Recently, while working on a baremetal project, I encountered a bug in the QEMU version I was using. And unfortunately, it was the latest version that was available for my host distribution. However, the official QEMU lineup was much ahead and already had the fix for the bug, that I was stuck with. This is one of the reason why you may want to build the QEMU yourself from the source. Another scenario could be when you want to enable QEMU debugging logs or control certain QEMU features.

In this post, we are going to look how you can pull the QEMU source yourself and build on your linux host machine. I am sitting on an Ubuntu 20.04.3 LTS, but the steps should be the same for your host machine, you might just need to change the commands corresponding to your package manager.

Step 1 : Pulling the source

You can pull the source either as a tar file from QEMU downloads page or from its git repository https://gitlab.com/qemu-project/qemu.git.

code@slashinit 

code@slashinit:/opt$ sudo wget https://download.qemu.org/qemu-6.2.0.tar.xz
--2022-01-05 17:44:25--  https://download.qemu.org/qemu-6.2.0.tar.xz
Resolving proxy-wsa.esl.cisco.com (proxy-wsa.esl.cisco.com)... 72.163.217.104
Connecting to proxy-wsa.esl.cisco.com (proxy-wsa.esl.cisco.com)|72.163.217.104|:80... connected.
Proxy request sent, awaiting response... 200 OK
Length: 115667324 (110M) [application/x-xz]
Saving to: ‘qemu-6.2.0.tar.xz’

qemu-6.2.0.tar.xz                                   100%[=================================================================================================================>] 110.31M   814KB/s    in 2m 23s

2022-01-05 17:46:49 (791 KB/s) - ‘qemu-6.2.0.tar.xz’ saved [115667324/115667324]

code@slashinit:/opt$

Step 2 : Extract the tar file

In case you downloaded the source as a tar file, extract it.

code@slashinit 

code@slashinit:/opt$ sudo tar -xvf qemu-6.2.0.tar.xz
qemu-6.2.0/
qemu-6.2.0/.patchew.yml
qemu-6.2.0/ebpf/
qemu-6.2.0/ebpf/meson.build
qemu-6.2.0/ebpf/rss.bpf.skeleton.h
qemu-6.2.0/ebpf/ebpf_rss.c
qemu-6.2.0/ebpf/ebpf_rss.h
qemu-6.2.0/ebpf/trace.h
qemu-6.2.0/ebpf/trace-events
qemu-6.2.0/ebpf/ebpf_rss-stub.c
qemu-6.2.0/.gitlab-ci.yml
...
...
qemu-6.2.0/subprojects/
qemu-6.2.0/subprojects/libvhost-user/
qemu-6.2.0/subprojects/libvhost-user/libvhost-user.c
qemu-6.2.0/subprojects/libvhost-user/meson.build
qemu-6.2.0/subprojects/libvhost-user/libvhost-user-glib.c
qemu-6.2.0/subprojects/libvhost-user/link-test.c
qemu-6.2.0/subprojects/libvhost-user/standard-headers/
qemu-6.2.0/subprojects/libvhost-user/standard-headers/linux
qemu-6.2.0/subprojects/libvhost-user/libvhost-user.h
qemu-6.2.0/subprojects/libvhost-user/include/
qemu-6.2.0/subprojects/libvhost-user/include/atomic.h
qemu-6.2.0/subprojects/libvhost-user/libvhost-user-glib.h
qemu-6.2.0/qemu.nsi
code@slashinit:/opt$

Step 3 : Install dependencies

code@slashinit 

code@slashinit:/opt$ sudo apt-get install ninja-build libglib2.0-dev libpixman-1-dev

Step 4 : Configure

code@slashinit 

code@slashinit:/opt$ cd qemu-6.2.0
code@slashinit:/opt/qemu-6.2.0$
code@slashinit:/opt/qemu-6.2.0$ ./configure
Using './build' as the directory for build output
The Meson build system
Version: 0.59.3
Source dir: /opt/qemu-6.2.0
Build dir: /opt/qemu-6.2.0/build
Build type: native build
Project name: qemu
Project version: 6.2.0
...
...
    libdaxctl support            : NO
    libudev                      : NO
    FUSE lseek                   : NO
    selinux                      : YES 3.0

  Subprojects
    libvhost-user                : YES

Found ninja-1.10.0 at /usr/bin/ninja

code@slashinit:/opt/qemu-6.2.0$

Step 5 : Make

code@slashinit 

code@slashinit:/opt/qemu-6.2.0$ make -j24
changing dir to build for make ""...
make[1]: Entering directory '/opt/qemu-6.2.0/build'
/usr/bin/ninja  build.ninja && touch build.ninja.stamp
ninja: no work to do.
/usr/bin/python3 -B /opt/qemu-6.2.0/meson/meson.py introspect --targets --tests --benchmarks | /usr/bin/python3 -B scripts/mtest2make.py > Makefile.mtest
  AS      multiboot.o
  AS      multiboot_dma.o
  AS      linuxboot.o
  CC      linuxboot_dma.o
  AS      kvmvapic.o
  AS      pvh.o
  CC      pvh_main.o
  BUILD   multiboot.img
  BUILD   multiboot_dma.img
  BUILD   linuxboot.img
  BUILD   linuxboot_dma.img
  BUILD   kvmvapic.img
  BUILD   pvh.img
  BUILD   multiboot_dma.raw
  BUILD   linuxboot.raw
  BUILD   linuxboot_dma.raw
  BUILD   multiboot.raw
  BUILD   pvh.raw
  BUILD   kvmvapic.raw
  SIGN    multiboot_dma.bin
  SIGN    multiboot.bin
  SIGN    kvmvapic.bin
  SIGN    pvh.bin
  SIGN    linuxboot_dma.bin
  SIGN    linuxboot.bin
[1/9610] Generating 'libqemu-alpha-linux-user.fa.p/syscall_nr.h'.
[2/9610] Compiling C object libcapstone.a.p/capstone_MCInstrDesc.c.o
  ...
  ...
[9609/9610] Compiling C object libqemu-xtensaeb-linux-user.fa.p/target_xtensa_core-dsp3400.c.o
[9610/9610] Linking target qemu-xtensaeb
make[1]: Leaving directory '/opt/qemu-6.2.0/build'
changing dir to build for make ""...
make[1]: Entering directory '/opt/qemu-6.2.0/build'
[1/177] Generating QAPI test (include) with a custom command
[2/144] Generating qemu-version.h with a custom command (wrapped by meson to capture output)
make[1]: Leaving directory '/opt/qemu-6.2.0/build'
code@slashinit:/opt/qemu-6.2.0$

The binaries can be found in the build/ folder.

Categories: Debugging , Virtualization , Assembly Tags: #qemu , #debugging , #virtualization , #assembly