On 5/13/20 10:09 AM, Dave Hansen wrote: > On 5/12/20 4:58 PM, Babu Moger wrote: >> +config X86_MEMORY_PROTECTION_KEYS >> + # Both Intel and AMD platforms support "Memory Protection Keys" >> + # feature. So add a generic option X86_MEMORY_PROTECTION_KEYS >> + # and set the option whenever X86_INTEL_MEMORY_PROTECTION_KEYS >> + # is set. This is to avoid the confusion about the feature >> + # availability on AMD platforms. Also renaming the old option >> + # would cause the user an extra prompt during the kernel >> + # configuration. So avoided changing the old config name. >> + def_bool X86_INTEL_MEMORY_PROTECTION_KEYS > > Hi Babu, > > I made a request earlier for an end date (or version) to be included > here. I believe that appeared in one of your earlier versions, but it > was removed in later ones. > > Was there a reason for that? Dave, Sorry, I misunderstood that. I thought we probably are not going to change the sources/makefile(ifdefs mostly) as it was technically not required. Now I am reading that we are going to change that in the future and just keep X86_MEMORY_PROTECTION_KEYS going forward. Sure. I will add the text you proposed. Please feel free to correct again. > > I'd really prefer to put some kind of expiration date on the config > option. It will outlive us all otherwise. > >> Memory Protection Keys for Userspace (PKU aka PKEYs) is a feature >> which is found on Intel's Skylake "Scalable Processor" Server CPUs. >> -It will be avalable in future non-server parts. >> +It will be available in future non-server parts. Also, AMD64 >> +Architecture Programmer’s Manual defines PKU feature in AMD processors. > > I actually worked pretty hard to make that sentence useful to Linux > users. Instead of forcing them to imply that it will be available on > future AMD CPUs, can we just come out and say it? Can we give any more > information to our users? > > Naming the AMD manual in which the feature is defined doesn't really > help our users. Let's not waste the bytes on it. > > How about: > > Memory Protection Keys for Userspace (PKU aka PKEYs) is a > feature which is found on Intel's Skylake (and later) "Scalable > Processor" Server CPUs. It will be avalable in future non- > server Intel parts and future AMD parts. This should be good enough. Thanks. > > Any clarity you can add, such as to say what AMD is doing for server vs. > client would be nice. > > BTW, when I first submitted pkeys, I didn't have any statement like this > in the changelog or documentation. Ingo, I think, asked for it and I > worked with folks inside Intel to figure out how much we could say > publicly about our plans. A similar effort from AMD would be much > appreciated here. >
