Why Huge pages must be enabled to boot a FreeBSD VM?

[Breno Leitao]

Hello,

I am wondering why Huge pages must be enabled in the hypervisor (KVM) in
order to boot FreeBSD as a guest.

I was facing the issue below, and then I found that I didn't have enough huge
pages available. Enabling the amount of huge pages available solved this issue.

  Kernel entry at 0x1023c0 ...
  panic: Page replacement error: -4
  cpuid = 0
  KDB: stack backtrace:
  #0 0x6144fc at ??+0
  #1 0x614598 at ??+0
  #2 0xa7b078 at ??+0
  #3 0xa31544 at ??+0
  #4 0xa33010 at ??+0
  #5 0xa7b480 at ??+0
  #6 0xa6b2bc at ??+0
  #7 0xa64c74 at ??+0
  #8 0x102458 at ??+0
  Uptime: 1s


If huge pages is not enabled, is there a way to proceed with normal pages
other than crashing the VM?

Thank you,
Breno