linux-kernel - Re: [RFC PATCH 0/4] x86/boot/KASLR: Parse ACPI table and limit kaslr in immovable memory.

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Date:   Tue, 3 Jul 2018 09:32:35 +0800
From:   Chao Fan <fanc.fnst@...fujitsu.com>
To:     Baoquan He <bhe@...hat.com>
CC:     <linux-kernel@...r.kernel.org>, <x86@...nel.org>, <hpa@...or.com>,
        <tglx@...utronix.de>, <mingo@...hat.com>, <keescook@...omium.org>,
        <yasu.isimatu@...il.com>, <indou.takao@...fujitsu.com>,
        <lcapitulino@...hat.com>, <caoj.fnst@...fujitsu.com>,
        <douly.fnst@...fujitsu.com>
Subject: Re: [RFC PATCH 0/4] x86/boot/KASLR: Parse ACPI table and limit kaslr
 in immovable memory.

On Mon, Jul 02, 2018 at 08:18:55PM +0800, Baoquan He wrote:
>Hi Chao,
>
>On 06/12/18 at 04:10pm, Chao Fan wrote:
>> *** Issues need be discussed
>> There are several issues I am not quite sure, please help review and
>> give suggestions:
>> 
>> 1) In PATCH 1, I copy the structures and functions from ACPI head file,
>>    so that ACPI head file will never been used here. I am not sure
>>    whether it's good to include ACPI head file or use the method in
>>    PATCH 1. If people think we can use ACPI head files directely, I
>>    will remove the PATCH 1.
>
>Usaully we try to reuse code even though they are located in different
>life space. I think it applies to this SRAT handling. Copying ACPI codes

Yes, you are right. But as you said, they are in different life space,
so I don't have a better method to dig the SRAT table.
If anyone have a good way or suggestion, please tell me.

Thanks,
Chao Fan

>to kernel decompressing looks messy. Is there better way to reuse ACPI
>code and read SRAT table, then get what we need in a simple way?
>
>Thanks
>Baoquan
>> 
>> ***Test results:
>>  - I did a very simple test, and it can get the memory information in
>>    bios and efi KVM guest machine, and put it by early printk. But no
>>    more tests, so it's with RFC tag.
>> 
>> Any comments will be welcome.
>> 
>> 
>> Chao Fan (4):
>>   x86/boot: Add acpitb.h to help parse acpi tables
>>   x86/boot: Add acpitb.c to parse acpi tables
>>   x86/boot/KASLR: Walk srat tables to filter immovable memory
>>   x86/boot/KASLR: Limit kaslr to choosing the immovable memory
>> 
>>  arch/x86/boot/compressed/Makefile |   1 +
>>  arch/x86/boot/compressed/acpitb.c | 245 ++++++++++++++++++++++++++++++
>>  arch/x86/boot/compressed/acpitb.h | 175 +++++++++++++++++++++
>>  arch/x86/boot/compressed/kaslr.c  | 120 +++++++++++++--
>>  4 files changed, 530 insertions(+), 11 deletions(-)
>>  create mode 100644 arch/x86/boot/compressed/acpitb.c
>>  create mode 100644 arch/x86/boot/compressed/acpitb.h
>> 
>> -- 
>> 2.17.0
>> 
>> 
>> 
>
>