On 09/24/2013 07:56 AM, Borislav Petkov wrote: > On Tue, September 24, 2013 2:45 pm, Dave Young wrote: >> Think again about this, how about 1:1 map them from a base address >> like -64G phy_addr -> (-64G + phy_addr), in this way we can avoid >> depending on the previous region size. > > Right, how we layout the regions is arbitrary as long as we start at > the same VA and use the same regions, in the same order and of the same > size... > >> For the zero region problem, we can resolve it as a standalone >> problem. > > ... however, we still need to understand why it fails mapping the boot > services region as some implementations apparently do call boot services > even after ExitBootServices(). IOW, we need that region mapped in the > kexec'ed kernel too. > I am starting to think that we really should explicitly pass along the EFI mappings to the secondary kernel. This will also help if we have to change the algorithm in a future kernel. The most logical way to do this is to define a new setup_data type and pass the entire set of physical-to-virtual mappings that way. For example: struct efi_mapping { u64 va; /* Virtual start address */ u64 pa; /* Physical start address */ u64 len; /* Length in bytes */ u64 type; /* Mapping type */ u64 reserved[3]; /* Reserved, must be zero */ }; Adding some reserved fields seems like a prudent precaution; the map shouldn't be all that large anyway. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html