KVM: s390: implement sigp external call

Implement sigp external call, which might be required for guests that
issue an external call instead of an emergency signal for IPI.

This fixes an issue with "KVM: unknown SIGP: 0x02" when booting
such an SMP guest.

Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

3 files changed, 76 insertions, 1 deletions

diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index c9aeb4b4d0b..87c16705b38 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -38,6 +38,11 @@ static int __interrupt_is_deliverable(struct kvm_vcpu *vcpu,
 				      struct kvm_s390_interrupt_info *inti)
 {
 	switch (inti->type) {
+	case KVM_S390_INT_EXTERNAL_CALL:
+		if (psw_extint_disabled(vcpu))
+			return 0;
+		if (vcpu->arch.sie_block->gcr[0] & 0x2000ul)
+			return 1;
 	case KVM_S390_INT_EMERGENCY:
 		if (psw_extint_disabled(vcpu))
 			return 0;
@@ -98,6 +103,7 @@ static void __set_intercept_indicator(struct kvm_vcpu *vcpu,
 				      struct kvm_s390_interrupt_info *inti)
 {
 	switch (inti->type) {
+	case KVM_S390_INT_EXTERNAL_CALL:
 	case KVM_S390_INT_EMERGENCY:
 	case KVM_S390_INT_SERVICE:
 	case KVM_S390_INT_VIRTIO:
@@ -143,6 +149,28 @@ static void __do_deliver_interrupt(struct kvm_vcpu *vcpu,
 			exception = 1;
 		break;
 
+	case KVM_S390_INT_EXTERNAL_CALL:
+		VCPU_EVENT(vcpu, 4, "%s", "interrupt: sigp ext call");
+		vcpu->stat.deliver_external_call++;
+		rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x1202);
+		if (rc == -EFAULT)
+			exception = 1;
+
+		rc = put_guest_u16(vcpu, __LC_CPU_ADDRESS, inti->extcall.code);
+		if (rc == -EFAULT)
+			exception = 1;
+
+		rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
+			 &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
+		if (rc == -EFAULT)
+			exception = 1;
+
+		rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
+			__LC_EXT_NEW_PSW, sizeof(psw_t));
+		if (rc == -EFAULT)
+			exception = 1;
+		break;
+
 	case KVM_S390_INT_SERVICE:
 		VCPU_EVENT(vcpu, 4, "interrupt: sclp parm:%x",
 			   inti->ext.ext_params);
@@ -522,6 +550,7 @@ int kvm_s390_inject_vm(struct kvm *kvm,
 		break;
 	case KVM_S390_PROGRAM_INT:
 	case KVM_S390_SIGP_STOP:
+	case KVM_S390_INT_EXTERNAL_CALL:
 	case KVM_S390_INT_EMERGENCY:
 	default:
 		kfree(inti);
@@ -581,6 +610,7 @@ int kvm_s390_inject_vcpu(struct kvm_vcpu *vcpu,
 		break;
 	case KVM_S390_SIGP_STOP:
 	case KVM_S390_RESTART:
+	case KVM_S390_INT_EXTERNAL_CALL:
 	case KVM_S390_INT_EMERGENCY:
 		VCPU_EVENT(vcpu, 3, "inject: type %x", s390int->type);
 		inti->type = s390int->type;
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 29635678b5e..9610ba41b97 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -46,6 +46,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	{ "instruction_lctlg", VCPU_STAT(instruction_lctlg) },
 	{ "instruction_lctl", VCPU_STAT(instruction_lctl) },
 	{ "deliver_emergency_signal", VCPU_STAT(deliver_emergency_signal) },
+	{ "deliver_external_call", VCPU_STAT(deliver_external_call) },
 	{ "deliver_service_signal", VCPU_STAT(deliver_service_signal) },
 	{ "deliver_virtio_interrupt", VCPU_STAT(deliver_virtio_interrupt) },
 	{ "deliver_stop_signal", VCPU_STAT(deliver_stop_signal) },
@@ -64,6 +65,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	{ "instruction_stfl", VCPU_STAT(instruction_stfl) },
 	{ "instruction_tprot", VCPU_STAT(instruction_tprot) },
 	{ "instruction_sigp_sense", VCPU_STAT(instruction_sigp_sense) },
+	{ "instruction_sigp_external_call", VCPU_STAT(instruction_sigp_external_call) },
 	{ "instruction_sigp_emergency", VCPU_STAT(instruction_sigp_emergency) },
 	{ "instruction_sigp_stop", VCPU_STAT(instruction_sigp_stop) },
 	{ "instruction_sigp_set_arch", VCPU_STAT(instruction_sigp_arch) },
diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c
index d6a50c1fb2e..f815118835f 100644
--- a/arch/s390/kvm/sigp.c
+++ b/arch/s390/kvm/sigp.c
@@ -87,6 +87,7 @@ static int __sigp_emergency(struct kvm_vcpu *vcpu, u16 cpu_addr)
 		return -ENOMEM;
 
 	inti->type = KVM_S390_INT_EMERGENCY;
+	inti->emerg.code = vcpu->vcpu_id;
 
 	spin_lock(&fi->lock);
 	li = fi->local_int[cpu_addr];
@@ -103,9 +104,47 @@ static int __sigp_emergency(struct kvm_vcpu *vcpu, u16 cpu_addr)
 		wake_up_interruptible(&li->wq);
 	spin_unlock_bh(&li->lock);
 	rc = 0; /* order accepted */
+	VCPU_EVENT(vcpu, 4, "sent sigp emerg to cpu %x", cpu_addr);
+unlock:
+	spin_unlock(&fi->lock);
+	return rc;
+}
+
+static int __sigp_external_call(struct kvm_vcpu *vcpu, u16 cpu_addr)
+{
+	struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
+	struct kvm_s390_local_interrupt *li;
+	struct kvm_s390_interrupt_info *inti;
+	int rc;
+
+	if (cpu_addr >= KVM_MAX_VCPUS)
+		return 3; /* not operational */
+
+	inti = kzalloc(sizeof(*inti), GFP_KERNEL);
+	if (!inti)
+		return -ENOMEM;
+
+	inti->type = KVM_S390_INT_EXTERNAL_CALL;
+	inti->extcall.code = vcpu->vcpu_id;
+
+	spin_lock(&fi->lock);
+	li = fi->local_int[cpu_addr];
+	if (li == NULL) {
+		rc = 3; /* not operational */
+		kfree(inti);
+		goto unlock;
+	}
+	spin_lock_bh(&li->lock);
+	list_add_tail(&inti->list, &li->list);
+	atomic_set(&li->active, 1);
+	atomic_set_mask(CPUSTAT_EXT_INT, li->cpuflags);
+	if (waitqueue_active(&li->wq))
+		wake_up_interruptible(&li->wq);
+	spin_unlock_bh(&li->lock);
+	rc = 0; /* order accepted */
+	VCPU_EVENT(vcpu, 4, "sent sigp ext call to cpu %x", cpu_addr);
 unlock:
 	spin_unlock(&fi->lock);
-	VCPU_EVENT(vcpu, 4, "sent sigp emerg to cpu %x", cpu_addr);
 	return rc;
 }
 
@@ -267,6 +306,10 @@ int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu)
 		rc = __sigp_sense(vcpu, cpu_addr,
 				  &vcpu->arch.guest_gprs[r1]);
 		break;
+	case SIGP_EXTERNAL_CALL:
+		vcpu->stat.instruction_sigp_external_call++;
+		rc = __sigp_external_call(vcpu, cpu_addr);
+		break;
 	case SIGP_EMERGENCY:
 		vcpu->stat.instruction_sigp_emergency++;
 		rc = __sigp_emergency(vcpu, cpu_addr);