xref: /openbmc/u-boot/doc/README.qemu-riscv (revision 17f2ffea)
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