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Date:   Fri, 29 Mar 2019 09:39:20 +0100
From:   Borislav Petkov <bp@alien8.de>
To:     Junichi Nomura <j-nomura@ce.jp.nec.com>,
        "fanc.fnst@cn.fujitsu.com" <fanc.fnst@cn.fujitsu.com>
Cc:     "bhe@redhat.com" <bhe@redhat.com>, Dave Young <dyoung@redhat.com>,
        "kasong@redhat.com" <kasong@redhat.com>,
        "x86@kernel.org" <x86@kernel.org>,
        "kexec@lists.infradead.org" <kexec@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] x86/boot: Use EFI setup data if provided
Message-ID: <20190329083920.GA21152@zn.tnic>
References: <20190325122302.GC13160@dhcp-128-65.nay.redhat.com>
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 <73322ba9-e436-68db-7863-afd31607d969@ce.jp.nec.com>
 <20190328064343.GA1877@MiWiFi-R3L-srv>
 <20190328074337.GA9470@jeru.linux.bs1.fc.nec.co.jp>
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On Fri, Mar 29, 2019 at 03:05:52AM +0000, Junichi Nomura wrote:
> > You don't need that variable and can return "table" or 0 after the endif
> > below.
> 
> I could do that but it will slightly change the current logic.
> 
> Existing code does this:
> 
>                 if (!(efi_guidcmp(guid, ACPI_TABLE_GUID)))
>                         rsdp_addr = table;
>                 else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID)))
>                         return table;
> 
> I thought it was to return the table for ACPI_20_TABLE_GUID
> if both tables exist.  If we remove rsdp_addr, the code will be:
> 
>                 if (!(efi_guidcmp(guid, ACPI_TABLE_GUID)))
>                         return table;
>                 else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID)))
>                         return table;
> 
> So if there are 2 tables, we return the one that comes first.
> Is it ok?

That's a good question.

Chao, what was the intention there, ACPI_20_TABLE_GUID is the preferred
table to return? If so, why?

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.