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

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Message-ID: <81a45045-56c3-af28-758f-f9eaec13d95e@cn.fujitsu.com>
Date:   Mon, 4 Sep 2017 16:52:39 +0800
From:   Dou Liyang <douly.fnst@...fujitsu.com>
To:     Baoquan He <bhe@...hat.com>
CC:     Chao Fan <fanc.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

Hi Baoquan,

At 09/04/2017 04:39 PM, 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.
>

Haha, extending it as movable_node=xxx@...rt is my last choice. I
don't want this option to be as complex as memmap is.

> 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.
>

I agree with you. That is why I send method 2.

> 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.
>

OK, go ahead, Chao.

Thanks,
	dou.


> 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
>>>
>>>
>>>
>>
>>
>
>
>