Re: CPU Lockups in KVM with deferred hrtimer rearming

Paolo Bonzini
2026-04-21T23:37:43Z

On Wed, Apr 22, 2026 at 12:34 AM Jim Mattson <jmattson@google.com> wrote:
>
> On Tue, Apr 21, 2026 at 4:16 PM Paolo Bonzini <pbonzini@redhat.com> wrote:
> > ...
> > There were two different steps. Posted interrupt support on the CPU
> > was introduced in Ivy Bridge. Posted interrupt support on the IOMMU in
> > Broadwell (and added to KVM with commit efc644048ecd, "KVM: x86:
> > Update IRTE for posted-interrupts", 2015-10-01). New virt features
> > used to come on the "tock" instead of the "tick").
>
> Nit: I believe posted interrupts were only introduced in the higher
> end Ivy Town parts, but I could be wrong. :)

Yes, they were fused out in Xeon E3 and below. I was only referring to
the processor generation ("v2" in the CPUID model id) - never heard
about "Town" until now.

Paolo