[Software] Specific Action in Windows KVM Guest Crashes Host

[renbo]

Hi all!

I have set up a Debian server to act as a host for several guest VMs, most Windows machines of different flavors, and a few Linux instances. Everything has been good and stable for a while.

In one of my Windows VMs, I have set up a development environment. I am running Visual Studio Code, and using a plugin to remotely develop on a Raspberry Pi 4B that is on the network.

I can use VS to log into the remote machine, but shortly thereafter, things freeze up. When I go look at the host, it appears to be rebooting.

I am at a loss on how that action in a guest could lead to a halt and reboot of the host?!?

If anyone's got tips on how this can be prevented, I'd be most appreciative. I tried web searches, but nothing so far. I tried ChatGPT, but it seems to think I am fishing for ways to crash a host from the VM and refuses to chime in.

--Reynolds

[CwF]

Sounds serious. I hope you can capture the net traffic causing the issue, I'm not much an expert on that.

I have crashed host though, not lately, always hardware related.

In this case what is the method providing eth? Bios enabled VT srvio, promiscuous l1 modes, vlans, macvtaps, dedicated physical vfio? That's worst to best...

Also, the machine type may be relevant, defined in the vm's xml.
<emulator>/usr/bin/kvm</emulator>???
<type arch='x86_64' machine='pc-q35-???'>hvm</type>

If the host rebooted then a watchdog or something was alive, there may be some logging of a shutdown on the host. And you do mean a reboot and not a DE logoff/logon cycle? I've seen both of those, in addition to the last crash type where the watchdog eats the canary and dies requiring a manual power cycle.

[renbo]

Here's the eth config in KVM:

<interface type="bridge">
  <mac address="...obscured..."/>
  <source network="Internal10" portid="07230389-c99f-4ac7-b640-07180420a280" bridge="br10"/>
  <target dev="vnet21"/>
  <model type="virtio"/>
  <alias name="net0"/>
  <address type="pci" domain="0x0000" bus="0x01" slot="0x00" function="0x0"/>
</interface>

[renbo]

And machine type stuff:

  <vcpu placement="static">16</vcpu>
  <os>
    <type arch="x86_64" machine="pc-q35-7.2">hvm</type>
    <loader readonly="yes" secure="yes" type="pflash">/usr/share/OVMF/OVMF_CODE_4M.secboot.fd</loader>
    <nvram>/var/lib/libvirt/qemu/nvram/myfirmware.fd</nvram>
    <boot dev="hd"/>
  </os>

[CwF]

Here's the eth config in KVM:

Code: Select all

[pre]<interface type="bridge">
  <mac address="...obscured..."/>
  <source network="Internal10" portid="07230389-c99f-4ac7-b640-07180420a280" bridge="br10"/>
  <target dev="vnet21"/>
  <model type="virtio"/>
  <alias name="net0"/>
  <address type="pci" domain="0x0000" bus="0x01" slot="0x00" function="0x0"/>
</interface>[/pre]

Use the code tags like above, these are short, so readable.

I don't have much of a guess other than listing these factors and further duplication on your end.