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

On Wed, 2025-12-03 at 00:50 +0000, Huang, Kai wrote:

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.

The simplest option is probably to fix the in-kernel I/O APIC at the same time, bumping the version to 0x20 and adding support for the EOI register in the KVM_SUPPRESS_EOI_ENABLED case.