Sean, On Thu, 11 Aug 2022 18:39:53 +0100, Sean Christopherson <seanjc@xxxxxxxxxx> wrote: > > +Will (for arm crud) When it comes to KVM/arm64, I'd appreciate if you could Cc me. > arm64 is also quite evil and circumvents KVM's hardware enabling > logic to some extent. kvm_arch_init() => init_subsystems() > unconditionally enables hardware, and for pKVM _leaves_ hardware > enabled. And then hyp_init_cpu_pm_notifier() disables/enables > hardware across lower power enter+exit, except if pKVM is enabled. > The icing on the cake is "disabling" hardware doesn't even do > anything (AFAICT) if the kernel is running at EL2 (which I think is > nVHE + not-pKVM?). In the cases where disabling doesn't do anything (which are the exact opposite of the cases you describe), that's because there is absolutely *nothing* to do: - If VHE, the kernel is the bloody hypervisor: disable virtualisation, kill the kernel. - if pKVM, the kernel is basically a guest, and has no business touching anything at all. So much the 'evil' behaviour. M. -- Without deviation from the norm, progress is not possible.
