virt/kvm/ioapic.c - third_party/linux - Git at Google

 /*
  *  Copyright (C) 2001  MandrakeSoft S.A.
  *
  *    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 <asm/processor.h>
 #include <asm/page.h>
 #include <asm/current.h>

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

 #if 0
 #define ioapic_debug(fmt,arg...) printk(KERN_WARNING fmt,##arg)
 #else
 #define ioapic_debug(fmt, arg...)
 #endif
 static void 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 void ioapic_service(struct kvm_ioapic *ioapic, unsigned int idx)
 {
 	union ioapic_redir_entry *pent;

 	pent = &ioapic->redirtbl[idx];

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

 static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
 {
 	unsigned index;

 	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;
 		if (ioapic->ioregsel & 1) {
 			ioapic->redirtbl[index].bits &= 0xffffffff;
 			ioapic->redirtbl[index].bits |= (u64) val << 32;
 		} else {
 			ioapic->redirtbl[index].bits &= ~0xffffffffULL;
 			ioapic->redirtbl[index].bits |= (u32) val;
 			ioapic->redirtbl[index].fields.remote_irr = 0;
 		}
 		if (ioapic->irr & (1 << index))
 			ioapic_service(ioapic, index);
 		break;
 	}
 }

 static void ioapic_inj_irq(struct kvm_ioapic *ioapic,
 			   struct kvm_vcpu *vcpu,
 			   u8 vector, u8 trig_mode, u8 delivery_mode)
 {
 	ioapic_debug("irq %d trig %d deliv %d\n", vector, trig_mode,
 		     delivery_mode);

 	ASSERT((delivery_mode == IOAPIC_FIXED) ||
 	       (delivery_mode == IOAPIC_LOWEST_PRIORITY));

 	kvm_apic_set_irq(vcpu, vector, trig_mode);
 }

 static u32 ioapic_get_delivery_bitmask(struct kvm_ioapic *ioapic, u8 dest,
 				       u8 dest_mode)
 {
 	u32 mask = 0;
 	int i;
 	struct kvm *kvm = ioapic->kvm;
 	struct kvm_vcpu *vcpu;

 	ioapic_debug("dest %d dest_mode %d\n", dest, dest_mode);

 	if (dest_mode == 0) {	/* Physical mode. */
 		if (dest == 0xFF) {	/* Broadcast. */
 			for (i = 0; i < KVM_MAX_VCPUS; ++i)
 				if (kvm->vcpus[i] && kvm->vcpus[i]->arch.apic)
 					mask |= 1 << i;
 			return mask;
 		}
 		for (i = 0; i < KVM_MAX_VCPUS; ++i) {
 			vcpu = kvm->vcpus[i];
 			if (!vcpu)
 				continue;
 			if (kvm_apic_match_physical_addr(vcpu->arch.apic, dest)) {
 				if (vcpu->arch.apic)
 					mask = 1 << i;
 				break;
 			}
 		}
 	} else if (dest != 0)	/* Logical mode, MDA non-zero. */
 		for (i = 0; i < KVM_MAX_VCPUS; ++i) {
 			vcpu = kvm->vcpus[i];
 			if (!vcpu)
 				continue;
 			if (vcpu->arch.apic &&
 			    kvm_apic_match_logical_addr(vcpu->arch.apic, dest))
 				mask |= 1 << vcpu->vcpu_id;
 		}
 	ioapic_debug("mask %x\n", mask);
 	return mask;
 }

 static void ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
 {
 	u8 dest = ioapic->redirtbl[irq].fields.dest_id;
 	u8 dest_mode = ioapic->redirtbl[irq].fields.dest_mode;
 	u8 delivery_mode = ioapic->redirtbl[irq].fields.delivery_mode;
 	u8 vector = ioapic->redirtbl[irq].fields.vector;
 	u8 trig_mode = ioapic->redirtbl[irq].fields.trig_mode;
 	u32 deliver_bitmask;
 	struct kvm_vcpu *vcpu;
 	int vcpu_id;

 	ioapic_debug("dest=%x dest_mode=%x delivery_mode=%x "
 		     "vector=%x trig_mode=%x\n",
 		     dest, dest_mode, delivery_mode, vector, trig_mode);

 	deliver_bitmask = ioapic_get_delivery_bitmask(ioapic, dest, dest_mode);
 	if (!deliver_bitmask) {
 		ioapic_debug("no target on destination\n");
 		return;
 	}

 	switch (delivery_mode) {
 	case IOAPIC_LOWEST_PRIORITY:
 		vcpu = kvm_get_lowest_prio_vcpu(ioapic->kvm, vector,
 				deliver_bitmask);
 		if (vcpu != NULL)
 			ioapic_inj_irq(ioapic, vcpu, vector,
 				       trig_mode, delivery_mode);
 		else
 			ioapic_debug("null lowest prio vcpu: "
 				     "mask=%x vector=%x delivery_mode=%x\n",
 				     deliver_bitmask, vector, IOAPIC_LOWEST_PRIORITY);
 		break;
 	case IOAPIC_FIXED:
 		for (vcpu_id = 0; deliver_bitmask != 0; vcpu_id++) {
 			if (!(deliver_bitmask & (1 << vcpu_id)))
 				continue;
 			deliver_bitmask &= ~(1 << vcpu_id);
 			vcpu = ioapic->kvm->vcpus[vcpu_id];
 			if (vcpu) {
 				ioapic_inj_irq(ioapic, vcpu, vector,
 					       trig_mode, delivery_mode);
 			}
 		}
 		break;

 		/* TODO: NMI */
 	default:
 		printk(KERN_WARNING "Unsupported delivery mode %d\n",
 		       delivery_mode);
 		break;
 	}
 }

 void kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level)
 {
 	u32 old_irr = ioapic->irr;
 	u32 mask = 1 << irq;
 	union ioapic_redir_entry entry;

 	if (irq >= 0 && irq < IOAPIC_NUM_PINS) {
 		entry = ioapic->redirtbl[irq];
 		level ^= entry.fields.polarity;
 		if (!level)
 			ioapic->irr &= ~mask;
 		else {
 			ioapic->irr |= mask;
 			if ((!entry.fields.trig_mode && old_irr != ioapic->irr)
 			    || !entry.fields.remote_irr)
 				ioapic_service(ioapic, irq);
 		}
 	}
 }

 static int get_eoi_gsi(struct kvm_ioapic *ioapic, int vector)
 {
 	int i;

 	for (i = 0; i < IOAPIC_NUM_PINS; i++)
 		if (ioapic->redirtbl[i].fields.vector == vector)
 			return i;
 	return -1;
 }

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

 	gsi = get_eoi_gsi(ioapic, vector);
 	if (gsi == -1) {
 		printk(KERN_WARNING "Can't find redir item for %d EOI\n",
 		       vector);
 		return;
 	}

 	ent = &ioapic->redirtbl[gsi];
 	ASSERT(ent->fields.trig_mode == IOAPIC_LEVEL_TRIG);

 	ent->fields.remote_irr = 0;
 	if (!ent->fields.mask && (ioapic->irr & (1 << gsi)))
 		ioapic_deliver(ioapic, gsi);
 }

 static int ioapic_in_range(struct kvm_io_device *this, gpa_t addr)
 {
 	struct kvm_ioapic *ioapic = (struct kvm_ioapic *)this->private;

 	return ((addr >= ioapic->base_address &&
 		 (addr < ioapic->base_address + IOAPIC_MEM_LENGTH)));
 }

 static void ioapic_mmio_read(struct kvm_io_device *this, gpa_t addr, int len,
 			     void *val)
 {
 	struct kvm_ioapic *ioapic = (struct kvm_ioapic *)this->private;
 	u32 result;

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

 	addr &= 0xff;
 	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;
 	}
 	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);
 	}
 }

 static void ioapic_mmio_write(struct kvm_io_device *this, gpa_t addr, int len,
 			      const void *val)
 {
 	struct kvm_ioapic *ioapic = (struct kvm_ioapic *)this->private;
 	u32 data;

 	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;
 	}

 	addr &= 0xff;
 	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->kvm, data);
 		break;
 #endif

 	default:
 		break;
 	}
 }

 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;
 }

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

 	ioapic = kzalloc(sizeof(struct kvm_ioapic), GFP_KERNEL);
 	if (!ioapic)
 		return -ENOMEM;
 	kvm->arch.vioapic = ioapic;
 	kvm_ioapic_reset(ioapic);
 	ioapic->dev.read = ioapic_mmio_read;
 	ioapic->dev.write = ioapic_mmio_write;
 	ioapic->dev.in_range = ioapic_in_range;
 	ioapic->dev.private = ioapic;
 	ioapic->kvm = kvm;
 	kvm_io_bus_register_dev(&kvm->mmio_bus, &ioapic->dev);
 	return 0;
 }
	/*
	* Copyright (C) 2001 MandrakeSoft S.A.
	*
	* 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 <asm/processor.h>
	#include <asm/page.h>
	#include <asm/current.h>

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

	#if 0
	#define ioapic_debug(fmt,arg...) printk(KERN_WARNING fmt,##arg)
	#else
	#define ioapic_debug(fmt, arg...)
	#endif
	static void 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 void ioapic_service(struct kvm_ioapic *ioapic, unsigned int idx)
	{
	union ioapic_redir_entry *pent;

	pent = &ioapic->redirtbl[idx];

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

	static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
	{
	unsigned index;

	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;
	if (ioapic->ioregsel & 1) {
	ioapic->redirtbl[index].bits &= 0xffffffff;
	ioapic->redirtbl[index].bits \|= (u64) val << 32;
	} else {
	ioapic->redirtbl[index].bits &= ~0xffffffffULL;
	ioapic->redirtbl[index].bits \|= (u32) val;
	ioapic->redirtbl[index].fields.remote_irr = 0;
	}
	if (ioapic->irr & (1 << index))
	ioapic_service(ioapic, index);
	break;
	}
	}

	static void ioapic_inj_irq(struct kvm_ioapic *ioapic,
	struct kvm_vcpu *vcpu,
	u8 vector, u8 trig_mode, u8 delivery_mode)
	{
	ioapic_debug("irq %d trig %d deliv %d\n", vector, trig_mode,
	delivery_mode);

	ASSERT((delivery_mode == IOAPIC_FIXED) \|\|
	(delivery_mode == IOAPIC_LOWEST_PRIORITY));

	kvm_apic_set_irq(vcpu, vector, trig_mode);
	}

	static u32 ioapic_get_delivery_bitmask(struct kvm_ioapic *ioapic, u8 dest,
	u8 dest_mode)
	{
	u32 mask = 0;
	int i;
	struct kvm *kvm = ioapic->kvm;
	struct kvm_vcpu *vcpu;

	ioapic_debug("dest %d dest_mode %d\n", dest, dest_mode);

	if (dest_mode == 0) { /* Physical mode. */
	if (dest == 0xFF) { /* Broadcast. */
	for (i = 0; i < KVM_MAX_VCPUS; ++i)
	if (kvm->vcpus[i] && kvm->vcpus[i]->arch.apic)
	mask \|= 1 << i;
	return mask;
	}
	for (i = 0; i < KVM_MAX_VCPUS; ++i) {
	vcpu = kvm->vcpus[i];
	if (!vcpu)
	continue;
	if (kvm_apic_match_physical_addr(vcpu->arch.apic, dest)) {
	if (vcpu->arch.apic)
	mask = 1 << i;
	break;
	}
	}
	} else if (dest != 0) /* Logical mode, MDA non-zero. */
	for (i = 0; i < KVM_MAX_VCPUS; ++i) {
	vcpu = kvm->vcpus[i];
	if (!vcpu)
	continue;
	if (vcpu->arch.apic &&
	kvm_apic_match_logical_addr(vcpu->arch.apic, dest))
	mask \|= 1 << vcpu->vcpu_id;
	}
	ioapic_debug("mask %x\n", mask);
	return mask;
	}

	static void ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
	{
	u8 dest = ioapic->redirtbl[irq].fields.dest_id;
	u8 dest_mode = ioapic->redirtbl[irq].fields.dest_mode;
	u8 delivery_mode = ioapic->redirtbl[irq].fields.delivery_mode;
	u8 vector = ioapic->redirtbl[irq].fields.vector;
	u8 trig_mode = ioapic->redirtbl[irq].fields.trig_mode;
	u32 deliver_bitmask;
	struct kvm_vcpu *vcpu;
	int vcpu_id;

	ioapic_debug("dest=%x dest_mode=%x delivery_mode=%x "
	"vector=%x trig_mode=%x\n",
	dest, dest_mode, delivery_mode, vector, trig_mode);

	deliver_bitmask = ioapic_get_delivery_bitmask(ioapic, dest, dest_mode);
	if (!deliver_bitmask) {
	ioapic_debug("no target on destination\n");
	return;
	}

	switch (delivery_mode) {
	case IOAPIC_LOWEST_PRIORITY:
	vcpu = kvm_get_lowest_prio_vcpu(ioapic->kvm, vector,
	deliver_bitmask);
	if (vcpu != NULL)
	ioapic_inj_irq(ioapic, vcpu, vector,
	trig_mode, delivery_mode);
	else
	ioapic_debug("null lowest prio vcpu: "
	"mask=%x vector=%x delivery_mode=%x\n",
	deliver_bitmask, vector, IOAPIC_LOWEST_PRIORITY);
	break;
	case IOAPIC_FIXED:
	for (vcpu_id = 0; deliver_bitmask != 0; vcpu_id++) {
	if (!(deliver_bitmask & (1 << vcpu_id)))
	continue;
	deliver_bitmask &= ~(1 << vcpu_id);
	vcpu = ioapic->kvm->vcpus[vcpu_id];
	if (vcpu) {
	ioapic_inj_irq(ioapic, vcpu, vector,
	trig_mode, delivery_mode);
	}
	}
	break;

	/* TODO: NMI */
	default:
	printk(KERN_WARNING "Unsupported delivery mode %d\n",
	delivery_mode);
	break;
	}
	}

	void kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level)
	{
	u32 old_irr = ioapic->irr;
	u32 mask = 1 << irq;
	union ioapic_redir_entry entry;

	if (irq >= 0 && irq < IOAPIC_NUM_PINS) {
	entry = ioapic->redirtbl[irq];
	level ^= entry.fields.polarity;
	if (!level)
	ioapic->irr &= ~mask;
	else {
	ioapic->irr \|= mask;
	if ((!entry.fields.trig_mode && old_irr != ioapic->irr)
	\|\| !entry.fields.remote_irr)
	ioapic_service(ioapic, irq);
	}
	}
	}

	static int get_eoi_gsi(struct kvm_ioapic *ioapic, int vector)
	{
	int i;

	for (i = 0; i < IOAPIC_NUM_PINS; i++)
	if (ioapic->redirtbl[i].fields.vector == vector)
	return i;
	return -1;
	}

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

	gsi = get_eoi_gsi(ioapic, vector);
	if (gsi == -1) {
	printk(KERN_WARNING "Can't find redir item for %d EOI\n",
	vector);
	return;
	}

	ent = &ioapic->redirtbl[gsi];
	ASSERT(ent->fields.trig_mode == IOAPIC_LEVEL_TRIG);

	ent->fields.remote_irr = 0;
	if (!ent->fields.mask && (ioapic->irr & (1 << gsi)))
	ioapic_deliver(ioapic, gsi);
	}

	static int ioapic_in_range(struct kvm_io_device *this, gpa_t addr)
	{
	struct kvm_ioapic ioapic = (struct kvm_ioapic )this->private;

	return ((addr >= ioapic->base_address &&
	(addr < ioapic->base_address + IOAPIC_MEM_LENGTH)));
	}

	static void ioapic_mmio_read(struct kvm_io_device *this, gpa_t addr, int len,
	void *val)
	{
	struct kvm_ioapic ioapic = (struct kvm_ioapic )this->private;
	u32 result;

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

	addr &= 0xff;
	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;
	}
	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);
	}
	}

	static void ioapic_mmio_write(struct kvm_io_device *this, gpa_t addr, int len,
	const void *val)
	{
	struct kvm_ioapic ioapic = (struct kvm_ioapic )this->private;
	u32 data;

	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;
	}

	addr &= 0xff;
	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->kvm, data);
	break;
	#endif

	default:
	break;
	}
	}

	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;
	}

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

	ioapic = kzalloc(sizeof(struct kvm_ioapic), GFP_KERNEL);
	if (!ioapic)
	return -ENOMEM;
	kvm->arch.vioapic = ioapic;
	kvm_ioapic_reset(ioapic);
	ioapic->dev.read = ioapic_mmio_read;
	ioapic->dev.write = ioapic_mmio_write;
	ioapic->dev.in_range = ioapic_in_range;
	ioapic->dev.private = ioapic;
	ioapic->kvm = kvm;
	kvm_io_bus_register_dev(&kvm->mmio_bus, &ioapic->dev);
	return 0;
	}