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Date:   Mon, 25 Mar 2019 13:01:49 +0100
From:   Borislav Petkov <bp@alien8.de>
To:     Junichi Nomura <j-nomura@ce.jp.nec.com>
Cc:     Dave Young <dyoung@redhat.com>,
        "fanc.fnst@cn.fujitsu.com" <fanc.fnst@cn.fujitsu.com>,
        "bhe@redhat.com" <bhe@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: <20190325120149.GI12016@zn.tnic>
References: <20190322152328.GD12472@zn.tnic>
 <20190325002740.GA6637@jeru.linux.bs1.fc.nec.co.jp>
 <20190325060128.GB9385@dhcp-128-65.nay.redhat.com>
 <20190325061929.GC9385@dhcp-128-65.nay.redhat.com>
 <bcb5bd29-a3b8-e42d-8da7-a8501f695c21@ce.jp.nec.com>
 <20190325065921.GA11096@dhcp-128-65.nay.redhat.com>
 <20190325082720.GA20771@jeru.linux.bs1.fc.nec.co.jp>
 <51D9A7D1-49BF-4679-B102-0FC5AC300C9F@alien8.de>
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On Mon, Mar 25, 2019 at 10:36:33AM +0000, Junichi Nomura wrote:
> AFAIU, early parsing is new code in v5.1-rc1 to support kexec on systems
> with hotpluggable memory with KASLR enabled. For systems that requires the
> new feature, it may be ok to say "you need to use another kexec interface"
> and/or "you need new kexec-tools".

No, this exactly should *not* happen. kexec is already full of duct tape
- don't need any more of that.

So I suggested that efi_get_rsdp_addr() should exit early on in the
kexeced kernel but making this all play nice with the kexec-ed kernel,
as Dave suggests, is better.

Now, my next question is: why does the RDSP address need to come from
kexec(1) (by way of efi_setup_data) and why can't the kexec'ed kernel
figure it out itself by parsing the EFI tables in a similar way to
efi_get_rsdp_addr ?

-- 
Regards/Gruss,
    Boris.

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