linux-kernel - RE: [PATCH V4 0/3] Add efi page fault handler to recover from page

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Message-ID: <FFF73D592F13FD46B8700F0A279B802F485BA631@ORSMSX114.amr.corp.intel.com>
Date:   Fri, 7 Sep 2018 19:13:55 +0000
From:   "Prakhya, Sai Praneeth" <sai.praneeth.prakhya@...el.com>
To:     Bhupesh Sharma <bhsharma@...hat.com>
CC:     "linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
        "Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>,
        "Neri, Ricardo" <ricardo.neri@...el.com>,
        Matt Fleming <matt@...eblueprint.co.uk>,
        Al Stone <astone@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Ingo Molnar <mingo@...nel.org>,
        Andy Lutomirski <luto@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>
Subject: RE: [PATCH V4 0/3] Add efi page fault handler to recover from page

> Thanks Sai for this work. I think this a step in the right direction.
> I tested this on qemu x86_64 with OVMF firmware modified to access some
> random address in the EFI_Reserved_Region. I was able to reboot the qemu
> instance successfully with the patches (see logs below) while without the
> patchset, reboot earlier used to get stuck.
> 
> So, feel free to add:
> Tested-by: Bhupesh Sharma <bhsharma@...hat.com>
> 

Thanks a lot Bhupesh, for trying the patches and as you said, the patches need a lot 
more testing on real machines.

> Qemu Console Logs:
> ---------------------------
> 
> # reboot
> 
> <snip..>
> 
> [   11.400004] ------------[ cut here ]------------
> [   11.400137] [Firmware Bug]: Page fault caused by firmware at PA: 0x7e924100
> [   11.400484] WARNING: CPU: 0 PID: 1111 at
> arch/x86/platform/efi/quirks.c:691
> efi_recover_from_page_fault+0x3b/0xf0
> [   11.400751] Modules linked in:
> [   11.400992] CPU: 0 PID: 1111 Comm: init Not tainted 4.18.0-rc5+ #1
> [   11.401146] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> BIOS 0.0.0 02/06/2015
> [   11.401397] RIP: 0010:efi_recover_from_page_fault+0x3b/0xf0

[snipped stack trace]

> [   11.410378]  ? entry_SYSCALL_64_after_hwframe+0x44/0xa9
> [   11.410554] ---[ end trace ad3d0a220a88a45b ]---
> [   11.410742] efi: efi_reset_system() buggy! Reboot through BIOS

Thanks for the log, it looks good to me.