Re: [PATCH v5 4/3] KVM: selftests: Add test cases for EOI suppression modes

[Sean Christopherson]

On Wed, Jan 28, 2026, David Woodhouse wrote:
> From: David Woodhouse <dwmw@xxxxxxxxxxxx>
> 
> Rather than being frightened of doing the right thing for the in-kernel
> I/O APIC because "there might be bugs", 

I'm not worried about bugs per se, I'm worried about breaking existing guests.
Even if KVM is 100% perfect, changes in behavior can still break guests,
especially for a feature like this where it seems like everyone got it wrong.

And as I said before, I'm not opposed to supporting directed EOI in the in-kernel
I/O APIC, but (a) I don't want to do it in conjunction with the fixes for stable@,
and (b) I'd prefer to not bother unless there's an actual use case for doing so.
The in-kernel I/O APIC isn't being deprecated, but AFAIK it's being de-prioritized
by pretty much every VMM.  I.e. the risk vs. reward isn't there for me.