diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index f708be3..792a4e7 100644
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -87,7 +87,7 @@
 head-y		:= arch/s390/kernel/head.o arch/s390/kernel/init_task.o
 
 core-y		+= arch/s390/mm/ arch/s390/kernel/ arch/s390/crypto/ \
-		   arch/s390/appldata/ arch/s390/hypfs/
+		   arch/s390/appldata/ arch/s390/hypfs/ arch/s390/kvm/
 libs-y		+= arch/s390/lib/
 drivers-y	+= drivers/s390/
 drivers-$(CONFIG_MATHEMU) += arch/s390/math-emu/
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index c5f05b3..ca90ee3 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -110,6 +110,7 @@
 	S390_lowcore.steal_clock -= cputime << 12;
 	account_system_time(tsk, 0, cputime);
 }
+EXPORT_SYMBOL_GPL(account_system_vtime);
 
 static inline void set_vtimer(__u64 expires)
 {
diff --git a/arch/s390/kvm/Makefile b/arch/s390/kvm/Makefile
new file mode 100644
index 0000000..0d8d113
--- /dev/null
+++ b/arch/s390/kvm/Makefile
@@ -0,0 +1,14 @@
+# Makefile for kernel virtual machines on s390
+#
+# Copyright IBM Corp. 2008
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License (version 2 only)
+# as published by the Free Software Foundation.
+
+common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o)
+
+EXTRA_CFLAGS += -Ivirt/kvm -Iarch/s390/kvm
+
+kvm-objs := $(common-objs) kvm-s390.o sie64a.o
+obj-$(CONFIG_KVM) += kvm.o
diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h
new file mode 100644
index 0000000..4e0633c
--- /dev/null
+++ b/arch/s390/kvm/gaccess.h
@@ -0,0 +1,274 @@
+/*
+ * gaccess.h -  access guest memory
+ *
+ * Copyright IBM Corp. 2008
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ *
+ *    Author(s): Carsten Otte <cotte@de.ibm.com>
+ */
+
+#ifndef __KVM_S390_GACCESS_H
+#define __KVM_S390_GACCESS_H
+
+#include <linux/compiler.h>
+#include <linux/kvm_host.h>
+#include <asm/uaccess.h>
+
+static inline void __user *__guestaddr_to_user(struct kvm_vcpu *vcpu,
+					       u64 guestaddr)
+{
+	u64 prefix  = vcpu->arch.sie_block->prefix;
+	u64 origin  = vcpu->kvm->arch.guest_origin;
+	u64 memsize = vcpu->kvm->arch.guest_memsize;
+
+	if (guestaddr < 2 * PAGE_SIZE)
+		guestaddr += prefix;
+	else if ((guestaddr >= prefix) && (guestaddr < prefix + 2 * PAGE_SIZE))
+		guestaddr -= prefix;
+
+	if (guestaddr > memsize)
+		return (void __user __force *) ERR_PTR(-EFAULT);
+
+	guestaddr += origin;
+
+	return (void __user *) guestaddr;
+}
+
+static inline int get_guest_u64(struct kvm_vcpu *vcpu, u64 guestaddr,
+				u64 *result)
+{
+	void __user *uptr = __guestaddr_to_user(vcpu, guestaddr);
+
+	BUG_ON(guestaddr & 7);
+
+	if (IS_ERR((void __force *) uptr))
+		return PTR_ERR((void __force *) uptr);
+
+	return get_user(*result, (u64 __user *) uptr);
+}
+
+static inline int get_guest_u32(struct kvm_vcpu *vcpu, u64 guestaddr,
+				u32 *result)
+{
+	void __user *uptr = __guestaddr_to_user(vcpu, guestaddr);
+
+	BUG_ON(guestaddr & 3);
+
+	if (IS_ERR((void __force *) uptr))
+		return PTR_ERR((void __force *) uptr);
+
+	return get_user(*result, (u32 __user *) uptr);
+}
+
+static inline int get_guest_u16(struct kvm_vcpu *vcpu, u64 guestaddr,
+				u16 *result)
+{
+	void __user *uptr = __guestaddr_to_user(vcpu, guestaddr);
+
+	BUG_ON(guestaddr & 1);
+
+	if (IS_ERR(uptr))
+		return PTR_ERR(uptr);
+
+	return get_user(*result, (u16 __user *) uptr);
+}
+
+static inline int get_guest_u8(struct kvm_vcpu *vcpu, u64 guestaddr,
+			       u8 *result)
+{
+	void __user *uptr = __guestaddr_to_user(vcpu, guestaddr);
+
+	if (IS_ERR((void __force *) uptr))
+		return PTR_ERR((void __force *) uptr);
+
+	return get_user(*result, (u8 __user *) uptr);
+}
+
+static inline int put_guest_u64(struct kvm_vcpu *vcpu, u64 guestaddr,
+				u64 value)
+{
+	void __user *uptr = __guestaddr_to_user(vcpu, guestaddr);
+
+	BUG_ON(guestaddr & 7);
+
+	if (IS_ERR((void __force *) uptr))
+		return PTR_ERR((void __force *) uptr);
+
+	return put_user(value, (u64 __user *) uptr);
+}
+
+static inline int put_guest_u32(struct kvm_vcpu *vcpu, u64 guestaddr,
+				u32 value)
+{
+	void __user *uptr = __guestaddr_to_user(vcpu, guestaddr);
+
+	BUG_ON(guestaddr & 3);
+
+	if (IS_ERR((void __force *) uptr))
+		return PTR_ERR((void __force *) uptr);
+
+	return put_user(value, (u32 __user *) uptr);
+}
+
+static inline int put_guest_u16(struct kvm_vcpu *vcpu, u64 guestaddr,
+				u16 value)
+{
+	void __user *uptr = __guestaddr_to_user(vcpu, guestaddr);
+
+	BUG_ON(guestaddr & 1);
+
+	if (IS_ERR((void __force *) uptr))
+		return PTR_ERR((void __force *) uptr);
+
+	return put_user(value, (u16 __user *) uptr);
+}
+
+static inline int put_guest_u8(struct kvm_vcpu *vcpu, u64 guestaddr,
+			       u8 value)
+{
+	void __user *uptr = __guestaddr_to_user(vcpu, guestaddr);
+
+	if (IS_ERR((void __force *) uptr))
+		return PTR_ERR((void __force *) uptr);
+
+	return put_user(value, (u8 __user *) uptr);
+}
+
+
+static inline int __copy_to_guest_slow(struct kvm_vcpu *vcpu, u64 guestdest,
+				       const void *from, unsigned long n)
+{
+	int rc;
+	unsigned long i;
+	const u8 *data = from;
+
+	for (i = 0; i < n; i++) {
+		rc = put_guest_u8(vcpu, guestdest++, *(data++));
+		if (rc < 0)
+			return rc;
+	}
+	return 0;
+}
+
+static inline int copy_to_guest(struct kvm_vcpu *vcpu, u64 guestdest,
+				const void *from, unsigned long n)
+{
+	u64 prefix  = vcpu->arch.sie_block->prefix;
+	u64 origin  = vcpu->kvm->arch.guest_origin;
+	u64 memsize = vcpu->kvm->arch.guest_memsize;
+
+	if ((guestdest < 2 * PAGE_SIZE) && (guestdest + n > 2 * PAGE_SIZE))
+		goto slowpath;
+
+	if ((guestdest < prefix) && (guestdest + n > prefix))
+		goto slowpath;
+
+	if ((guestdest < prefix + 2 * PAGE_SIZE)
+	    && (guestdest + n > prefix + 2 * PAGE_SIZE))
+		goto slowpath;
+
+	if (guestdest < 2 * PAGE_SIZE)
+		guestdest += prefix;
+	else if ((guestdest >= prefix) && (guestdest < prefix + 2 * PAGE_SIZE))
+		guestdest -= prefix;
+
+	if (guestdest + n > memsize)
+		return -EFAULT;
+
+	if (guestdest + n < guestdest)
+		return -EFAULT;
+
+	guestdest += origin;
+
+	return copy_to_user((void __user *) guestdest, from, n);
+slowpath:
+	return __copy_to_guest_slow(vcpu, guestdest, from, n);
+}
+
+static inline int __copy_from_guest_slow(struct kvm_vcpu *vcpu, void *to,
+					 u64 guestsrc, unsigned long n)
+{
+	int rc;
+	unsigned long i;
+	u8 *data = to;
+
+	for (i = 0; i < n; i++) {
+		rc = get_guest_u8(vcpu, guestsrc++, data++);
+		if (rc < 0)
+			return rc;
+	}
+	return 0;
+}
+
+static inline int copy_from_guest(struct kvm_vcpu *vcpu, void *to,
+				  u64 guestsrc, unsigned long n)
+{
+	u64 prefix  = vcpu->arch.sie_block->prefix;
+	u64 origin  = vcpu->kvm->arch.guest_origin;
+	u64 memsize = vcpu->kvm->arch.guest_memsize;
+
+	if ((guestsrc < 2 * PAGE_SIZE) && (guestsrc + n > 2 * PAGE_SIZE))
+		goto slowpath;
+
+	if ((guestsrc < prefix) && (guestsrc + n > prefix))
+		goto slowpath;
+
+	if ((guestsrc < prefix + 2 * PAGE_SIZE)
+	    && (guestsrc + n > prefix + 2 * PAGE_SIZE))
+		goto slowpath;
+
+	if (guestsrc < 2 * PAGE_SIZE)
+		guestsrc += prefix;
+	else if ((guestsrc >= prefix) && (guestsrc < prefix + 2 * PAGE_SIZE))
+		guestsrc -= prefix;
+
+	if (guestsrc + n > memsize)
+		return -EFAULT;
+
+	if (guestsrc + n < guestsrc)
+		return -EFAULT;
+
+	guestsrc += origin;
+
+	return copy_from_user(to, (void __user *) guestsrc, n);
+slowpath:
+	return __copy_from_guest_slow(vcpu, to, guestsrc, n);
+}
+
+static inline int copy_to_guest_absolute(struct kvm_vcpu *vcpu, u64 guestdest,
+					 const void *from, unsigned long n)
+{
+	u64 origin  = vcpu->kvm->arch.guest_origin;
+	u64 memsize = vcpu->kvm->arch.guest_memsize;
+
+	if (guestdest + n > memsize)
+		return -EFAULT;
+
+	if (guestdest + n < guestdest)
+		return -EFAULT;
+
+	guestdest += origin;
+
+	return copy_to_user((void __user *) guestdest, from, n);
+}
+
+static inline int copy_from_guest_absolute(struct kvm_vcpu *vcpu, void *to,
+					   u64 guestsrc, unsigned long n)
+{
+	u64 origin  = vcpu->kvm->arch.guest_origin;
+	u64 memsize = vcpu->kvm->arch.guest_memsize;
+
+	if (guestsrc + n > memsize)
+		return -EFAULT;
+
+	if (guestsrc + n < guestsrc)
+		return -EFAULT;
+
+	guestsrc += origin;
+
+	return copy_from_user(to, (void __user *) guestsrc, n);
+}
+#endif
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
new file mode 100644
index 0000000..6e1e1d3
--- /dev/null
+++ b/arch/s390/kvm/kvm-s390.c
@@ -0,0 +1,566 @@
+/*
+ * s390host.c --  hosting zSeries kernel virtual machines
+ *
+ * Copyright IBM Corp. 2008
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ *
+ *    Author(s): Carsten Otte <cotte@de.ibm.com>
+ *               Christian Borntraeger <borntraeger@de.ibm.com>
+ *               Heiko Carstens <heiko.carstens@de.ibm.com>
+ */
+
+#include <linux/compiler.h>
+#include <linux/err.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <asm/lowcore.h>
+#include <asm/pgtable.h>
+
+#include "gaccess.h"
+
+#define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU
+
+struct kvm_stats_debugfs_item debugfs_entries[] = {
+	{ "userspace_handled", VCPU_STAT(exit_userspace) },
+	{ NULL }
+};
+
+
+/* Section: not file related */
+void kvm_arch_hardware_enable(void *garbage)
+{
+	/* every s390 is virtualization enabled ;-) */
+}
+
+void kvm_arch_hardware_disable(void *garbage)
+{
+}
+
+void decache_vcpus_on_cpu(int cpu)
+{
+}
+
+int kvm_arch_hardware_setup(void)
+{
+	return 0;
+}
+
+void kvm_arch_hardware_unsetup(void)
+{
+}
+
+void kvm_arch_check_processor_compat(void *rtn)
+{
+}
+
+int kvm_arch_init(void *opaque)
+{
+	return 0;
+}
+
+void kvm_arch_exit(void)
+{
+}
+
+/* Section: device related */
+long kvm_arch_dev_ioctl(struct file *filp,
+			unsigned int ioctl, unsigned long arg)
+{
+	if (ioctl == KVM_S390_ENABLE_SIE)
+		return s390_enable_sie();
+	return -EINVAL;
+}
+
+int kvm_dev_ioctl_check_extension(long ext)
+{
+	return 0;
+}
+
+/* Section: vm related */
+/*
+ * Get (and clear) the dirty memory log for a memory slot.
+ */
+int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
+			       struct kvm_dirty_log *log)
+{
+	return 0;
+}
+
+long kvm_arch_vm_ioctl(struct file *filp,
+		       unsigned int ioctl, unsigned long arg)
+{
+	struct kvm *kvm = filp->private_data;
+	void __user *argp = (void __user *)arg;
+	int r;
+
+	switch (ioctl) {
+	default:
+		r = -EINVAL;
+	}
+
+	return r;
+}
+
+struct kvm *kvm_arch_create_vm(void)
+{
+	struct kvm *kvm;
+	int rc;
+	char debug_name[16];
+
+	rc = s390_enable_sie();
+	if (rc)
+		goto out_nokvm;
+
+	rc = -ENOMEM;
+	kvm = kzalloc(sizeof(struct kvm), GFP_KERNEL);
+	if (!kvm)
+		goto out_nokvm;
+
+	kvm->arch.sca = (struct sca_block *) get_zeroed_page(GFP_KERNEL);
+	if (!kvm->arch.sca)
+		goto out_nosca;
+
+	sprintf(debug_name, "kvm-%u", current->pid);
+
+	kvm->arch.dbf = debug_register(debug_name, 8, 2, 8 * sizeof(long));
+	if (!kvm->arch.dbf)
+		goto out_nodbf;
+
+	debug_register_view(kvm->arch.dbf, &debug_sprintf_view);
+	VM_EVENT(kvm, 3, "%s", "vm created");
+
+	try_module_get(THIS_MODULE);
+
+	return kvm;
+out_nodbf:
+	free_page((unsigned long)(kvm->arch.sca));
+out_nosca:
+	kfree(kvm);
+out_nokvm:
+	return ERR_PTR(rc);
+}
+
+void kvm_arch_destroy_vm(struct kvm *kvm)
+{
+	debug_unregister(kvm->arch.dbf);
+	free_page((unsigned long)(kvm->arch.sca));
+	kfree(kvm);
+	module_put(THIS_MODULE);
+}
+
+/* Section: vcpu related */
+int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
+{
+	return 0;
+}
+
+void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu)
+{
+	/* kvm common code refers to this, but does'nt call it */
+	BUG();
+}
+
+void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
+{
+	save_fp_regs(&vcpu->arch.host_fpregs);
+	save_access_regs(vcpu->arch.host_acrs);
+	vcpu->arch.guest_fpregs.fpc &= FPC_VALID_MASK;
+	restore_fp_regs(&vcpu->arch.guest_fpregs);
+	restore_access_regs(vcpu->arch.guest_acrs);
+
+	if (signal_pending(current))
+		atomic_set_mask(CPUSTAT_STOP_INT,
+			&vcpu->arch.sie_block->cpuflags);
+}
+
+void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
+{
+	save_fp_regs(&vcpu->arch.guest_fpregs);
+	save_access_regs(vcpu->arch.guest_acrs);
+	restore_fp_regs(&vcpu->arch.host_fpregs);
+	restore_access_regs(vcpu->arch.host_acrs);
+}
+
+static void kvm_s390_vcpu_initial_reset(struct kvm_vcpu *vcpu)
+{
+	/* this equals initial cpu reset in pop, but we don't switch to ESA */
+	vcpu->arch.sie_block->gpsw.mask = 0UL;
+	vcpu->arch.sie_block->gpsw.addr = 0UL;
+	vcpu->arch.sie_block->prefix    = 0UL;
+	vcpu->arch.sie_block->ihcpu     = 0xffff;
+	vcpu->arch.sie_block->cputm     = 0UL;
+	vcpu->arch.sie_block->ckc       = 0UL;
+	vcpu->arch.sie_block->todpr     = 0;
+	memset(vcpu->arch.sie_block->gcr, 0, 16 * sizeof(__u64));
+	vcpu->arch.sie_block->gcr[0]  = 0xE0UL;
+	vcpu->arch.sie_block->gcr[14] = 0xC2000000UL;
+	vcpu->arch.guest_fpregs.fpc = 0;
+	asm volatile("lfpc %0" : : "Q" (vcpu->arch.guest_fpregs.fpc));
+	vcpu->arch.sie_block->gbea = 1;
+}
+
+int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
+{
+	atomic_set(&vcpu->arch.sie_block->cpuflags, CPUSTAT_ZARCH);
+	vcpu->arch.sie_block->gmslm = 0xffffffffffUL;
+	vcpu->arch.sie_block->gmsor = 0x000000000000;
+	vcpu->arch.sie_block->ecb   = 2;
+	vcpu->arch.sie_block->eca   = 0xC1002001U;
+
+	return 0;
+}
+
+struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
+				      unsigned int id)
+{
+	struct kvm_vcpu *vcpu = kzalloc(sizeof(struct kvm_vcpu), GFP_KERNEL);
+	int rc = -ENOMEM;
+
+	if (!vcpu)
+		goto out_nomem;
+
+	vcpu->arch.sie_block = (struct sie_block *) get_zeroed_page(GFP_KERNEL);
+
+	if (!vcpu->arch.sie_block)
+		goto out_free_cpu;
+
+	vcpu->arch.sie_block->icpua = id;
+	BUG_ON(!kvm->arch.sca);
+	BUG_ON(kvm->arch.sca->cpu[id].sda);
+	kvm->arch.sca->cpu[id].sda = (__u64) vcpu->arch.sie_block;
+	vcpu->arch.sie_block->scaoh = (__u32)(((__u64)kvm->arch.sca) >> 32);
+	vcpu->arch.sie_block->scaol = (__u32)(__u64)kvm->arch.sca;
+
+	rc = kvm_vcpu_init(vcpu, kvm, id);
+	if (rc)
+		goto out_free_cpu;
+	VM_EVENT(kvm, 3, "create cpu %d at %p, sie block at %p", id, vcpu,
+		 vcpu->arch.sie_block);
+
+	try_module_get(THIS_MODULE);
+
+	return vcpu;
+out_free_cpu:
+	kfree(vcpu);
+out_nomem:
+	return ERR_PTR(rc);
+}
+
+void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
+{
+	VCPU_EVENT(vcpu, 3, "%s", "destroy cpu");
+	free_page((unsigned long)(vcpu->arch.sie_block));
+	kfree(vcpu);
+	module_put(THIS_MODULE);
+}
+
+int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
+{
+	/* kvm common code refers to this, but never calls it */
+	BUG();
+	return 0;
+}
+
+static int kvm_arch_vcpu_ioctl_initial_reset(struct kvm_vcpu *vcpu)
+{
+	vcpu_load(vcpu);
+	kvm_s390_vcpu_initial_reset(vcpu);
+	vcpu_put(vcpu);
+	return 0;
+}
+
+int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
+{
+	vcpu_load(vcpu);
+	memcpy(&vcpu->arch.guest_gprs, &regs->gprs, sizeof(regs->gprs));
+	vcpu_put(vcpu);
+	return 0;
+}
+
+int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
+{
+	vcpu_load(vcpu);
+	memcpy(&regs->gprs, &vcpu->arch.guest_gprs, sizeof(regs->gprs));
+	vcpu_put(vcpu);
+	return 0;
+}
+
+int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
+				  struct kvm_sregs *sregs)
+{
+	vcpu_load(vcpu);
+	memcpy(&vcpu->arch.guest_acrs, &sregs->acrs, sizeof(sregs->acrs));
+	memcpy(&vcpu->arch.sie_block->gcr, &sregs->crs, sizeof(sregs->crs));
+	vcpu_put(vcpu);
+	return 0;
+}
+
+int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
+				  struct kvm_sregs *sregs)
+{
+	vcpu_load(vcpu);
+	memcpy(&sregs->acrs, &vcpu->arch.guest_acrs, sizeof(sregs->acrs));
+	memcpy(&sregs->crs, &vcpu->arch.sie_block->gcr, sizeof(sregs->crs));
+	vcpu_put(vcpu);
+	return 0;
+}
+
+int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
+{
+	vcpu_load(vcpu);
+	memcpy(&vcpu->arch.guest_fpregs.fprs, &fpu->fprs, sizeof(fpu->fprs));
+	vcpu->arch.guest_fpregs.fpc = fpu->fpc;
+	vcpu_put(vcpu);
+	return 0;
+}
+
+int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
+{
+	vcpu_load(vcpu);
+	memcpy(&fpu->fprs, &vcpu->arch.guest_fpregs.fprs, sizeof(fpu->fprs));
+	fpu->fpc = vcpu->arch.guest_fpregs.fpc;
+	vcpu_put(vcpu);
+	return 0;
+}
+
+static int kvm_arch_vcpu_ioctl_set_initial_psw(struct kvm_vcpu *vcpu, psw_t psw)
+{
+	int rc = 0;
+
+	vcpu_load(vcpu);
+	if (atomic_read(&vcpu->arch.sie_block->cpuflags) & CPUSTAT_RUNNING)
+		rc = -EBUSY;
+	else
+		vcpu->arch.sie_block->gpsw = psw;
+	vcpu_put(vcpu);
+	return rc;
+}
+
+int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
+				  struct kvm_translation *tr)
+{
+	return -EINVAL; /* not implemented yet */
+}
+
+int kvm_arch_vcpu_ioctl_debug_guest(struct kvm_vcpu *vcpu,
+				    struct kvm_debug_guest *dbg)
+{
+	return -EINVAL; /* not implemented yet */
+}
+
+static void __vcpu_run(struct kvm_vcpu *vcpu)
+{
+	memcpy(&vcpu->arch.sie_block->gg14, &vcpu->arch.guest_gprs[14], 16);
+
+	if (need_resched())
+		schedule();
+
+	vcpu->arch.sie_block->icptcode = 0;
+	local_irq_disable();
+	kvm_guest_enter();
+	local_irq_enable();
+	VCPU_EVENT(vcpu, 6, "entering sie flags %x",
+		   atomic_read(&vcpu->arch.sie_block->cpuflags));
+	sie64a(vcpu->arch.sie_block, vcpu->arch.guest_gprs);
+	VCPU_EVENT(vcpu, 6, "exit sie icptcode %d",
+		   vcpu->arch.sie_block->icptcode);
+	local_irq_disable();
+	kvm_guest_exit();
+	local_irq_enable();
+
+	memcpy(&vcpu->arch.guest_gprs[14], &vcpu->arch.sie_block->gg14, 16);
+}
+
+int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
+{
+	sigset_t sigsaved;
+
+	vcpu_load(vcpu);
+
+	if (vcpu->sigset_active)
+		sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved);
+
+	atomic_set_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
+
+	__vcpu_run(vcpu);
+
+	if (vcpu->sigset_active)
+		sigprocmask(SIG_SETMASK, &sigsaved, NULL);
+
+	vcpu_put(vcpu);
+
+	vcpu->stat.exit_userspace++;
+	return 0;
+}
+
+static int __guestcopy(struct kvm_vcpu *vcpu, u64 guestdest, const void *from,
+		       unsigned long n, int prefix)
+{
+	if (prefix)
+		return copy_to_guest(vcpu, guestdest, from, n);
+	else
+		return copy_to_guest_absolute(vcpu, guestdest, from, n);
+}
+
+/*
+ * store status at address
+ * we use have two special cases:
+ * KVM_S390_STORE_STATUS_NOADDR: -> 0x1200 on 64 bit
+ * KVM_S390_STORE_STATUS_PREFIXED: -> prefix
+ */
+int __kvm_s390_vcpu_store_status(struct kvm_vcpu *vcpu, unsigned long addr)
+{
+	const unsigned char archmode = 1;
+	int prefix;
+
+	if (addr == KVM_S390_STORE_STATUS_NOADDR) {
+		if (copy_to_guest_absolute(vcpu, 163ul, &archmode, 1))
+			return -EFAULT;
+		addr = SAVE_AREA_BASE;
+		prefix = 0;
+	} else if (addr == KVM_S390_STORE_STATUS_PREFIXED) {
+		if (copy_to_guest(vcpu, 163ul, &archmode, 1))
+			return -EFAULT;
+		addr = SAVE_AREA_BASE;
+		prefix = 1;
+	} else
+		prefix = 0;
+
+	if (__guestcopy(vcpu, addr + offsetof(struct save_area_s390x, fp_regs),
+			vcpu->arch.guest_fpregs.fprs, 128, prefix))
+		return -EFAULT;
+
+	if (__guestcopy(vcpu, addr + offsetof(struct save_area_s390x, gp_regs),
+			vcpu->arch.guest_gprs, 128, prefix))
+		return -EFAULT;
+
+	if (__guestcopy(vcpu, addr + offsetof(struct save_area_s390x, psw),
+			&vcpu->arch.sie_block->gpsw, 16, prefix))
+		return -EFAULT;
+
+	if (__guestcopy(vcpu, addr + offsetof(struct save_area_s390x, pref_reg),
+			&vcpu->arch.sie_block->prefix, 4, prefix))
+		return -EFAULT;
+
+	if (__guestcopy(vcpu,
+			addr + offsetof(struct save_area_s390x, fp_ctrl_reg),
+			&vcpu->arch.guest_fpregs.fpc, 4, prefix))
+		return -EFAULT;
+
+	if (__guestcopy(vcpu, addr + offsetof(struct save_area_s390x, tod_reg),
+			&vcpu->arch.sie_block->todpr, 4, prefix))
+		return -EFAULT;
+
+	if (__guestcopy(vcpu, addr + offsetof(struct save_area_s390x, timer),
+			&vcpu->arch.sie_block->cputm, 8, prefix))
+		return -EFAULT;
+
+	if (__guestcopy(vcpu, addr + offsetof(struct save_area_s390x, clk_cmp),
+			&vcpu->arch.sie_block->ckc, 8, prefix))
+		return -EFAULT;
+
+	if (__guestcopy(vcpu, addr + offsetof(struct save_area_s390x, acc_regs),
+			&vcpu->arch.guest_acrs, 64, prefix))
+		return -EFAULT;
+
+	if (__guestcopy(vcpu,
+			addr + offsetof(struct save_area_s390x, ctrl_regs),
+			&vcpu->arch.sie_block->gcr, 128, prefix))
+		return -EFAULT;
+	return 0;
+}
+
+static int kvm_s390_vcpu_store_status(struct kvm_vcpu *vcpu, unsigned long addr)
+{
+	int rc;
+
+	vcpu_load(vcpu);
+	rc = __kvm_s390_vcpu_store_status(vcpu, addr);
+	vcpu_put(vcpu);
+	return rc;
+}
+
+long kvm_arch_vcpu_ioctl(struct file *filp,
+			 unsigned int ioctl, unsigned long arg)
+{
+	struct kvm_vcpu *vcpu = filp->private_data;
+	void __user *argp = (void __user *)arg;
+
+	switch (ioctl) {
+	case KVM_S390_STORE_STATUS:
+		return kvm_s390_vcpu_store_status(vcpu, arg);
+	case KVM_S390_SET_INITIAL_PSW: {
+		psw_t psw;
+
+		if (copy_from_user(&psw, argp, sizeof(psw)))
+			return -EFAULT;
+		return kvm_arch_vcpu_ioctl_set_initial_psw(vcpu, psw);
+	}
+	case KVM_S390_INITIAL_RESET:
+		return kvm_arch_vcpu_ioctl_initial_reset(vcpu);
+	default:
+		;
+	}
+	return -EINVAL;
+}
+
+/* Section: memory related */
+int kvm_arch_set_memory_region(struct kvm *kvm,
+				struct kvm_userspace_memory_region *mem,
+				struct kvm_memory_slot old,
+				int user_alloc)
+{
+	/* A few sanity checks. We can have exactly one memory slot which has
+	   to start at guest virtual zero and which has to be located at a
+	   page boundary in userland and which has to end at a page boundary.
+	   The memory in userland is ok to be fragmented into various different
+	   vmas. It is okay to mmap() and munmap() stuff in this slot after
+	   doing this call at any time */
+
+	if (mem->slot)
+		return -EINVAL;
+
+	if (mem->guest_phys_addr)
+		return -EINVAL;
+
+	if (mem->userspace_addr & (PAGE_SIZE - 1))
+		return -EINVAL;
+
+	if (mem->memory_size & (PAGE_SIZE - 1))
+		return -EINVAL;
+
+	kvm->arch.guest_origin = mem->userspace_addr;
+	kvm->arch.guest_memsize = mem->memory_size;
+
+	/* FIXME: we do want to interrupt running CPUs and update their memory
+	   configuration now to avoid race conditions. But hey, changing the
+	   memory layout while virtual CPUs are running is usually bad
+	   programming practice. */
+
+	return 0;
+}
+
+gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
+{
+	return gfn;
+}
+
+static int __init kvm_s390_init(void)
+{
+	return kvm_init(NULL, sizeof(struct kvm_vcpu), THIS_MODULE);
+}
+
+static void __exit kvm_s390_exit(void)
+{
+	kvm_exit();
+}
+
+module_init(kvm_s390_init);
+module_exit(kvm_s390_exit);
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
new file mode 100644
index 0000000..ed64a22
--- /dev/null
+++ b/arch/s390/kvm/kvm-s390.h
@@ -0,0 +1,29 @@
+/*
+ * kvm_s390.h -  definition for kvm on s390
+ *
+ * Copyright IBM Corp. 2008
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ *
+ *    Author(s): Carsten Otte <cotte@de.ibm.com>
+ *               Christian Borntraeger <borntraeger@de.ibm.com>
+ */
+
+#ifndef ARCH_S390_KVM_S390_H
+#define ARCH_S390_KVM_S390_H
+#define VM_EVENT(d_kvm, d_loglevel, d_string, d_args...)\
+do { \
+	debug_sprintf_event(d_kvm->arch.dbf, d_loglevel, d_string "\n", \
+	  d_args); \
+} while (0)
+
+#define VCPU_EVENT(d_vcpu, d_loglevel, d_string, d_args...)\
+do { \
+	debug_sprintf_event(d_vcpu->kvm->arch.dbf, d_loglevel, \
+	  "%02d[%016lx-%016lx]: " d_string "\n", d_vcpu->vcpu_id, \
+	  d_vcpu->arch.sie_block->gpsw.mask, d_vcpu->arch.sie_block->gpsw.addr,\
+	  d_args); \
+} while (0)
+#endif
diff --git a/arch/s390/kvm/sie64a.S b/arch/s390/kvm/sie64a.S
new file mode 100644
index 0000000..934fd6a
--- /dev/null
+++ b/arch/s390/kvm/sie64a.S
@@ -0,0 +1,47 @@
+/*
+ * sie64a.S - low level sie call
+ *
+ * Copyright IBM Corp. 2008
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ *
+ *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
+ */
+
+#include <linux/errno.h>
+#include <asm/asm-offsets.h>
+
+SP_R5 =	5 * 8	# offset into stackframe
+SP_R6 =	6 * 8
+
+/*
+ * sie64a calling convention:
+ * %r2 pointer to sie control block
+ * %r3 guest register save area
+ */
+	.globl	sie64a
+sie64a:
+	lgr	%r5,%r3
+	stmg	%r5,%r14,SP_R5(%r15)	# save register on entry
+	lgr	%r14,%r2		# pointer to sie control block
+	lmg	%r0,%r13,0(%r3)		# load guest gprs 0-13
+sie_inst:
+	sie	0(%r14)
+	lg	%r14,SP_R5(%r15)
+	stmg	%r0,%r13,0(%r14)	# save guest gprs 0-13
+	lghi	%r2,0
+	lmg	%r6,%r14,SP_R6(%r15)
+	br	%r14
+
+sie_err:
+	lg	%r14,SP_R5(%r15)
+	stmg	%r0,%r13,0(%r14)	# save guest gprs 0-13
+	lghi	%r2,-EFAULT
+	lmg	%r6,%r14,SP_R6(%r15)
+	br	%r14
+
+	.section __ex_table,"a"
+	.quad	sie_inst,sie_err
+	.previous
diff --git a/include/asm-s390/Kbuild b/include/asm-s390/Kbuild
index e92b429..13c9805 100644
--- a/include/asm-s390/Kbuild
+++ b/include/asm-s390/Kbuild
@@ -7,6 +7,7 @@
 header-y += ucontext.h
 header-y += vtoc.h
 header-y += zcrypt.h
+header-y += kvm.h
 
 unifdef-y += cmb.h
 unifdef-y += debug.h
diff --git a/include/asm-s390/kvm.h b/include/asm-s390/kvm.h
index 573f2a3..d74002f 100644
--- a/include/asm-s390/kvm.h
+++ b/include/asm-s390/kvm.h
@@ -1,6 +1,45 @@
 #ifndef __LINUX_KVM_S390_H
 #define __LINUX_KVM_S390_H
 
-/* s390 does not support KVM */
+/*
+ * asm-s390/kvm.h - KVM s390 specific structures and definitions
+ *
+ * Copyright IBM Corp. 2008
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ *
+ *    Author(s): Carsten Otte <cotte@de.ibm.com>
+ *               Christian Borntraeger <borntraeger@de.ibm.com>
+ */
+#include <asm/types.h>
+
+/* for KVM_GET_IRQCHIP and KVM_SET_IRQCHIP */
+struct kvm_pic_state {
+	/* no PIC for s390 */
+};
+
+struct kvm_ioapic_state {
+	/* no IOAPIC for s390 */
+};
+
+/* for KVM_GET_REGS and KVM_SET_REGS */
+struct kvm_regs {
+	/* general purpose regs for s390 */
+	__u64 gprs[16];
+};
+
+/* for KVM_GET_SREGS and KVM_SET_SREGS */
+struct kvm_sregs {
+	__u32 acrs[16];
+	__u64 crs[16];
+};
+
+/* for KVM_GET_FPU and KVM_SET_FPU */
+struct kvm_fpu {
+	__u32 fpc;
+	__u64 fprs[16];
+};
 
 #endif
diff --git a/include/asm-s390/kvm_host.h b/include/asm-s390/kvm_host.h
new file mode 100644
index 0000000..c9d6533
--- /dev/null
+++ b/include/asm-s390/kvm_host.h
@@ -0,0 +1,127 @@
+/*
+ * asm-s390/kvm_host.h - definition for kernel virtual machines on s390
+ *
+ * Copyright IBM Corp. 2008
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ *
+ *    Author(s): Carsten Otte <cotte@de.ibm.com>
+ */
+
+
+#ifndef ASM_KVM_HOST_H
+#define ASM_KVM_HOST_H
+#include <linux/kvm_host.h>
+#include <asm/debug.h>
+
+#define KVM_MAX_VCPUS 64
+#define KVM_MEMORY_SLOTS 32
+/* memory slots that does not exposed to userspace */
+#define KVM_PRIVATE_MEM_SLOTS 4
+
+struct kvm_guest_debug {
+};
+
+struct sca_entry {
+	atomic_t scn;
+	__u64	reserved;
+	__u64	sda;
+	__u64	reserved2[2];
+} __attribute__((packed));
+
+
+struct sca_block {
+	__u64	ipte_control;
+	__u64	reserved[5];
+	__u64	mcn;
+	__u64	reserved2;
+	struct sca_entry cpu[64];
+} __attribute__((packed));
+
+#define KVM_PAGES_PER_HPAGE 256
+
+#define CPUSTAT_HOST       0x80000000
+#define CPUSTAT_WAIT       0x10000000
+#define CPUSTAT_ECALL_PEND 0x08000000
+#define CPUSTAT_STOP_INT   0x04000000
+#define CPUSTAT_IO_INT     0x02000000
+#define CPUSTAT_EXT_INT    0x01000000
+#define CPUSTAT_RUNNING    0x00800000
+#define CPUSTAT_RETAINED   0x00400000
+#define CPUSTAT_TIMING_SUB 0x00020000
+#define CPUSTAT_SIE_SUB    0x00010000
+#define CPUSTAT_RRF        0x00008000
+#define CPUSTAT_SLSV       0x00004000
+#define CPUSTAT_SLSR       0x00002000
+#define CPUSTAT_ZARCH      0x00000800
+#define CPUSTAT_MCDS       0x00000100
+#define CPUSTAT_SM         0x00000080
+#define CPUSTAT_G          0x00000008
+#define CPUSTAT_J          0x00000002
+#define CPUSTAT_P          0x00000001
+
+struct sie_block {
+	atomic_t cpuflags;		/* 0x0000 */
+	__u32	prefix;			/* 0x0004 */
+	__u8	reserved8[32];		/* 0x0008 */
+	__u64	cputm;			/* 0x0028 */
+	__u64	ckc;			/* 0x0030 */
+	__u64	epoch;			/* 0x0038 */
+	__u8	reserved40[4];		/* 0x0040 */
+	__u16   lctl;			/* 0x0044 */
+	__s16	icpua;			/* 0x0046 */
+	__u32	ictl;			/* 0x0048 */
+	__u32	eca;			/* 0x004c */
+	__u8	icptcode;		/* 0x0050 */
+	__u8	reserved51;		/* 0x0051 */
+	__u16	ihcpu;			/* 0x0052 */
+	__u8	reserved54[2];		/* 0x0054 */
+	__u16	ipa;			/* 0x0056 */
+	__u32	ipb;			/* 0x0058 */
+	__u32	scaoh;			/* 0x005c */
+	__u8	reserved60;		/* 0x0060 */
+	__u8	ecb;			/* 0x0061 */
+	__u8	reserved62[2];		/* 0x0062 */
+	__u32	scaol;			/* 0x0064 */
+	__u8	reserved68[4];		/* 0x0068 */
+	__u32	todpr;			/* 0x006c */
+	__u8	reserved70[16];		/* 0x0070 */
+	__u64	gmsor;			/* 0x0080 */
+	__u64	gmslm;			/* 0x0088 */
+	psw_t	gpsw;			/* 0x0090 */
+	__u64	gg14;			/* 0x00a0 */
+	__u64	gg15;			/* 0x00a8 */
+	__u8	reservedb0[80];		/* 0x00b0 */
+	__u64	gcr[16];		/* 0x0100 */
+	__u64	gbea;			/* 0x0180 */
+	__u8	reserved188[120];	/* 0x0188 */
+} __attribute__((packed));
+
+struct kvm_vcpu_stat {
+	u32 exit_userspace;
+};
+
+struct kvm_vcpu_arch {
+	struct sie_block *sie_block;
+	unsigned long	  guest_gprs[16];
+	s390_fp_regs      host_fpregs;
+	unsigned int      host_acrs[NUM_ACRS];
+	s390_fp_regs      guest_fpregs;
+	unsigned int      guest_acrs[NUM_ACRS];
+};
+
+struct kvm_vm_stat {
+	u32 remote_tlb_flush;
+};
+
+struct kvm_arch{
+	unsigned long guest_origin;
+	unsigned long guest_memsize;
+	struct sca_block *sca;
+	debug_info_t *dbf;
+};
+
+extern int sie64a(struct sie_block *, __u64 *);
+#endif
diff --git a/include/asm-s390/kvm_para.h b/include/asm-s390/kvm_para.h
new file mode 100644
index 0000000..e9bd3fb
--- /dev/null
+++ b/include/asm-s390/kvm_para.h
@@ -0,0 +1,30 @@
+/*
+ * asm-s390/kvm_para.h - definition for paravirtual devices on s390
+ *
+ * Copyright IBM Corp. 2008
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ *
+ *    Author(s): Christian Borntraeger <borntraeger@de.ibm.com>
+ */
+
+#ifndef __S390_KVM_PARA_H
+#define __S390_KVM_PARA_H
+
+/*
+ * No hypercalls for KVM on s390
+ */
+
+static inline int kvm_para_available(void)
+{
+	return 0;
+}
+
+static inline unsigned int kvm_arch_para_features(void)
+{
+	return 0;
+}
+
+#endif /* __S390_KVM_PARA_H */
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 3bd3828..2367ff0 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -205,6 +205,11 @@
 	__u64 vapic_addr;
 };
 
+struct kvm_s390_psw {
+	__u64 mask;
+	__u64 addr;
+};
+
 #define KVMIO 0xAE
 
 /*
@@ -213,6 +218,8 @@
 #define KVM_GET_API_VERSION       _IO(KVMIO,   0x00)
 #define KVM_CREATE_VM             _IO(KVMIO,   0x01) /* returns a VM fd */
 #define KVM_GET_MSR_INDEX_LIST    _IOWR(KVMIO, 0x02, struct kvm_msr_list)
+
+#define KVM_S390_ENABLE_SIE       _IO(KVMIO,   0x06)
 /*
  * Check if a kvm extension is available.  Argument is extension number,
  * return is 1 (yes) or 0 (no, sorry).
@@ -291,5 +298,13 @@
 #define KVM_TPR_ACCESS_REPORTING  _IOWR(KVMIO,  0x92, struct kvm_tpr_access_ctl)
 /* Available with KVM_CAP_VAPIC */
 #define KVM_SET_VAPIC_ADDR        _IOW(KVMIO,  0x93, struct kvm_vapic_addr)
+/* store status for s390 */
+#define KVM_S390_STORE_STATUS_NOADDR    (-1ul)
+#define KVM_S390_STORE_STATUS_PREFIXED  (-2ul)
+#define KVM_S390_STORE_STATUS	  _IOW(KVMIO,  0x95, unsigned long)
+/* initial ipl psw for s390 */
+#define KVM_S390_SET_INITIAL_PSW  _IOW(KVMIO,  0x96, struct kvm_s390_psw)
+/* initial reset for s390 */
+#define KVM_S390_INITIAL_RESET    _IO(KVMIO,  0x97)
 
 #endif