Re: [RFC v2 2/5] hw/arm: Allow setting KVM vGIC maintenance IRQ

[Peter Maydell]

On Fri, 9 Feb 2024 at 16:00, Eric Auger <eric.auger@redhat.com> wrote:
>
> From: Haibo Xu <haibo.xu@linaro.org>
>
> Allow virt arm machine to set the intid for the KVM GIC maintenance
> interrupt.
>
> Signed-off-by: Haibo Xu <haibo.xu@linaro.org>
> Signed-off-by: Miguel Luis <miguel.luis@oracle.com>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>
> ---
> v1 -> v2:
> - [Miguel] replaced the has_virt_extensions by the maintenance irq
>   intid property. [Eric] restored kvm_device_check_attr and
>   kvm_device_access standard usage and conditionally call those
>   if the prop is set

This seems reasonable, but it's not the same way we opted to
handle telling the kernel the IRQ number for the PMU interrupt
(where we use kvm_arm_pmu_set_irq()). I guess we have to do
it this way because it's a device attr so we need to set it
in gic realize, though?

By the way, does the kernel automatically complain and fail
if we try to enable nested-virt with a GICv2 or with a
userspace GIC, or do we need to catch and produce error
messages for those (invalid) combinations ourselves?

thanks
-- PMM