Kernel panic

This morning one of my freeBSD production machine did crash. Beeing a
VM running under qemu/kvm on an ubuntu linux hardware, I was unable to
get the panic video message issued when the machine crashed. Of course
at the reboot I got a vmcore file in /var/crash, along with core.txt
and info. The file core.txt says:

Unable to find a kernel debugger.
Please install the devel/gdb port or gdb package.

while the info file is:

Dump header from device: /dev/vtbd0s2b
  Architecture: powerpc64
  Architecture Version: 1
  Dump Length: 865083392
  Blocksize: 512
  Compression: none
  Dumptime: 2023-09-19 09:04:31 +0200
  Hostname: numeron
  Magic: FreeBSD Kernel Dump
  Version String: FreeBSD 13.1-RELEASE-p5 releng/13.1-n250174-753d65a19a55 GENERIC
  Panic String: data storage interrupt trap
  Dump Parity: 907562729
  Bounds: 1
  Dump Status: good

what shoukd I do to know what did kill my machine?

Thanks to all,

Luciano.
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