On 1/25/23 11:02, Jeff Xu wrote: > I'm investigating if there is a need to backport x86/pkeys > fix/feature into earlier kernel versions, Chrome is starting to use > PKEY in x86, and I hope experts here can give advice on this. > > For background, ChromeOS regularly syncs with upstream kernel > versions, and has production that uses 4.4/4.14/4.19/5.4/5.10/5.15. To be honest, I haven't got the foggiest idea what you need to backport. I can barely keep track of mainline. Are there really production 4.4 kernels that you need to run on pkey-capable hardware? That would mean running a 2015-era kernel on a CPU released in late 2020. I think Q3'2020 is when the 11th gen CPUs came out which were the first non-server CPUs that had pkeys. On a positive note, the pkeys selftest has been pretty consistently updated as we find bugs. I'd be curious how well a mainline version of that selftests runs on old kernels. But, I'm too scared to find out what's down that particular rabbit hole myself.
