From: Borislav Petkov <bp@alien8.de>
To: Lianbo Jiang <lijiang@redhat.com>
Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org,
x86@kernel.org, tglx@linutronix.de, mingo@redhat.com,
akpm@linux-foundation.org, dyoung@redhat.com, bhe@redhat.com
Subject: Re: [PATCH 1/2 v6] x86/kexec_file: add e820 entry in case e820 type string matches to io resource name
Date: Wed, 14 Nov 2018 12:26:01 +0100 [thread overview]
Message-ID: <20181114112600.GD13926@zn.tnic> (raw)
In-Reply-To: <20181114072926.13312-2-lijiang@redhat.com>
On Wed, Nov 14, 2018 at 03:29:25PM +0800, Lianbo Jiang wrote:
> When load the kernel image and initramfs by kexec_file_load syscall, it can
> not add exact e820 reserved type to kdump kernel e820 table.
>
> Kdump uses walk_iomem_res_desc() to iterate io resources, then adds matched
> desc to e820 table for kdump kernel. But, when convert the e820 type into
> the iores descriptors, several e820 types are converted to 'IORES_DES_NONE'
> in this function e820_type_to_iores_desc(). So the walk_iomem_res_desc()
> will get these unnecessary types(E820_TYPE_RAM/E820_TYPE_UNUSABLE/E820_TYPE
> _KERN) when iterate io resources by the 'IORES_DES_NONE'.
>
> It needs filter out these redundant type(such as E820_TYPE_RAM/E820_TYPE_
> UNUSABLE/E820_TYPE_KERN) in order to add exact e820 reserved type to kdump
> kernel e820 table. Thus it also needs an extra checking in memmap_entry_
> callback() to match the e820 type and resource name.
Ok, it took me a while to parse what this is trying to say so let's
start from the top:
* What resource type do you do need in the second kernel?
* The most important question: why?
* If it is the reserved resource, why aren't you adding
IORES_DESC_RESERVED or so which to look for instead of this hacky string
comparison?
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
next prev parent reply other threads:[~2018-11-14 11:26 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-14 7:29 [PATCH 0/2 v6] add reserved e820 ranges to the kdump kernel e820 table Lianbo Jiang
2018-11-14 7:29 ` [PATCH 1/2 v6] x86/kexec_file: add e820 entry in case e820 type string matches to io resource name Lianbo Jiang
2018-11-14 11:26 ` Borislav Petkov [this message]
2018-11-15 5:44 ` lijiang
2018-11-15 5:58 ` Dave Young
2018-11-16 1:34 ` lijiang
2018-11-15 10:39 ` Borislav Petkov
2018-11-16 3:25 ` lijiang
2018-11-18 11:52 ` Borislav Petkov
2018-11-20 4:07 ` lijiang
2018-11-21 10:54 ` lijiang
2018-11-21 13:06 ` Boris Petkov
2018-11-19 9:55 ` Dave Young
2018-11-19 10:28 ` Borislav Petkov
2018-11-20 3:37 ` lijiang
2018-11-20 19:29 ` Borislav Petkov
2018-11-20 20:43 ` Bjorn Helgaas
2018-11-21 18:42 ` Borislav Petkov
2018-11-14 7:29 ` [PATCH 2/2 v6] x86/kexec_file: add reserved e820 ranges to kdump kernel e820 table Lianbo Jiang
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