Revision as of 23:38, 13 March 2011

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

Today the (currently existing) -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.

@@ Line 8: / Line 8: @@
 an x86 or x86-64 system.  To enable PC system flash, this parameter
 would now be used on x86 & x86-64 systems.
-The -bios parameter would take priority over
+The -bios and -pflash parameters would both now have a use with qemu/kvm:
--pflash, but one or both could be used with qemu/kvm as follows:
 {| class='wikitable' border=1
@@ Line 15: / Line 14: @@
 |-
 | <Center>No</Center> || <Center>No</Center> || (no change) 'bios.bin' will be loaded as rom image.
-|-
-| <Center>Yes</Center> || <Center>No</Center> || (no change) -bios parameter will be loaded as rom image.
 |-
 | <Center>No</Center> || <Center>Yes</Center>
@@ Line 22: / Line 19: @@
 'bios.bin' will be ''ignored''.
+|-
+| <Center>Yes</Center> || <Center>No</Center> || (no change) -bios parameter will be loaded as rom image.
 |-
 | <Center>Yes</Center> || <Center>Yes</Center>