arch/s390/kvm/priv.c - kernel/windcharger - Git at Google

 /*
  * priv.c - handling privileged instructions
  *
  * 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 <linux/kvm.h>
 #include <linux/gfp.h>
 #include <linux/errno.h>
 #include <asm/current.h>
 #include <asm/debug.h>
 #include <asm/ebcdic.h>
 #include <asm/sysinfo.h>
 #include "gaccess.h"
 #include "kvm-s390.h"

 static int handle_set_prefix(struct kvm_vcpu *vcpu)
 {
 	int base2 = vcpu->arch.sie_block->ipb >> 28;
 	int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
 	u64 operand2;
 	u32 address = 0;
 	u8 tmp;

 	vcpu->stat.instruction_spx++;

 	operand2 = disp2;
 	if (base2)
 		operand2 += vcpu->arch.guest_gprs[base2];

 	/* must be word boundary */
 	if (operand2 & 3) {
 		kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 		goto out;
 	}

 	/* get the value */
 	if (get_guest_u32(vcpu, operand2, &address)) {
 		kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 		goto out;
 	}

 	address = address & 0x7fffe000u;

 	/* make sure that the new value is valid memory */
 	if (copy_from_guest_absolute(vcpu, &tmp, address, 1) ||
 	   (copy_from_guest_absolute(vcpu, &tmp, address + PAGE_SIZE, 1))) {
 		kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 		goto out;
 	}

 	vcpu->arch.sie_block->prefix = address;
 	vcpu->arch.sie_block->ihcpu = 0xffff;

 	VCPU_EVENT(vcpu, 5, "setting prefix to %x", address);
 out:
 	return 0;
 }

 static int handle_store_prefix(struct kvm_vcpu *vcpu)
 {
 	int base2 = vcpu->arch.sie_block->ipb >> 28;
 	int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
 	u64 operand2;
 	u32 address;

 	vcpu->stat.instruction_stpx++;
 	operand2 = disp2;
 	if (base2)
 		operand2 += vcpu->arch.guest_gprs[base2];

 	/* must be word boundary */
 	if (operand2 & 3) {
 		kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 		goto out;
 	}

 	address = vcpu->arch.sie_block->prefix;
 	address = address & 0x7fffe000u;

 	/* get the value */
 	if (put_guest_u32(vcpu, operand2, address)) {
 		kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 		goto out;
 	}

 	VCPU_EVENT(vcpu, 5, "storing prefix to %x", address);
 out:
 	return 0;
 }

 static int handle_store_cpu_address(struct kvm_vcpu *vcpu)
 {
 	int base2 = vcpu->arch.sie_block->ipb >> 28;
 	int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
 	u64 useraddr;
 	int rc;

 	vcpu->stat.instruction_stap++;
 	useraddr = disp2;
 	if (base2)
 		useraddr += vcpu->arch.guest_gprs[base2];

 	if (useraddr & 1) {
 		kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 		goto out;
 	}

 	rc = put_guest_u16(vcpu, useraddr, vcpu->vcpu_id);
 	if (rc == -EFAULT) {
 		kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 		goto out;
 	}

 	VCPU_EVENT(vcpu, 5, "storing cpu address to %llx", useraddr);
 out:
 	return 0;
 }

 static int handle_skey(struct kvm_vcpu *vcpu)
 {
 	vcpu->stat.instruction_storage_key++;
 	vcpu->arch.sie_block->gpsw.addr -= 4;
 	VCPU_EVENT(vcpu, 4, "%s", "retrying storage key operation");
 	return 0;
 }

 static int handle_stsch(struct kvm_vcpu *vcpu)
 {
 	vcpu->stat.instruction_stsch++;
 	VCPU_EVENT(vcpu, 4, "%s", "store subchannel - CC3");
 	/* condition code 3 */
 	vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
 	vcpu->arch.sie_block->gpsw.mask |= (3 & 3ul) << 44;
 	return 0;
 }

 static int handle_chsc(struct kvm_vcpu *vcpu)
 {
 	vcpu->stat.instruction_chsc++;
 	VCPU_EVENT(vcpu, 4, "%s", "channel subsystem call - CC3");
 	/* condition code 3 */
 	vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
 	vcpu->arch.sie_block->gpsw.mask |= (3 & 3ul) << 44;
 	return 0;
 }

 static int handle_stfl(struct kvm_vcpu *vcpu)
 {
 	unsigned int facility_list;
 	int rc;

 	vcpu->stat.instruction_stfl++;
 	/* only pass the facility bits, which we can handle */
 	facility_list = S390_lowcore.stfl_fac_list & 0xff00fff3;

 	rc = copy_to_guest(vcpu, offsetof(struct _lowcore, stfl_fac_list),
 			   &facility_list, sizeof(facility_list));
 	if (rc == -EFAULT)
 		kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 	else
 		VCPU_EVENT(vcpu, 5, "store facility list value %x",
 			   facility_list);
 	return 0;
 }

 static int handle_stidp(struct kvm_vcpu *vcpu)
 {
 	int base2 = vcpu->arch.sie_block->ipb >> 28;
 	int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
 	u64 operand2;
 	int rc;

 	vcpu->stat.instruction_stidp++;
 	operand2 = disp2;
 	if (base2)
 		operand2 += vcpu->arch.guest_gprs[base2];

 	if (operand2 & 7) {
 		kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 		goto out;
 	}

 	rc = put_guest_u64(vcpu, operand2, vcpu->arch.stidp_data);
 	if (rc == -EFAULT) {
 		kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 		goto out;
 	}

 	VCPU_EVENT(vcpu, 5, "%s", "store cpu id");
 out:
 	return 0;
 }

 static void handle_stsi_3_2_2(struct kvm_vcpu *vcpu, struct sysinfo_3_2_2 *mem)
 {
 	struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
 	int cpus = 0;
 	int n;

 	spin_lock(&fi->lock);
 	for (n = 0; n < KVM_MAX_VCPUS; n++)
 		if (fi->local_int[n])
 			cpus++;
 	spin_unlock(&fi->lock);

 	/* deal with other level 3 hypervisors */
 	if (stsi(mem, 3, 2, 2) == -ENOSYS)
 		mem->count = 0;
 	if (mem->count < 8)
 		mem->count++;
 	for (n = mem->count - 1; n > 0 ; n--)
 		memcpy(&mem->vm[n], &mem->vm[n - 1], sizeof(mem->vm[0]));

 	mem->vm[0].cpus_total = cpus;
 	mem->vm[0].cpus_configured = cpus;
 	mem->vm[0].cpus_standby = 0;
 	mem->vm[0].cpus_reserved = 0;
 	mem->vm[0].caf = 1000;
 	memcpy(mem->vm[0].name, "KVMguest", 8);
 	ASCEBC(mem->vm[0].name, 8);
 	memcpy(mem->vm[0].cpi, "KVM/Linux       ", 16);
 	ASCEBC(mem->vm[0].cpi, 16);
 }

 static int handle_stsi(struct kvm_vcpu *vcpu)
 {
 	int fc = (vcpu->arch.guest_gprs[0] & 0xf0000000) >> 28;
 	int sel1 = vcpu->arch.guest_gprs[0] & 0xff;
 	int sel2 = vcpu->arch.guest_gprs[1] & 0xffff;
 	int base2 = vcpu->arch.sie_block->ipb >> 28;
 	int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
 	u64 operand2;
 	unsigned long mem;

 	vcpu->stat.instruction_stsi++;
 	VCPU_EVENT(vcpu, 4, "stsi: fc: %x sel1: %x sel2: %x", fc, sel1, sel2);

 	operand2 = disp2;
 	if (base2)
 		operand2 += vcpu->arch.guest_gprs[base2];

 	if (operand2 & 0xfff && fc > 0)
 		return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);

 	switch (fc) {
 	case 0:
 		vcpu->arch.guest_gprs[0] = 3 << 28;
 		vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
 		return 0;
 	case 1: /* same handling for 1 and 2 */
 	case 2:
 		mem = get_zeroed_page(GFP_KERNEL);
 		if (!mem)
 			goto out_fail;
 		if (stsi((void *) mem, fc, sel1, sel2) == -ENOSYS)
 			goto out_mem;
 		break;
 	case 3:
 		if (sel1 != 2 || sel2 != 2)
 			goto out_fail;
 		mem = get_zeroed_page(GFP_KERNEL);
 		if (!mem)
 			goto out_fail;
 		handle_stsi_3_2_2(vcpu, (void *) mem);
 		break;
 	default:
 		goto out_fail;
 	}

 	if (copy_to_guest_absolute(vcpu, operand2, (void *) mem, PAGE_SIZE)) {
 		kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 		goto out_mem;
 	}
 	free_page(mem);
 	vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
 	vcpu->arch.guest_gprs[0] = 0;
 	return 0;
 out_mem:
 	free_page(mem);
 out_fail:
 	/* condition code 3 */
 	vcpu->arch.sie_block->gpsw.mask |= 3ul << 44;
 	return 0;
 }

 static intercept_handler_t priv_handlers[256] = {
 	[0x02] = handle_stidp,
 	[0x10] = handle_set_prefix,
 	[0x11] = handle_store_prefix,
 	[0x12] = handle_store_cpu_address,
 	[0x29] = handle_skey,
 	[0x2a] = handle_skey,
 	[0x2b] = handle_skey,
 	[0x34] = handle_stsch,
 	[0x5f] = handle_chsc,
 	[0x7d] = handle_stsi,
 	[0xb1] = handle_stfl,
 };

 int kvm_s390_handle_b2(struct kvm_vcpu *vcpu)
 {
 	intercept_handler_t handler;

 	/*
 	 * a lot of B2 instructions are priviledged. We first check for
 	 * the privileged ones, that we can handle in the kernel. If the
 	 * kernel can handle this instruction, we check for the problem
 	 * state bit and (a) handle the instruction or (b) send a code 2
 	 * program check.
 	 * Anything else goes to userspace.*/
 	handler = priv_handlers[vcpu->arch.sie_block->ipa & 0x00ff];
 	if (handler) {
 		if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
 			return kvm_s390_inject_program_int(vcpu,
 						   PGM_PRIVILEGED_OPERATION);
 		else
 			return handler(vcpu);
 	}
 	return -EOPNOTSUPP;
 }

 static int handle_tprot(struct kvm_vcpu *vcpu)
 {
 	int base1 = (vcpu->arch.sie_block->ipb & 0xf0000000) >> 28;
 	int disp1 = (vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16;
 	int base2 = (vcpu->arch.sie_block->ipb & 0xf000) >> 12;
 	int disp2 = vcpu->arch.sie_block->ipb & 0x0fff;
 	u64 address1 = disp1 + base1 ? vcpu->arch.guest_gprs[base1] : 0;
 	u64 address2 = disp2 + base2 ? vcpu->arch.guest_gprs[base2] : 0;
 	struct vm_area_struct *vma;
 	unsigned long user_address;

 	vcpu->stat.instruction_tprot++;

 	/* we only handle the Linux memory detection case:
 	 * access key == 0
 	 * guest DAT == off
 	 * everything else goes to userspace. */
 	if (address2 & 0xf0)
 		return -EOPNOTSUPP;
 	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
 		return -EOPNOTSUPP;


 	/* we must resolve the address without holding the mmap semaphore.
 	 * This is ok since the userspace hypervisor is not supposed to change
 	 * the mapping while the guest queries the memory. Otherwise the guest
 	 * might crash or get wrong info anyway. */
 	user_address = (unsigned long) __guestaddr_to_user(vcpu, address1);

 	down_read(&current->mm->mmap_sem);
 	vma = find_vma(current->mm, user_address);
 	if (!vma) {
 		up_read(&current->mm->mmap_sem);
 		return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 	}

 	vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
 	if (!(vma->vm_flags & VM_WRITE) && (vma->vm_flags & VM_READ))
 		vcpu->arch.sie_block->gpsw.mask |= (1ul << 44);
 	if (!(vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_READ))
 		vcpu->arch.sie_block->gpsw.mask |= (2ul << 44);

 	up_read(&current->mm->mmap_sem);
 	return 0;
 }

 int kvm_s390_handle_e5(struct kvm_vcpu *vcpu)
 {
 	/* For e5xx... instructions we only handle TPROT */
 	if ((vcpu->arch.sie_block->ipa & 0x00ff) == 0x01)
 		return handle_tprot(vcpu);
 	return -EOPNOTSUPP;
 }
	/*
	* priv.c - handling privileged instructions
	*
	* 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 <linux/kvm.h>
	#include <linux/gfp.h>
	#include <linux/errno.h>
	#include <asm/current.h>
	#include <asm/debug.h>
	#include <asm/ebcdic.h>
	#include <asm/sysinfo.h>
	#include "gaccess.h"
	#include "kvm-s390.h"

	static int handle_set_prefix(struct kvm_vcpu *vcpu)
	{
	int base2 = vcpu->arch.sie_block->ipb >> 28;
	int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
	u64 operand2;
	u32 address = 0;
	u8 tmp;

	vcpu->stat.instruction_spx++;

	operand2 = disp2;
	if (base2)
	operand2 += vcpu->arch.guest_gprs[base2];

	/* must be word boundary */
	if (operand2 & 3) {
	kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
	goto out;
	}

	/* get the value */
	if (get_guest_u32(vcpu, operand2, &address)) {
	kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
	goto out;
	}

	address = address & 0x7fffe000u;

	/* make sure that the new value is valid memory */
	if (copy_from_guest_absolute(vcpu, &tmp, address, 1) \|\|
	(copy_from_guest_absolute(vcpu, &tmp, address + PAGE_SIZE, 1))) {
	kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
	goto out;
	}

	vcpu->arch.sie_block->prefix = address;
	vcpu->arch.sie_block->ihcpu = 0xffff;

	VCPU_EVENT(vcpu, 5, "setting prefix to %x", address);
	out:
	return 0;
	}

	static int handle_store_prefix(struct kvm_vcpu *vcpu)
	{
	int base2 = vcpu->arch.sie_block->ipb >> 28;
	int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
	u64 operand2;
	u32 address;

	vcpu->stat.instruction_stpx++;
	operand2 = disp2;
	if (base2)
	operand2 += vcpu->arch.guest_gprs[base2];

	/* must be word boundary */
	if (operand2 & 3) {
	kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
	goto out;
	}

	address = vcpu->arch.sie_block->prefix;
	address = address & 0x7fffe000u;

	/* get the value */
	if (put_guest_u32(vcpu, operand2, address)) {
	kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
	goto out;
	}

	VCPU_EVENT(vcpu, 5, "storing prefix to %x", address);
	out:
	return 0;
	}

	static int handle_store_cpu_address(struct kvm_vcpu *vcpu)
	{
	int base2 = vcpu->arch.sie_block->ipb >> 28;
	int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
	u64 useraddr;
	int rc;

	vcpu->stat.instruction_stap++;
	useraddr = disp2;
	if (base2)
	useraddr += vcpu->arch.guest_gprs[base2];

	if (useraddr & 1) {
	kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
	goto out;
	}

	rc = put_guest_u16(vcpu, useraddr, vcpu->vcpu_id);
	if (rc == -EFAULT) {
	kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
	goto out;
	}

	VCPU_EVENT(vcpu, 5, "storing cpu address to %llx", useraddr);
	out:
	return 0;
	}

	static int handle_skey(struct kvm_vcpu *vcpu)
	{
	vcpu->stat.instruction_storage_key++;
	vcpu->arch.sie_block->gpsw.addr -= 4;
	VCPU_EVENT(vcpu, 4, "%s", "retrying storage key operation");
	return 0;
	}

	static int handle_stsch(struct kvm_vcpu *vcpu)
	{
	vcpu->stat.instruction_stsch++;
	VCPU_EVENT(vcpu, 4, "%s", "store subchannel - CC3");
	/* condition code 3 */
	vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
	vcpu->arch.sie_block->gpsw.mask \|= (3 & 3ul) << 44;
	return 0;
	}

	static int handle_chsc(struct kvm_vcpu *vcpu)
	{
	vcpu->stat.instruction_chsc++;
	VCPU_EVENT(vcpu, 4, "%s", "channel subsystem call - CC3");
	/* condition code 3 */
	vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
	vcpu->arch.sie_block->gpsw.mask \|= (3 & 3ul) << 44;
	return 0;
	}

	static int handle_stfl(struct kvm_vcpu *vcpu)
	{
	unsigned int facility_list;
	int rc;

	vcpu->stat.instruction_stfl++;
	/* only pass the facility bits, which we can handle */
	facility_list = S390_lowcore.stfl_fac_list & 0xff00fff3;

	rc = copy_to_guest(vcpu, offsetof(struct _lowcore, stfl_fac_list),
	&facility_list, sizeof(facility_list));
	if (rc == -EFAULT)
	kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
	else
	VCPU_EVENT(vcpu, 5, "store facility list value %x",
	facility_list);
	return 0;
	}

	static int handle_stidp(struct kvm_vcpu *vcpu)
	{
	int base2 = vcpu->arch.sie_block->ipb >> 28;
	int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
	u64 operand2;
	int rc;

	vcpu->stat.instruction_stidp++;
	operand2 = disp2;
	if (base2)
	operand2 += vcpu->arch.guest_gprs[base2];

	if (operand2 & 7) {
	kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
	goto out;
	}

	rc = put_guest_u64(vcpu, operand2, vcpu->arch.stidp_data);
	if (rc == -EFAULT) {
	kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
	goto out;
	}

	VCPU_EVENT(vcpu, 5, "%s", "store cpu id");
	out:
	return 0;
	}

	static void handle_stsi_3_2_2(struct kvm_vcpu vcpu, struct sysinfo_3_2_2 mem)
	{
	struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
	int cpus = 0;
	int n;

	spin_lock(&fi->lock);
	for (n = 0; n < KVM_MAX_VCPUS; n++)
	if (fi->local_int[n])
	cpus++;
	spin_unlock(&fi->lock);

	/* deal with other level 3 hypervisors */
	if (stsi(mem, 3, 2, 2) == -ENOSYS)
	mem->count = 0;
	if (mem->count < 8)
	mem->count++;
	for (n = mem->count - 1; n > 0 ; n--)
	memcpy(&mem->vm[n], &mem->vm[n - 1], sizeof(mem->vm[0]));

	mem->vm[0].cpus_total = cpus;
	mem->vm[0].cpus_configured = cpus;
	mem->vm[0].cpus_standby = 0;
	mem->vm[0].cpus_reserved = 0;
	mem->vm[0].caf = 1000;
	memcpy(mem->vm[0].name, "KVMguest", 8);
	ASCEBC(mem->vm[0].name, 8);
	memcpy(mem->vm[0].cpi, "KVM/Linux ", 16);
	ASCEBC(mem->vm[0].cpi, 16);
	}

	static int handle_stsi(struct kvm_vcpu *vcpu)
	{
	int fc = (vcpu->arch.guest_gprs[0] & 0xf0000000) >> 28;
	int sel1 = vcpu->arch.guest_gprs[0] & 0xff;
	int sel2 = vcpu->arch.guest_gprs[1] & 0xffff;
	int base2 = vcpu->arch.sie_block->ipb >> 28;
	int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
	u64 operand2;
	unsigned long mem;

	vcpu->stat.instruction_stsi++;
	VCPU_EVENT(vcpu, 4, "stsi: fc: %x sel1: %x sel2: %x", fc, sel1, sel2);

	operand2 = disp2;
	if (base2)
	operand2 += vcpu->arch.guest_gprs[base2];

	if (operand2 & 0xfff && fc > 0)
	return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);

	switch (fc) {
	case 0:
	vcpu->arch.guest_gprs[0] = 3 << 28;
	vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
	return 0;
	case 1: /* same handling for 1 and 2 */
	case 2:
	mem = get_zeroed_page(GFP_KERNEL);
	if (!mem)
	goto out_fail;
	if (stsi((void *) mem, fc, sel1, sel2) == -ENOSYS)
	goto out_mem;
	break;
	case 3:
	if (sel1 != 2 \|\| sel2 != 2)
	goto out_fail;
	mem = get_zeroed_page(GFP_KERNEL);
	if (!mem)
	goto out_fail;
	handle_stsi_3_2_2(vcpu, (void *) mem);
	break;
	default:
	goto out_fail;
	}

	if (copy_to_guest_absolute(vcpu, operand2, (void *) mem, PAGE_SIZE)) {
	kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
	goto out_mem;
	}
	free_page(mem);
	vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
	vcpu->arch.guest_gprs[0] = 0;
	return 0;
	out_mem:
	free_page(mem);
	out_fail:
	/* condition code 3 */
	vcpu->arch.sie_block->gpsw.mask \|= 3ul << 44;
	return 0;
	}

	static intercept_handler_t priv_handlers[256] = {
	[0x02] = handle_stidp,
	[0x10] = handle_set_prefix,
	[0x11] = handle_store_prefix,
	[0x12] = handle_store_cpu_address,
	[0x29] = handle_skey,
	[0x2a] = handle_skey,
	[0x2b] = handle_skey,
	[0x34] = handle_stsch,
	[0x5f] = handle_chsc,
	[0x7d] = handle_stsi,
	[0xb1] = handle_stfl,
	};

	int kvm_s390_handle_b2(struct kvm_vcpu *vcpu)
	{
	intercept_handler_t handler;

	/*
	* a lot of B2 instructions are priviledged. We first check for
	* the privileged ones, that we can handle in the kernel. If the
	* kernel can handle this instruction, we check for the problem
	* state bit and (a) handle the instruction or (b) send a code 2
	* program check.
	* Anything else goes to userspace.*/
	handler = priv_handlers[vcpu->arch.sie_block->ipa & 0x00ff];
	if (handler) {
	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
	return kvm_s390_inject_program_int(vcpu,
	PGM_PRIVILEGED_OPERATION);
	else
	return handler(vcpu);
	}
	return -EOPNOTSUPP;
	}

	static int handle_tprot(struct kvm_vcpu *vcpu)
	{
	int base1 = (vcpu->arch.sie_block->ipb & 0xf0000000) >> 28;
	int disp1 = (vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16;
	int base2 = (vcpu->arch.sie_block->ipb & 0xf000) >> 12;
	int disp2 = vcpu->arch.sie_block->ipb & 0x0fff;
	u64 address1 = disp1 + base1 ? vcpu->arch.guest_gprs[base1] : 0;
	u64 address2 = disp2 + base2 ? vcpu->arch.guest_gprs[base2] : 0;
	struct vm_area_struct *vma;
	unsigned long user_address;

	vcpu->stat.instruction_tprot++;

	/* we only handle the Linux memory detection case:
	* access key == 0
	* guest DAT == off
	* everything else goes to userspace. */
	if (address2 & 0xf0)
	return -EOPNOTSUPP;
	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
	return -EOPNOTSUPP;


	/* we must resolve the address without holding the mmap semaphore.
	* This is ok since the userspace hypervisor is not supposed to change
	* the mapping while the guest queries the memory. Otherwise the guest
	* might crash or get wrong info anyway. */
	user_address = (unsigned long) __guestaddr_to_user(vcpu, address1);

	down_read(&current->mm->mmap_sem);
	vma = find_vma(current->mm, user_address);
	if (!vma) {
	up_read(&current->mm->mmap_sem);
	return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
	}

	vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
	if (!(vma->vm_flags & VM_WRITE) && (vma->vm_flags & VM_READ))
	vcpu->arch.sie_block->gpsw.mask \|= (1ul << 44);
	if (!(vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_READ))
	vcpu->arch.sie_block->gpsw.mask \|= (2ul << 44);

	up_read(&current->mm->mmap_sem);
	return 0;
	}

	int kvm_s390_handle_e5(struct kvm_vcpu *vcpu)
	{
	/* For e5xx... instructions we only handle TPROT */
	if ((vcpu->arch.sie_block->ipa & 0x00ff) == 0x01)
	return handle_tprot(vcpu);
	return -EOPNOTSUPP;
	}