diff options
| -rw-r--r-- | arch/powerpc/include/asm/kvm_host.h | 1 | ||||
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv.c | 60 |
2 files changed, 32 insertions, 29 deletions
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 047855619cc4..7cf94a5e8411 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -297,6 +297,7 @@ struct kvmppc_vcore { struct list_head runnable_threads; spinlock_t lock; wait_queue_head_t wq; + spinlock_t stoltb_lock; /* protects stolen_tb and preempt_tb */ u64 stolen_tb; u64 preempt_tb; struct kvm_vcpu *runner; diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 1a7a281be3bd..74afa2d06fbc 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -135,11 +135,10 @@ static void kvmppc_fast_vcpu_kick_hv(struct kvm_vcpu *vcpu) * stolen. * * Updates to busy_stolen are protected by arch.tbacct_lock; - * updates to vc->stolen_tb are protected by the arch.tbacct_lock - * of the vcpu that has taken responsibility for running the vcore - * (i.e. vc->runner). The stolen times are measured in units of - * timebase ticks. (Note that the != TB_NIL checks below are - * purely defensive; they should never fail.) + * updates to vc->stolen_tb are protected by the vcore->stoltb_lock + * lock. The stolen times are measured in units of timebase ticks. + * (Note that the != TB_NIL checks below are purely defensive; + * they should never fail.) */ static void kvmppc_core_vcpu_load_hv(struct kvm_vcpu *vcpu, int cpu) @@ -147,12 +146,21 @@ static void kvmppc_core_vcpu_load_hv(struct kvm_vcpu *vcpu, int cpu) struct kvmppc_vcore *vc = vcpu->arch.vcore; unsigned long flags; - spin_lock_irqsave(&vcpu->arch.tbacct_lock, flags); - if (vc->runner == vcpu && vc->vcore_state != VCORE_INACTIVE && - vc->preempt_tb != TB_NIL) { - vc->stolen_tb += mftb() - vc->preempt_tb; - vc->preempt_tb = TB_NIL; + /* + * We can test vc->runner without taking the vcore lock, + * because only this task ever sets vc->runner to this + * vcpu, and once it is set to this vcpu, only this task + * ever sets it to NULL. + */ + if (vc->runner == vcpu && vc->vcore_state != VCORE_INACTIVE) { + spin_lock_irqsave(&vc->stoltb_lock, flags); + if (vc->preempt_tb != TB_NIL) { + vc->stolen_tb += mftb() - vc->preempt_tb; + vc->preempt_tb = TB_NIL; + } + spin_unlock_irqrestore(&vc->stoltb_lock, flags); } + spin_lock_irqsave(&vcpu->arch.tbacct_lock, flags); if (vcpu->arch.state == KVMPPC_VCPU_BUSY_IN_HOST && vcpu->arch.busy_preempt != TB_NIL) { vcpu->arch.busy_stolen += mftb() - vcpu->arch.busy_preempt; @@ -166,9 +174,12 @@ static void kvmppc_core_vcpu_put_hv(struct kvm_vcpu *vcpu) struct kvmppc_vcore *vc = vcpu->arch.vcore; unsigned long flags; - spin_lock_irqsave(&vcpu->arch.tbacct_lock, flags); - if (vc->runner == vcpu && vc->vcore_state != VCORE_INACTIVE) + if (vc->runner == vcpu && vc->vcore_state != VCORE_INACTIVE) { + spin_lock_irqsave(&vc->stoltb_lock, flags); vc->preempt_tb = mftb(); + spin_unlock_irqrestore(&vc->stoltb_lock, flags); + } + spin_lock_irqsave(&vcpu->arch.tbacct_lock, flags); if (vcpu->arch.state == KVMPPC_VCPU_BUSY_IN_HOST) vcpu->arch.busy_preempt = mftb(); spin_unlock_irqrestore(&vcpu->arch.tbacct_lock, flags); @@ -505,25 +516,14 @@ static void kvmppc_update_vpas(struct kvm_vcpu *vcpu) static u64 vcore_stolen_time(struct kvmppc_vcore *vc, u64 now) { u64 p; + unsigned long flags; - /* - * If we are the task running the vcore, then since we hold - * the vcore lock, we can't be preempted, so stolen_tb/preempt_tb - * can't be updated, so we don't need the tbacct_lock. - * If the vcore is inactive, it can't become active (since we - * hold the vcore lock), so the vcpu load/put functions won't - * update stolen_tb/preempt_tb, and we don't need tbacct_lock. - */ + spin_lock_irqsave(&vc->stoltb_lock, flags); + p = vc->stolen_tb; if (vc->vcore_state != VCORE_INACTIVE && - vc->runner->arch.run_task != current) { - spin_lock_irq(&vc->runner->arch.tbacct_lock); - p = vc->stolen_tb; - if (vc->preempt_tb != TB_NIL) - p += now - vc->preempt_tb; - spin_unlock_irq(&vc->runner->arch.tbacct_lock); - } else { - p = vc->stolen_tb; - } + vc->preempt_tb != TB_NIL) + p += now - vc->preempt_tb; + spin_unlock_irqrestore(&vc->stoltb_lock, flags); return p; } @@ -1359,6 +1359,7 @@ static struct kvmppc_vcore *kvmppc_vcore_create(struct kvm *kvm, int core) INIT_LIST_HEAD(&vcore->runnable_threads); spin_lock_init(&vcore->lock); + spin_lock_init(&vcore->stoltb_lock); init_waitqueue_head(&vcore->wq); vcore->preempt_tb = TB_NIL; vcore->lpcr = kvm->arch.lpcr; @@ -1696,6 +1697,7 @@ static void kvmppc_run_core(struct kvmppc_vcore *vc) vc->n_woken = 0; vc->nap_count = 0; vc->entry_exit_count = 0; + vc->preempt_tb = TB_NIL; vc->vcore_state = VCORE_STARTING; vc->in_guest = 0; vc->napping_threads = 0; |