| 1 | 'virt' generic virtual platform |
| 2 | =============================== |
| 3 | |
| 4 | The ``virt`` board is a platform which does not correspond to any |
| 5 | real hardware; it is designed for use in virtual machines. |
| 6 | It is the recommended board type if you simply want to run |
| 7 | a guest such as Linux and do not care about reproducing the |
| 8 | idiosyncrasies and limitations of a particular bit of real-world |
| 9 | hardware. |
| 10 | |
| 11 | Supported devices |
| 12 | ----------------- |
| 13 | |
| 14 | * PCI/PCIe devices |
| 15 | * 8 virtio-mmio transport devices |
| 16 | * 16550A UART |
| 17 | * Goldfish RTC |
| 18 | * SiFive Test device for poweroff and reboot |
| 19 | * SMP (OpenRISC multicore using ompic) |
| 20 | |
| 21 | Boot options |
| 22 | ------------ |
| 23 | |
| 24 | The virt machine can be started using the ``-kernel`` and ``-initrd`` options |
| 25 | to load a Linux kernel and optional disk image. For example: |
| 26 | |
| 27 | .. code-block:: bash |
| 28 | |
| 29 | $ qemu-system-or1k -cpu or1220 -M or1k-sim -nographic \ |
| 30 | -device virtio-net-device,netdev=user -netdev user,id=user,net=10.9.0.1/24,host=10.9.0.100 \ |
| 31 | -device virtio-blk-device,drive=d0 -drive file=virt.qcow2,id=d0,if=none,format=qcow2 \ |
| 32 | -kernel vmlinux \ |
| 33 | -initrd initramfs.cpio.gz \ |
| 34 | -m 128 |
| 35 | |
| 36 | Linux guest kernel configuration |
| 37 | """""""""""""""""""""""""""""""" |
| 38 | |
| 39 | The 'virt_defconfig' for Linux openrisc kernels includes the right drivers for |
| 40 | the ``virt`` machine. |
| 41 | |
| 42 | Hardware configuration information |
| 43 | """""""""""""""""""""""""""""""""" |
| 44 | |
| 45 | The ``virt`` board automatically generates a device tree blob ("dtb") which it |
| 46 | passes to the guest. This provides information about the addresses, interrupt |
| 47 | lines and other configuration of the various devices in the system. |
| 48 | |
| 49 | The location of the DTB will be passed in register ``r3`` to the guest operating |
| 50 | system. |