diff options
| -rw-r--r-- | arch/x86/kvm/vmx/posted_intr.c | 29 |
1 files changed, 16 insertions, 13 deletions
diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c index 110fb19848ab..d4826a6b674f 100644 --- a/arch/x86/kvm/vmx/posted_intr.c +++ b/arch/x86/kvm/vmx/posted_intr.c @@ -73,13 +73,10 @@ void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu) /* * If the vCPU wasn't on the wakeup list and wasn't migrated, then the * full update can be skipped as neither the vector nor the destination - * needs to be changed. + * needs to be changed. Clear SN even if there is no assigned device, + * again for simplicity. */ if (pi_desc->nv != POSTED_INTR_WAKEUP_VECTOR && vcpu->cpu == cpu) { - /* - * Clear SN if it was set due to being preempted. Again, do - * this even if there is no assigned device for simplicity. - */ if (pi_test_and_clear_sn(pi_desc)) goto after_clear_sn; return; @@ -225,17 +222,23 @@ void vmx_vcpu_pi_put(struct kvm_vcpu *vcpu) if (!vmx_needs_pi_wakeup(vcpu)) return; - if (kvm_vcpu_is_blocking(vcpu) && + /* + * If the vCPU is blocking with IRQs enabled and ISN'T being preempted, + * enable the wakeup handler so that notification IRQ wakes the vCPU as + * expected. There is no need to enable the wakeup handler if the vCPU + * is preempted between setting its wait state and manually scheduling + * out, as the task is still runnable, i.e. doesn't need a wake event + * from KVM to be scheduled in. + * + * If the wakeup handler isn't being enabled, Suppress Notifications as + * the cost of propagating PIR.IRR to PID.ON is negligible compared to + * the cost of a spurious IRQ, and vCPU put/load is a slow path. + */ + if (!vcpu->preempted && kvm_vcpu_is_blocking(vcpu) && ((is_td_vcpu(vcpu) && tdx_interrupt_allowed(vcpu)) || (!is_td_vcpu(vcpu) && !vmx_interrupt_blocked(vcpu)))) pi_enable_wakeup_handler(vcpu); - - /* - * Set SN when the vCPU is preempted. Note, the vCPU can both be seen - * as blocking and preempted, e.g. if it's preempted between setting - * its wait state and manually scheduling out. - */ - if (vcpu->preempted) + else pi_set_sn(pi_desc); } |