Windows Virtual Machines randomly crash and blue screen errors when running on RHEL 8 based hypervisors

Environment

• Red Hat Virtualization (RHV) 4.4
• Red Hat Enterprise Linux (RHEL) 8
  • 8.3
  • 8.4
  • 8.5
• KVM

Issue

• Windows VMs reboot randomly.
• Windows VMs display blue screen errors (BSOD) with traces of memory corruption.

Resolution

• Upgrade hypervisor to latest RHEL 8.4.z, this was fixed by RHSA-2022:0777 in kernel-4.18.0-305.37.1.el8_4.
• Upgrade hypervisor to latest RHEL 8.5.z, this was fixed by RHSA-2022:0825 in kernel-4.18.0-348.15.1.el8_5.

Workarounds

* Red Hat Virtualization: edit the Virtual Machine and set the Operating System to `Other`, this will disable all Hyper-V enlightenments, including `tlbflush`.
* RHEL 8 KVM: edit the Virtual Machine XML in `/etc/libvirt/qemu` and set the Hyper-V enlightenment named `tlbflush` to `off`, as below:

                <hyperv>
                      ...
                      <tlbflush state='off'/>
                      ...
                </hyperv>

Root Cause

• This is a KVM bug that causes the Virtual Machine memory to appear corrupted. It is being investigated in This content is not included.Bugzilla 1868572 - Windows guest random Bsod when 'hv-tlbflush' enlightenment is enabled.

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