Windows 10/11 HVMs with Xen PV drivers installed are unbootable, and installation crashes the VM

[jcoscia]

Qubes OS release

Qubes OS 4.2.1
QWT 4.1.69

Brief summary

After upgrading from Qubes 4.1.2 to 4.2.1 (clean install), I found that installing the Xen PV drivers in a Windows 10 or 11 HVM using QWT or the (proprietary?) XenServer VM Tools causes the VM to crash upon installation, and become unbootable. The boot process will hang on the Windows logo, so no error message or BSOD. This occurs both on VMs restored from backup, and new VMs created in 4.2.1.

Restoring to an earlier System Restore point makes the VM bootable again, presumably by removing the drivers. Installing the Qubes Core Agent without the Xen PV drivers does not break the system.

Installing the Xen PV drivers from https://xenbits.xen.org/pvdrivers/win/ doesn't work; the install fails for no discernible reason, but also with no adverse effects. This may or may not be a separate issue.

Steps to reproduce

1. Install Windows 10/11 in an HVM.
2. Install QWT, and select the Xen PV drivers. Alternatively, install the XenServer VM Tools
3. The VM becomes unresponsive and crashes.
4. Reboot, and observe the system hanging on the Windows logo.

Expected behavior

Installing the Windows PV drivers via QWT does not break the system, and the drivers are functional.

Actual behavior

Installing the Windows PV drivers via QWT crashes the system and renders it unbootable, until the change is reverted.

[andrewdavidwong]

Possible duplicate of #1861 (and partially #9102).