From: Baoquan He <bhe@redhat.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Kairui Song <kasong@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org,
Junichi Nomura <j-nomura@ce.jp.nec.com>,
Dave Young <dyoung@redhat.com>,
Chao Fan <fanc.fnst@cn.fujitsu.com>,
"x86@kernel.org" <x86@kernel.org>,
"kexec@lists.infradead.org" <kexec@lists.infradead.org>
Subject: Re: [RFC PATCH] kexec, x86/boot: map systab region in identity mapping before accessing it
Date: Fri, 19 Apr 2019 19:44:21 +0800 [thread overview]
Message-ID: <20190419114421.GH11060@MiWiFi-R3L-srv> (raw)
In-Reply-To: <20190419112801.GB10324@zn.tnic>
On 04/19/19 at 01:28pm, Borislav Petkov wrote:
> Why does that "seem" so?
>
> Read again what I said: "should all be passed through boot_params".
> Which means, boot_params should be extended with a field of a flag to
> say: "this is a kexec'ed kernel".
>
> If it "seems" then it should be made to not "seem" but to work properly.
No objection to extending with fields of a flag to mark kexec'ed kernel.
Or kdump kernel either. We now check kdump kernel by /proc/vmcore.
>
> > Yeah, adding the systab mapping looks good. Kairui put it in
> > decompressing stage just because he wants to cover the case in which the
> > old kernel kexec jumping to 2nd kernel. Now it seems not very
> > reasonable, we also have the new kernel kexec jumping to old 2nd kernel.
>
> I don't think we can guarantee kexec between old<->new kernel to always
> work. Otherwise, we can forget all development and improvements of new
> kernel.
I personally agree with this. Very earlier, we tried to remove the
896 MB limitation of crashkernel=xM, to extend it to 4G or the whole
RAM, but rejcted by linus since he worried it could break the old kernel
kdumping. I may not remember well.
next prev parent reply other threads:[~2019-04-19 18:53 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-19 10:17 [RFC PATCH] kexec, x86/boot: map systab region in identity mapping before accessing it Borislav Petkov
2019-04-19 10:50 ` Baoquan He
2019-04-19 10:55 ` Baoquan He
2019-04-19 11:20 ` Kairui Song
2019-04-19 11:34 ` Borislav Petkov
2019-04-19 11:50 ` Kairui Song
2019-04-19 14:19 ` [PATCH] x86/boot: Disable RSDP parsing temporarily Borislav Petkov
2019-04-22 9:46 ` [tip:x86/urgent] " tip-bot for Borislav Petkov
2019-04-19 11:28 ` [RFC PATCH] kexec, x86/boot: map systab region in identity mapping before accessing it Borislav Petkov
2019-04-19 11:36 ` Borislav Petkov
2019-04-22 14:33 ` Baoquan He
2019-04-22 15:17 ` Borislav Petkov
2019-04-26 9:51 ` Baoquan He
2019-04-26 9:58 ` Borislav Petkov
2019-04-26 10:16 ` Baoquan He
2019-04-19 11:44 ` Baoquan He [this message]
-- strict thread matches above, loose matches on Subject: below --
2019-04-16 9:52 [PATCH] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernels Borislav Petkov
2019-04-19 8:34 ` [RFC PATCH] kexec, x86/boot: map systab region in identity mapping before accessing it Kairui Song
2019-04-19 8:58 ` Baoquan He
2019-04-19 9:39 ` Kairui Song
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