Hi Sean, Thank you for reviewing my patches. On 2/26/2025 6:08 AM, Sean Christopherson wrote: > On Tue, Jan 28, 2025, Manali Shukla wrote: >> + if (kvm_cpu_has(X86_FEATURE_IDLE_HLT)) > > Well, shoot. I gave you bad input, and we're stuck. > > this_cpu_has() isn't correct, because the part of my previous feedback about > needing to check *KVM* support was 100% correct. But kvm_cpu_has() isn't right > either, because that checks what KVM supports exposing to the guest, not what > KVM itself supports/uses. E.g. even if we add full nested support, the test would > fail if nested=0 due to KVM not "supporting" Idle HLT despite using it under the > hood. > > The lack of a way for KVM to communicate support to the user has come up in the > past, e.g. in discussion around /proc/cpuinfo. Sadly, AFAIK there are no (good) > ideas on what that should look like. > > For now, I'll just skip this patch, even though doing so makes me quite sad. I understand your point. -Manali
