linux-kernel - Re: [PATCH] x86/kexec: Add ACPI NVS region to the ident map

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Message-ID: <20190610095150.GA5488@zn.tnic>
Date:   Mon, 10 Jun 2019 11:51:50 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Kairui Song <kasong@...hat.com>
Cc:     linux-kernel@...r.kernel.org, Baoquan He <bhe@...hat.com>,
        Junichi Nomura <j-nomura@...jp.nec.com>,
        Dave Young <dyoung@...hat.com>,
        Dirk van der Merwe <dirk.vandermerwe@...ronome.com>,
        Chao Fan <fanc.fnst@...fujitsu.com>,
        Ingo Molnar <mingo@...nel.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org,
        kexec@...ts.infradead.org
Subject: Re: [PATCH] x86/kexec: Add ACPI NVS region to the ident map

On Mon, Jun 10, 2019 at 03:36:17PM +0800, Kairui Song wrote:
> With the recent addition of RSDP parsing in decompression stage, kexec
> kernel now needs ACPI tables to be covered by the identity mapping.
> And in commit 6bbeb276b71f ("x86/kexec: Add the EFI system tables and
> ACPI tables to the ident map"), ACPI tables memory region was added to
> the ident map.
> 
> But on some machines, there is only ACPI NVS memory region, and the ACPI
> tables is located in the NVS region instead. In such case second kernel

*are* located - plural.

> will still fail when trying to access ACPI tables.
> 
> So, to fix the problem, add NVS memory region in the ident map as well.
> 
> Fixes: 6bbeb276b71f ("x86/kexec: Add the EFI system tables and ACPI tables to the ident map")
> Suggested-by: Junichi Nomura <j-nomura@...jp.nec.com>
> Signed-off-by: Kairui Song <kasong@...hat.com>
> ---
> 
> Tested with my laptop and VM, on top of current tip:x86/boot.

You tested this in a VM and not on the *actual* machine with the NVS
region?

This is a joke, right?

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.