port-amd64/59769: Booting 10.1/amd64 from qemu, keyboard input at boot menu doesn't work

[riz%tastylime.net@localhost]

>Number:         59769
>Category:       port-amd64
>Synopsis:       Booting 10.1/amd64 from qemu, keyboard input at boot menu doesn't work
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-amd64-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Nov 16 22:00:00 +0000 2025
>Originator:     Jeff Rizzo
>Release:        NetBSD 11.0_BETA
>Organization:
>Environment:
NetBSD rambutan.tastylime.net 11.0_BETA NetBSD 11.0_BETA (GENERIC) #0: Fri Nov 14 15:25:51 PST 2025  riz%rambutan.tastylime.net@localhost:/tank/netbsd/netbsd-11/obj/sys/arch/amd64/compile/GENERIC amd64
>Description:
When booting a virtual machine under qemu 10.1.0 like so:

qemu-system-x86_64 -cdrom boot-com.iso -nographic

... the bootloader splash screen does not get any keyboard input.  Once the VM is booted, keyboard works normally.

Reporting this with the 10.1 boot-com.iso, but the problem happens on current (11.99.4) as well.
>How-To-Repeat:
pkgin install qemu
ftp ftp https://nycdn.netbsd.org/pub/NetBSD-daily/HEAD/20251116090151Z/amd64/installation/cdrom/boot-com.iso

Start the VM like so:

qemu-system-x86_64 -cdrom boot-com.iso -nographic

...observe the splash screen counting down, try to stop the countdown.

>Fix: