Re: [RFC PATCH v3 0/5] x86/kvm: Virtual suspend time injection support

Marc Zyngier
2021-10-20T13:52:36Z

Hi Hikaru,

On Wed, 20 Oct 2021 13:04:25 +0100,
Hikaru Nishida <hikalium@chromium.org> wrote:
>
>
> Hi,
>
> This patch series adds virtual suspend time injection support to KVM.
> It is an updated version of the following series:
> v2:
> https://lore.kernel.org/kvm/20210806100710.2425336-1-hikalium@chromium.org/
> v1:
> https://lore.kernel.org/kvm/20210426090644.2218834-1-hikalium@chromium.org/
>
> Please take a look again.
>
> To kvm/arm64 folks:
> I'm going to implement this mechanism to ARM64 as well but not
> sure which function should be used to make an IRQ (like kvm_apic_set_irq
> in x86) and if it is okay to use kvm_gfn_to_hva_cache /
> kvm_write_guest_cached for sharing the suspend duration.

Before we discuss interrupt injection, I want to understand what this
is doing, and how this is doing it. And more precisely, I want to find
out how you solve the various problems described by Thomas here [1].

Assuming you solve these, you should model the guest memory access
similarly to what we do for stolen time. As for injecting an
interrupt, why can't this be a userspace thing?

Thanks,

M.

[1] https://lore.kernel.org/all/871r557jls.ffs@tglx

--
Without deviation from the norm, progress is not possible.