Application on VM causing BSOD

Pilow

@tsukraw disable VIRIDIAN in advanced tab of the VM ? and put network card in E1000 (I think this one is taken into account only if PV Tools are not present)

restart VM and relaunch app ?

you could also try to prevent debug registers to happen, in the VM :

bcdedit /enum

to check current config

bcdedit /debug off
shutdown /r /t 0

to disable debug

tsukraw

@Pilow said:

bcdedit /debug off

Thank you @pilow fir the ideas but neither were fruitful
I have disabled VIRIDIAN and set the debug to off and both resulted in the system crashing and rebooting.

Pilow

@tsukraw if it's working on VMWARE, and same OS/same app, there is some cpu flag that is not presented in xen/xcp to the app that provoke the crash I guess

above my level of competency to know for sure how to mask CPU flags in a VM params

does bcdedit /enum tells auto for hypervisorlaunchtype ?

if yes, try to

bcdedit /set hypervisorlaunchtype off
shutdown /r /t 0

summoning some pro support guru ... @danp ?

flakpyro

After the VM crashes check for output from "xl dmesg" on the hypervisor via ssh. It may provide some information on why the VM crashed.

I ran into an issue with Blue Iris crashing on recent Intel CPUs and the fix was to relax MSR enforcement on the VM by running:

xe vm-param-add uuid=VM_UUID param-name=platform msr-relaxed=true

However this was after determining this was the issue via xl dmesg.

tsukraw

I tried bcdedit /set hypervisorlaunchtype off
This did not make any difference.

Attached is the output form the "xl dmesg"
Not 100% sure what I would expect to see in here.
One thing i thought was odd and maybe it isnt but the fact is asy VIRIDIAN even though i turned that off under the advanced settings for the VM in question.
xl dmesg.txt

tsukraw

Hot damn!!

@flakpyro
For kicks and giggles I tried what you had sent

xe vm-param-add uuid=VM_UUID param-name=platform msr-relaxed=true

And sure enough it worked!!
Not exactly sure the technical details on what setting msr-relaxed=true does but hey if it works it works

flakpyro

@tsukraw Another thing i remember from my time troubleshooting blue iris was capturing a crash dump using Xentrace:

xentrace -D -e 0x0008f000 xentrace.dmp

From there i was able to determine the MSR related issue. Not at all saying thats the issue you are having but it may shed some light or be useful for those more knowledgeable with Xen than myself.

dinhngtu

Hi, it's a known issue on newer CPUs: https://docs.xcp-ng.org/troubleshooting/windows-pv-tools/#bsod-0x3b-system_service_exception-on-newer-intel-cpus

~~What's your CPU Vendor value shown in xl dmesg?~~

Never mind, I missed your log: CPU Vendor: Intel, Family 6 (0x6), Model 143 (0x8f), Stepping 8 (raw 000806f8)

TeddyAstie

@tsukraw Can you give the output of xen-cpuid -p (in Dom0) ?

flakpyro

@tsukraw Glad this helped!