linux-kernel - Re: [PATCH v2 2/2] x86, kexec_file_load: make it work with efi=noruntime or efi=old

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Message-ID: <20190121011830.GA1554@localhost.localdomain>
Date:   Mon, 21 Jan 2019 09:18:30 +0800
From:   Chao Fan <fanc.fnst@...fujitsu.com>
To:     Borislav Petkov <bp@...en8.de>
CC:     Kairui Song <kasong@...hat.com>, <linux-kernel@...r.kernel.org>,
        <tglx@...utronix.de>, <mingo@...hat.com>, <hpa@...or.com>,
        <x86@...nel.org>, Dave Young <dyoung@...hat.com>,
        Baoquan He <bhe@...hat.com>, <kexec@...ts.infradead.org>,
        <akpm@...ux-foundation.org>, <robert.moore@...el.com>,
        <erik.schmauss@...el.com>, <rafael.j.wysocki@...el.com>,
        Len Brown <lenb@...nel.org>
Subject: Re: [PATCH v2 2/2] x86, kexec_file_load: make it work with
 efi=noruntime or efi=old_map

On Fri, Jan 18, 2019 at 11:26:36AM +0100, Borislav Petkov wrote:
>On Thu, Jan 17, 2019 at 03:41:13PM +0800, Kairui Song wrote:
>> How about we refill the boot_params.acpi_rsdp_addr if it is not valid
>> in early code, so it could be used as a reliable RSDP address source?
>> That should make things easier.
>> 
>> But if early code should parse it and store it should be done in
>> Chao's patch, or I can post another patch to do it if Chao's patch is
>> merged.
>
>Chao's stuff does the as early as possible parsing of RDSP. Then, it
>should be saved into boot_params and everything else should read it from
>there. Simple.

Hi Boris,

So I have changed as this method and put in my mail thread, you may not
notice, so I put here for my function if I need to fill the
boot_parameters:

static inline acpi_physical_address get_boot_params_rsdp(void)
{
        return boot_params->acpi_rsdp_addr;
}

static acpi_physical_address get_rsdp_addr(void)
{
        bool boot_params_rsdp_exist;
        acpi_physical_address pa;

        pa = get_acpi_rsdp();

        if (!pa)
                pa = get_boot_params_rsdp();

        if (!pa) {
                pa = efi_get_rsdp_addr();
                boot_params_rsdp_exist = false;
        }
        else
                boot_params_rsdp_exist = true;

        if (!pa)
                pa = bios_get_rsdp_addr();

        if (pa && !boot_params_rsdp_exist)
                boot_params.acpi_rsdp_addr = pa;

        return pa;
}

At the same time, I notice kernel only parses it when
"#ifdef CONFIG_ACPI", we should keep sync with kernel, but I think
we are parsing SRAT, CONFIG_ACPI is needed sure, so I am going to
update the define of EARLY_SRAT_PARSE:

config EARLY_SRAT_PARSE
        bool "EARLY SRAT parsing"
        def_bool y
        depends on RANDOMIZE_BASE && MEMORY_HOTREMOVE && ACPI

If I miss something, please let me know.
Or in my PATCHSET, I don't need to fill boot_parameters, just
leave the job another PATCH?

Thanks,
Chao Fan

>
>-- 
>Regards/Gruss,
>    Boris.
>
>Good mailing practices for 400: avoid top-posting and trim the reply.
>
>