b14df228d7
Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Stafford Horne <shorne@gmail.com>
51 lines
1.6 KiB
ReStructuredText
51 lines
1.6 KiB
ReStructuredText
'virt' generic virtual platform
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===============================
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The ``virt`` board is a platform which does not correspond to any
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real hardware; it is designed for use in virtual machines.
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It is the recommended board type if you simply want to run
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a guest such as Linux and do not care about reproducing the
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idiosyncrasies and limitations of a particular bit of real-world
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hardware.
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Supported devices
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-----------------
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* PCI/PCIe devices
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* 8 virtio-mmio transport devices
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* 16550A UART
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* Goldfish RTC
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* SiFive Test device for poweroff and reboot
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* SMP (OpenRISC multicore using ompic)
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Boot options
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------------
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The virt machine can be started using the ``-kernel`` and ``-initrd`` options
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to load a Linux kernel and optional disk image. For example:
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.. code-block:: bash
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$ qemu-system-or1k -cpu or1220 -M or1k-sim -nographic \
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-device virtio-net-device,netdev=user -netdev user,id=user,net=10.9.0.1/24,host=10.9.0.100 \
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-device virtio-blk-device,drive=d0 -drive file=virt.qcow2,id=d0,if=none,format=qcow2 \
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-kernel vmlinux \
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-initrd initramfs.cpio.gz \
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-m 128
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Linux guest kernel configuration
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""""""""""""""""""""""""""""""""
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The 'virt_defconfig' for Linux openrisc kernels includes the right drivers for
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the ``virt`` machine.
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Hardware configuration information
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""""""""""""""""""""""""""""""""""
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The ``virt`` board automatically generates a device tree blob ("dtb") which it
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passes to the guest. This provides information about the addresses, interrupt
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lines and other configuration of the various devices in the system.
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The location of the DTB will be passed in register ``r3`` to the guest operating
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system.
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