qemu change virtual hardware after update

[Simon Becherer]

Hi,

i am new here on this list, so if this problem was discussed/solved
somewhere else, please point me to it.

i use qemu (at the moment 5.2) with virt-manager on opensuse tumbleweed.

is there a way to prevent qemu from updating virtualized hardware inside
the virtualization?

as example: sometimes when qemu is updated, the virtual machines OS
(windows 10 or windows xp) find new "hardware"
and at least in windows xp i have now a huge amount of broken
(most is invisible inside system-control) hardware. (this machine
runs since 2011)
and of course the "fingerprint" of the system will change.

there is the parameter -machine pc-q35-4.2
inside my command line. i was thinking this will stay always at same
hardware. but this parameter is since 15.juni2020 (generation of the
libvirt xml file) inside.
but after an update of my system and of course with the system also
qemu, in jan. 2021, some components
(not only but also the networkadapter), inside qemu has changed.
the networkadapter is also inside the config line: e1000e.
but windows10 has found a new one (a new e1000e) and i have
had to set for the new adapter my fixed ipv4 adres.

this results in my main problem:

i see this virtual-hardware-updates at least two times in the last 2 years.

and it brakes for me my installation of a proprietary software in win10 who has
a copy protection. i have then always to make a phone call to the
software company and ask for new key-number.
that's annoying. (i own a permanent license for one computer but the computer
should not change the hardware) - the host did not change, but qemu (or libvirt)
(but libvirt has always the same xml file, so i think its qemu itself) changed
the virtual hardware.
and maybe sometimes in future the company will tell me to buy support for the 
software.
because the license did not include support or phone calls for new
license numbers.

stay on same hardware do not update software "or anything", that is one of the 
reasons i like to use a
virtualized environment. and of course to be portable with the emulation to 
move on at host side
the hard and software.

so what must i do to tell qemu "stay ALWAYS on hardware qemu version X.y never 
change it."

simoN

-- 
www.becherer.de

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