玩转RISC-V系列1 在QEMU中运行RISC-V

本系列逐步RISC-V的相关知识，范围可能比较广，也可能有时比较专，都是实际用到的使用经验，自己做个笔记也希望能帮助一同学习的朋友们。

一重功力：快速启动RISC-V的方法[1]

apt install opensbi  u-boot-qemu qemu-system-misc

## risc-v ubuntu image 官网 https://ubuntu.com/download/risc-v
wget https://cdimage.ubuntu.com/releases/24.04.2/release/ubuntu-24.04.2-preinstalled-server-riscv64.img.xz
xz -d ubuntu-24.04.2-preinstalled-server-riscv64.img.xz

./qemu/build/qemu-system-riscv64        \                                              
        -machine virt -vga none -nographic -m 2048 -smp 4       \                      
        -kernel /usr/lib/u-boot/qemu-riscv64_smode/uboot.elf    \                      
        -device virtio-rng-pci  \                                                      
        -drive file=ubuntu-24.04.2-preinstalled-server-riscv64.img,format=raw,if=virtio

二重功力：内核+QEMU+busybox开发流程[2]

依赖包

apt install autoconf automake autotools-dev curl libmpc-dev libmpfr-dev libgmp-dev \
            gawk build-essential bison flex texinfo gperf libtool patchutils bc \
            zlib1g-dev libexpat-dev github

REPOS

git clone https://github.com/torvalds/linux
git clone https://github.com/qemu/qemu
git clone https://git.busybox.net/busybox

QEMU编译安装

./configure --target-list=riscv64-softmmu
make -j $(nproc)
sudo make install

内核编译

cd linux
make ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- defconfig
make ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- -j $(nproc)

编译busybox

cd busybox
git chekcout 1_36_stable # 其他稳定版本都编译不过
修改.config中这个配置如下：
CONFIG_TC=n

make menuconfig
勾选选项 "Settings/Build static binary(no shared libs)" [3]

CROSS_COMPILE=riscv64-linux-gnu- make oldconfig
CROSS_COMPILE=riscv64-linux-gnu- make -j $(nproc)
CROSS_COMPILE=riscv64-linux-gnu- make install

创建文件系统rootfs

Option 1/N busybox生成rootfs

# Create root filesystem image
mkdir rootfs
cd rootfs
dd if=/dev/zero of=rootfs.img bs=1M count=50
mkfs.ext2 -L riscv-rootfs rootfs.img
sudo mkdir /mnt/rootfs
sudo mount rootfs.img /mnt/rootfs
sudo cp -ar ../_install/* /mnt/rootfs
sudo mkdir /mnt/rootfs/{dev,home,mnt,proc,sys,tmp,var}
sudo chown -R -h root:root /mnt/rootfs
sudo umount /mnt/rootfs
sudo rmdir /mnt/rootfs

Option 2/N buldroot生成rootfs

cd $WORK_DIR/
git clone https://github.com/buildroot/buildroot.git
cd $WORK_DIR/buildroot
make qemu_riscv64_virt_defconfig
make rootfs-ext2

运行QEMU 自编译内核+busybox

sudo qemu-system-riscv64 -nographic -machine virt \
     -kernel linux/arch/riscv/boot/Image -append "root=/dev/vda ro console=ttyS0" \
     -drive if=none,file=rootfs.img,format=raw,id=hd0 \
     -device virtio-blk-device,drive=hd0

三重功力：内核 + QEMU + UEFI + UbuntuOS + opensbi开发流程

REPOS

git clone https://github.com/tianocore/edk2.git tianocore/edk2
git clone https://github.com/tianocore/edk2-platforms.git tianocore/edk2-platforms

Workaround

edk2 repo:
git checkout 3c0d567c3719675b9d8ecf07c31706d96467e31b
git submodule update --init --recursive --force

edk2-platforms:
git checkout 727e458d638784d5e1e9385c61ffc28f23809109
git submodule update --init --recursive --force
git am --3way --ignore-space-change --keep-cr 0001-Riscv-support-based-on-Qemu-mode.patch

编译opensbi (已经默认集成到了QEMU，可以不需要这步了)

这步的产出是一个elf，作为bios, 通过QEMU的-bios参数传递。

git clone https://github.com/riscv-software-src/opensbi.git
cd $WORK_DIR/opensbi
make ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- PLATFORM=generic

编译EDK2 [4]

git clone --recurse-submodule git@github.com:tianocore/edk2.git
export WORKSPACE=`pwd`
export GCC5_RISCV64_PREFIX=riscv64-linux-gnu-
export PACKAGES_PATH=$WORKSPACE/edk2
export EDK_TOOLS_PATH=$WORKSPACE/edk2/BaseTools

#最新的edk2 已经包含了RiscVVirtQemu
#export PACKAGES_PATH=$WORKSPACE/edk2:$WORKSPACE/edk2-platforms
git submodule update --init --recursive
source edk2/edksetup.sh --reconfig
make -C edk2/BaseTools clean
make -C edk2/BaseTools

source edk2/edksetup.sh BaseTools
build -a RISCV64 --buildtarget RELEASE -p OvmfPkg/RiscVVirt/RiscVVirtQemu.dsc -t GCC5
 
truncate -s 32M Build/RiscVVirtQemu/RELEASE_GCC5/FV/RISCV_VIRT_CODE.fd
truncate -s 32M Build/RiscVVirtQemu/RELEASE_GCC5/FV/RISCV_VIRT_VARS.fd

上面的build参数可以在edk2-platforms/Conf/target.txt中配置：

edk2-platforms/Conf/target.txt:
ACTIVE_PLATFORM       = Platform/Qemu/RiscvVirt/RiscVPlatformPkg.dsc
TARGET                = DEBUG
TARGET_ARCH           = RISCV64
TOOL_CHAIN_TAG        = GCC5

运行QEMU

#!/bin/bash
./qemu/build/qemu-system-riscv64	\
    -M virt,pflash0=pflash0,pflash1=pflash1,acpi=off \
    -vga none  -nographic -m 4096 -smp 1 \
    -serial mon:stdio \
    -device virtio-rng-pci \
    -blockdev node-name=pflash0,driver=file,read-only=on,filename=RISCV_VIRT_CODE.fd \
    -blockdev node-name=pflash1,driver=file,filename=RISCV_VIRT_VARS.fd \
    -drive file=isar-image-riscv-devel-debian-sid-ports-qemuriscv64.wic,format=raw,if=virtio
#    -drive if=none,file=ubuntu-24.04.2-preinstalled-server-riscv64.img,format=raw,id=hd0 \
#    -device virtio-blk-device,drive=hd0

参考

[1]https://canonical-ubuntu-boards.readthedocs-hosted.com/en/latest/how-to/qemu-riscv/
[2]https://risc-v-getting-started-guide.readthedocs.io/en/latest/linux-qemu.html
[3]https://github.com/riscvarchive/risc-v-getting-started-guide/issues/29
[4]https://github.com/riscv-admin/riscv-uefi-edk2-docs?tab=readme-ov-file
[5]https://lf-rise.atlassian.net/wiki/spaces/HOME/pages/8589371/EDK2_00_18+-+RISC-V+QEMU+Server+Reference+Platform