linux-kernel - Re: [PATCH v2] kaslr: get ACPI SRAT table to avoid movable memory

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Message-ID: <20170904090357.GB10604@localhost.localdomain>
Date:   Mon, 4 Sep 2017 17:03:57 +0800
From:   Chao Fan <fanc.fnst@...fujitsu.com>
To:     Baoquan He <bhe@...hat.com>
CC:     Dou Liyang <douly.fnst@...fujitsu.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        <linux-kernel@...r.kernel.org>, <x86@...nel.org>,
        <linux-acpi@...r.kernel.org>, <hpa@...or.com>,
        <tglx@...utronix.de>, <mingo@...hat.com>, <keescook@...omium.org>,
        <arnd@...db.de>, <dyoung@...hat.com>, <dave.jiang@...el.com>,
        <lv.zheng@...el.com>, <indou.takao@...fujitsu.com>,
        <izumi.taku@...fujitsu.com>, <yasu.isimatu@...il.com>
Subject: Re: [PATCH v2] kaslr: get ACPI SRAT table to avoid movable memory

On Mon, Sep 04, 2017 at 04:39:14PM +0800, Baoquan He wrote:
>On 09/04/17 at 04:17pm, Dou Liyang wrote:
>> With "movable_node=1024M" option in cmdline, KASLR will can't access
>> the node3 memory.
>
>So you have extended the movable_node option from no value specified to
>adding a limit value, then why don't you go one step further to extend
>it as movable_node=xxx@...rt. With this, you can eat the cake you have.
>
>My personal opinion, could that other peopel have better idea. But dig
>into acpi tables to grab the srat table, that is really not a good idea.
>
>Chao has spent time to know the srat table, maybe he can try to make a
>patch with the "movable_node=xxx@...rt" handling in kaslr.c, let's see
>what it looks like.

Hi Bao

That means the user should know the detail information of the srat
table, including the memory location and length. But I have no idea
that if it's elegant leaving it for users to fill the parameter.
BTW, it may be like this: "movable_node=xxx@...rt,xxx@...rt,..."
And I was also wondering if anyone has a better solution.

Thanks,
Chao Fan

>
>Thanks
>Baoquan
>
>> 
>> I am looking for the solution of this. Not find a good way.
>> 
>> Sometimes, I will remember that proverb:
>> 
>>   You cannot have your cake and eat it too. :-)
>> 
>> Thanks,
>> 	dou.
>> > touch ACPI tables with so many lines of code.
>> > 
>> > Thanks
>> > Baoquan
>> > 
>> > 
>> > 
>> 
>> 
>
>