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From: "H. Peter Anvin" <hpa@zytor.com>
To: Thomas Renninger <trenn@suse.de>
Cc: x86@kernel.org, kexec@lists.infradead.org,
	linux-kernel@vger.kernel.org, horms@verge.net.au,
	yinghai@kernel.org, vgoyal@redhat.com
Subject: Re: [PATCH 2/2] x86 e820: Introduce memmap=resetusablemap for kdump usage
Date: Tue, 22 Jan 2013 09:54:08 -0600	[thread overview]
Message-ID: <50FEB620.3020805@zytor.com> (raw)
In-Reply-To: <1358868049-19884-3-git-send-email-trenn@suse.de>

On 01/22/2013 09:20 AM, Thomas Renninger wrote:
> From: Yinghai Lu <yinghai@kernel.org>
> 
> kdump voided the whole original e820 map and half way made
> it up via memmap= options passed via kdump boot params again.
> 
> But this is conceptionally wrong. The whole original memory ranges
> which are declared reserved, ACPI data/nvs or however are not usable
> must stay the same and get honored by the kdump kernel.
> 
> Therefore memmap=resetusablemap gets introduced.
> kdump passes this one and only the usable e820 ranges are removed.
> kdump passes the usable ranges to use via memmap=x@y parameter(s).
> The not usable e820 ranges are preserved.
> 
> This for example fixes mmconf (extended PCI config access) and
> possibly other kernel parts which rely on remapped memory to be
> in reserved or ACPI (data/nvs) declared e820 memory areas.
> 
> Tested-by: Thomas Renninger <trenn@suse.de>
> Reviewed-by: Thomas Renninger <trenn@suse.de>
> Signed-off-by: Thomas Renninger <trenn@suse.de>

Tested-by: and Reviewed-by: are rather redundant with Signed-off-by:.
Also, you should have a Signed-off-by: from the author (Yinghai).

However, when thinking about it this really doesn't seem to be the right
interface, either.  Something like "memmap=reserveram" which turns all
RAM areas into reserved areas, which can then be overridden by memmap=
options would make more sense.

Even more sense would be to pass the modified memmap to kexec...

	-hpa



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kexec@lists.infradead.org
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WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: Thomas Renninger <trenn@suse.de>
Cc: yinghai@kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org,
	kexec@lists.infradead.org, vgoyal@redhat.com, horms@verge.net.au
Subject: Re: [PATCH 2/2] x86 e820: Introduce memmap=resetusablemap for kdump usage
Date: Tue, 22 Jan 2013 09:54:08 -0600	[thread overview]
Message-ID: <50FEB620.3020805@zytor.com> (raw)
In-Reply-To: <1358868049-19884-3-git-send-email-trenn@suse.de>

On 01/22/2013 09:20 AM, Thomas Renninger wrote:
> From: Yinghai Lu <yinghai@kernel.org>
> 
> kdump voided the whole original e820 map and half way made
> it up via memmap= options passed via kdump boot params again.
> 
> But this is conceptionally wrong. The whole original memory ranges
> which are declared reserved, ACPI data/nvs or however are not usable
> must stay the same and get honored by the kdump kernel.
> 
> Therefore memmap=resetusablemap gets introduced.
> kdump passes this one and only the usable e820 ranges are removed.
> kdump passes the usable ranges to use via memmap=x@y parameter(s).
> The not usable e820 ranges are preserved.
> 
> This for example fixes mmconf (extended PCI config access) and
> possibly other kernel parts which rely on remapped memory to be
> in reserved or ACPI (data/nvs) declared e820 memory areas.
> 
> Tested-by: Thomas Renninger <trenn@suse.de>
> Reviewed-by: Thomas Renninger <trenn@suse.de>
> Signed-off-by: Thomas Renninger <trenn@suse.de>

Tested-by: and Reviewed-by: are rather redundant with Signed-off-by:.
Also, you should have a Signed-off-by: from the author (Yinghai).

However, when thinking about it this really doesn't seem to be the right
interface, either.  Something like "memmap=reserveram" which turns all
RAM areas into reserved areas, which can then be overridden by memmap=
options would make more sense.

Even more sense would be to pass the modified memmap to kexec...

	-hpa



  reply	other threads:[~2013-01-22 15:54 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-22 15:20 [PATCH 0/2] Only parse exactmap once, introduce memmap=resetusablemap Thomas Renninger
2013-01-22 15:20 ` Thomas Renninger
2013-01-22 15:20 ` [PATCH 1/2] x86 e820: Check for exactmap appearance when parsing first memmap option Thomas Renninger
2013-01-22 15:20   ` Thomas Renninger
2013-01-22 19:33   ` Yinghai Lu
2013-01-22 19:33     ` Yinghai Lu
2013-01-29  1:09   ` H. Peter Anvin
2013-01-29  1:09     ` H. Peter Anvin
2013-01-29  2:01     ` Yinghai Lu
2013-01-29  2:01       ` Yinghai Lu
2013-01-22 15:20 ` [PATCH 2/2] x86 e820: Introduce memmap=resetusablemap for kdump usage Thomas Renninger
2013-01-22 15:20   ` Thomas Renninger
2013-01-22 15:54   ` H. Peter Anvin [this message]
2013-01-22 15:54     ` H. Peter Anvin
2013-01-22 16:23     ` Thomas Renninger
2013-01-22 16:23       ` Thomas Renninger
2013-01-22 16:32       ` H. Peter Anvin
2013-01-22 16:32         ` H. Peter Anvin
2013-01-22 20:06         ` Yinghai Lu
2013-01-24  4:07           ` Yinghai Lu
2013-01-24  4:07             ` Yinghai Lu
2013-01-29  1:05             ` Thomas Renninger
2013-01-29  1:05               ` Thomas Renninger
2013-01-29  1:11               ` H. Peter Anvin
2013-01-29  1:11                 ` H. Peter Anvin
2013-01-29  2:10                 ` Yinghai Lu
2013-01-29  2:10                   ` Yinghai Lu
2013-01-29  2:11                   ` H. Peter Anvin
2013-01-29  2:11                     ` H. Peter Anvin
2013-01-29  2:19                     ` Yinghai Lu
2013-01-29  2:19                       ` Yinghai Lu
2013-01-29  2:20                       ` H. Peter Anvin
2013-01-29  2:20                         ` H. Peter Anvin
2013-01-29  2:27                       ` H. Peter Anvin
2013-01-29  2:27                         ` H. Peter Anvin
2013-01-29  2:31                         ` Yinghai Lu
2013-01-29  2:31                           ` Yinghai Lu
2013-01-29  3:33                           ` H. Peter Anvin
2013-01-29  3:33                             ` H. Peter Anvin
2013-01-29  9:47                   ` Thomas Renninger
2013-01-29  9:47                     ` Thomas Renninger

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