after latest stable update i can no longer launch my vms from virtual machine manager. i posted about it here: [Stable Update] 2021-12-16 - Kernels, KDE Gear 21.12.0, Gnome Extensions, LibreOffice - #55 by fredvej
Error starting domain: internal error: qemu unexpectedly closed the monitor: 2021-12-17T21:12:09.862776Z qemu-system-x86_64: warning: host doesn't support requested feature: MSR(48DH).vmx-posted-intr [bit 7]
2021-12-17T21:12:09.863790Z qemu-system-x86_64: warning: host doesn't support requested feature: MSR(48DH).vmx-posted-intr [bit 7]
2021-12-17T21:12:09.864289Z qemu-system-x86_64: warning: host doesn't support requested feature: MSR(48DH).vmx-posted-intr [bit 7]
2021-12-17T21:12:09.864664Z qemu-system-x86_64: warning: host doesn't support requested feature: MSR(48DH).vmx-posted-intr [bit 7]
qxl_send_events: spice-server bug: guest stopped, ignoring
kvm_set_irq: Input/output error
Traceback (most recent call last):
File "/usr/share/virt-manager/virtManager/asyncjob.py", line 65, in cb_wrapper
callback(asyncjob, *args, **kwargs)
File "/usr/share/virt-manager/virtManager/asyncjob.py", line 101, in tmpcb
callback(*args, **kwargs)
File "/usr/share/virt-manager/virtManager/object/libvirtobject.py", line 57, in newfn
ret = fn(self, *args, **kwargs)
File "/usr/share/virt-manager/virtManager/object/domain.py", line 1329, in startup
self._backend.create()
File "/usr/lib/python3.9/site-packages/libvirt.py", line 1353, in create
raise libvirtError('virDomainCreate() failed')
libvirt.libvirtError: internal error: qemu unexpectedly closed the monitor: 2021-12-17T21:12:09.862776Z qemu-system-x86_64: warning: host doesn't support requested feature: MSR(48DH).vmx-posted-intr [bit 7]
2021-12-17T21:12:09.863790Z qemu-system-x86_64: warning: host doesn't support requested feature: MSR(48DH).vmx-posted-intr [bit 7]
2021-12-17T21:12:09.864289Z qemu-system-x86_64: warning: host doesn't support requested feature: MSR(48DH).vmx-posted-intr [bit 7]
2021-12-17T21:12:09.864664Z qemu-system-x86_64: warning: host doesn't support requested feature: MSR(48DH).vmx-posted-intr [bit 7]
qxl_send_events: spice-server bug: guest stopped, ignoring
kvm_set_irq: Input/output error
people from the VFIO discord channel have the same issue on arch and one mentioned that rolling back to libvirt 7.8.0 works. i havent tried that but am trying to find discussion on the issue.