On 01/22/2013 09:20 AM, Thomas Renninger wrote: > From: Yinghai Lu <yinghai at 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 at 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 at suse.de> > Reviewed-by: Thomas Renninger <trenn at suse.de> > Signed-off-by: Thomas Renninger <trenn at 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
