target-arm.rst (4085B)
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/sabrelite 87 arm/digic 88 arm/cubieboard 89 arm/emcraft-sf2 90 arm/highbank 91 arm/musicpal 92 arm/gumstix 93 arm/mainstone 94 arm/kzm 95 arm/nrf 96 arm/nseries 97 arm/nuvoton 98 arm/imx25-pdk 99 arm/orangepi 100 arm/palm 101 arm/raspi 102 arm/xscale 103 arm/collie 104 arm/sx1 105 arm/stellaris 106 arm/stm32 107 arm/virt 108 arm/xlnx-versal-virt 109 110 Emulated CPU architecture support 111 ================================= 112 113 .. toctree:: 114 arm/emulation 115 116 Arm CPU features 117 ================ 118 119 .. toctree:: 120 arm/cpu-features