KVM: s390: handle pending local interrupts via bitmap

This patch adapts handling of local interrupts to be more compliant with
the z/Architecture Principles of Operation and introduces a data
structure
which allows more efficient handling of interrupts.

* get rid of li->active flag, use bitmap instead
* Keep interrupts in a bitmap instead of a list
* Deliver interrupts in the order of their priority as defined in the
  PoP
* Use a second bitmap for sigp emergency requests, as a CPU can have
  one request pending from every other CPU in the system.
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

arch/s390/include/asm/kvm_host.h

@@ -398,8 +398,6 @@ struct kvm_s390_irq_payload {
 
 struct kvm_s390_local_interrupt {
 	spinlock_t lock;
-	struct list_head list;
-	atomic_t active;
 	struct kvm_s390_float_interrupt *float_int;
 	wait_queue_head_t *wq;
 	atomic_t *cpuflags;

arch/s390/kvm/intercept.c

@@ -257,7 +257,7 @@ static int handle_instruction_and_prog(struct kvm_vcpu *vcpu)
 static int handle_external_interrupt(struct kvm_vcpu *vcpu)
 {
 	u16 eic = vcpu->arch.sie_block->eic;
-	struct kvm_s390_interrupt irq;
+	struct kvm_s390_irq irq;
 	psw_t newpsw;
 	int rc;
 
@@ -282,7 +282,7 @@ static int handle_external_interrupt(struct kvm_vcpu *vcpu)
 		if (kvm_s390_si_ext_call_pending(vcpu))
 			return 0;
 		irq.type = KVM_S390_INT_EXTERNAL_CALL;
-		irq.parm = vcpu->arch.sie_block->extcpuaddr;
+		irq.u.extcall.code = vcpu->arch.sie_block->extcpuaddr;
 		break;
 	default:
 		return -EOPNOTSUPP;

arch/s390/kvm/kvm-s390.c

@@ -719,7 +719,6 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
 	}
 
 	spin_lock_init(&vcpu->arch.local_int.lock);
-	INIT_LIST_HEAD(&vcpu->arch.local_int.list);
 	vcpu->arch.local_int.float_int = &kvm->arch.float_int;
 	vcpu->arch.local_int.wq = &vcpu->wq;
 	vcpu->arch.local_int.cpuflags = &vcpu->arch.sie_block->cpuflags;
@@ -1122,13 +1121,15 @@ static void __kvm_inject_pfault_token(struct kvm_vcpu *vcpu, bool start_token,
 				      unsigned long token)
 {
 	struct kvm_s390_interrupt inti;
-	inti.parm64 = token;
+	struct kvm_s390_irq irq;
 
 	if (start_token) {
-		inti.type = KVM_S390_INT_PFAULT_INIT;
-		WARN_ON_ONCE(kvm_s390_inject_vcpu(vcpu, &inti));
+		irq.u.ext.ext_params2 = token;
+		irq.type = KVM_S390_INT_PFAULT_INIT;
+		WARN_ON_ONCE(kvm_s390_inject_vcpu(vcpu, &irq));
 	} else {
 		inti.type = KVM_S390_INT_PFAULT_DONE;
+		inti.parm64 = token;
 		WARN_ON_ONCE(kvm_s390_inject_vm(vcpu->kvm, &inti));
 	}
 }
@@ -1622,11 +1623,14 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 	switch (ioctl) {
 	case KVM_S390_INTERRUPT: {
 		struct kvm_s390_interrupt s390int;
+		struct kvm_s390_irq s390irq;
 
 		r = -EFAULT;
 		if (copy_from_user(&s390int, argp, sizeof(s390int)))
 			break;
-		r = kvm_s390_inject_vcpu(vcpu, &s390int);
+		if (s390int_to_s390irq(&s390int, &s390irq))
+			return -EINVAL;
+		r = kvm_s390_inject_vcpu(vcpu, &s390irq);
 		break;
 	}
 	case KVM_S390_STORE_STATUS:

arch/s390/kvm/kvm-s390.h

@@ -142,7 +142,7 @@ void kvm_s390_clear_float_irqs(struct kvm *kvm);
 int __must_check kvm_s390_inject_vm(struct kvm *kvm,
 				    struct kvm_s390_interrupt *s390int);
 int __must_check kvm_s390_inject_vcpu(struct kvm_vcpu *vcpu,
-				      struct kvm_s390_interrupt *s390int);
+				      struct kvm_s390_irq *irq);
 int __must_check kvm_s390_inject_program_int(struct kvm_vcpu *vcpu, u16 code);
 struct kvm_s390_interrupt_info *kvm_s390_get_io_int(struct kvm *kvm,
 						    u64 cr6, u64 schid);
@@ -224,6 +224,9 @@ static inline int kvm_s390_inject_prog_cond(struct kvm_vcpu *vcpu, int rc)
 	return kvm_s390_inject_prog_irq(vcpu, &vcpu->arch.pgm);
 }
 
+int s390int_to_s390irq(struct kvm_s390_interrupt *s390int,
+			struct kvm_s390_irq *s390irq);
+
 /* implemented in interrupt.c */
 int kvm_cpu_has_interrupt(struct kvm_vcpu *vcpu);
 int psw_extint_disabled(struct kvm_vcpu *vcpu);

arch/s390/kvm/sigp.c

@@ -49,13 +49,13 @@ static int __sigp_sense(struct kvm_vcpu *vcpu, struct kvm_vcpu *dst_vcpu,
 static int __inject_sigp_emergency(struct kvm_vcpu *vcpu,
 				    struct kvm_vcpu *dst_vcpu)
 {
-	struct kvm_s390_interrupt s390int = {
+	struct kvm_s390_irq irq = {
 		.type = KVM_S390_INT_EMERGENCY,
-		.parm = vcpu->vcpu_id,
+		.u.emerg.code = vcpu->vcpu_id,
 	};
 	int rc = 0;
 
-	rc = kvm_s390_inject_vcpu(dst_vcpu, &s390int);
+	rc = kvm_s390_inject_vcpu(dst_vcpu, &irq);
 	if (!rc)
 		VCPU_EVENT(vcpu, 4, "sent sigp emerg to cpu %x",
 			   dst_vcpu->vcpu_id);
@@ -98,13 +98,13 @@ static int __sigp_conditional_emergency(struct kvm_vcpu *vcpu,
 static int __sigp_external_call(struct kvm_vcpu *vcpu,
 				struct kvm_vcpu *dst_vcpu)
 {
-	struct kvm_s390_interrupt s390int = {
+	struct kvm_s390_irq irq = {
 		.type = KVM_S390_INT_EXTERNAL_CALL,
-		.parm = vcpu->vcpu_id,
+		.u.extcall.code = vcpu->vcpu_id,
 	};
 	int rc;
 
-	rc = kvm_s390_inject_vcpu(dst_vcpu, &s390int);
+	rc = kvm_s390_inject_vcpu(dst_vcpu, &irq);
 	if (!rc)
 		VCPU_EVENT(vcpu, 4, "sent sigp ext call to cpu %x",
 			   dst_vcpu->vcpu_id);
@@ -115,29 +115,20 @@ static int __sigp_external_call(struct kvm_vcpu *vcpu,
 static int __inject_sigp_stop(struct kvm_vcpu *dst_vcpu, int action)
 {
 	struct kvm_s390_local_interrupt *li = &dst_vcpu->arch.local_int;
-	struct kvm_s390_interrupt_info *inti;
 	int rc = SIGP_CC_ORDER_CODE_ACCEPTED;
 
-	inti = kzalloc(sizeof(*inti), GFP_ATOMIC);
-	if (!inti)
-		return -ENOMEM;
-	inti->type = KVM_S390_SIGP_STOP;
-
 	spin_lock(&li->lock);
 	if (li->action_bits & ACTION_STOP_ON_STOP) {
 		/* another SIGP STOP is pending */
-		kfree(inti);
 		rc = SIGP_CC_BUSY;
 		goto out;
 	}
 	if ((atomic_read(li->cpuflags) & CPUSTAT_STOPPED)) {
-		kfree(inti);
 		if ((action & ACTION_STORE_ON_STOP) != 0)
 			rc = -ESHUTDOWN;
 		goto out;
 	}
-	list_add_tail(&inti->list, &li->list);
-	atomic_set(&li->active, 1);
+	set_bit(IRQ_PEND_SIGP_STOP, &li->pending_irqs);
 	li->action_bits |= action;
 	atomic_set_mask(CPUSTAT_STOP_INT, li->cpuflags);
 	kvm_s390_vcpu_wakeup(dst_vcpu);
@@ -207,7 +198,6 @@ static int __sigp_set_prefix(struct kvm_vcpu *vcpu, struct kvm_vcpu *dst_vcpu,
 			     u32 address, u64 *reg)
 {
 	struct kvm_s390_local_interrupt *li;
-	struct kvm_s390_interrupt_info *inti;
 	int rc;
 
 	li = &dst_vcpu->arch.local_int;
@@ -224,25 +214,17 @@ static int __sigp_set_prefix(struct kvm_vcpu *vcpu, struct kvm_vcpu *dst_vcpu,
 		return SIGP_CC_STATUS_STORED;
 	}
 
-	inti = kzalloc(sizeof(*inti), GFP_KERNEL);
-	if (!inti)
-		return SIGP_CC_BUSY;
-
 	spin_lock(&li->lock);
 	/* cpu must be in stopped state */
 	if (!(atomic_read(li->cpuflags) & CPUSTAT_STOPPED)) {
 		*reg &= 0xffffffff00000000UL;
 		*reg |= SIGP_STATUS_INCORRECT_STATE;
 		rc = SIGP_CC_STATUS_STORED;
-		kfree(inti);
 		goto out_li;
 	}
 
-	inti->type = KVM_S390_SIGP_SET_PREFIX;
-	inti->prefix.address = address;
-
-	list_add_tail(&inti->list, &li->list);
-	atomic_set(&li->active, 1);
+	li->irq.prefix.address = address;
+	set_bit(IRQ_PEND_SET_PREFIX, &li->pending_irqs);
 	kvm_s390_vcpu_wakeup(dst_vcpu);
 	rc = SIGP_CC_ORDER_CODE_ACCEPTED;