> On 2 Dec 2018, at 18:31, Kevin O'Connor <ke...@koconnor.net> wrote: > > On Fri, Nov 30, 2018 at 09:53:05PM +0200, Liran Alon wrote: >>> On 30 Nov 2018, at 21:25, Kevin O'Connor <ke...@koconnor.net> wrote: >>> These tables are considered static in SeaBIOS. We've found that any >>> change to these legacy tables tends to break something. We moved the >>> generation of SMBIOS and ACPI to QEMU for this reason. I don't think >>> MPTable was moved into QEMU, but I think that should be the way >>> forward if a particular guest needs different content in this table. >> >> Makes sense. >> >> Until that MPTable will be propagated to SeaBIOS via fw_cfg from QEMU, don’t >> you think it makes sense to revert this commit for now? >> As it caused a real guest workload to break (with non-trivial issue to >> diagnose) and doesn’t provide a real value of it’s own (or am I missing >> something?). >> > > Hi Liran, > > The original commit is from almost six years ago. I know it's very > difficult to track down these types of regressions. I don't doubt it > took a large effort to find the root cause. However, there's a very > real risk that a change (any change) would introduce a further > regression. > > Even when the change is correct, we know from experience that > different operating systems sometimes take unexpected actions when > parsing these tables. In particular, we've seen in the past that > innocuous changes to the bios tables can cause some operating systems > to redo "hardware scans". For these (and other) reasons we've moved > bios table generation out of SeaBIOS. > > So, I don't think it would be a good idea to make this change to > SeaBIOS. > > Thanks, > -Kevin
Hmm OK. I understand your point. BTW, we have run a big variety of OSes with this change and haven’t seen a regression. So you recommend that even if we implement the mechanism to pass mptable via fw_cfg from QEMU that this specific behaviour will be controlled by a flag? That is doable. Just wondering on your opinion. -Liran _______________________________________________ SeaBIOS mailing list SeaBIOS@seabios.org https://mail.coreboot.org/mailman/listinfo/seabios
