The below is from https://github.com/qemu/qemu:
The following points clarify the QEMU license:
QEMU as a whole is released under the GNU General Public License, version 2.
Parts of QEMU have specific licenses which are compatible with the GNU General Public License, version 2. Hence each source file contains its own licensing information. Source files with no licensing information are released under the GNU General Public License, version 2 or (at your option) any later version.
As of July 2013, contributions under version 2 of the GNU General Public License (and no later version) are only accepted for the following files or directories: bsd-user/, linux-user/, hw/vfio/, hw/xen/xen_pt*.
The Tiny Code Generator (TCG) is released under the BSD license (see license headers in files).
QEMU is a trademark of Fabrice Bellard.
Fabrice Bellard and the QEMU team