RE: [PATCH V5 0/2] Add efi page fault handler to recover from page

From: Prakhya, Sai Praneeth
Date: Mon Sep 10 2018 - 15:49:36 EST


Hi All,

> Changes from V4 to V5:
> ----------------------
> 1. Drop config option that enables efi page fault handler, instead make
> it default.
> 2. Call schedule() in an infinite loop to account for spurious wake ups.
> 3. Introduce "NONE" as an efi runtime service function identifier so that
> it could be used in efi_recover_from_page_fault() to check if the page
> fault was indeed triggered by an efi runtime service.

Please note that apart from dropping the config knob and accounting for
spurious wake ups, I have added a third change.

I realized that when kernel command line option efi=old_map is passed, the efi
page fault handler in V4 wouldn't work because, it checks for efi_mm.

In the efi page fault handler, I have also added an explicit check for x86_64 because
AFAIK, x86_32 bit machines do not suffer from this problem (Boris, please correct me if I am wrong).
Also, I was unable to trigger page faults with buggy OVMF for x86_32.

Just wanted to state the third change explicitly here so that it doesn't escape reviewers eyes.

Regards,
Sai