Re: [PATCH v3] KVM: x86: Add x2APIC "features" to control EOI broadcast suppression

[Huang, Kai]

> -#define KVM_X2APIC_API_USE_32BIT_IDS            (1ULL << 0)
> -#define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK  (1ULL << 1)
> +#define KVM_X2APIC_API_USE_32BIT_IDS			(_BITULL(0))
> +#define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK		(_BITULL(1))
> +#define KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST	(_BITULL(2))
> +#define KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST	(_BITULL(3))

I hate to say, but wants to ask again:

Since it's uAPI, are we expecting the two flags to have impact on in-kernel
ioapic?

I think there should no harm to make the two also apply to in-kernel ioapic.

E.g., for now we can reject KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST flag for
in-kernel ioapic.  In the future, we might add EOI register support to in-kernel
ioapic and report supporting suppress EOI broadcast, then we can in-kernel
ioapic to honor these two flags too.