nuvoton
|
|
arm/orangepi
|
|
arm/palm
|
|
arm/xscale
|
|
arm/collie
|
|
arm/sx1
|
|
arm/stellaris
|
|
arm/virt
|
|
arm/xlnx-versal-virt
|
|
|
|
Arm CPU features
|
|
================
|
|
|
|
.. toctree::
|
|
arm/cpu-features
|