On Tue, 2013-01-22 at 00:29 +0000, Li, Elvin wrote: > You can make a try to implement such CSM16 to return back to EFI, > GenericLegacyBoot() > thus returns EFI_DEVICE_UNSUPPORTED, but it is BDS which initially > calls "LegacyBios->LegacyBoot ()" to launch legacy boot, you can add > error handling after LegacyBoot () returns and reconnect EFI drivers > and go to next boot options.
Thanks. I'll maybe try to deal with that later, as well as the question of what I should be doing if an option ROM calls INT 16h for keyboard services during a Legacy16DispatchOprom call, before we've taken over the hardware. For now I'm trying to work out how the various bootable devices are supposed to end up in the BBS table. I'm so confused I can't even formulate coherent questions about it for now, so I'll keep staring at the code... :) The entries for different IDE hard drives in the BBS_TABLE that we hand to the CSM appear to be *identical*. The only way to tell them apart is that they appear in a fixed location. The primary IDE master is always BBS_TABLE[2], primary slave is [3], secondary master is [4] and secondary slave is [5]. Is the CSM really supposed to know which device is which *just* because of its position in the table? The PCI b/d/f are obviously the same for all four IDE devices. Is there not an 'index' or 'lun' field which identifies different disks attached to the same controller? I might be able to infer it for the basic IDE disks, but what if I have a SCSI controller and the user elects to boot the device at LUN 5? How would the CSM know? Not that SCSI controllers *do* appear there, of course. And neither does virtio, as I just mentioned. And we only invoke the iPXE ROM on the network card *after* the user has seen the boot menu (without that option), so the user never gets to choose that. I think I need some more coffee... -- dwmw2
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