On Tue, May 10, 2011 at 01:47:34PM +0100, Ian Campbell wrote:
Hi,
It looks like it is but I just thought I should check, is starting SeaBIOS via the ELF entry point (post32 in romlayout.S) rather than via the 16 bit reset vector valid from the SeaBIOS point of view?
It is valid - all coreboot users enter via the post32 stub.
I'm considering it as an option for supporting SeaBIOS inside a Xen HVM (AKA fully virtualised) guest. Currently Xen loads "hvmloader" as the initial code to run within the guest. hvmloader does some initial setup, copies the BIOS (previously ROMBIOS but there is now very early support for SeaBIOS too) into the right place and then trampolines to the 16 bit entry point. However almost all of the initial setup is (or at least seems like it will end up being once I've checked it all out) ROMBIOS specific so I am considering the option of just loading SeaBIOS directly in place of hvmloader.
That's interesting. Some questions - how will Xen obtain the address of post32 - will it use the bios.bin.elf file? On CPU reset / S3 resume (if supported at all), will Xen also call post32 or do a regular real-mode entry?
-Kevin