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From: Baoquan He <bhe@redhat.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>,
	Junichi Nomura <j-nomura@ce.jp.nec.com>,
	"fanc.fnst@cn.fujitsu.com" <fanc.fnst@cn.fujitsu.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"x86@kernel.org" <x86@kernel.org>
Subject: Re: [PATCH] x86/boot: Use EFI setup data if provided
Date: Mon, 25 Mar 2019 17:03:49 +0800	[thread overview]
Message-ID: <20190325090349.GE3659@MiWiFi-R3L-srv> (raw)
In-Reply-To: <alpine.DEB.2.21.1903250941020.1798@nanos.tec.linutronix.de>

On 03/25/19 at 09:43am, Thomas Gleixner wrote:
> On Mon, 25 Mar 2019, Baoquan He wrote:
> 
> > On 03/25/19 at 08:53am, Borislav Petkov wrote:
> > > On Mon, Mar 25, 2019 at 03:27:10PM +0800, Baoquan He wrote:
> > > > Kexec kernel also need to get rsdp to get SRAT tables so that KASLR can
> > > > avoid those hotpluggable regions in boot compression stage.
> > > > 
> > > > The kexec_file_load has filled in acpi_rsdp_addr of kexec kernel in
> > > > below code. It will return direclty in get_rsdp_addr() since
> > > > acpi_rsdp_addr is got from boot_params->acpi_rsdp_addr.
> > > > 
> > > > arch/x86/kernel/kexec-bzimage64.c <<setup_boot_parameters>>
> > > > 	params->acpi_rsdp_addr = boot_params.acpi_rsdp_addr;
> > > > 
> > > > The other interface, kexec_load, its boot_params filling is done in user
> > > > space kexec_tools. And we haven't made the acpi_rsdp_addr filling yet.
> > > > And the old kexec_tools utility can also cause the new kexec kernel to
> > > > search efi rspd pointer even thought it's fixed.
> > > 
> > > Yes, kexec is a pile of ugly and fragile hackery.
> > 
> > Well, yes, we have to admit that, since kexec is based on hacking.
> 
> Well, then the right thing to do is to think about it proper and replace
> the hackery by something well thought out instead of adding duct tape to it
> every other day.

I could make mistakes on expressing. I meant the mechanism of kexec is
based on hacking into kernel booting stuff. So sometime we call kexec a
bootloader, at least a bootloader variant. That means we may need to adapt
code when any change is made in kernel boot side.

E.g for this acpi_rsdp_addr adding, it happened in boot compressing
stage, to get rsdp to fix the conflict between KASLR and HOTPLUG.
Accordingly, kexec code need be adpated too.

So, when maintain kexec/kdump, we have to track and test any change
which could happen in kernel boot.

Thanks
Baoquan

      reply	other threads:[~2019-03-25  9:03 UTC|newest]

Thread overview: 90+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-22 11:03 [PATCH] x86/boot: Use EFI setup data if provided Junichi Nomura
2019-03-22 15:23 ` Borislav Petkov
2019-03-25  0:27   ` Junichi Nomura
2019-03-25  6:01     ` Dave Young
2019-03-25  6:19       ` Dave Young
2019-03-25  6:45         ` Kairui Song
2019-03-25  6:47         ` Junichi Nomura
2019-03-25  6:59           ` Dave Young
2019-03-25  8:27             ` [PATCH v2] " Junichi Nomura
2019-03-25  8:54               ` Boris Petkov
2019-03-25  9:25                 ` [PATCH v2] x86/boot: Don't try to search RSDP from EFI when kexec-booted Junichi Nomura
2019-03-25 10:15                 ` [PATCH v2] x86/boot: Use EFI setup data if provided Dave Young
2019-03-25 10:36                   ` Junichi Nomura
2019-03-25 11:16                     ` Dave Young
2019-03-25 12:01                     ` Borislav Petkov
2019-03-25 12:23                       ` Dave Young
2019-03-25 12:32                         ` Borislav Petkov
2019-03-25 23:10                           ` Junichi Nomura
2019-03-26 12:46                             ` Dave Young
2019-03-26 13:57                             ` Borislav Petkov
2019-03-27  1:48                               ` bhe
2019-03-27 12:14                                 ` Borislav Petkov
2019-03-28  4:17                                 ` Junichi Nomura
2019-03-28  6:26                                   ` Chao Fan
2019-03-28  6:43                                   ` bhe
2019-03-28  7:43                                     ` Junichi Nomura
2019-03-28 15:52                                       ` Borislav Petkov
2019-03-29  3:05                                         ` Junichi Nomura
2019-03-29  8:39                                           ` Borislav Petkov
2019-03-29  9:05                                             ` Chao Fan
2019-03-29  9:16                                               ` Borislav Petkov
2019-03-29  9:37                                                 ` Junichi Nomura
2019-03-29  9:44                                                   ` Chao Fan
2019-03-29  9:56                                                     ` Junichi Nomura
2019-03-29  7:20                                         ` [PATCH] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel Junichi Nomura
2019-03-29  7:49                                           ` bhe
2019-03-29  8:29                                           ` Chao Fan
2019-03-29  8:39                                             ` Junichi Nomura
2019-03-29  9:18                                               ` Chao Fan
2019-03-29  9:16                                             ` bhe
2019-03-29  9:20                                               ` Chao Fan
2019-04-01  0:08                                         ` [PATCH v2] " Junichi Nomura
2019-04-02  9:41                                           ` Chao Fan
2019-04-02  9:53                                             ` Junichi Nomura
2019-04-02 11:06                                               ` Chao Fan
2019-04-02 10:22                                                 ` Junichi Nomura
2019-04-02 12:03                                           ` Dave Young
2019-04-03  5:35                                             ` Chao Fan
2019-04-03  5:53                                               ` Dave Young
2019-04-03  6:39                                                 ` Dave Young
2019-04-03  7:30                                                   ` Chao Fan
2019-04-03  7:50                                                     ` bhe
2019-04-03  8:23                                                       ` Dave Young
2019-04-03  8:26                                                         ` Dave Young
2019-04-03 16:14                                                           ` Borislav Petkov
2019-04-04  1:02                                                             ` Chao Fan
2019-04-03  9:28                                                       ` Chao Fan
2019-04-03  7:21                                                 ` Chao Fan
2019-04-03  8:09                                                   ` Dave Young
2019-04-03  8:23                                                     ` Chao Fan
2019-04-03  9:02                                                       ` Chao Fan
2019-04-03  9:39                                                         ` Chao Fan
2019-04-04  1:23                                                         ` Junichi Nomura
2019-04-04  2:52                                                           ` Dave Young
2019-04-04  3:00                                                             ` bhe
2019-04-04  3:10                                                               ` bhe
2019-04-04  3:22                                                                 ` Dave Young
2019-04-04  6:41                                                                   ` Dave Young
2019-04-04  7:20                                                                     ` Chao Fan
2019-04-04  7:41                                                                       ` Dave Young
2019-04-04  7:48                                                                         ` Chao Fan
2019-04-04 12:22                                                                         ` Borislav Petkov
2019-04-04 14:08                                                                           ` Dave Young
2019-04-03  8:18                                                   ` Dave Young
2019-04-02 10:25                                         ` [PATCH v3] " Junichi Nomura
2019-04-04  7:32                                           ` Dave Young
2019-04-04 12:24                                             ` Borislav Petkov
2019-04-04 14:12                                               ` Dave Young
2019-04-04 14:41                                                 ` Borislav Petkov
2019-04-05  1:36                                                   ` Dave Young
2019-04-05  4:19                                             ` Junichi Nomura
2019-03-28 23:11                                       ` [PATCH v2] x86/boot: Use EFI setup data if provided bhe
2019-03-29  3:34                                         ` Junichi Nomura
2019-03-29  3:52                                           ` bhe
2019-03-29  5:16                                             ` Junichi Nomura
2019-03-25  7:27   ` [PATCH] " Baoquan He
2019-03-25  7:53     ` Borislav Petkov
2019-03-25  8:21       ` Baoquan He
2019-03-25  8:43         ` Thomas Gleixner
2019-03-25  9:03           ` Baoquan He [this message]

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