On Wed, 2021-05-26 at 12:49 +0200, Paolo Bonzini wrote: > On 26/05/21 01:45, Ben Gardon wrote: > > At Google we have an informal practice of adding sysctls to control some > > KVM features. Usually these just act as simple "chicken bits" which > > allow us to turn off a feature without having to stall a kernel rollout > > if some feature causes problems. (Sysctls were used for reasons specific > > to Google infrastructure, not because they're necessarily better.) > > > > We'd like to get rid of this divergence with upstream by converting the > > sysctls to writable module parameters, but I'm not sure what the general > > guidance is on writable module parameters. Looking through KVM, it seems > > like we have several writable parameters, but they're mostly read-only. > > Sure, making them writable is okay. Most KVM parameters are read-only > because it's much simpler (the usecase for introducing them was simply > "test what would happen on old processors"). What are these features > that you'd like to control? > > > I also don't see central documentation of the module parameters. They're > > mentioned in the documentation for other features, but don't have their > > own section / file. Should they? > > They probably should, yes. > > Paolo > I vote (because I have fun with my win98 once in a while), to make 'npt' writable, since that is the only way to make it run on KVM on AMD. My personal itch only though! Best regards, Maxim Levitsky
