It looks to me like this is fixed in the VirtualBox package in Sid:
user@ks-build-d13:~$ apt-file find
/usr/lib/modprobe.d/virtualbox-dkms.conf virtualbox-dkms:
/usr/lib/modprobe.d/virtualbox-dkms.conf user@ks-build-d13:~$ cat
/usr/lib/modprobe.d/virtualbox-dkms.conf #
# In kernel 6.12, KVM initializes virtualization on module loading
by # default. This prevents VirtualBox VMs from starting. In order
to # avoid this, block loading kvm module by default.
# (No need to do manually execute modprobe -r kvm_xxx and so on)
# See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1082157
#
options kvm enable_virt_at_load=0I verified that I am able to launch a VirtualBox VM with the kvm and kvm_intel modules loaded without adding any of my own modprobe or GRUB configuration. Should this bug be closed?
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