This file describes the virtual device of qemu for supporting this test suite.

Services supplied by the testdev device:

serial output: write only, on io port 0xf1
exit process: write only, on io port 0xf4, value used as exit code
ram size: read-only, on io port 0xd1, 4 bytes' size
irq line setting: write only, on io ports 0x2000 - 0x2018, value to set/clear
simple io: read/write, on io port 0xe0, 1/2/4 bytes

Test device used a char device for actual output