Features/PC System Flash: Difference between revisions

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! -bios used !! -pflash used !! Result
! -bios used !! -pflash used !! Result
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| <Center>No</Center> || <Center>No</Center> || (no change) 'bios.bin' will be loaded as rom image.
| <Center>No</Center> || <Center>No</Center>
| (no change) 'bios.bin' will be loaded as rom image.
 
No system flash is available.
|-
|-
| <Center>No</Center> || <Center>Yes</Center>
| <Center>No</Center> || <Center>Yes</Center>
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'bios.bin' will be ''ignored''.
'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>No</Center>
| (no change) -bios parameter will be loaded as rom image.
 
No system flash is available.
|-
|-
| <Center>Yes</Center> || <Center>Yes</Center>
| <Center>Yes</Center> || <Center>Yes</Center>

Revision as of 00:18, 14 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

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 system flash is available.

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.

No system flash is available.

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.