Re: [PATCH Part2 v6 05/49] x86/sev: Add RMP entry lookup helpers

Dave Hansen
2022-06-22T18:43:11Z

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.