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>
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 00ff00d..1ca5de0 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -119,6 +119,7 @@
 	u32 instruction_lctlg;
 	u32 exit_program_interruption;
 	u32 exit_instr_and_program;
+	u32 deliver_external_call;
 	u32 deliver_emergency_signal;
 	u32 deliver_service_signal;
 	u32 deliver_virtio_interrupt;
@@ -138,6 +139,7 @@
 	u32 instruction_stfl;
 	u32 instruction_tprot;
 	u32 instruction_sigp_sense;
+	u32 instruction_sigp_external_call;
 	u32 instruction_sigp_emergency;
 	u32 instruction_sigp_stop;
 	u32 instruction_sigp_arch;
@@ -174,6 +176,10 @@
 	__u32 address;
 };
 
+struct kvm_s390_extcall_info {
+	__u16 code;
+};
+
 struct kvm_s390_emerg_info {
 	__u16 code;
 };
@@ -186,6 +192,7 @@
 		struct kvm_s390_ext_info ext;
 		struct kvm_s390_pgm_info pgm;
 		struct kvm_s390_emerg_info emerg;
+		struct kvm_s390_extcall_info extcall;
 		struct kvm_s390_prefix_info prefix;
 	};
 };
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index c9aeb4b..87c1670 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -38,6 +38,11 @@
 				      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 @@
 				      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 @@
 			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 @@
 		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 @@
 		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 2963567..9610ba4 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -46,6 +46,7 @@
 	{ "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 @@
 	{ "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 d6a50c1..f815118 100644
--- a/arch/s390/kvm/sigp.c
+++ b/arch/s390/kvm/sigp.c
@@ -87,6 +87,7 @@
 		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 @@
 		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);
-	VCPU_EVENT(vcpu, 4, "sent sigp emerg to cpu %x", cpu_addr);
+	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);
 	return rc;
 }
 
@@ -267,6 +306,10 @@
 		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);
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 6884054..f47fcd3 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -371,6 +371,7 @@
 #define KVM_S390_INT_VIRTIO		0xffff2603u
 #define KVM_S390_INT_SERVICE		0xffff2401u
 #define KVM_S390_INT_EMERGENCY		0xffff1201u
+#define KVM_S390_INT_EXTERNAL_CALL	0xffff1202u
 
 struct kvm_s390_interrupt {
 	__u32 type;