Re: [PATCH] KVM: x86: Clamp the EOI vector if its OOB instead of bugging the kernel

[Huang, Kai]

On Thu, 2026-06-18 at 11:55 -0700, Sean Christopherson wrote:
> If KVM handles an I/O APIC EOI exit request with a bad vector, clamp the
> vector to 255 and hope for the best instead of bugging the host.  In all
> likelihood, a missed EOI is survivable for the guest, and it's most
> definitely not remotely fatal to the host, i.e. potentially panicking the
> host is completely unjustified.  Arbitrarily use 255 for the dummy vector,
> the goal is purely to ensure the vector is covered by the bitmap.

255 is a valid vector.  How about use a CPU reserved one instead (e.g., vector
0) and hope for the best?