Hi everyone !
The fix included in Qemu 7.0 seems to work fine.
No VM from Windows 2012 to 2022 has more problems in reboot.
Windows 2008 never introduced them.
There remains a small problem, in my opinion related, at least to the timer and long time to run type.
All Windows 7 VMs (and only those), I'm talking about a dozen VMs with different histories ... import from vmware, import from bare metal, etc. all working perfectly (within Windows limits) when restarted after a prolonged uptime (greater than 15-20 days) typically during the upgrade phase (yes, we will use them until 12/31 with extended security support) they crash in the reboot phase. All the same way, but BEFORE the reboot ... windows reboot in progress and they remain (stop start and as usual the problem is solved). If I restart the VM after a shorter uptime, no problem.
It looks like something related to the problem just solved, but it shows up in the pre-reboot reboot phase and not immediately after the reboot.
I forgot, the problem also occurred in Qemu 6.x