Messages in this thread | | | Date | Thu, 01 Sep 2022 10:03:16 +0100 | From | Marc Zyngier <> | Subject | Re: [PATCH v8 003/103] KVM: Refactor CPU compatibility check on module initialization |
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Sean,
On Thu, 11 Aug 2022 18:39:53 +0100, Sean Christopherson <seanjc@google.com> 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.
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