Hello Ard, On Thu, Sep 12, 2024 at 12:51:57PM +0200, Ard Biesheuvel wrote: > I don't see how this could be an EFI bug, given that it does not deal > with E820 tables at all.
I want to back up a little bit and make sure I am following the discussion. >From what I understand from previous discussion, we have an EFI bug as the root cause of this issue. This happens because the EFI does NOT mark the EFI TPM event log memory region as reserved (EFI_RESERVED_TYPE). Not having an entry for the event table memory in EFI memory mapped, then libstub will ignore it completely (the TPM event log memory range) and not populate e820 table with it. Once the e820 table does not have the memory range for TPM event log, then the kernel is free to overwrite that memory region, causing corruptions all across the board. >From what I understand from the thread discussion, there are three ways to "solve" it: 1) Fix the EFI to pass the TPM event log memory as reserved. 2) Workaround it in libstub, and considering the TPM event log memory range when populating the e820 table. (As proposed in https://lore.kernel.org/all/2542182d-aa79-4705-91b6-fa593bacf...@gmail.com/) 3) Workaround in later in the kernel, as proposed in https://lore.kernel.org/all/20240911104109.1831501-1-usamaarif...@gmail.com/ Please let me know if my understanding is flawed here. Thank you! --breno _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
