> > That changes some of the goals the memory management subsystem has, > > from "use all the resources effectively" to "use as few resources as > > necessary, in case the host needs the memory for something else". Also "and take guidance/provide telemetry" - because you want to tune the VM behaviours based upon policy and to learn from them for when you re-run that container. > Beyond memory consumption, I would be interested whether we can harden the kernel by the paravirt interfaces for memory protection in VMs (if any). For example, the hypervisor could write-protect part of the page tables or kernel data structures in VMs, and does it help? There are four behaviours I can think of, some of which you see in various hypervisors and security hardening systems - die on write (a write here causes a security trap and termination after the guest has marked the page range die on write, and it cannot be unmarked). The guest OS at boot can for example mark all it's code as die-on-write. - irrevocably read only (VM never allows page to be rewritten by guest after the guest marks the page range irrevocably r/o) - asynchronous faulting (pages the guest thinks are in it's memory but are in fact on the hosts swap cause a subscribable fault in the guest so that it can (where possible) be context switched - free if needed - marking pages as freed up and either you get a page back as it was or a fault and a zeroed page Alan -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
