KVM: s390: cleanup handle_wait by reusing kvm_vcpu_block

This patch cleans up the code in handle_wait by reusing the common code
function kvm_vcpu_block.

signal_pending(), kvm_cpu_has_pending_timer() and kvm_arch_vcpu_runnable() are
sufficient for checking if we need to wake-up that VCPU. kvm_vcpu_block
uses these functions, so no checks are lost.

The flag "timer_due" can be removed - kvm_cpu_has_pending_timer() tests whether
the timer is pending, thus the vcpu is correctly woken up.

Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index c2ba020..b3acf28 100644 (file)
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -305,7 +305,6 @@ struct kvm_s390_local_interrupt {
        struct list_head list;
        atomic_t active;
        struct kvm_s390_float_interrupt *float_int;
-       int timer_due; /* event indicator for waitqueue below */
        wait_queue_head_t *wq;
        atomic_t *cpuflags;
        unsigned int action_bits;

diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 90c8de2..5fd11ce 100644 (file)
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -585,60 +585,32 @@ int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
 int kvm_s390_handle_wait(struct kvm_vcpu *vcpu)
 {
        u64 now, sltime;
-       DECLARE_WAITQUEUE(wait, current);
 
        vcpu->stat.exit_wait_state++;
-       if (kvm_cpu_has_interrupt(vcpu))
-               return 0;
 
-       __set_cpu_idle(vcpu);
-       spin_lock_bh(&vcpu->arch.local_int.lock);
-       vcpu->arch.local_int.timer_due = 0;
-       spin_unlock_bh(&vcpu->arch.local_int.lock);
+       /* fast path */
+       if (kvm_cpu_has_pending_timer(vcpu) || kvm_arch_vcpu_runnable(vcpu))
+               return 0;
 
        if (psw_interrupts_disabled(vcpu)) {
                VCPU_EVENT(vcpu, 3, "%s", "disabled wait");
-               __unset_cpu_idle(vcpu);
                return -EOPNOTSUPP; /* disabled wait */
        }
 
+       __set_cpu_idle(vcpu);
        if (!ckc_interrupts_enabled(vcpu)) {
                VCPU_EVENT(vcpu, 3, "%s", "enabled wait w/o timer");
                goto no_timer;
        }
 
        now = get_tod_clock_fast() + vcpu->arch.sie_block->epoch;
-       if (vcpu->arch.sie_block->ckc < now) {
-               __unset_cpu_idle(vcpu);
-               return 0;
-       }
-
        sltime = tod_to_ns(vcpu->arch.sie_block->ckc - now);
-
        hrtimer_start(&vcpu->arch.ckc_timer, ktime_set (0, sltime) , HRTIMER_MODE_REL);
        VCPU_EVENT(vcpu, 5, "enabled wait via clock comparator: %llx ns", sltime);
 no_timer:
        srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
-       spin_lock(&vcpu->arch.local_int.float_int->lock);
-       spin_lock_bh(&vcpu->arch.local_int.lock);
-       add_wait_queue(&vcpu->wq, &wait);
-       while (list_empty(&vcpu->arch.local_int.list) &&
-               list_empty(&vcpu->arch.local_int.float_int->list) &&
-               (!vcpu->arch.local_int.timer_due) &&
-               !signal_pending(current) &&
-               !kvm_s390_si_ext_call_pending(vcpu)) {
-               set_current_state(TASK_INTERRUPTIBLE);
-               spin_unlock_bh(&vcpu->arch.local_int.lock);
-               spin_unlock(&vcpu->arch.local_int.float_int->lock);
-               schedule();
-               spin_lock(&vcpu->arch.local_int.float_int->lock);
-               spin_lock_bh(&vcpu->arch.local_int.lock);
-       }
+       kvm_vcpu_block(vcpu);
        __unset_cpu_idle(vcpu);
-       __set_current_state(TASK_RUNNING);
-       remove_wait_queue(&vcpu->wq, &wait);
-       spin_unlock_bh(&vcpu->arch.local_int.lock);
-       spin_unlock(&vcpu->arch.local_int.float_int->lock);
        vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
 
        hrtimer_try_to_cancel(&vcpu->arch.ckc_timer);
@@ -649,11 +621,8 @@ void kvm_s390_tasklet(unsigned long parm)
 {
        struct kvm_vcpu *vcpu = (struct kvm_vcpu *) parm;
 
-       spin_lock(&vcpu->arch.local_int.lock);
-       vcpu->arch.local_int.timer_due = 1;
        if (waitqueue_active(&vcpu->wq))
                wake_up_interruptible(&vcpu->wq);
-       spin_unlock(&vcpu->arch.local_int.lock);
 }
 
 /*

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index fdf88f7..ecb1357 100644 (file)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1068,6 +1068,9 @@ retry:
                goto retry;
        }
 
+       /* nothing to do, just clear the request */
+       clear_bit(KVM_REQ_UNHALT, &vcpu->requests);
+
        return 0;
 }