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From: Borislav Petkov <bp@alien8.de>
To: Toshi Kani <toshi.kani@hp.com>, Dave Young <dyoung@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org,
	x86@kernel.org, mjg59@srcf.ucam.org, hpa@zytor.com,
	James.Bottomley@HansenPartnership.com, vgoyal@redhat.com,
	ebiederm@xmission.com, horms@verge.net.au,
	kexec@lists.infradead.org, greg@kroah.com,
	matt@console-pimps.org
Subject: Re: [PATCH v4 07/12] efi: passing kexec necessary efi data via setup_data
Date: Thu, 5 Dec 2013 21:52:50 +0100	[thread overview]
Message-ID: <20131205205250.GF14407@pd.tnic> (raw)
In-Reply-To: <1386258962.1791.268.camel@misato.fc.hp.com>

On Thu, Dec 05, 2013 at 08:56:02AM -0700, Toshi Kani wrote:
> The smbios in efi_setup_data is necessary for kexec to pass the physical
> address of the SMBIOS table from the 1st kernel to the 2nd kernel.
> 
> The kernel boot sequence proceeds in the following order.  Step 2
> requires efi.smbios to be the physical address.  However, Dave found
> that EFI system table has a virtual address of SMBIOS in step 1.  Hence,
> he sets it back to the physical address with the smbios in
> efi_setup_data.  (When it is still the physical address, it simply sets
> the same value.)
> 
> 1. efi_init() - Set efi.smbios from EFI system table
> 2. dmi_scan_machine() - Temporary map efi.smbios to access SMBIOS table
> 3. efi_enter_virtual_mode() - Map EFI ranges

Thanks Toshi, it is all clear now.

@Dave: you might want to put Toshi's explanation in the commit message
of your patch so that we know *why* the change is needed.

Thanks.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
--

  reply	other threads:[~2013-12-05 20:53 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-26  5:57 [PATCH v4 00/12] kexec kernel efi runtime support Dave Young
2013-11-26  5:57 ` [PATCH v4 01/12] efi: remove unused variables in __map_region Dave Young
2013-11-26  5:57 ` [PATCH v4 02/12] efi: add a wrapper function efi_map_region_fixed Dave Young
2013-11-26  5:57 ` [PATCH v4 03/12] efi: reserve boot service fix Dave Young
2013-11-26  5:57 ` [PATCH v4 04/12] efi: cleanup efi_enter_virtual_mode function Dave Young
2013-11-26 14:51   ` Matt Fleming
2013-11-26  5:57 ` [PATCH v4 05/12] efi: export more efi table variable to sysfs Dave Young
2013-11-26  8:50   ` Borislav Petkov
2013-11-26  9:13     ` Dave Young
2013-11-26 15:57   ` Matt Fleming
2013-11-27  2:53     ` Dave Young
2013-11-26  5:57 ` [PATCH v4 06/12] efi: export efi runtime memory mapping " Dave Young
2013-11-26 19:30   ` Matt Fleming
2013-11-27  3:07     ` Dave Young
2013-11-27  8:17       ` Dave Young
2013-11-27 11:44   ` Borislav Petkov
2013-11-29  9:40     ` Dave Young
2013-11-29 11:50       ` Borislav Petkov
2013-11-29 11:59         ` Matt Fleming
2013-12-02  2:51           ` Dave Young
2013-12-02  2:59         ` Dave Young
2013-12-02  9:40           ` Borislav Petkov
2013-12-07  9:01             ` Dave Young
2013-12-07 13:30               ` Borislav Petkov
2013-12-07 21:46                 ` H. Peter Anvin
2013-12-09  2:23                 ` Dave Young
2013-11-26  5:57 ` [PATCH v4 07/12] efi: passing kexec necessary efi data via setup_data Dave Young
2013-11-26 22:04   ` Matt Fleming
2013-11-27  4:52     ` Dave Young
2013-11-27 10:17       ` Matt Fleming
2013-11-29  9:46         ` Dave Young
2013-11-27 14:07   ` Borislav Petkov
2013-11-29  9:14     ` Dave Young
2013-11-29 16:46       ` Borislav Petkov
2013-12-02  2:49         ` Dave Young
2013-12-02  9:44           ` Borislav Petkov
2013-12-02 22:33       ` Toshi Kani
2013-12-03  1:31         ` Toshi Kani
2013-12-03  1:56           ` Dave Young
2013-12-03 15:39             ` Toshi Kani
2013-12-04  2:46               ` Dave Young
2013-12-04 16:43                 ` Toshi Kani
2013-12-05  1:56                   ` Dave Young
2013-12-05 11:51                     ` Borislav Petkov
2013-12-05 15:56                       ` Toshi Kani
2013-12-05 20:52                         ` Borislav Petkov [this message]
2013-12-06  1:31                           ` Dave Young
2013-11-26  5:57 ` [PATCH v4 08/12] efi: only print saved efi runtime maps instead of all memmap ranges for kexec Dave Young
2013-11-27 10:27   ` Matt Fleming
2013-11-27 14:27     ` Borislav Petkov
2013-11-29  8:50       ` Dave Young
2013-11-29 16:47         ` Borislav Petkov
2013-12-02  2:38           ` Dave Young
2013-11-29  8:47     ` Dave Young
2013-11-26  5:57 ` [PATCH v4 09/12] x86: add xloadflags bit for efi runtime support on kexec Dave Young
2013-11-27 14:27   ` Borislav Petkov
2013-11-29  8:44     ` Dave Young
2013-11-26  5:57 ` [PATCH v4 10/12] x86: export x86 boot_params to sysfs Dave Young
2013-11-27 11:20   ` Matt Fleming
2013-11-29  9:44     ` Dave Young
2013-11-27 14:56   ` Borislav Petkov
2013-11-29  8:42     ` Dave Young
2013-11-26  5:57 ` [PATCH v4 11/12] x86: reserve setup_data ranges late after parsing memmap cmdline Dave Young
2013-11-27 15:07   ` Borislav Petkov
2013-11-29  8:35     ` Dave Young
2013-11-29 16:56       ` Borislav Petkov
2013-11-26  5:57 ` [PATCH v4 12/12] x86: kdebugfs do not use __va for getting setup_data virt addr Dave Young
2013-11-26  6:04 ` [PATCH v4 00/12] kexec kernel efi runtime support Dave Young
2013-11-27 12:50 ` Matt Fleming
2013-11-28  2:08   ` Dave Young
2013-11-29  8:28     ` Dave Young
2013-11-29 17:02       ` Borislav Petkov
2013-12-02  2:32         ` Dave Young

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