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dinhngtu

@john.c Indeed I skipped over the part that the host is still on 7.6, that's a rather big upgrade blocker I think.

dinhngtu

Also, I'd recommend upgrading to Server 2019 or even Server 2025 if that's feasible, since support for Server 2016 is ending soon anyway.

dinhngtu

@hrvojer You should remove old tools before doing an in-place upgrade because the older ones are almost guaranteed to cause upgrade failures or BSODs if they're still installed when the upgrade takes place. Also note that removal of older tools (and installation in some cases) will wipe out your static IP config if you happen to depend on it.

dinhngtu

@hrvojer Ever since 2012 R2 went out of support, there have been multiple compatibility breaks in the drivers and guest agents since they now target Server 2016+. It might be possible to get the drivers working on 2012 R2 in a testing environment, but bringing that to production is another topic.

dinhngtu

@hrvojer I can't tell for sure without detailed troubleshooting, but your crash reminds me of a bug in XenVbd that was fixed in the XCP-ng 9.1.200 tools (Apr 2026). It's unlikely that updating to an old Xen tools version would help in that case.

dinhngtu

@hrvojer There are many bugs in older versions of the Xen PV drivers. I suggest running Windows without guest tools and drivers if you can take the performance and functionality hit (no suspend/migration on UEFI VMs, no metric reporting, etc).

TeddyAstie

@bvitnik
Various reasons :

In some niche cases, it can cause compatibility issues with guests.
Viridian exposes additionnal attack surface e.g VSA-2025-006 and VSA-2026-031
and given that this is generally unused for non-Windows guests, there is no good reason to expose it to the guest

For Windows guests, use of the dedicated Windows template is strongly encouraged, as it brings additional viridian flags and other tunings for better compatibility and performance.

dinhngtu

Hello, this issue has been fixed in XAPI 26.1.19-1.1 available in the testing updates. For now you have to configure your VMs manually (https://docs.xcp-ng.org/troubleshooting/common-problems/#pci-passthrough-error-unsupported-msi-delivery-mode-7) but the fix will be activated by default in the future.

dinhngtu

@ovicz Which exact version of XAPI do you have? If you have 26.1.19-1.1 from testing, you should be able to fix it by setting hvm-pirq=false using the instructions here: https://docs.xcp-ng.org/troubleshooting/common-problems/#pci-passthrough-error-unsupported-msi-delivery-mode-7

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