On 6/22/22 11:34, Kalra, Ashish wrote: >> So, if the RMP entry format changes in future processors, how do we >> make sure that the kernel does not try to use *this* code on those >> processors? > Functions snp_lookup_rmpentry() and dump_rmpentry() which rely on > this structure definition will need to handle it accordingly. In other words, old kernels will break on new hardware? I think that needs to be fixed. It should be as simple as a model/family check, though. If someone (for example) attempts to use SNP (and thus snp_lookup_rmpentry() and dump_rmpentry()) code on a newer CPU, the kernel should refuse.