Re: [PATCH 1/2][RFC] x86/boot/e820: Introduce e820_table_ori to represent the real original e820 layout

From: Ingo Molnar
Date: Thu Jun 22 2017 - 05:40:39 EST

* Chen Yu <yu.c.chen@xxxxxxxxx> wrote:

> Currently we try to have e820_table_firmware to represent the
> original firmware memory layout passed to us by the bootloader,
> however it is not the case, the e820_table_firmware might still
> be modified by linux:
> 1. During bootup, the efi boot stub might allocate memory via
> efi service for the PCI device information structure, then
> later e820_reserve_setup_data() reserved these dynamically
> allocated structures(AKA, setup_data) in e820_table_firmware
> accordingly.
> 2. The kexec might also modify the e820_table_firmware.

Hm, so why does the EFI code modify e280_table_firmware - why doesn't
it modify e820_table?

I.e. what is the point of having 3 different versions of the
memory layout table?