diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 281179d92a28..c1fcb7a3c125 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3304,3 +3304,31 @@ Returns: 0 on success, negative value on error
 Allows use of the vector registers introduced with z13 processor, and
 provides for the synchronization between host and user space.  Will
 return -EINVAL if the machine does not support vectors.
+
+7.4 KVM_CAP_S390_USER_STSI
+
+Architectures: s390
+Parameters: none
+
+This capability allows post-handlers for the STSI instruction. After
+initial handling in the kernel, KVM exits to user space with
+KVM_EXIT_S390_STSI to allow user space to insert further data.
+
+Before exiting to userspace, kvm handlers should fill in s390_stsi field of
+vcpu->run:
+struct {
+	__u64 addr;
+	__u8 ar;
+	__u8 reserved;
+	__u8 fc;
+	__u8 sel1;
+	__u16 sel2;
+} s390_stsi;
+
+@addr - guest address of STSI SYSIB
+@fc   - function code
+@sel1 - selector 1
+@sel2 - selector 2
+@ar   - access register number
+
+KVM handlers should exit to userspace with rc = -EREMOTE.
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 347a3333d618..2356a8c660b3 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -565,6 +565,7 @@ struct kvm_arch{
 	int use_vectors;
 	int user_cpu_state_ctrl;
 	int user_sigp;
+	int user_stsi;
 	struct s390_io_adapter *adapters[MAX_S390_IO_ADAPTERS];
 	wait_queue_head_t ipte_wq;
 	int ipte_lock_count;
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index b7ecef98b668..fdfa10662700 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -178,6 +178,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_VM_ATTRIBUTES:
 	case KVM_CAP_MP_STATE:
 	case KVM_CAP_S390_USER_SIGP:
+	case KVM_CAP_S390_USER_STSI:
 		r = 1;
 		break;
 	case KVM_CAP_S390_MEM_OP:
@@ -280,6 +281,10 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
 		kvm->arch.use_vectors = MACHINE_HAS_VX;
 		r = MACHINE_HAS_VX ? 0 : -EINVAL;
 		break;
+	case KVM_CAP_S390_USER_STSI:
+		kvm->arch.user_stsi = 1;
+		r = 0;
+		break;
 	default:
 		r = -EINVAL;
 		break;
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index f4fe02e84326..5e4658d20c77 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -496,6 +496,17 @@ static void handle_stsi_3_2_2(struct kvm_vcpu *vcpu, struct sysinfo_3_2_2 *mem)
 	ASCEBC(mem->vm[0].cpi, 16);
 }
 
+static void insert_stsi_usr_data(struct kvm_vcpu *vcpu, u64 addr, ar_t ar,
+				 u8 fc, u8 sel1, u16 sel2)
+{
+	vcpu->run->exit_reason = KVM_EXIT_S390_STSI;
+	vcpu->run->s390_stsi.addr = addr;
+	vcpu->run->s390_stsi.ar = ar;
+	vcpu->run->s390_stsi.fc = fc;
+	vcpu->run->s390_stsi.sel1 = sel1;
+	vcpu->run->s390_stsi.sel2 = sel2;
+}
+
 static int handle_stsi(struct kvm_vcpu *vcpu)
 {
 	int fc = (vcpu->run->s.regs.gprs[0] & 0xf0000000) >> 28;
@@ -556,11 +567,15 @@ static int handle_stsi(struct kvm_vcpu *vcpu)
 		rc = kvm_s390_inject_prog_cond(vcpu, rc);
 		goto out;
 	}
+	if (vcpu->kvm->arch.user_stsi) {
+		insert_stsi_usr_data(vcpu, operand2, ar, fc, sel1, sel2);
+		rc = -EREMOTE;
+	}
 	trace_kvm_s390_handle_stsi(vcpu, fc, sel1, sel2, operand2);
 	free_page(mem);
 	kvm_s390_set_psw_cc(vcpu, 0);
 	vcpu->run->s.regs.gprs[0] = 0;
-	return 0;
+	return rc;
 out_no_data:
 	kvm_s390_set_psw_cc(vcpu, 3);
 out:
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 0e16f2c9f0de..57445ef88097 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -172,6 +172,7 @@ struct kvm_pit_config {
 #define KVM_EXIT_S390_TSCH        22
 #define KVM_EXIT_EPR              23
 #define KVM_EXIT_SYSTEM_EVENT     24
+#define KVM_EXIT_S390_STSI        25
 
 /* For KVM_EXIT_INTERNAL_ERROR */
 /* Emulate instruction failed. */
@@ -309,6 +310,15 @@ struct kvm_run {
 			__u32 type;
 			__u64 flags;
 		} system_event;
+		/* KVM_EXIT_S390_STSI */
+		struct {
+			__u64 addr;
+			__u8 ar;
+			__u8 reserved;
+			__u8 fc;
+			__u8 sel1;
+			__u16 sel2;
+		} s390_stsi;
 		/* Fix the size of the union. */
 		char padding[256];
 	};
@@ -780,6 +790,7 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_S390_USER_SIGP 106
 #define KVM_CAP_S390_VECTOR_REGISTERS 107
 #define KVM_CAP_S390_MEM_OP 108
+#define KVM_CAP_S390_USER_STSI 109
 
 #ifdef KVM_CAP_IRQ_ROUTING