.. SPDX-License-Identifier: GPL-2.0+ .. Copyright (C) 2018, Bin Meng QEMU RISC-V =========== QEMU for RISC-V supports a special 'virt' machine and 'spike' machine designed for emulation and virtualization purposes. This document describes how to run U-Boot under it. Both 32-bit and 64-bit targets are supported, running in either machine or supervisor mode. The QEMU virt machine models a generic RISC-V virtual machine with support for the VirtIO standard networking and block storage devices. It has CLINT, PLIC, 16550A UART devices in addition to VirtIO and it also uses device-tree to pass configuration information to guest software. It implements the latest RISC-V privileged architecture. See :doc:`../../develop/devicetree/dt_qemu` for information on how to see the devicetree actually generated by QEMU. The QEMU spike machine models a minimalistic RISC-V virtual machine with only CLINT and HTIF devices. It also uses device-tree to pass configuration information to guest software and implements the latest RISC-V privileged architecture. Building U-Boot --------------- Set the CROSS_COMPILE environment variable as usual, and run: - For 32-bit RISC-V:: make qemu-riscv32_defconfig make - For 64-bit RISC-V:: make qemu-riscv64_defconfig make This will compile U-Boot for machine mode. To build supervisor mode binaries, use the configurations qemu-riscv32_smode_defconfig and qemu-riscv64_smode_defconfig instead. Note that U-Boot running in supervisor mode requires a supervisor binary interface (SBI), such as RISC-V OpenSBI. Running U-Boot -------------- The minimal QEMU command line to get U-Boot up and running is: - For 32-bit RISC-V virt machine:: qemu-system-riscv32 -nographic -machine virt -bios u-boot.bin - For 64-bit RISC-V virt machine:: qemu-system-riscv64 -nographic -machine virt -bios u-boot.bin - For 64-bit RISC-V spike machine:: qemu-system-riscv64 -nographic -machine spike -bios u-boot.bin The commands above create targets with 128MiB memory by default. A freely configurable amount of RAM can be created via the '-m' parameter. For example, '-m 2G' creates 2GiB memory for the target, and the memory node in the embedded DTB created by QEMU reflects the new setting. For instructions on how to run U-Boot in supervisor mode on QEMU with OpenSBI, see the documentation available with OpenSBI: https://github.com/riscv/opensbi/blob/master/docs/platform/qemu_virt.md https://github.com/riscv/opensbi/blob/master/docs/platform/spike.md These have been tested in QEMU 5.0.0. Running U-Boot SPL ------------------ In the default SPL configuration, U-Boot SPL starts in machine mode. U-Boot proper and OpenSBI (FW_DYNAMIC firmware) are bundled as FIT image and made available to U-Boot SPL. Both are then loaded by U-Boot SPL and the location of U-Boot proper is passed to OpenSBI. After initialization, U-Boot proper is started in supervisor mode by OpenSBI. OpenSBI must be compiled before compiling U-Boot. Version 0.4 and higher is supported by U-Boot. Clone the OpenSBI repository and run the following command. .. code-block:: console git clone https://github.com/riscv/opensbi.git cd opensbi make PLATFORM=generic See the OpenSBI documentation for full details: https://github.com/riscv/opensbi/blob/master/docs/platform/qemu_virt.md https://github.com/riscv/opensbi/blob/master/docs/platform/spike.md To make the FW_DYNAMIC binary (build/platform/generic/firmware/fw_dynamic.bin) available to U-Boot, either copy it into the U-Boot root directory or specify its location with the OPENSBI environment variable. Afterwards, compile U-Boot with the following commands. - For 32-bit RISC-V:: make qemu-riscv32_spl_defconfig make - For 64-bit RISC-V:: make qemu-riscv64_spl_defconfig make The minimal QEMU commands to run U-Boot SPL in both 32-bit and 64-bit configurations are: - For 32-bit RISC-V virt machine:: qemu-system-riscv32 -nographic -machine virt -bios spl/u-boot-spl.bin \ -device loader,file=u-boot.itb,addr=0x80200000 - For 64-bit RISC-V virt machine:: qemu-system-riscv64 -nographic -machine virt -bios spl/u-boot-spl.bin \ -device loader,file=u-boot.itb,addr=0x80200000 - For 64-bit RISC-V spike machine:: qemu-system-riscv64 -nographic -machine spike -bios spl/u-boot-spl.bin \ -device loader,file=u-boot.itb,addr=0x80200000 An attached disk can be emulated in RISC-V virt machine by adding:: -device ich9-ahci,id=ahci \ -drive if=none,file=riscv64.img,format=raw,id=mydisk \ -device ide-hd,drive=mydisk,bus=ahci.0 You will have to run 'scsi scan' to use it. Debug UART ---------- The following settings provide a debug UART for the virt machine:: CONFIG_DEBUG_UART=y CONFIG_DEBUG_UART_NS16550=y CONFIG_DEBUG_UART_BASE=0x10000000 CONFIG_DEBUG_UART_CLOCK=3686400