linux-kernel - Re: [PATCH v6 1/2] x86/kexec: Build identity mapping for EFI systab and ACPI tables

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Date:   Tue, 21 May 2019 10:43:30 +0000
From:   Junichi Nomura <j-nomura@...jp.nec.com>
To:     Kairui Song <kasong@...hat.com>, Borislav Petkov <bp@...en8.de>
CC:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Baoquan He <bhe@...hat.com>,
        "dyoung@...hat.com" <dyoung@...hat.com>,
        "fanc.fnst@...fujitsu.com" <fanc.fnst@...fujitsu.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "kexec@...ts.infradead.org" <kexec@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "hpa@...or.com" <hpa@...or.com>,
        "tglx@...utronix.de" <tglx@...utronix.de>
Subject: Re: [PATCH v6 1/2] x86/kexec: Build identity mapping for EFI systab
 and ACPI tables

On 2019/05/21 18:02, Kairui Song wrote:
> On Wed, May 15, 2019 at 3:10 PM Junichi Nomura <j-nomura@...jp.nec.com> wrote:
>> On 5/15/19 3:58 PM, Borislav Petkov wrote:
>>> On Wed, May 15, 2019 at 05:17:19AM +0000, Junichi Nomura wrote:
>>>> I found kexec(1) fails to load kernel on a few machines if this patch
>>>> is applied.  Those machines don't have IORES_DESC_ACPI_TABLES region
>>>> and have ACPI tables in IORES_DESC_ACPI_NV_STORAGE region instead.
>>>
>>> Why? What kind of machines are those?
>>
>> I don't know.  They are just general purpose Xeon-based servers
>> and not some special purpose machines.  So I guess there are other
>> such machines in the wild.
> 
> Hi, I think it's reasonable to update the patch to include the
> NV_STORAGE regions as well, most likely the firmware only provided
> NV_STORAGE region? Can you help confirm if the e820 didn't contain
> ACPI data, and only ACPI NVS?

Yes, those machines only have ACPI NVS region as far as I see from kernel log.

> I had a try with this update patch, it worked and didn't break anything.
> 
> Hi Boris, would you prefer to just fold Junichi update patch into the
> previous one or I should send an updated patch?

-- 
Jun'ichi Nomura, NEC Corporation / NEC Solution Innovators, Ltd.