[SeaBIOS] QEMU detect and PCI Configuration Space

[SeaBIOS]

Dear all,
     I am reading the source code of SeaBIOS. In QEMU detection part (qemu_detect()), I notice the method to detect QEMU is the same as detect other PCI devices through PCI Configuration Space (I/O port: 0xcf8 and 0xcfc). Does QEMU emulate the PCI Configuration Space?  Any help or comments will be appreciated.

Thank you
Best,

Min Li