This is a proposal for PC System Flash emulation for on QEMU/KVM.

Flash Hardware

Leverage the pre-existing CFI flash support in qemu/hw/pflash_cfi01.c. (Another option is to use qemu/hw/pflash_cfi02.c.)

Command line interface

Currently the -pflash parameter has no use with an x86 or x86-64 system. To enable PC system flash, this parameter would now be used on x86 & x86-64 systems.

The -bios and -pflash parameters would both now have a use with qemu/kvm:

-bios used	-pflash used	Result
No	No	(no change) 'bios.bin' will be loaded as rom image.
No	Yes	(changing) -pflash parameter will be loaded as flash image just below 4GB. 'bios.bin' will be ignored.
Yes	No	(no change) -bios parameter will be loaded as rom image.
Yes	Yes	(changing) -bios parameter will be loaded as rom image just below 4GB. -pflash parameter will be loaded as flash image just below the bios rom image.

Known Issues

KVM will not boot if -pflash is used and -bios is not used. KVM currently only functions with this support if code is not attempting to run from the emulated flash. This issue does not affect QEMU.