linux-kernel - [RFC] should BIOS change the efi type when we set CONFIG_X86_RESERVE

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Message-ID: <5ACEBB47.3060300@huawei.com>
Date:   Thu, 12 Apr 2018 09:49:59 +0800
From:   Xishi Qiu <qiuxishi@...wei.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "Ard Biesheuvel" <ard.biesheuvel@...aro.org>,
        "H. Peter Anvin" <hpa@...or.com>
CC:     yeyunfeng <yeyunfeng@...wei.com>, Wenan Mao <maowenan@...wei.com>,
        "Linux MM" <linux-mm@...ck.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [RFC] should BIOS change the efi type when we set CONFIG_X86_RESERVE_LOW
 ?

Hi, I find CONFIG_X86_RESERVE_LOW=64 in my system, so trim_low_memory_range()
will reserve low 64kb memory. But efi_free_boot_services() will free it to
buddy system again later because BIOS set the type to EFI_BOOT_SERVICES_CODE.

Here is the log:
...
efi: mem03: type=3, attr=0xf, range=[0x000000000000e000-0x0000000000010000) (0MB
...