It is true that the machine contains 'pc-i440fx-4.0'. I am using Ubuntu18.04 and libvirt-4.0.0

This is probably a separate issue, but while updating the machine name neither "virsh define" or "virsh edit" updates the name to "pc".

I was reading the FAQ of libvirt on updating the configuration at :https://wiki.libvirt.org/page/FAQ#What_is_the_.27virsh_edit.27_command_and_how_do_I_use_it.3F

"... A common problem seen when people edit the on-disk XML is a VM that simply vanishes the next time libvirtd is restarted after the edit. The VM disappears from libvirt because the XML has become invalid, after which libvirt can't do anything with it. "

Is it also true for virsh?

I also tried creating a new VM by "virsh dumpxml" and editing the xml with new "name" and "pc" and removed the "uuid" field and then "virsh define". virsh creates a new domain with UUID, but with machine='pc-i440fx-4.0'. Is it possible the virsh is using some configuration that resetting to predefined machine name?

On Fri, Jul 19, 2019 at 12:36 PM Daniel P. Berrangé <berrange@redhat.com> wrote:

On Fri, Jul 19, 2019 at 12:16:25PM -0500, Probir Roy wrote:
> Hi,
>
> I am trying to run Qemu-4.0 installed from source code.
>
> When I run virt-manager to create a VM, I get the following error:
>
> ```
> Unable to complete install: 'internal error: process exited while
> connecting to monitor: 2019-07-19T17:06:35.954242Z qemu-system-x86_64:
> -enable-kvm: unsupported machine type
> Use -machine help to list supported machines'

You don't mention what your OS is ? Some OS vendors patch QEMU
to have different machine types than upstream QEMU provides, and
I guess that's what you've hit.

If you look in your libvirt XML 'virsh dumpxml $GUESTNAME' you'll
see a machine type listed - probably "pc-$SOMETHING" or "q35-$SOMETHING".

If you simply delete the "-$SOMETHING" part to leave just "pc" or
just "q35", then libvirt will expand the machine type into the
latest one available with your self-built QEMU

Regards,
Daniel
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