docs/system/target-arm.rst

   1 .. _ARM-System-emulator:
   2
   3 Arm System emulator
   4 -------------------
   5
   6 QEMU can emulate both 32-bit and 64-bit Arm CPUs. Use the
   7 ``qemu-system-aarch64`` executable to simulate a 64-bit Arm machine.
   8 You can use either ``qemu-system-arm`` or ``qemu-system-aarch64``
   9 to simulate a 32-bit Arm machine: in general, command lines that
  10 work for ``qemu-system-arm`` will behave the same when used with
  11 ``qemu-system-aarch64``.
  12
  13 QEMU has generally good support for Arm guests. It has support for
  14 nearly fifty different machines. The reason we support so many is that
  15 Arm hardware is much more widely varying than x86 hardware. Arm CPUs
  16 are generally built into "system-on-chip" (SoC) designs created by
  17 many different companies with different devices, and these SoCs are
  18 then built into machines which can vary still further even if they use
  19 the same SoC. Even with fifty boards QEMU does not cover more than a
  20 small fraction of the Arm hardware ecosystem.
  21
  22 The situation for 64-bit Arm is fairly similar, except that we don't
  23 implement so many different machines.
  24
  25 As well as the more common "A-profile" CPUs (which have MMUs and will
  26 run Linux) QEMU also supports "M-profile" CPUs such as the Cortex-M0,
  27 Cortex-M4 and Cortex-M33 (which are microcontrollers used in very
  28 embedded boards). For most boards the CPU type is fixed (matching what
  29 the hardware has), so typically you don't need to specify the CPU type
  30 by hand, except for special cases like the ``virt`` board.
  31
  32 Choosing a board model
  33 ======================
  34
  35 For QEMU's Arm system emulation, you must specify which board
  36 model you want to use with the ``-M`` or ``--machine`` option;
  37 there is no default.
  38
  39 Because Arm systems differ so much and in fundamental ways, typically
  40 operating system or firmware images intended to run on one machine
  41 will not run at all on any other. This is often surprising for new
  42 users who are used to the x86 world where every system looks like a
  43 standard PC. (Once the kernel has booted, most userspace software
  44 cares much less about the detail of the hardware.)
  45
  46 If you already have a system image or a kernel that works on hardware
  47 and you want to boot with QEMU, check whether QEMU lists that machine
  48 in its ``-machine help`` output. If it is listed, then you can probably
  49 use that board model. If it is not listed, then unfortunately your image
  50 will almost certainly not boot on QEMU. (You might be able to
  51 extract the filesystem and use that with a different kernel which
  52 boots on a system that QEMU does emulate.)
  53
  54 If you don't care about reproducing the idiosyncrasies of a particular
  55 bit of hardware, such as small amount of RAM, no PCI or other hard
  56 disk, etc., and just want to run Linux, the best option is to use the
  57 ``virt`` board. This is a platform which doesn't correspond to any
  58 real hardware and is designed for use in virtual machines. You'll
  59 need to compile Linux with a suitable configuration for running on
  60 the ``virt`` board. ``virt`` supports PCI, virtio, recent CPUs and
  61 large amounts of RAM. It also supports 64-bit CPUs.
  62
  63 Board-specific documentation
  64 ============================
  65
  66 Unfortunately many of the Arm boards QEMU supports are currently
  67 undocumented; you can get a complete list by running
  68 ``qemu-system-aarch64 --machine help``.
  69
  70 ..
  71    This table of contents should be kept sorted alphabetically
  72    by the title text of each file, which isn't the same ordering
  73    as an alphabetical sort by filename.
  74
  75 .. toctree::
  76    :maxdepth: 1
  77
  78    arm/integratorcp
  79    arm/mps2
  80    arm/musca
  81    arm/realview
  82    arm/sbsa
  83    arm/versatile
  84    arm/vexpress
  85    arm/aspeed
  86    arm/bananapi_m2u.rst
  87    arm/sabrelite
  88    arm/digic
  89    arm/cubieboard
  90    arm/emcraft-sf2
  91    arm/highbank
  92    arm/musicpal
  93    arm/gumstix
  94    arm/mainstone
  95    arm/kzm
  96    arm/nrf
  97    arm/nseries
  98    arm/nuvoton
  99    arm/imx25-pdk
 100    arm/orangepi
 101    arm/palm
 102    arm/raspi
 103    arm/xscale
 104    arm/collie
 105    arm/sx1
 106    arm/stellaris
 107    arm/stm32
 108    arm/virt
 109    arm/xlnx-versal-virt
 110    arm/xenpvh
 111
 112 Emulated CPU architecture support
 113 =================================
 114
 115 .. toctree::
 116    arm/emulation
 117
 118 Arm CPU features
 119 ================
 120
 121 .. toctree::
 122    arm/cpu-features