| 'virt' generic virtual platform |
| =============================== |
| |
| The ``virt`` board is a platform which does not correspond to any |
| real hardware; it is designed for use in virtual machines. |
| It is the recommended board type if you simply want to run |
| a guest such as Linux and do not care about reproducing the |
| idiosyncrasies and limitations of a particular bit of real-world |
| hardware. |
| |
| Supported devices |
| ----------------- |
| |
| * PCI/PCIe devices |
| * 8 virtio-mmio transport devices |
| * 16550A UART |
| * Goldfish RTC |
| * SiFive Test device for poweroff and reboot |
| * SMP (OpenRISC multicore using ompic) |
| |
| Boot options |
| ------------ |
| |
| The virt machine can be started using the ``-kernel`` and ``-initrd`` options |
| to load a Linux kernel and optional disk image. For example: |
| |
| .. code-block:: bash |
| |
| $ qemu-system-or1k -cpu or1220 -M or1k-sim -nographic \ |
| -device virtio-net-device,netdev=user -netdev user,id=user,net=10.9.0.1/24,host=10.9.0.100 \ |
| -device virtio-blk-device,drive=d0 -drive file=virt.qcow2,id=d0,if=none,format=qcow2 \ |
| -kernel vmlinux \ |
| -initrd initramfs.cpio.gz \ |
| -m 128 |
| |
| Linux guest kernel configuration |
| """""""""""""""""""""""""""""""" |
| |
| The 'virt_defconfig' for Linux openrisc kernels includes the right drivers for |
| the ``virt`` machine. |
| |
| Hardware configuration information |
| """""""""""""""""""""""""""""""""" |
| |
| The ``virt`` board automatically generates a device tree blob ("dtb") which it |
| passes to the guest. This provides information about the addresses, interrupt |
| lines and other configuration of the various devices in the system. |
| |
| The location of the DTB will be passed in register ``r3`` to the guest operating |
| system. |
