1# SPDX-License-Identifier: GPL-2.0+ 2# 3# Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com> 4 5U-Boot on QEMU's 'virt' machine on RISC-V 6========================================= 7 8QEMU for RISC-V supports a special 'virt' machine designed for emulation and 9virtualization purposes. This document describes how to run U-Boot under it. 10Both 32-bit 64-bit targets are supported. 11 12The QEMU virt machine models a generic RISC-V virtual machine with support for 13the VirtIO standard networking and block storage devices. It has CLINT, PLIC, 1416550A UART devices in addition to VirtIO and it also uses device-tree to pass 15configuration information to guest software. It implements RISC-V privileged 16architecture spec v1.10. 17 18Building U-Boot 19--------------- 20Set the CROSS_COMPILE environment variable as usual, and run: 21 22- For 32-bit RISC-V: 23 make qemu-riscv32_defconfig 24 make 25 26- For 64-bit RISC-V: 27 make qemu-riscv64_defconfig 28 make 29 30Running U-Boot 31-------------- 32The minimal QEMU command line to get U-Boot up and running is: 33 34- For 32-bit RISC-V: 35 qemu-system-riscv32 -nographic -machine virt -kernel u-boot 36 37- For 64-bit RISC-V: 38 qemu-system-riscv64 -nographic -machine virt -kernel u-boot 39 40The commands above create targets with 128MiB memory by default. 41A freely configurable amount of RAM can be created via the '-m' 42parameter. For example, '-m 2G' creates 2GiB memory for the target, 43and the memory node in the embedded DTB created by QEMU reflects 44the new setting. 45 46These have been tested in QEMU 3.0.0. 47