Migrate existing Mac installation to VirtualBox
It's completely legal if the host is also a Mac.
Use a disk cloning software (AFAIK CarbonCopyCloner/Superduper or anything else like that, not my area). It should be able to export to ISO. This command will apparently turn it into a virtualbox hard drive.
VBoxManage convertfromraw /path/to/output/disk-image.iso /path/to/output/disk-image.vdi
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