KVM: s390: protvirt: Add SCLP interrupt handling

The sclp interrupt is kind of special. The ultravisor polices that we
do not inject an sclp interrupt with payload if no sccb is outstanding.
On the other hand we have "asynchronous" event interrupts, e.g. for
console input.
We separate both variants into sclp interrupt and sclp event interrupt.
The sclp interrupt is masked until a previous servc instruction has
finished (sie exit 108).

[frankja@linux.ibm.com: factoring out write_sclp]
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 77 insertions, 18 deletions

diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index fc55f09938eb..145cccd498d7 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -324,8 +324,11 @@ static inline int gisa_tac_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gisc)
 
 static inline unsigned long pending_irqs_no_gisa(struct kvm_vcpu *vcpu)
 {
-	return vcpu->kvm->arch.float_int.pending_irqs |
-		vcpu->arch.local_int.pending_irqs;
+	unsigned long pending = vcpu->kvm->arch.float_int.pending_irqs |
+				vcpu->arch.local_int.pending_irqs;
+
+	pending &= ~vcpu->kvm->arch.float_int.masked_irqs;
+	return pending;
 }
 
 static inline unsigned long pending_irqs(struct kvm_vcpu *vcpu)
@@ -383,8 +386,10 @@ static unsigned long deliverable_irqs(struct kvm_vcpu *vcpu)
 		__clear_bit(IRQ_PEND_EXT_CLOCK_COMP, &active_mask);
 	if (!(vcpu->arch.sie_block->gcr[0] & CR0_CPU_TIMER_SUBMASK))
 		__clear_bit(IRQ_PEND_EXT_CPU_TIMER, &active_mask);
-	if (!(vcpu->arch.sie_block->gcr[0] & CR0_SERVICE_SIGNAL_SUBMASK))
+	if (!(vcpu->arch.sie_block->gcr[0] & CR0_SERVICE_SIGNAL_SUBMASK)) {
 		__clear_bit(IRQ_PEND_EXT_SERVICE, &active_mask);
+		__clear_bit(IRQ_PEND_EXT_SERVICE_EV, &active_mask);
+	}
 	if (psw_mchk_disabled(vcpu))
 		active_mask &= ~IRQ_PEND_MCHK_MASK;
 	/* PV guest cpus can have a single interruption injected at a time. */
@@ -946,20 +951,49 @@ static int __must_check __deliver_prog(struct kvm_vcpu *vcpu)
 	return rc ? -EFAULT : 0;
 }
 
+#define SCCB_MASK 0xFFFFFFF8
+#define SCCB_EVENT_PENDING 0x3
+
+static int write_sclp(struct kvm_vcpu *vcpu, u32 parm)
+{
+	int rc;
+
+	if (kvm_s390_pv_cpu_get_handle(vcpu)) {
+		vcpu->arch.sie_block->iictl = IICTL_CODE_EXT;
+		vcpu->arch.sie_block->eic = EXT_IRQ_SERVICE_SIG;
+		vcpu->arch.sie_block->eiparams = parm;
+		return 0;
+	}
+
+	rc  = put_guest_lc(vcpu, EXT_IRQ_SERVICE_SIG, (u16 *)__LC_EXT_INT_CODE);
+	rc |= put_guest_lc(vcpu, 0, (u16 *)__LC_EXT_CPU_ADDR);
+	rc |= write_guest_lc(vcpu, __LC_EXT_OLD_PSW,
+			     &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
+	rc |= read_guest_lc(vcpu, __LC_EXT_NEW_PSW,
+			    &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
+	rc |= put_guest_lc(vcpu, parm,
+			   (u32 *)__LC_EXT_PARAMS);
+
+	return rc ? -EFAULT : 0;
+}
+
 static int __must_check __deliver_service(struct kvm_vcpu *vcpu)
 {
 	struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
 	struct kvm_s390_ext_info ext;
-	int rc = 0;
 
 	spin_lock(&fi->lock);
-	if (!(test_bit(IRQ_PEND_EXT_SERVICE, &fi->pending_irqs))) {
+	if (test_bit(IRQ_PEND_EXT_SERVICE, &fi->masked_irqs) ||
+	    !(test_bit(IRQ_PEND_EXT_SERVICE, &fi->pending_irqs))) {
 		spin_unlock(&fi->lock);
 		return 0;
 	}
 	ext = fi->srv_signal;
 	memset(&fi->srv_signal, 0, sizeof(ext));
 	clear_bit(IRQ_PEND_EXT_SERVICE, &fi->pending_irqs);
+	clear_bit(IRQ_PEND_EXT_SERVICE_EV, &fi->pending_irqs);
+	if (kvm_s390_pv_cpu_is_protected(vcpu))
+		set_bit(IRQ_PEND_EXT_SERVICE, &fi->masked_irqs);
 	spin_unlock(&fi->lock);
 
 	VCPU_EVENT(vcpu, 4, "deliver: sclp parameter 0x%x",
@@ -968,16 +1002,31 @@ static int __must_check __deliver_service(struct kvm_vcpu *vcpu)
 	trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, KVM_S390_INT_SERVICE,
 					 ext.ext_params, 0);
 
-	rc  = put_guest_lc(vcpu, EXT_IRQ_SERVICE_SIG, (u16 *)__LC_EXT_INT_CODE);
-	rc |= put_guest_lc(vcpu, 0, (u16 *)__LC_EXT_CPU_ADDR);
-	rc |= write_guest_lc(vcpu, __LC_EXT_OLD_PSW,
-			     &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
-	rc |= read_guest_lc(vcpu, __LC_EXT_NEW_PSW,
-			    &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
-	rc |= put_guest_lc(vcpu, ext.ext_params,
-			   (u32 *)__LC_EXT_PARAMS);
+	return write_sclp(vcpu, ext.ext_params);
+}
 
-	return rc ? -EFAULT : 0;
+static int __must_check __deliver_service_ev(struct kvm_vcpu *vcpu)
+{
+	struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
+	struct kvm_s390_ext_info ext;
+
+	spin_lock(&fi->lock);
+	if (!(test_bit(IRQ_PEND_EXT_SERVICE_EV, &fi->pending_irqs))) {
+		spin_unlock(&fi->lock);
+		return 0;
+	}
+	ext = fi->srv_signal;
+	/* only clear the event bit */
+	fi->srv_signal.ext_params &= ~SCCB_EVENT_PENDING;
+	clear_bit(IRQ_PEND_EXT_SERVICE_EV, &fi->pending_irqs);
+	spin_unlock(&fi->lock);
+
+	VCPU_EVENT(vcpu, 4, "%s", "deliver: sclp parameter event");
+	vcpu->stat.deliver_service_signal++;
+	trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, KVM_S390_INT_SERVICE,
+					 ext.ext_params, 0);
+
+	return write_sclp(vcpu, SCCB_EVENT_PENDING);
 }
 
 static int __must_check __deliver_pfault_done(struct kvm_vcpu *vcpu)
@@ -1382,6 +1431,9 @@ int __must_check kvm_s390_deliver_pending_interrupts(struct kvm_vcpu *vcpu)
 		case IRQ_PEND_EXT_SERVICE:
 			rc = __deliver_service(vcpu);
 			break;
+		case IRQ_PEND_EXT_SERVICE_EV:
+			rc = __deliver_service_ev(vcpu);
+			break;
 		case IRQ_PEND_PFAULT_DONE:
 			rc = __deliver_pfault_done(vcpu);
 			break;
@@ -1734,9 +1786,6 @@ out:
 	return inti;
 }
 
-#define SCCB_MASK 0xFFFFFFF8
-#define SCCB_EVENT_PENDING 0x3
-
 static int __inject_service(struct kvm *kvm,
 			     struct kvm_s390_interrupt_info *inti)
 {
@@ -1745,6 +1794,11 @@ static int __inject_service(struct kvm *kvm,
 	kvm->stat.inject_service_signal++;
 	spin_lock(&fi->lock);
 	fi->srv_signal.ext_params |= inti->ext.ext_params & SCCB_EVENT_PENDING;
+
+	/* We always allow events, track them separately from the sccb ints */
+	if (fi->srv_signal.ext_params & SCCB_EVENT_PENDING)
+		set_bit(IRQ_PEND_EXT_SERVICE_EV, &fi->pending_irqs);
+
 	/*
 	 * Early versions of the QEMU s390 bios will inject several
 	 * service interrupts after another without handling a
@@ -2141,6 +2195,10 @@ void kvm_s390_clear_float_irqs(struct kvm *kvm)
 	struct kvm_s390_float_interrupt *fi = &kvm->arch.float_int;
 	int i;
 
+	mutex_lock(&kvm->lock);
+	if (!kvm_s390_pv_is_protected(kvm))
+		fi->masked_irqs = 0;
+	mutex_unlock(&kvm->lock);
 	spin_lock(&fi->lock);
 	fi->pending_irqs = 0;
 	memset(&fi->srv_signal, 0, sizeof(fi->srv_signal));
@@ -2207,7 +2265,8 @@ static int get_all_floating_irqs(struct kvm *kvm, u8 __user *usrbuf, u64 len)
 			n++;
 		}
 	}
-	if (test_bit(IRQ_PEND_EXT_SERVICE, &fi->pending_irqs)) {
+	if (test_bit(IRQ_PEND_EXT_SERVICE, &fi->pending_irqs) ||
+	    test_bit(IRQ_PEND_EXT_SERVICE_EV, &fi->pending_irqs)) {
 		if (n == max_irqs) {
 			/* signal userspace to try again */
 			ret = -ENOMEM;