Add hibernation maintainers in to: list [sent with gmail web ui, sorry for the format issues] On Fri, 10 Jan 2025 at 14:29, Dave Young <dyoung@xxxxxxxxxx> wrote: > > > BTW, the conversation below drived me to read the e820 code: > > https://lore.kernel.org/all/CAMj1kXG1hbiafKRyC5qM1Vj5X7x-dmLndqqo2AYnHMRxDz-80w@xxxxxxxxxxxxxx/T/#u > > > > It could be better to clean up the e820 tables, anyway the comment fix > > in this patch itself is good for now. > > > > Basically e820_table_firmware is used by kexec-tools kexec_load > > implementation, e820_table_kexec is used by kexec_file_load code to > > pass to the 2nd kernel in boot params. > > > > The e820_table_firmware is said to not be modified by the kernel in > > the code comment, but this is not true, at least the sev code updates > > the table. The hibernate code generates crc32 checksum and verifies > > it, but since AFAIK e820 table update only happens in boot phase, it > > will be stable on runtime. So we can just use e820_table_firmware for > > kexec use and drop the e820_table_kexec. With the change the > > kexec_file_load and kexec_load see the same memory ranges. > > > > Otherwise I thought we can use just one e820 table, dropping > > e820_table_firmware and e820_table_kexec, but then there will be > > fragments and memory waste due to the setup_data ranges are reserved > > and updated in e820_table, so the e820_table_firmware being still be > > used for kexec makes sense. > > > > Anyway I need to think more about it, please let me know if you have > > any concerns. > > Reread the old commit 12df216c61c89e31e27e74146115a9728880ca6f > x86/boot/e820: Introduce the bootloader provided e820_table_firmware[] table > > It seems the e820_table_firmware was changed to be exported in sysfs > instead of e820_table_kexec, but I suspect this is wrong. > kexec-tools (kexec_load) use the exported sysfs memmap info, but > e820_table_firmware was created by above commit to be used by > hibernation and the table should not be changed, the fact is there > are changes happen from time to time. > > Question is does hibernation use the sysfs entries from its userspace > tools? If yes, then we should have both kexec table and firmware > table exported because they are for different purposes and one may > change, another not. > > If hibernation only uses the table within the kernel then it makes no > sense to export it to sysfs, we should only export the kexec table for > kexec-tools use. In this way both kexec_load (userspace) and > kexec_file_load (kernel load) can use same e820 table, it will reduce > the bugs and be easier to maintain. > > Thanks > Dave
