My qemu builds and simple script to install it on ubuntu 18.04(maybe works on Disco, Eoan, Focal, etc)

install_new_qemu-mm -> install new qemu binary and allow it in apparmor

You must set the path in libvirt domain configuration to the correct QEMU binary:

<devices>
...
<emulator>/usr/local/bin/qemu4.2-system-x86_64</emulator>
...
</devices>

The path you're replacing probably was /usr/bin/kvm-spice or /usr/bin/kvm, but it is actually the QEMU binary and has nothing to do with the spice display. It's just how its named on Ubuntu.

Only steps, what i do is:

git clone https://github.com/qemu/qemu.git
mv qemu qemu-builds-mm
cd qemu-builds-mm
git checkout stable-4.2
git submodule init
git submodule update --recursive
apt install build-dep qemu
./configure --target-list=x86_64-softmmu --audio-drv-list=alsa,pa
make
git remote set-url origin https://git.my-web.xyz/milan/qemu-builds-mm.git
git add x86_64-softmmu -f
git commit -m after_configure_and_make
git push

Make install_new_qemu-mm and README.md

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