diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index ee47998e..f03178d 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2716,6 +2716,52 @@ The fields in each entry are defined as follows:
    eax, ebx, ecx, edx: the values returned by the cpuid instruction for
          this function/index combination
 
+4.89 KVM_S390_MEM_OP
+
+Capability: KVM_CAP_S390_MEM_OP
+Architectures: s390
+Type: vcpu ioctl
+Parameters: struct kvm_s390_mem_op (in)
+Returns: = 0 on success,
+         < 0 on generic error (e.g. -EFAULT or -ENOMEM),
+         > 0 if an exception occurred while walking the page tables
+
+Read or write data from/to the logical (virtual) memory of a VPCU.
+
+Parameters are specified via the following structure:
+
+struct kvm_s390_mem_op {
+	__u64 gaddr;		/* the guest address */
+	__u64 flags;		/* arch specific flags */
+	__u32 size;		/* amount of bytes */
+	__u32 op;		/* type of operation */
+	__u64 buf;		/* buffer in userspace */
+	__u8 ar;		/* the access register number */
+	__u8 reserved[31];	/* should be set to 0 */
+};
+
+The type of operation is specified in the "op" field. It is either
+KVM_S390_MEMOP_LOGICAL_READ for reading from logical memory space or
+KVM_S390_MEMOP_LOGICAL_WRITE for writing to logical memory space. The
+KVM_S390_MEMOP_F_CHECK_ONLY flag can be set in the "flags" field to check
+whether the corresponding memory access would create an access exception
+(without touching the data in the memory at the destination). In case an
+access exception occurred while walking the MMU tables of the guest, the
+ioctl returns a positive error number to indicate the type of exception.
+This exception is also raised directly at the corresponding VCPU if the
+flag KVM_S390_MEMOP_F_INJECT_EXCEPTION is set in the "flags" field.
+
+The start address of the memory region has to be specified in the "gaddr"
+field, and the length of the region in the "size" field. "buf" is the buffer
+supplied by the userspace application where the read data should be written
+to for KVM_S390_MEMOP_LOGICAL_READ, or where the data that should be written
+is stored for a KVM_S390_MEMOP_LOGICAL_WRITE. "buf" is unused and can be NULL
+when KVM_S390_MEMOP_F_CHECK_ONLY is specified. "ar" designates the access
+register number to be used.
+
+The "reserved" field is meant for future extensions. It is not used by
+KVM with the currently defined set of flags.
+
 5. The kvm_run structure
 ------------------------
 
diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
index c230904..04a7c67 100644
--- a/arch/s390/kvm/gaccess.c
+++ b/arch/s390/kvm/gaccess.c
@@ -697,6 +697,28 @@ int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva,
 }
 
 /**
+ * check_gva_range - test a range of guest virtual addresses for accessibility
+ */
+int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva,
+		    unsigned long length, int is_write)
+{
+	unsigned long gpa;
+	unsigned long currlen;
+	int rc = 0;
+
+	ipte_lock(vcpu);
+	while (length > 0 && !rc) {
+		currlen = min(length, PAGE_SIZE - (gva % PAGE_SIZE));
+		rc = guest_translate_address(vcpu, gva, &gpa, is_write);
+		gva += currlen;
+		length -= currlen;
+	}
+	ipte_unlock(vcpu);
+
+	return rc;
+}
+
+/**
  * kvm_s390_check_low_addr_prot_real - check for low-address protection
  * @gra: Guest real address
  *
diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h
index 20de77e..d0de110 100644
--- a/arch/s390/kvm/gaccess.h
+++ b/arch/s390/kvm/gaccess.h
@@ -157,6 +157,8 @@ int read_guest_lc(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
 
 int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva,
 			    unsigned long *gpa, int write);
+int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva,
+		    unsigned long length, int is_write);
 
 int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, void *data,
 		 unsigned long len, int write);
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 4075acb..92855e2 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -25,6 +25,7 @@
 #include <linux/random.h>
 #include <linux/slab.h>
 #include <linux/timer.h>
+#include <linux/vmalloc.h>
 #include <asm/asm-offsets.h>
 #include <asm/lowcore.h>
 #include <asm/pgtable.h>
@@ -38,6 +39,8 @@
 #include "trace.h"
 #include "trace-s390.h"
 
+#define MEM_OP_MAX_SIZE 65536	/* Maximum transfer size for KVM_S390_MEM_OP */
+
 #define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU
 
 struct kvm_stats_debugfs_item debugfs_entries[] = {
@@ -177,6 +180,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_S390_USER_SIGP:
 		r = 1;
 		break;
+	case KVM_CAP_S390_MEM_OP:
+		r = MEM_OP_MAX_SIZE;
+		break;
 	case KVM_CAP_NR_VCPUS:
 	case KVM_CAP_MAX_VCPUS:
 		r = KVM_MAX_VCPUS;
@@ -2185,6 +2191,65 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
 	return r;
 }
 
+static long kvm_s390_guest_mem_op(struct kvm_vcpu *vcpu,
+				  struct kvm_s390_mem_op *mop)
+{
+	void __user *uaddr = (void __user *)mop->buf;
+	void *tmpbuf = NULL;
+	int r, srcu_idx;
+	const u64 supported_flags = KVM_S390_MEMOP_F_INJECT_EXCEPTION
+				    | KVM_S390_MEMOP_F_CHECK_ONLY;
+
+	if (mop->flags & ~supported_flags)
+		return -EINVAL;
+
+	if (mop->size > MEM_OP_MAX_SIZE)
+		return -E2BIG;
+
+	if (!(mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)) {
+		tmpbuf = vmalloc(mop->size);
+		if (!tmpbuf)
+			return -ENOMEM;
+	}
+
+	srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+
+	switch (mop->op) {
+	case KVM_S390_MEMOP_LOGICAL_READ:
+		if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY) {
+			r = check_gva_range(vcpu, mop->gaddr, mop->size, false);
+			break;
+		}
+		r = read_guest(vcpu, mop->gaddr, tmpbuf, mop->size);
+		if (r == 0) {
+			if (copy_to_user(uaddr, tmpbuf, mop->size))
+				r = -EFAULT;
+		}
+		break;
+	case KVM_S390_MEMOP_LOGICAL_WRITE:
+		if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY) {
+			r = check_gva_range(vcpu, mop->gaddr, mop->size, true);
+			break;
+		}
+		if (copy_from_user(tmpbuf, uaddr, mop->size)) {
+			r = -EFAULT;
+			break;
+		}
+		r = write_guest(vcpu, mop->gaddr, tmpbuf, mop->size);
+		break;
+	default:
+		r = -EINVAL;
+	}
+
+	srcu_read_unlock(&vcpu->kvm->srcu, srcu_idx);
+
+	if (r > 0 && (mop->flags & KVM_S390_MEMOP_F_INJECT_EXCEPTION) != 0)
+		kvm_s390_inject_prog_irq(vcpu, &vcpu->arch.pgm);
+
+	vfree(tmpbuf);
+	return r;
+}
+
 long kvm_arch_vcpu_ioctl(struct file *filp,
 			 unsigned int ioctl, unsigned long arg)
 {
@@ -2284,6 +2349,15 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 		r = kvm_vcpu_ioctl_enable_cap(vcpu, &cap);
 		break;
 	}
+	case KVM_S390_MEM_OP: {
+		struct kvm_s390_mem_op mem_op;
+
+		if (copy_from_user(&mem_op, argp, sizeof(mem_op)) == 0)
+			r = kvm_s390_guest_mem_op(vcpu, &mem_op);
+		else
+			r = -EFAULT;
+		break;
+	}
 	default:
 		r = -ENOTTY;
 	}
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 82634a4..74bbd9a 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -365,6 +365,24 @@ struct kvm_translation {
 	__u8  pad[5];
 };
 
+/* for KVM_S390_MEM_OP */
+struct kvm_s390_mem_op {
+	/* in */
+	__u64 gaddr;		/* the guest address */
+	__u64 flags;		/* arch specific flags */
+	__u32 size;		/* amount of bytes */
+	__u32 op;		/* type of operation */
+	__u64 buf;		/* buffer in userspace */
+	__u8 ar;		/* the access register number */
+	__u8 reserved[31];	/* should be set to 0 */
+};
+/* types for kvm_s390_mem_op->op */
+#define KVM_S390_MEMOP_LOGICAL_READ	0
+#define KVM_S390_MEMOP_LOGICAL_WRITE	1
+/* flags for kvm_s390_mem_op->flags */
+#define KVM_S390_MEMOP_F_CHECK_ONLY		(1ULL << 0)
+#define KVM_S390_MEMOP_F_INJECT_EXCEPTION	(1ULL << 1)
+
 /* for KVM_INTERRUPT */
 struct kvm_interrupt {
 	/* in */
@@ -761,6 +779,7 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_CHECK_EXTENSION_VM 105
 #define KVM_CAP_S390_USER_SIGP 106
 #define KVM_CAP_S390_VECTOR_REGISTERS 107
+#define KVM_CAP_S390_MEM_OP 108
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -1136,6 +1155,8 @@ struct kvm_s390_ucas_mapping {
 #define KVM_ARM_VCPU_INIT	  _IOW(KVMIO,  0xae, struct kvm_vcpu_init)
 #define KVM_ARM_PREFERRED_TARGET  _IOR(KVMIO,  0xaf, struct kvm_vcpu_init)
 #define KVM_GET_REG_LIST	  _IOWR(KVMIO, 0xb0, struct kvm_reg_list)
+/* Available with KVM_CAP_S390_MEM_OP */
+#define KVM_S390_MEM_OP		  _IOW(KVMIO,  0xb1, struct kvm_s390_mem_op)
 
 #define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)
 #define KVM_DEV_ASSIGN_PCI_2_3		(1 << 1)
