Ubuntut 20.04 and QEMU Virt-Manager - Nested virtualization suddenly doesnt work

[TheOne]

Hello,


Ubuntut 20.04 and QEMU Virt-Manager - Nested virtualization suddenly doesnt work

Since Yesterday when i want start Windows 10 VM in Ubuntu 20.04 and QEMU 4.2.1 also tryed 5.2 and 6.2 and latest

i get this error:

qemu-system-x86_64: error: failed to set MSR 0x48f to 0xffffff00036dfb
qemu-system-x86_64: /home/user/qemu-4.2.1/target/i386/kvm.c:2691: kvm_buf_set_msrs: Assertion `ret == cpu->kvm_msr_buf->nmsrs' failed.

i have kvm ignore_msrs=1 and so on tryed ON and OFF like before it worked in XML

<cpu mode="host-passthrough" check="none" migratable="on">
    <topology sockets="1" dies="1" cores="11" threads="2"/>
    <cache mode="passthrough"/>
    <feature policy="require" name="hypervisor"/>
    <feature policy="disable" name="mpx"/>
    <feature policy="require" name="ibpb"/>
    <feature policy="require" name="md-clear"/>
    <feature policy="require" name="spec-ctrl"/>
    <feature policy="require" name="ssbd"/>
    <feature policy="require" name="invtsc"/>
  </cpu>

Anyone can help it worked now for years but now not anymore since apt update and apt upgrade need downgrade Ubuntu Linux Kernel?


i need CPU Host-Passthrough otherwise Windows 10 has no good performance like in all Windows 10 Gaming VM GPU Passthrough Tutorials stand and also i tested

Hope any one can help here also GRUB

 GRUB_CMDLINE_LINUX_DEFAULT="quiet splash intel_iommu=on kvm.ignore_msrs=1 video=efifb:off vfio-pci.ids=10de:2486,10de:228b,10de:2503,10de:228e isolcpus=3-13,17-27 nohz_full=3-13,17-27 rcu_nocbs=3-13,17-27 msr.allow_writes=on kvm.intel_nested=1"

A and
Ubuntu Linux Kernel
5.11.0-43-generic



and when start MacOS VM also with CPU Host-Passthrough it work witout an Error hmm

Thank ya
Kind Regards

 

[TheOne]

No one thank you some much hope can someone help im down cant fix try since days

 

[dcsapak]

what is your pveversion -v ? and the kernel version in the guest ? (uname -a)

Anyone can help it worked now for years but now not anymore since apt update and apt upgrade need downgrade Ubuntu Linux Kernel?

nested virtualization very much depends on the kernel, so yes changing the kernel version could help (but i'd suggest to upgrade the kernel version instead of downgrading..)