On Tue, 11 Jan 2022 18:46:59 +0300
Andrew Randrianasulu <randrianasulu@gmail.com> wrote:

<snip>
> > > I think you already using system mode (full system emulation - so
> > > you can run NetBsd or MacOS or windows - they see emulated/virtual
> > > machine to run on..) User-mode qemu run Linux binaries on top of
> > > same kernel BUT they can belong to another architecture! So
> > > overhead can be less.. (no mmu emulation). You can edit files
> > > inside proot 'vm' from host - no need for samba/nfs. 
> >
> > I have macOS in user mode, it runs fine (but need to re-install). It
> > also ran fine in system mode (since deleted). I have not checked if
> > there is a speed difference between the two nodes, nothing very
> > noticable anyway. 
>
>
> I think your terminology on system/user modes a bit different from
> assumed by qemu?
>
> Can you try to explain what you mean by those two modes in your own
> words/experience?

In virt-manager you can have two kinds of VMs: QEMU/KVM and QEMU/KVM
User Session. The first is referred to as "system", the second as
"session". The default on Fedora_35 is (user) session, where qemu runs
under the user's profile. If you use virsh to e.g.
edit the VM's config you can type e.g. "virsh edit Debian11_aarch64" .
If you want to use a VM under system, you have to type "virsh --connect
qemu:///system edit Debian11_aarch64".
The VMs have a different domain specified in the XML that defines a VM.
user mode has domain "qemu", system mode domain "kvm".
I noticed that whereas in user (session) mode you can define pretty
much any hardware for the VM, in system mode some things are not
available, like PCIe controllers.

MatN