> I have been investigating a regression in our environment where pstore > (efi-pstore specifically but I suspect this would affect all > implementations) no longer works after upgrading from a 4.4 to 5.0 > kernel when running under xen. (This is an Ubuntu kernel but I don't > think there are patches which affect this area.)
I don't have any answer for this ... but want to throw out the idea that VMM systems could provide some hypercalls to guests to save/return some blob of memory (perhaps the "save" triggers automagically if the guest crashes?). That would provide a much better pstore back end than relying on emulation of EFI persistent variables (which have severe contraints on size, and don't support some pstore modes because you can't dynamically update EFI variables hundreds of times per second). -Tony
