+Paolo, Wanpeng, and Vitaly In the future, use get_maintainers.pl to build To: and Cc: so that the right folks see the patch. Not everyone habitually scours the KVM list. :-) On Wed, Feb 15, 2023, lirongqing@xxxxxxxxx wrote: > From: Li RongQing <lirongqing@xxxxxxxxx> > > Check whether vcpu is preempted or not when HLT is trapped or there > is not realtime hint. Please explain _why_ there's no need to check for preemption in this setup. What may be obvious to you isn't necessarily obvious to reviewers or readers. > In other words, it is unnecessary to check preemption if HLT is not > intercepted and guest has realtime hint > > Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx> > --- > arch/x86/kernel/kvm.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c > index 1cceac5..1a2744d 100644 > --- a/arch/x86/kernel/kvm.c > +++ b/arch/x86/kernel/kvm.c > @@ -820,8 +820,10 @@ static void __init kvm_guest_init(void) > has_steal_clock = 1; > static_call_update(pv_steal_clock, kvm_steal_clock); > > - pv_ops.lock.vcpu_is_preempted = > - PV_CALLEE_SAVE(__kvm_vcpu_is_preempted); > + if (kvm_para_has_feature(KVM_FEATURE_PV_UNHALT) || Rather than have the guest rely on host KVM behavior clearing PV_UNHALT when HLT is passed through), would it make sense to add something like KVM_HINTS_HLT_PASSTHROUGH to more explicitly tell the guest that HLT isn't intercepted? > + !kvm_para_has_hint(KVM_HINTS_REALTIME)) Misaligned indentation (one too many spaces). > + pv_ops.lock.vcpu_is_preempted = > + PV_CALLEE_SAVE(__kvm_vcpu_is_preempted); > } > > if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) > -- > 2.9.4 >
