Messages in this thread | | | Date | Tue, 22 Jan 2013 09:54:08 -0600 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 2/2] x86 e820: Introduce memmap=resetusablemap for kdump usage |
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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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