Laszlo Ersek <lersek@xxxxxxxxxx> writes: > On 05/31/13 09:09, Jordan Justen wrote: > > Due to licensing differences I can't just port code from SeaBIOS to > OVMF <soapbox> Fork OVMF, drop the fat module, and just add GPL code. It's an easily solvable problem. Rewriting BSD implementations of everything is silly. Every other vendor that uses TianoCore has a proprietary fork. Maintaining a GPL fork seems just as reasonable. </soapbox> Regards, Anthony Liguori > (and I never have without explicit permission), so it's been a lot of > back and forth with acpidump / iasl -d in guests (massage OVMF, boot > guest, check guest dmesg / lspci, dump tables, compare, repeat), brain > picking colleagues, the ACPI and PIIX specs and so on. I have a page on > the RH intranet dedicated to this. When something around these parts is > being changed (or looks like it could be changed) in SeaBIOS, or between > qemu and SeaBIOS, I always must be alert and consider reimplementing it > in, or porting it with permission to, OVMF. (Most recent example: > pvpanic device -- currently only in SeaBIOS.) > > It worries me that if I slack off, or am busy with something else, or > simply don't notice, then the gap will widen again. I appreciate > learning a bunch about ACPI, and don't mind the days of work that went > into some of my simple-looking ACPI patches for OVMF, but had the tables > come from a common (programmatic) source, none of this would have been > an issue, and I wouldn't have felt even occasionally that ACPI patches > for OVMF were both duplicate work *and* futile (considering how much > ahead SeaBIOS was). > > I don't mind reimplementing stuff, or porting it with permission, going > forward, but the sophisticated parts in SeaBIOS are a hard nut. For > example I'll never be able to auto-extract offsets from generated AML > and patch the AML using those offsets; the edk2 build tools (a project > separate from edk2) don't support this, and it takes several months to > get a thing as simple as gcc-47 build flags into edk2-buildtools. > > Instead I have to write template ASL, compile it to AML, hexdump the > result, verify it against the AML grammar in the ACPI spec (offsets > aren't obvious, BytePrefix and friends are a joy), define & initialize a > packed struct or array in OVMF, and patch the template AML using fixed > field names or array subscripts. Workable, but dog slow. If the ACPI > payload came from up above, we might be as well provided with a list of > (canonical name, offset, size) triplets, and could perhaps blindly patch > the contents. (Not unlike Michael's linker code for connecting tables > into a hierarchy.) > > AFAIK most recently iasl got built-in support for offset extraction (and > in the process the current SeaBIOS build method was broken...), so that > part might get easier in the future. > > Oh well it's Friday, sorry about this rant! :) I'll happily do what I > can in the current status quo, but frequently, it won't amount to much. > > Thanks, > Laszlo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
