RealTimeIsUniversal - Windows VM - PV driver does not work

jiri.hadamek

We installed new VM (Windows 11 - 24H2) in XCP-ng (latest-version, from source).
Everything works fine, XEN tools work fine

Management agent 9.4.1-160 detected and works

We set-up in windows registry QWORD value HKLM\CurrentControlSet\CurrentControl\TimeZoeInformation\RealTimeIsUniversal=1
(We need this settings for many computers/VM with dual boot)

The VM cannot boot with using PV drivers - it use QEMU drivers.

2, in XOA the VM reported "management agent NOT installed" (In windows is reported as installed)

XOA is unable report memory usage

If we tried to remove (manualy, by GPO or by script) this registry entry, VM is unable to boot (error: unaccesible boot device) or crashed (rarely).

I think it is bug in management agent/PV drivers for Windows.
Have you any solution for using PV drivers in Windows with setting BIOS/UEFI using real time clock as UTC?

olivierlambert

Hi,

Question for @dinhngtu

dinhngtu

@jiri.hadamek The drivers don't like that value being a REG_QWORD. Try using REG_DWORD instead.

jiri.hadamek

@dinhngtu "The drivers don't like that value being a REG_QWORD" - if you mean by that: "The PV driver doesn´t work correctly with qword value" then I will try set it to REG_DWORD even every documentation on Internet and in Microsoft demand QWORD.

Then I will put result here.

jiri.hadamek

With DWORD value the PV drivers work.
But the PV driver´s instability with QWORD value is worth to "be corrected". (by my opinion)

Solved.

dinhngtu

@jiri.hadamek Yes, it's a driver bug. I'll plan for a fix.

dinhngtu

Fix committed upstream.