install/56885: Starting NetBSD-9.99 in a VirtualBox with 3 CPUs hangs at startup

[roland.illig%gmx.de@localhost]

>Number:         56885
>Category:       install
>Synopsis:       Starting NetBSD-9.99 in a VirtualBox with 3 CPUs hangs at startup
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    install-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Jun 14 21:25:00 +0000 2022
>Originator:     Roland Illig
>Release:        9.99.97
>Organization:
>Environment:
NetBSD nbinst.fritz.box 9.99.97 NetBSD 9.99.97 (GENERIC) #0: Mon Jun 13 20:16:53 UTC 2022  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/amd64/compile/GENERIC amd64
>Description:
Install NetBSD in a VirtualBox VM, using the default settings.
I am using VirtualBox 6.1.34r150636 on Windows.
Shut down the VM.
In VirtualBox, change the CPUs from 1 to 3.
Start the VM.

The VM hangs after the following green line:
[   4.0805657] : NetBSD (0x0000) OHCI root hub(0x0000), class 9/0, rev 1.00/1.00, addr 1

After that, there is no further progress, all 3 CPUs are busy.
Typing some keys doesn't show anything on the screen.
Pressing Num Lock, Caps Lock or Scroll Lock toggles the keyboard LEDs.
The VirtualBox statistics show high VM exits between 10k and 20k per second.

Killing the VM and then starting it with a single CPU works flawlessly.

I tried it a few more times:

 2. works fine
 3. hang after 'acpicpu2 at cpu2: ACPI CPU'
 4. hang after 'acpicpu2 at cpu2: ACPI CPU'
 5. hang after 'acpicpu2 at cpu2: ACPI CPU'
 6. hang after 'acpicpu2 at cpu2: ACPI CPU'
 7. hang after 'acpicpu2 at cpu2: ACPI CPU'
 8. hang after 'acpicpu2 at cpu2: ACPI CPU'
 9. (with 1 CPU) works fine
10. (with 3 CPUs) boots successfully, fast keyboard (see PR 56883)
11. hang after 'acpicpu2 at cpu2: ACPI CPU'
12. hang after 'acpibat0: normal capacity on 'charge state'' (3 CPUs busy)
13. hang after 'acpicpu2 at cpu2: ACPI CPU'
>How-To-Repeat:

>Fix: