virt/kvm/ioapic.c - kernel/msm-4.9 - Gitiles

 /*
  *  Copyright (C) 2001  MandrakeSoft S.A.
  *  Copyright 2010 Red Hat, Inc. and/or its affiliates.
  *
  *    MandrakeSoft S.A.
  *    43, rue d'Aboukir
  *    75002 Paris - France
  *    http://www.linux-mandrake.com/
  *    http://www.mandrakesoft.com/
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public
  *  License as published by the Free Software Foundation; either
  *  version 2 of the License, or (at your option) any later version.
  *
  *  This library is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  *  Lesser General Public License for more details.
  *
  *  You should have received a copy of the GNU Lesser General Public
  *  License along with this library; if not, write to the Free Software
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  *
  *  Yunhong Jiang <yunhong.jiang@intel.com>
  *  Yaozu (Eddie) Dong <eddie.dong@intel.com>
  *  Based on Xen 3.1 code.
  */

 #include <linux/kvm_host.h>
 #include <linux/kvm.h>
 #include <linux/mm.h>
 #include <linux/highmem.h>
 #include <linux/smp.h>
 #include <linux/hrtimer.h>
 #include <linux/io.h>
 #include <linux/slab.h>
 #include <asm/processor.h>
 #include <asm/page.h>
 #include <asm/current.h>
 #include <trace/events/kvm.h>

 #include "ioapic.h"
 #include "lapic.h"
 #include "irq.h"

 #if 0
 #define ioapic_debug(fmt,arg...) printk(KERN_WARNING fmt,##arg)
 #else
 #define ioapic_debug(fmt, arg...)
 #endif
 static int ioapic_deliver(struct kvm_ioapic *vioapic, int irq);

 static unsigned long ioapic_read_indirect(struct kvm_ioapic *ioapic,
 					  unsigned long addr,
 					  unsigned long length)
 {
 	unsigned long result = 0;

 	switch (ioapic->ioregsel) {
 	case IOAPIC_REG_VERSION:
 		result = ((((IOAPIC_NUM_PINS - 1) & 0xff) << 16)
 			  | (IOAPIC_VERSION_ID & 0xff));
 		break;

 	case IOAPIC_REG_APIC_ID:
 	case IOAPIC_REG_ARB_ID:
 		result = ((ioapic->id & 0xf) << 24);
 		break;

 	default:
 		{
 			u32 redir_index = (ioapic->ioregsel - 0x10) >> 1;
 			u64 redir_content;

 			ASSERT(redir_index < IOAPIC_NUM_PINS);

 			redir_content = ioapic->redirtbl[redir_index].bits;
 			result = (ioapic->ioregsel & 0x1) ?
 			    (redir_content >> 32) & 0xffffffff :
 			    redir_content & 0xffffffff;
 			break;
 		}
 	}

 	return result;
 }

 static int ioapic_service(struct kvm_ioapic *ioapic, unsigned int idx)
 {
 	union kvm_ioapic_redirect_entry *pent;
 	int injected = -1;

 	pent = &ioapic->redirtbl[idx];

 	if (!pent->fields.mask) {
 		injected = ioapic_deliver(ioapic, idx);
 		if (injected && pent->fields.trig_mode == IOAPIC_LEVEL_TRIG)
 			pent->fields.remote_irr = 1;
 	}

 	return injected;
 }

 static void update_handled_vectors(struct kvm_ioapic *ioapic)
 {
 	DECLARE_BITMAP(handled_vectors, 256);
 	int i;

 	memset(handled_vectors, 0, sizeof(handled_vectors));
 	for (i = 0; i < IOAPIC_NUM_PINS; ++i)
 		__set_bit(ioapic->redirtbl[i].fields.vector, handled_vectors);
 	memcpy(ioapic->handled_vectors, handled_vectors,
 	       sizeof(handled_vectors));
 	smp_wmb();
 }

 static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
 {
 	unsigned index;
 	bool mask_before, mask_after;
 	union kvm_ioapic_redirect_entry *e;

 	switch (ioapic->ioregsel) {
 	case IOAPIC_REG_VERSION:
 		/* Writes are ignored. */
 		break;

 	case IOAPIC_REG_APIC_ID:
 		ioapic->id = (val >> 24) & 0xf;
 		break;

 	case IOAPIC_REG_ARB_ID:
 		break;

 	default:
 		index = (ioapic->ioregsel - 0x10) >> 1;

 		ioapic_debug("change redir index %x val %x\n", index, val);
 		if (index >= IOAPIC_NUM_PINS)
 			return;
 		e = &ioapic->redirtbl[index];
 		mask_before = e->fields.mask;
 		if (ioapic->ioregsel & 1) {
 			e->bits &= 0xffffffff;
 			e->bits |= (u64) val << 32;
 		} else {
 			e->bits &= ~0xffffffffULL;
 			e->bits |= (u32) val;
 			e->fields.remote_irr = 0;
 		}
 		update_handled_vectors(ioapic);
 		mask_after = e->fields.mask;
 		if (mask_before != mask_after)
 			kvm_fire_mask_notifiers(ioapic->kvm, index, mask_after);
 		if (e->fields.trig_mode == IOAPIC_LEVEL_TRIG
 		    && ioapic->irr & (1 << index))
 			ioapic_service(ioapic, index);
 		break;
 	}
 }

 static int ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
 {
 	union kvm_ioapic_redirect_entry *entry = &ioapic->redirtbl[irq];
 	struct kvm_lapic_irq irqe;

 	ioapic_debug("dest=%x dest_mode=%x delivery_mode=%x "
 		     "vector=%x trig_mode=%x\n",
 		     entry->fields.dest, entry->fields.dest_mode,
 		     entry->fields.delivery_mode, entry->fields.vector,
 		     entry->fields.trig_mode);

 	irqe.dest_id = entry->fields.dest_id;
 	irqe.vector = entry->fields.vector;
 	irqe.dest_mode = entry->fields.dest_mode;
 	irqe.trig_mode = entry->fields.trig_mode;
 	irqe.delivery_mode = entry->fields.delivery_mode << 8;
 	irqe.level = 1;
 	irqe.shorthand = 0;

 #ifdef CONFIG_X86
 	/* Always delivery PIT interrupt to vcpu 0 */
 	if (irq == 0) {
 		irqe.dest_mode = 0; /* Physical mode. */
 		/* need to read apic_id from apic regiest since
 		 * it can be rewritten */
 		irqe.dest_id = ioapic->kvm->bsp_vcpu->vcpu_id;
 	}
 #endif
 	return kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe);
 }

 int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level)
 {
 	u32 old_irr;
 	u32 mask = 1 << irq;
 	union kvm_ioapic_redirect_entry entry;
 	int ret = 1;

 	spin_lock(&ioapic->lock);
 	old_irr = ioapic->irr;
 	if (irq >= 0 && irq < IOAPIC_NUM_PINS) {
 		entry = ioapic->redirtbl[irq];
 		level ^= entry.fields.polarity;
 		if (!level)
 			ioapic->irr &= ~mask;
 		else {
 			int edge = (entry.fields.trig_mode == IOAPIC_EDGE_TRIG);
 			ioapic->irr |= mask;
 			if ((edge && old_irr != ioapic->irr) ||
 			    (!edge && !entry.fields.remote_irr))
 				ret = ioapic_service(ioapic, irq);
 			else
 				ret = 0; /* report coalesced interrupt */
 		}
 		trace_kvm_ioapic_set_irq(entry.bits, irq, ret == 0);
 	}
 	spin_unlock(&ioapic->lock);

 	return ret;
 }

 static void __kvm_ioapic_update_eoi(struct kvm_ioapic *ioapic, int vector,
 				     int trigger_mode)
 {
 	int i;

 	for (i = 0; i < IOAPIC_NUM_PINS; i++) {
 		union kvm_ioapic_redirect_entry *ent = &ioapic->redirtbl[i];

 		if (ent->fields.vector != vector)
 			continue;

 		/*
 		 * We are dropping lock while calling ack notifiers because ack
 		 * notifier callbacks for assigned devices call into IOAPIC
 		 * recursively. Since remote_irr is cleared only after call
 		 * to notifiers if the same vector will be delivered while lock
 		 * is dropped it will be put into irr and will be delivered
 		 * after ack notifier returns.
 		 */
 		spin_unlock(&ioapic->lock);
 		kvm_notify_acked_irq(ioapic->kvm, KVM_IRQCHIP_IOAPIC, i);
 		spin_lock(&ioapic->lock);

 		if (trigger_mode != IOAPIC_LEVEL_TRIG)
 			continue;

 		ASSERT(ent->fields.trig_mode == IOAPIC_LEVEL_TRIG);
 		ent->fields.remote_irr = 0;
 		if (!ent->fields.mask && (ioapic->irr & (1 << i)))
 			ioapic_service(ioapic, i);
 	}
 }

 void kvm_ioapic_update_eoi(struct kvm *kvm, int vector, int trigger_mode)
 {
 	struct kvm_ioapic *ioapic = kvm->arch.vioapic;

 	smp_rmb();
 	if (!test_bit(vector, ioapic->handled_vectors))
 		return;
 	spin_lock(&ioapic->lock);
 	__kvm_ioapic_update_eoi(ioapic, vector, trigger_mode);
 	spin_unlock(&ioapic->lock);
 }

 static inline struct kvm_ioapic *to_ioapic(struct kvm_io_device *dev)
 {
 	return container_of(dev, struct kvm_ioapic, dev);
 }

 static inline int ioapic_in_range(struct kvm_ioapic *ioapic, gpa_t addr)
 {
 	return ((addr >= ioapic->base_address &&
 		 (addr < ioapic->base_address + IOAPIC_MEM_LENGTH)));
 }

 static int ioapic_mmio_read(struct kvm_io_device *this, gpa_t addr, int len,
 			    void *val)
 {
 	struct kvm_ioapic *ioapic = to_ioapic(this);
 	u32 result;
 	if (!ioapic_in_range(ioapic, addr))
 		return -EOPNOTSUPP;

 	ioapic_debug("addr %lx\n", (unsigned long)addr);
 	ASSERT(!(addr & 0xf));	/* check alignment */

 	addr &= 0xff;
 	spin_lock(&ioapic->lock);
 	switch (addr) {
 	case IOAPIC_REG_SELECT:
 		result = ioapic->ioregsel;
 		break;

 	case IOAPIC_REG_WINDOW:
 		result = ioapic_read_indirect(ioapic, addr, len);
 		break;

 	default:
 		result = 0;
 		break;
 	}
 	spin_unlock(&ioapic->lock);

 	switch (len) {
 	case 8:
 		*(u64 *) val = result;
 		break;
 	case 1:
 	case 2:
 	case 4:
 		memcpy(val, (char *)&result, len);
 		break;
 	default:
 		printk(KERN_WARNING "ioapic: wrong length %d\n", len);
 	}
 	return 0;
 }

 static int ioapic_mmio_write(struct kvm_io_device *this, gpa_t addr, int len,
 			     const void *val)
 {
 	struct kvm_ioapic *ioapic = to_ioapic(this);
 	u32 data;
 	if (!ioapic_in_range(ioapic, addr))
 		return -EOPNOTSUPP;

 	ioapic_debug("ioapic_mmio_write addr=%p len=%d val=%p\n",
 		     (void*)addr, len, val);
 	ASSERT(!(addr & 0xf));	/* check alignment */

 	if (len == 4 || len == 8)
 		data = *(u32 *) val;
 	else {
 		printk(KERN_WARNING "ioapic: Unsupported size %d\n", len);
 		return 0;
 	}

 	addr &= 0xff;
 	spin_lock(&ioapic->lock);
 	switch (addr) {
 	case IOAPIC_REG_SELECT:
 		ioapic->ioregsel = data;
 		break;

 	case IOAPIC_REG_WINDOW:
 		ioapic_write_indirect(ioapic, data);
 		break;
 #ifdef	CONFIG_IA64
 	case IOAPIC_REG_EOI:
 		__kvm_ioapic_update_eoi(ioapic, data, IOAPIC_LEVEL_TRIG);
 		break;
 #endif

 	default:
 		break;
 	}
 	spin_unlock(&ioapic->lock);
 	return 0;
 }

 void kvm_ioapic_reset(struct kvm_ioapic *ioapic)
 {
 	int i;

 	for (i = 0; i < IOAPIC_NUM_PINS; i++)
 		ioapic->redirtbl[i].fields.mask = 1;
 	ioapic->base_address = IOAPIC_DEFAULT_BASE_ADDRESS;
 	ioapic->ioregsel = 0;
 	ioapic->irr = 0;
 	ioapic->id = 0;
 	update_handled_vectors(ioapic);
 }

 static const struct kvm_io_device_ops ioapic_mmio_ops = {
 	.read     = ioapic_mmio_read,
 	.write    = ioapic_mmio_write,
 };

 int kvm_ioapic_init(struct kvm *kvm)
 {
 	struct kvm_ioapic *ioapic;
 	int ret;

 	ioapic = kzalloc(sizeof(struct kvm_ioapic), GFP_KERNEL);
 	if (!ioapic)
 		return -ENOMEM;
 	spin_lock_init(&ioapic->lock);
 	kvm->arch.vioapic = ioapic;
 	kvm_ioapic_reset(ioapic);
 	kvm_iodevice_init(&ioapic->dev, &ioapic_mmio_ops);
 	ioapic->kvm = kvm;
 	mutex_lock(&kvm->slots_lock);
 	ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, &ioapic->dev);
 	mutex_unlock(&kvm->slots_lock);
 	if (ret < 0) {
 		kvm->arch.vioapic = NULL;
 		kfree(ioapic);
 	}

 	return ret;
 }

 void kvm_ioapic_destroy(struct kvm *kvm)
 {
 	struct kvm_ioapic *ioapic = kvm->arch.vioapic;

 	if (ioapic) {
 		kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS, &ioapic->dev);
 		kvm->arch.vioapic = NULL;
 		kfree(ioapic);
 	}
 }

 int kvm_get_ioapic(struct kvm *kvm, struct kvm_ioapic_state *state)
 {
 	struct kvm_ioapic *ioapic = ioapic_irqchip(kvm);
 	if (!ioapic)
 		return -EINVAL;

 	spin_lock(&ioapic->lock);
 	memcpy(state, ioapic, sizeof(struct kvm_ioapic_state));
 	spin_unlock(&ioapic->lock);
 	return 0;
 }

 int kvm_set_ioapic(struct kvm *kvm, struct kvm_ioapic_state *state)
 {
 	struct kvm_ioapic *ioapic = ioapic_irqchip(kvm);
 	if (!ioapic)
 		return -EINVAL;

 	spin_lock(&ioapic->lock);
 	memcpy(ioapic, state, sizeof(struct kvm_ioapic_state));
 	update_handled_vectors(ioapic);
 	spin_unlock(&ioapic->lock);
 	return 0;
 }
	/*
	* Copyright (C) 2001 MandrakeSoft S.A.
	* Copyright 2010 Red Hat, Inc. and/or its affiliates.
	*
	* MandrakeSoft S.A.
	* 43, rue d'Aboukir
	* 75002 Paris - France
	* http://www.linux-mandrake.com/
	* http://www.mandrakesoft.com/
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2 of the License, or (at your option) any later version.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this library; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*
	* Yunhong Jiang <yunhong.jiang@intel.com>
	* Yaozu (Eddie) Dong <eddie.dong@intel.com>
	* Based on Xen 3.1 code.
	*/

	#include <linux/kvm_host.h>
	#include <linux/kvm.h>
	#include <linux/mm.h>
	#include <linux/highmem.h>
	#include <linux/smp.h>
	#include <linux/hrtimer.h>
	#include <linux/io.h>
	#include <linux/slab.h>
	#include <asm/processor.h>
	#include <asm/page.h>
	#include <asm/current.h>
	#include <trace/events/kvm.h>

	#include "ioapic.h"
	#include "lapic.h"
	#include "irq.h"

	#if 0
	#define ioapic_debug(fmt,arg...) printk(KERN_WARNING fmt,##arg)
	#else
	#define ioapic_debug(fmt, arg...)
	#endif
	static int ioapic_deliver(struct kvm_ioapic *vioapic, int irq);

	static unsigned long ioapic_read_indirect(struct kvm_ioapic *ioapic,
	unsigned long addr,
	unsigned long length)
	{
	unsigned long result = 0;

	switch (ioapic->ioregsel) {
	case IOAPIC_REG_VERSION:
	result = ((((IOAPIC_NUM_PINS - 1) & 0xff) << 16)
	\| (IOAPIC_VERSION_ID & 0xff));
	break;

	case IOAPIC_REG_APIC_ID:
	case IOAPIC_REG_ARB_ID:
	result = ((ioapic->id & 0xf) << 24);
	break;

	default:
	{
	u32 redir_index = (ioapic->ioregsel - 0x10) >> 1;
	u64 redir_content;

	ASSERT(redir_index < IOAPIC_NUM_PINS);

	redir_content = ioapic->redirtbl[redir_index].bits;
	result = (ioapic->ioregsel & 0x1) ?
	(redir_content >> 32) & 0xffffffff :
	redir_content & 0xffffffff;
	break;
	}
	}

	return result;
	}

	static int ioapic_service(struct kvm_ioapic *ioapic, unsigned int idx)
	{
	union kvm_ioapic_redirect_entry *pent;
	int injected = -1;

	pent = &ioapic->redirtbl[idx];

	if (!pent->fields.mask) {
	injected = ioapic_deliver(ioapic, idx);
	if (injected && pent->fields.trig_mode == IOAPIC_LEVEL_TRIG)
	pent->fields.remote_irr = 1;
	}

	return injected;
	}

	static void update_handled_vectors(struct kvm_ioapic *ioapic)
	{
	DECLARE_BITMAP(handled_vectors, 256);
	int i;

	memset(handled_vectors, 0, sizeof(handled_vectors));
	for (i = 0; i < IOAPIC_NUM_PINS; ++i)
	__set_bit(ioapic->redirtbl[i].fields.vector, handled_vectors);
	memcpy(ioapic->handled_vectors, handled_vectors,
	sizeof(handled_vectors));
	smp_wmb();
	}

	static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
	{
	unsigned index;
	bool mask_before, mask_after;
	union kvm_ioapic_redirect_entry *e;

	switch (ioapic->ioregsel) {
	case IOAPIC_REG_VERSION:
	/* Writes are ignored. */
	break;

	case IOAPIC_REG_APIC_ID:
	ioapic->id = (val >> 24) & 0xf;
	break;

	case IOAPIC_REG_ARB_ID:
	break;

	default:
	index = (ioapic->ioregsel - 0x10) >> 1;

	ioapic_debug("change redir index %x val %x\n", index, val);
	if (index >= IOAPIC_NUM_PINS)
	return;
	e = &ioapic->redirtbl[index];
	mask_before = e->fields.mask;
	if (ioapic->ioregsel & 1) {
	e->bits &= 0xffffffff;
	e->bits \|= (u64) val << 32;
	} else {
	e->bits &= ~0xffffffffULL;
	e->bits \|= (u32) val;
	e->fields.remote_irr = 0;
	}
	update_handled_vectors(ioapic);
	mask_after = e->fields.mask;
	if (mask_before != mask_after)
	kvm_fire_mask_notifiers(ioapic->kvm, index, mask_after);
	if (e->fields.trig_mode == IOAPIC_LEVEL_TRIG
	&& ioapic->irr & (1 << index))
	ioapic_service(ioapic, index);
	break;
	}
	}

	static int ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
	{
	union kvm_ioapic_redirect_entry *entry = &ioapic->redirtbl[irq];
	struct kvm_lapic_irq irqe;

	ioapic_debug("dest=%x dest_mode=%x delivery_mode=%x "
	"vector=%x trig_mode=%x\n",
	entry->fields.dest, entry->fields.dest_mode,
	entry->fields.delivery_mode, entry->fields.vector,
	entry->fields.trig_mode);

	irqe.dest_id = entry->fields.dest_id;
	irqe.vector = entry->fields.vector;
	irqe.dest_mode = entry->fields.dest_mode;
	irqe.trig_mode = entry->fields.trig_mode;
	irqe.delivery_mode = entry->fields.delivery_mode << 8;
	irqe.level = 1;
	irqe.shorthand = 0;

	#ifdef CONFIG_X86
	/* Always delivery PIT interrupt to vcpu 0 */
	if (irq == 0) {
	irqe.dest_mode = 0; /* Physical mode. */
	/* need to read apic_id from apic regiest since
	* it can be rewritten */
	irqe.dest_id = ioapic->kvm->bsp_vcpu->vcpu_id;
	}
	#endif
	return kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe);
	}

	int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level)
	{
	u32 old_irr;
	u32 mask = 1 << irq;
	union kvm_ioapic_redirect_entry entry;
	int ret = 1;

	spin_lock(&ioapic->lock);
	old_irr = ioapic->irr;
	if (irq >= 0 && irq < IOAPIC_NUM_PINS) {
	entry = ioapic->redirtbl[irq];
	level ^= entry.fields.polarity;
	if (!level)
	ioapic->irr &= ~mask;
	else {
	int edge = (entry.fields.trig_mode == IOAPIC_EDGE_TRIG);
	ioapic->irr \|= mask;
	if ((edge && old_irr != ioapic->irr) \|\|
	(!edge && !entry.fields.remote_irr))
	ret = ioapic_service(ioapic, irq);
	else
	ret = 0; /* report coalesced interrupt */
	}
	trace_kvm_ioapic_set_irq(entry.bits, irq, ret == 0);
	}
	spin_unlock(&ioapic->lock);

	return ret;
	}

	static void __kvm_ioapic_update_eoi(struct kvm_ioapic *ioapic, int vector,
	int trigger_mode)
	{
	int i;

	for (i = 0; i < IOAPIC_NUM_PINS; i++) {
	union kvm_ioapic_redirect_entry *ent = &ioapic->redirtbl[i];

	if (ent->fields.vector != vector)
	continue;

	/*
	* We are dropping lock while calling ack notifiers because ack
	* notifier callbacks for assigned devices call into IOAPIC
	* recursively. Since remote_irr is cleared only after call
	* to notifiers if the same vector will be delivered while lock
	* is dropped it will be put into irr and will be delivered
	* after ack notifier returns.
	*/
	spin_unlock(&ioapic->lock);
	kvm_notify_acked_irq(ioapic->kvm, KVM_IRQCHIP_IOAPIC, i);
	spin_lock(&ioapic->lock);

	if (trigger_mode != IOAPIC_LEVEL_TRIG)
	continue;

	ASSERT(ent->fields.trig_mode == IOAPIC_LEVEL_TRIG);
	ent->fields.remote_irr = 0;
	if (!ent->fields.mask && (ioapic->irr & (1 << i)))
	ioapic_service(ioapic, i);
	}
	}

	void kvm_ioapic_update_eoi(struct kvm *kvm, int vector, int trigger_mode)
	{
	struct kvm_ioapic *ioapic = kvm->arch.vioapic;

	smp_rmb();
	if (!test_bit(vector, ioapic->handled_vectors))
	return;
	spin_lock(&ioapic->lock);
	__kvm_ioapic_update_eoi(ioapic, vector, trigger_mode);
	spin_unlock(&ioapic->lock);
	}

	static inline struct kvm_ioapic to_ioapic(struct kvm_io_device dev)
	{
	return container_of(dev, struct kvm_ioapic, dev);
	}

	static inline int ioapic_in_range(struct kvm_ioapic *ioapic, gpa_t addr)
	{
	return ((addr >= ioapic->base_address &&
	(addr < ioapic->base_address + IOAPIC_MEM_LENGTH)));
	}

	static int ioapic_mmio_read(struct kvm_io_device *this, gpa_t addr, int len,
	void *val)
	{
	struct kvm_ioapic *ioapic = to_ioapic(this);
	u32 result;
	if (!ioapic_in_range(ioapic, addr))
	return -EOPNOTSUPP;

	ioapic_debug("addr %lx\n", (unsigned long)addr);
	ASSERT(!(addr & 0xf)); /* check alignment */

	addr &= 0xff;
	spin_lock(&ioapic->lock);
	switch (addr) {
	case IOAPIC_REG_SELECT:
	result = ioapic->ioregsel;
	break;

	case IOAPIC_REG_WINDOW:
	result = ioapic_read_indirect(ioapic, addr, len);
	break;

	default:
	result = 0;
	break;
	}
	spin_unlock(&ioapic->lock);

	switch (len) {
	case 8:
	(u64 ) val = result;
	break;
	case 1:
	case 2:
	case 4:
	memcpy(val, (char *)&result, len);
	break;
	default:
	printk(KERN_WARNING "ioapic: wrong length %d\n", len);
	}
	return 0;
	}

	static int ioapic_mmio_write(struct kvm_io_device *this, gpa_t addr, int len,
	const void *val)
	{
	struct kvm_ioapic *ioapic = to_ioapic(this);
	u32 data;
	if (!ioapic_in_range(ioapic, addr))
	return -EOPNOTSUPP;

	ioapic_debug("ioapic_mmio_write addr=%p len=%d val=%p\n",
	(void*)addr, len, val);
	ASSERT(!(addr & 0xf)); /* check alignment */

	if (len == 4 \|\| len == 8)
	data = (u32 ) val;
	else {
	printk(KERN_WARNING "ioapic: Unsupported size %d\n", len);
	return 0;
	}

	addr &= 0xff;
	spin_lock(&ioapic->lock);
	switch (addr) {
	case IOAPIC_REG_SELECT:
	ioapic->ioregsel = data;
	break;

	case IOAPIC_REG_WINDOW:
	ioapic_write_indirect(ioapic, data);
	break;
	#ifdef CONFIG_IA64
	case IOAPIC_REG_EOI:
	__kvm_ioapic_update_eoi(ioapic, data, IOAPIC_LEVEL_TRIG);
	break;
	#endif

	default:
	break;
	}
	spin_unlock(&ioapic->lock);
	return 0;
	}

	void kvm_ioapic_reset(struct kvm_ioapic *ioapic)
	{
	int i;

	for (i = 0; i < IOAPIC_NUM_PINS; i++)
	ioapic->redirtbl[i].fields.mask = 1;
	ioapic->base_address = IOAPIC_DEFAULT_BASE_ADDRESS;
	ioapic->ioregsel = 0;
	ioapic->irr = 0;
	ioapic->id = 0;
	update_handled_vectors(ioapic);
	}

	static const struct kvm_io_device_ops ioapic_mmio_ops = {
	.read = ioapic_mmio_read,
	.write = ioapic_mmio_write,
	};

	int kvm_ioapic_init(struct kvm *kvm)
	{
	struct kvm_ioapic *ioapic;
	int ret;

	ioapic = kzalloc(sizeof(struct kvm_ioapic), GFP_KERNEL);
	if (!ioapic)
	return -ENOMEM;
	spin_lock_init(&ioapic->lock);
	kvm->arch.vioapic = ioapic;
	kvm_ioapic_reset(ioapic);
	kvm_iodevice_init(&ioapic->dev, &ioapic_mmio_ops);
	ioapic->kvm = kvm;
	mutex_lock(&kvm->slots_lock);
	ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, &ioapic->dev);
	mutex_unlock(&kvm->slots_lock);
	if (ret < 0) {
	kvm->arch.vioapic = NULL;
	kfree(ioapic);
	}

	return ret;
	}

	void kvm_ioapic_destroy(struct kvm *kvm)
	{
	struct kvm_ioapic *ioapic = kvm->arch.vioapic;

	if (ioapic) {
	kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS, &ioapic->dev);
	kvm->arch.vioapic = NULL;
	kfree(ioapic);
	}
	}

	int kvm_get_ioapic(struct kvm kvm, struct kvm_ioapic_state state)
	{
	struct kvm_ioapic *ioapic = ioapic_irqchip(kvm);
	if (!ioapic)
	return -EINVAL;

	spin_lock(&ioapic->lock);
	memcpy(state, ioapic, sizeof(struct kvm_ioapic_state));
	spin_unlock(&ioapic->lock);
	return 0;
	}

	int kvm_set_ioapic(struct kvm kvm, struct kvm_ioapic_state state)
	{
	struct kvm_ioapic *ioapic = ioapic_irqchip(kvm);
	if (!ioapic)
	return -EINVAL;

	spin_lock(&ioapic->lock);
	memcpy(ioapic, state, sizeof(struct kvm_ioapic_state));
	update_handled_vectors(ioapic);
	spin_unlock(&ioapic->lock);
	return 0;
	}