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Michael Clark edited this page Apr 25, 2018 · 36 revisions

RISC-V QEMU

Welcome to the riscv-qemu wiki!

Overview

The RISC-V QEMU port implements the following specifications:

  • RISC-V Instruction Set Manual Volume I: User-Level ISA Version 2.2
  • RISC-V Instruction Set Manual Volume II: Privileged ISA Version 1.9.1
  • RISC-V Instruction Set Manual Volume II: Privileged ISA Version 1.10

The RISC-V QEMU port supports the following instruction set extensions:

  • RV32GC with Supervisor-mode and User-mode (RV32IMAFDCSU)
  • RV64GC with Supervisor-mode and User-mode (RV64IMAFDCSU)

The QEMU Wiki platform page for RISC-V is here:

Targets

The RISC-V QEMU port supports the following targets:

  • riscv32-softmmu (RV32 full-system emulator)
  • riscv64-softmmu (RV64 full-system emulator)
  • riscv32-linux-user (RV32 linux user-mode emulator)
  • riscv64-linux-user (RV64 linux user-mode emulator)

Features

The RISC-V QEMU port supports the following hardware blocks and features:

  • HTIF Console (Host Target Interface)
  • SiFive CLINT (Core Local Interruptor) for Timer interrupts and IPIs
  • SiFive PLIC (Platform Level Interrupt Controller)
  • SiFive Test (Test Finisher) for exiting simulation
  • SiFive UART, PRCI, AON, PWM, QSPI support is partially implemented
  • VirtIO MMIO (GPEX PCI support will be added in a future patch)
  • Generic 16550A UART emulation using 'hw/char/serial.c'
  • MTTCG and SMP support (PLIC and CLINT) on the 'virt' machine

Machines

The RISC-V QEMU full system emulator supports 5 machines:

  • 'spike_v1.9.1'; CLINT, PLIC, HTIF console, config-string, Priv ISA v1.9.1
  • 'spike_v1.10'; CLINT, PLIC, HTIF console, device-tree, Priv ISA v1.10
  • 'sifive_e'; CLINT, PLIC, SiFive UART, HiFive1 compat, Priv ISA v1.10
  • 'sifive_u'; CLINT, PLIC, SiFive UART, device-tree, Priv ISA v1.10
  • 'virt'; CLINT, PLIC, 16550A UART, VirtIO, device-tree, Priv ISA v1.10

Build and Install

Building the full system emulator and the user mode emulator on Linux:

git clone --recursive https://github.com/riscv/riscv-qemu.git
cd riscv-qemu
./configure \
    --target-list=riscv64-softmmu,riscv32-softmmu,riscv64-linux-user,riscv32-linux-user
make -j$(nproc)
make install

Building the full system emulator on macOS or other platforms:

git clone --recursive https://github.com/riscv/riscv-qemu.git
cd riscv-qemu
./configure \
    --target-list=riscv64-softmmu,riscv32-softmmu
make -j$(nproc)
make install

Invocation

Invoking the spike machine:

qemu-system-riscv64 -nographic -machine spike_v1.10 -kernel bbl-linux-4.15

Note: this depends on bbl configured with a linux kernel plus initramfs payload.

Invoking the sifive_e300 machine with a HiFive1 binary:

qemu-system-riscv32 -nographic -machine sifive_e -kernel freedom-e-sdk/software/hello/hello

Note: this depends on SiFive's freedom-e-sdk examples compiled for the HiFive1.

Invoking the virt machine with virtual disk and tun/tap networking:

qemu-system-riscv64 -nographic -machine virt -kernel bbl-linux-4.15 \
    -append "root=/dev/vda ro console=ttyS0" \
    -drive file=root.bin,format=raw,id=hd0 \
    -device virtio-blk-device,drive=hd0 \
    -netdev type=tap,script=qemu-ifup,downscript=qemu-ifdown,id=net0 \
    -device virtio-net-device,netdev=net0

Note: this depends on a filesystem in root.bin as well as qemu-ifup and qemu-ifdown scripts for your platform. The invoking user also requires privileges to create the tun/tap device.

Linux Images

Here are instructions for building a busybox+dropbear root image for the virt machine:

Information on the most recent Fedora images for RISC-V:

Information on the most recent Debian images for RISC-V:

Below are instructions for building riscv-qemu, riscv-linux, and a root filesystem based on buildroot using SiFive's freedom-u-sdk:

Note: When building freedom-u-sdk, make sure to unset the RISCV environment variable because buildroot needs a specific version of riscv-gnu-toolchain which is included in the freedom-u-sdk.

unset RISCV
git clone --recursive https://github.com/sifive/freedom-u-sdk.git
cd freedom-u-sdk
make qemu

Linux SMP Support

To use SMP support in riscv-linux, you'll need a recent version of riscv-qemu, either riscv-next or at least the qemu-upstream-v5 branch. You will also need to use the virt machine which is currently the only machine that allows more than 1 processor (up to 8 processor with the default version of riscv-pk/bbl).

To build an SMP kernel,checkout riscv-linux and configure with defaults:

git clone --depth 1 --branch riscv-linux-4.15 https://github.com/riscv/riscv-linux.git
cd riscv-linux
make ARCH=riscv defconfig

Note: Shallow clone is used for speed as this only downloads the required objects, not the entire linux history. If you want to be able to switch branches them omit the --depth 1 option from the command line.

Run menuconfig:

git clone https://github.com/riscv/riscv-linux.git
cd riscv-linux
make ARCH=riscv menuconfig

Enable SMP:

  • "Platform Type" -> "Symmetric Multi-Processing" = [*]

Select Compiler:

  • "General Setup" -> "Cross-compiler tool prefix" = riscv64-unknown-elf

Build Linux kernel:

make ARCH=riscv -j$(nproc)

Check out riscv-pk and build:

cd ..
git clone https://github.com/riscv/riscv-pk.git
cd riscv-pk
mkdir build
cd build
../configure --host=riscv64-unknown-elf --with-payload=../../riscv-linux/vmlinux
make
cp bbl ../../qemu-images/bbl-linux-4.15

To enable SMP in QEMU, add -smp cpus=4 to the command line.

This command line invokes the virt machine with 4 CPUs and a root filesystem in root.bin:

qemu-system-riscv64 -nographic -machine virt -smp cpus=4 \
    -kernel qemu-images/bbl-linux-4.15 \
    -append "root=/dev/vda ro" \
    -drive file=root.bin,format=raw,id=hd0 \
    -device virtio-blk-device,drive=hd0`

SMP has been tested with the following riscv-linux branches.

Contributors

This is a list of RISC-V QEMU Port Contributors:

  • Alex Suykov
  • Andreas Schwab
  • Antony Pavlov
  • Bastian Koppelmann
  • Bruce Hoult
  • Chih-Min Chao
  • Daire McNamara
  • Darius Rad
  • David Abdurachmanov
  • Hesham Almatary
  • Ivan Griffin
  • Jim Wilson
  • Kito Cheng
  • Michael Clark
  • Palmer Dabbelt
  • Richard Henderson
  • Sagar Karandikar
  • Shea Levy
  • Stefan O'Rear
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