KVM: Emulate local APIC in kernel

Because lightweight exits (exits which don't involve userspace) are many
times faster than heavyweight exits, it makes sense to emulate high usage
devices in the kernel.  The local APIC is one such device, especially for
Windows and for SMP, so we add an APIC model to kvm.

It also allows in-kernel host-side drivers to inject interrupts without
going through userspace.

[compile fix on i386 from Jindrich Makovicka]

Signed-off-by: Yaozu (Eddie) Dong <Eddie.Dong@intel.com>
Signed-off-by: Qing He <qing.he@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

8 files changed, 1065 insertions, 31 deletions

diff --git a/drivers/kvm/Makefile b/drivers/kvm/Makefile
index 952dff3..3bf7276 100644
--- a/drivers/kvm/Makefile
+++ b/drivers/kvm/Makefile
@@ -2,7 +2,7 @@
 # Makefile for Kernel-based Virtual Machine module
 #
 
-kvm-objs := kvm_main.o mmu.o x86_emulate.o i8259.o irq.o
+kvm-objs := kvm_main.o mmu.o x86_emulate.o i8259.o irq.o lapic.o
 obj-$(CONFIG_KVM) += kvm.o
 kvm-intel-objs = vmx.o
 obj-$(CONFIG_KVM_INTEL) += kvm-intel.o
diff --git a/drivers/kvm/irq.c b/drivers/kvm/irq.c
index b08005c..0b4430a 100644
--- a/drivers/kvm/irq.c
+++ b/drivers/kvm/irq.c
@@ -30,14 +30,13 @@
  */
 int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
 {
-	struct kvm_pic *s = pic_irqchip(v->kvm);
-
-	if (s->output)	/* PIC */
-		return 1;
-	/*
-	 * TODO: APIC
-	 */
-	return 0;
+	struct kvm_pic *s;
+
+	if (kvm_apic_has_interrupt(v) == -1) {	/* LAPIC */
+		s = pic_irqchip(v->kvm);	/* PIC */
+		return s->output;
+	}
+	return 1;
 }
 EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
 
@@ -46,16 +45,36 @@ EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
  */
 int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
 {
-	struct kvm_pic *s = pic_irqchip(v->kvm);
+	struct kvm_pic *s;
 	int vector;
 
-	s->output = 0;
-	vector = kvm_pic_read_irq(s);
-	if (vector != -1)
-		return vector;
-	/*
-	 * TODO: APIC
-	 */
-	return -1;
+	vector = kvm_get_apic_interrupt(v);	/* APIC */
+	if (vector == -1) {
+		s = pic_irqchip(v->kvm);
+		s->output = 0;		/* PIC */
+		vector = kvm_pic_read_irq(s);
+	}
+	return vector;
 }
 EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
+
+static void vcpu_kick_intr(void *info)
+{
+#ifdef DEBUG
+	struct kvm_vcpu *vcpu = (struct kvm_vcpu *)info;
+	printk(KERN_DEBUG "vcpu_kick_intr %p \n", vcpu);
+#endif
+}
+
+void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
+{
+	int ipi_pcpu = vcpu->cpu;
+
+	if (vcpu->guest_mode)
+		smp_call_function_single(ipi_pcpu, vcpu_kick_intr, vcpu, 0, 0);
+}
+
+void kvm_ioapic_update_eoi(struct kvm *kvm, int vector)
+{
+	/* TODO: for kernel IOAPIC */
+}
diff --git a/drivers/kvm/irq.h b/drivers/kvm/irq.h
index bdb2fc3..57e23bd 100644
--- a/drivers/kvm/irq.h
+++ b/drivers/kvm/irq.h
@@ -26,7 +26,6 @@
 
 typedef void irq_request_func(void *opaque, int level);
 
-struct kvm_pic;
 struct kvm_kpic_state {
 	u8 last_irr;	/* edge detection */
 	u8 irr;		/* interrupt request register */
@@ -61,4 +60,44 @@ int kvm_pic_read_irq(struct kvm_pic *s);
 int kvm_cpu_get_interrupt(struct kvm_vcpu *v);
 int kvm_cpu_has_interrupt(struct kvm_vcpu *v);
 
+struct kvm_lapic {
+	unsigned long base_address;
+	struct kvm_io_device dev;
+	struct {
+		atomic_t pending;
+		s64 period;	/* unit: ns */
+		u32 divide_count;
+		ktime_t last_update;
+		struct hrtimer dev;
+	} timer;
+	struct kvm_vcpu *vcpu;
+	struct page *regs_page;
+	void *regs;
+};
+
+#ifdef DEBUG
+#define ASSERT(x)  							\
+do {									\
+	if (!(x)) {							\
+		printk(KERN_EMERG "assertion failed %s: %d: %s\n",	\
+		       __FILE__, __LINE__, #x);				\
+		BUG();							\
+	}								\
+} while (0)
+#else
+#define ASSERT(x) do { } while (0)
+#endif
+
+void kvm_vcpu_kick(struct kvm_vcpu *vcpu);
+int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu);
+int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu);
+int kvm_create_lapic(struct kvm_vcpu *vcpu);
+void kvm_free_apic(struct kvm_lapic *apic);
+u64 kvm_lapic_get_cr8(struct kvm_vcpu *vcpu);
+void kvm_lapic_set_tpr(struct kvm_vcpu *vcpu, unsigned long cr8);
+void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value);
+u64 kvm_get_apic_base(struct kvm_vcpu *vcpu);
+void kvm_set_apic_base(struct kvm_vcpu *vcpu, u64 data);
+void kvm_ioapic_update_eoi(struct kvm *kvm, int vector);
+
 #endif
diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index e0a2f13..a5790cb 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -324,6 +324,7 @@ struct kvm_vcpu {
 	u64 pdptrs[4]; /* pae */
 	u64 shadow_efer;
 	u64 apic_base;
+	struct kvm_lapic *apic;    /* kernel irqchip context */
 	u64 ia32_misc_enable_msr;
 
 	struct kvm_mmu mmu;
@@ -569,8 +570,6 @@ void set_cr3(struct kvm_vcpu *vcpu, unsigned long cr0);
 void set_cr4(struct kvm_vcpu *vcpu, unsigned long cr0);
 void set_cr8(struct kvm_vcpu *vcpu, unsigned long cr0);
 unsigned long get_cr8(struct kvm_vcpu *vcpu);
-u64 kvm_get_apic_base(struct kvm_vcpu *vcpu);
-void kvm_set_apic_base(struct kvm_vcpu *vcpu, u64 data);
 void lmsw(struct kvm_vcpu *vcpu, unsigned long msw);
 
 int kvm_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata);
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index f879efb..401e3cd 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -281,6 +281,7 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_init);
 void kvm_vcpu_uninit(struct kvm_vcpu *vcpu)
 {
 	kvm_mmu_destroy(vcpu);
+	kvm_free_apic(vcpu->apic);
 	free_page((unsigned long)vcpu->pio_data);
 	free_page((unsigned long)vcpu->run);
 }
@@ -598,25 +599,38 @@ void set_cr8(struct kvm_vcpu *vcpu, unsigned long cr8)
 		inject_gp(vcpu);
 		return;
 	}
-	vcpu->cr8 = cr8;
+	if (irqchip_in_kernel(vcpu->kvm))
+		kvm_lapic_set_tpr(vcpu, cr8);
+	else
+		vcpu->cr8 = cr8;
 }
 EXPORT_SYMBOL_GPL(set_cr8);
 
 unsigned long get_cr8(struct kvm_vcpu *vcpu)
 {
-	return vcpu->cr8;
+	if (irqchip_in_kernel(vcpu->kvm))
+		return kvm_lapic_get_cr8(vcpu);
+	else
+		return vcpu->cr8;
 }
 EXPORT_SYMBOL_GPL(get_cr8);
 
 u64 kvm_get_apic_base(struct kvm_vcpu *vcpu)
 {
-	return vcpu->apic_base;
+	if (irqchip_in_kernel(vcpu->kvm))
+		return vcpu->apic_base;
+	else
+		return vcpu->apic_base;
 }
 EXPORT_SYMBOL_GPL(kvm_get_apic_base);
 
 void kvm_set_apic_base(struct kvm_vcpu *vcpu, u64 data)
 {
-	vcpu->apic_base = data;
+	/* TODO: reserve bits check */
+	if (irqchip_in_kernel(vcpu->kvm))
+		kvm_lapic_set_base(vcpu, data);
+	else
+		vcpu->apic_base = data;
 }
 EXPORT_SYMBOL_GPL(kvm_set_apic_base);
 
@@ -986,15 +1000,31 @@ static int emulator_write_std(unsigned long addr,
 	return X86EMUL_UNHANDLEABLE;
 }
 
+/*
+ * Only apic need an MMIO device hook, so shortcut now..
+ */
+static struct kvm_io_device *vcpu_find_pervcpu_dev(struct kvm_vcpu *vcpu,
+						gpa_t addr)
+{
+	struct kvm_io_device *dev;
+
+	if (vcpu->apic) {
+		dev = &vcpu->apic->dev;
+		if (dev->in_range(dev, addr))
+			return dev;
+	}
+	return NULL;
+}
+
 static struct kvm_io_device *vcpu_find_mmio_dev(struct kvm_vcpu *vcpu,
 						gpa_t addr)
 {
-	/*
-	 * Note that its important to have this wrapper function because
-	 * in the very near future we will be checking for MMIOs against
-	 * the LAPIC as well as the general MMIO bus
-	 */
-	return kvm_io_bus_find_dev(&vcpu->kvm->mmio_bus, addr);
+	struct kvm_io_device *dev;
+
+	dev = vcpu_find_pervcpu_dev(vcpu, addr);
+	if (dev == NULL)
+		dev = kvm_io_bus_find_dev(&vcpu->kvm->mmio_bus, addr);
+	return dev;
 }
 
 static struct kvm_io_device *vcpu_find_pio_dev(struct kvm_vcpu *vcpu,
@@ -2256,6 +2286,8 @@ static int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu,
 {
 	if (irq->irq < 0 || irq->irq >= 256)
 		return -EINVAL;
+	if (irqchip_in_kernel(vcpu->kvm))
+		return -ENXIO;
 	vcpu_load(vcpu);
 
 	set_bit(irq->irq, vcpu->irq_pending);
diff --git a/drivers/kvm/lapic.c b/drivers/kvm/lapic.c
new file mode 100644
index 0000000..4b5c77d
--- /dev/null
+++ b/drivers/kvm/lapic.c
@@ -0,0 +1,933 @@
+
+/*
+ * Local APIC virtualization
+ *
+ * Copyright (C) 2006 Qumranet, Inc.
+ * Copyright (C) 2007 Novell
+ * Copyright (C) 2007 Intel
+ *
+ * Authors:
+ *   Dor Laor <dor.laor@qumranet.com>
+ *   Gregory Haskins <ghaskins@novell.com>
+ *   Yaozu (Eddie) Dong <eddie.dong@intel.com>
+ *
+ * Based on Xen 3.1 code, Copyright (c) 2004, Intel Corporation.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ */
+
+#include "kvm.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/module.h>
+#include <asm/processor.h>
+#include <asm/msr.h>
+#include <asm/page.h>
+#include <asm/current.h>
+#include <asm/apicdef.h>
+#include <asm/atomic.h>
+#include <asm/div64.h>
+#include "irq.h"
+
+#define PRId64 "d"
+#define PRIx64 "llx"
+#define PRIu64 "u"
+#define PRIo64 "o"
+
+#define APIC_BUS_CYCLE_NS 1
+
+/* #define apic_debug(fmt,arg...) printk(KERN_WARNING fmt,##arg) */
+#define apic_debug(fmt, arg...)
+
+#define APIC_LVT_NUM			6
+/* 14 is the version for Xeon and Pentium 8.4.8*/
+#define APIC_VERSION			(0x14UL | ((APIC_LVT_NUM - 1) << 16))
+#define LAPIC_MMIO_LENGTH		(1 << 12)
+/* followed define is not in apicdef.h */
+#define APIC_SHORT_MASK			0xc0000
+#define APIC_DEST_NOSHORT		0x0
+#define APIC_DEST_MASK			0x800
+#define MAX_APIC_VECTOR			256
+
+#define VEC_POS(v) ((v) & (32 - 1))
+#define REG_POS(v) (((v) >> 5) << 4)
+static inline u32 apic_get_reg(struct kvm_lapic *apic, int reg_off)
+{
+	return *((u32 *) (apic->regs + reg_off));
+}
+
+static inline void apic_set_reg(struct kvm_lapic *apic, int reg_off, u32 val)
+{
+	*((u32 *) (apic->regs + reg_off)) = val;
+}
+
+static inline int apic_test_and_set_vector(int vec, void *bitmap)
+{
+	return test_and_set_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
+}
+
+static inline int apic_test_and_clear_vector(int vec, void *bitmap)
+{
+	return test_and_clear_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
+}
+
+static inline void apic_set_vector(int vec, void *bitmap)
+{
+	set_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
+}
+
+static inline void apic_clear_vector(int vec, void *bitmap)
+{
+	clear_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
+}
+
+static inline int apic_hw_enabled(struct kvm_lapic *apic)
+{
+	return (apic)->vcpu->apic_base & MSR_IA32_APICBASE_ENABLE;
+}
+
+static inline int  apic_sw_enabled(struct kvm_lapic *apic)
+{
+	return apic_get_reg(apic, APIC_SPIV) & APIC_SPIV_APIC_ENABLED;
+}
+
+static inline int apic_enabled(struct kvm_lapic *apic)
+{
+	return apic_sw_enabled(apic) &&	apic_hw_enabled(apic);
+}
+
+#define LVT_MASK	\
+	(APIC_LVT_MASKED | APIC_SEND_PENDING | APIC_VECTOR_MASK)
+
+#define LINT_MASK	\
+	(LVT_MASK | APIC_MODE_MASK | APIC_INPUT_POLARITY | \
+	 APIC_LVT_REMOTE_IRR | APIC_LVT_LEVEL_TRIGGER)
+
+static inline int kvm_apic_id(struct kvm_lapic *apic)
+{
+	return (apic_get_reg(apic, APIC_ID) >> 24) & 0xff;
+}
+
+static inline int apic_lvt_enabled(struct kvm_lapic *apic, int lvt_type)
+{
+	return !(apic_get_reg(apic, lvt_type) & APIC_LVT_MASKED);
+}
+
+static inline int apic_lvt_vector(struct kvm_lapic *apic, int lvt_type)
+{
+	return apic_get_reg(apic, lvt_type) & APIC_VECTOR_MASK;
+}
+
+static inline int apic_lvtt_period(struct kvm_lapic *apic)
+{
+	return apic_get_reg(apic, APIC_LVTT) & APIC_LVT_TIMER_PERIODIC;
+}
+
+static unsigned int apic_lvt_mask[APIC_LVT_NUM] = {
+	LVT_MASK | APIC_LVT_TIMER_PERIODIC,	/* LVTT */
+	LVT_MASK | APIC_MODE_MASK,	/* LVTTHMR */
+	LVT_MASK | APIC_MODE_MASK,	/* LVTPC */
+	LINT_MASK, LINT_MASK,	/* LVT0-1 */
+	LVT_MASK		/* LVTERR */
+};
+
+static int find_highest_vector(void *bitmap)
+{
+	u32 *word = bitmap;
+	int word_offset = MAX_APIC_VECTOR >> 5;
+
+	while ((word_offset != 0) && (word[(--word_offset) << 2] == 0))
+		continue;
+
+	if (likely(!word_offset && !word[0]))
+		return -1;
+	else
+		return fls(word[word_offset << 2]) - 1 + (word_offset << 5);
+}
+
+static inline int apic_test_and_set_irr(int vec, struct kvm_lapic *apic)
+{
+	return apic_test_and_set_vector(vec, apic->regs + APIC_IRR);
+}
+
+static inline void apic_clear_irr(int vec, struct kvm_lapic *apic)
+{
+	apic_clear_vector(vec, apic->regs + APIC_IRR);
+}
+
+static inline int apic_find_highest_irr(struct kvm_lapic *apic)
+{
+	int result;
+
+	result = find_highest_vector(apic->regs + APIC_IRR);
+	ASSERT(result == -1 || result >= 16);
+
+	return result;
+}
+
+int kvm_apic_set_irq(struct kvm_lapic *apic, u8 vec, u8 trig)
+{
+	if (!apic_test_and_set_irr(vec, apic)) {
+		/* a new pending irq is set in IRR */
+		if (trig)
+			apic_set_vector(vec, apic->regs + APIC_TMR);
+		else
+			apic_clear_vector(vec, apic->regs + APIC_TMR);
+		kvm_vcpu_kick(apic->vcpu);
+		return 1;
+	}
+	return 0;
+}
+
+static inline int apic_find_highest_isr(struct kvm_lapic *apic)
+{
+	int result;
+
+	result = find_highest_vector(apic->regs + APIC_ISR);
+	ASSERT(result == -1 || result >= 16);
+
+	return result;
+}
+
+static void apic_update_ppr(struct kvm_lapic *apic)
+{
+	u32 tpr, isrv, ppr;
+	int isr;
+
+	tpr = apic_get_reg(apic, APIC_TASKPRI);
+	isr = apic_find_highest_isr(apic);
+	isrv = (isr != -1) ? isr : 0;
+
+	if ((tpr & 0xf0) >= (isrv & 0xf0))
+		ppr = tpr & 0xff;
+	else
+		ppr = isrv & 0xf0;
+
+	apic_debug("vlapic %p, ppr 0x%x, isr 0x%x, isrv 0x%x",
+		   apic, ppr, isr, isrv);
+
+	apic_set_reg(apic, APIC_PROCPRI, ppr);
+}
+
+static void apic_set_tpr(struct kvm_lapic *apic, u32 tpr)
+{
+	apic_set_reg(apic, APIC_TASKPRI, tpr);
+	apic_update_ppr(apic);
+}
+
+int kvm_apic_match_physical_addr(struct kvm_lapic *apic, u16 dest)
+{
+	return kvm_apic_id(apic) == dest;
+}
+
+int kvm_apic_match_logical_addr(struct kvm_lapic *apic, u8 mda)
+{
+	int result = 0;
+	u8 logical_id;
+
+	logical_id = GET_APIC_LOGICAL_ID(apic_get_reg(apic, APIC_LDR));
+
+	switch (apic_get_reg(apic, APIC_DFR)) {
+	case APIC_DFR_FLAT:
+		if (logical_id & mda)
+			result = 1;
+		break;
+	case APIC_DFR_CLUSTER:
+		if (((logical_id >> 4) == (mda >> 0x4))
+		    && (logical_id & mda & 0xf))
+			result = 1;
+		break;
+	default:
+		printk(KERN_WARNING "Bad DFR vcpu %d: %08x\n",
+		       apic->vcpu->vcpu_id, apic_get_reg(apic, APIC_DFR));
+		break;
+	}
+
+	return result;
+}
+
+static int apic_match_dest(struct kvm_vcpu *vcpu, struct kvm_lapic *source,
+			   int short_hand, int dest, int dest_mode)
+{
+	int result = 0;
+	struct kvm_lapic *target = vcpu->apic;
+
+	apic_debug("target %p, source %p, dest 0x%x, "
+		   "dest_mode 0x%x, short_hand 0x%x",
+		   target, source, dest, dest_mode, short_hand);
+
+	ASSERT(!target);
+	switch (short_hand) {
+	case APIC_DEST_NOSHORT:
+		if (dest_mode == 0) {
+			/* Physical mode. */
+			if ((dest == 0xFF) || (dest == kvm_apic_id(target)))
+				result = 1;
+		} else
+			/* Logical mode. */
+			result = kvm_apic_match_logical_addr(target, dest);
+		break;
+	case APIC_DEST_SELF:
+		if (target == source)
+			result = 1;
+		break;
+	case APIC_DEST_ALLINC:
+		result = 1;
+		break;
+	case APIC_DEST_ALLBUT:
+		if (target != source)
+			result = 1;
+		break;
+	default:
+		printk(KERN_WARNING "Bad dest shorthand value %x\n",
+		       short_hand);
+		break;
+	}
+
+	return result;
+}
+
+/*
+ * Add a pending IRQ into lapic.
+ * Return 1 if successfully added and 0 if discarded.
+ */
+static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
+			     int vector, int level, int trig_mode)
+{
+	int result = 0;
+
+	switch (delivery_mode) {
+	case APIC_DM_FIXED:
+	case APIC_DM_LOWEST:
+		/* FIXME add logic for vcpu on reset */
+		if (unlikely(!apic_enabled(apic)))
+			break;
+
+		if (apic_test_and_set_irr(vector, apic) && trig_mode) {
+			apic_debug("level trig mode repeatedly for vector %d",
+				   vector);
+			break;
+		}
+
+		if (trig_mode) {
+			apic_debug("level trig mode for vector %d", vector);
+			apic_set_vector(vector, apic->regs + APIC_TMR);
+		} else
+			apic_clear_vector(vector, apic->regs + APIC_TMR);
+
+		kvm_vcpu_kick(apic->vcpu);
+
+		result = 1;
+		break;
+
+	case APIC_DM_REMRD:
+		printk(KERN_DEBUG "Ignoring delivery mode 3\n");
+		break;
+
+	case APIC_DM_SMI:
+		printk(KERN_DEBUG "Ignoring guest SMI\n");
+		break;
+	case APIC_DM_NMI:
+		printk(KERN_DEBUG "Ignoring guest NMI\n");
+		break;
+
+	case APIC_DM_INIT:
+		printk(KERN_DEBUG "Ignoring guest INIT\n");
+		break;
+
+	case APIC_DM_STARTUP:
+		printk(KERN_DEBUG "Ignoring guest STARTUP\n");
+		break;
+
+	default:
+		printk(KERN_ERR "TODO: unsupported delivery mode %x\n",
+		       delivery_mode);
+		break;
+	}
+	return result;
+}
+
+struct kvm_lapic *kvm_apic_round_robin(struct kvm *kvm, u8 vector,
+				       unsigned long bitmap)
+{
+	int vcpu_id;
+
+	/* TODO for real round robin */
+	vcpu_id = fls(bitmap) - 1;
+	if (vcpu_id < 0)
+		printk(KERN_DEBUG "vcpu not ready for apic_round_robin\n");
+	return kvm->vcpus[vcpu_id]->apic;
+}
+
+static void apic_set_eoi(struct kvm_lapic *apic)
+{
+	int vector = apic_find_highest_isr(apic);
+
+	/*
+	 * Not every write EOI will has corresponding ISR,
+	 * one example is when Kernel check timer on setup_IO_APIC
+	 */
+	if (vector == -1)
+		return;
+
+	apic_clear_vector(vector, apic->regs + APIC_ISR);
+	apic_update_ppr(apic);
+
+	if (apic_test_and_clear_vector(vector, apic->regs + APIC_TMR))
+		kvm_ioapic_update_eoi(apic->vcpu->kvm, vector);
+}
+
+static void apic_send_ipi(struct kvm_lapic *apic)
+{
+	u32 icr_low = apic_get_reg(apic, APIC_ICR);
+	u32 icr_high = apic_get_reg(apic, APIC_ICR2);
+
+	unsigned int dest = GET_APIC_DEST_FIELD(icr_high);
+	unsigned int short_hand = icr_low & APIC_SHORT_MASK;
+	unsigned int trig_mode = icr_low & APIC_INT_LEVELTRIG;
+	unsigned int level = icr_low & APIC_INT_ASSERT;
+	unsigned int dest_mode = icr_low & APIC_DEST_MASK;
+	unsigned int delivery_mode = icr_low & APIC_MODE_MASK;
+	unsigned int vector = icr_low & APIC_VECTOR_MASK;
+
+	struct kvm_lapic *target;
+	struct kvm_vcpu *vcpu;
+	unsigned long lpr_map = 0;
+	int i;
+
+	apic_debug("icr_high 0x%x, icr_low 0x%x, "
+		   "short_hand 0x%x, dest 0x%x, trig_mode 0x%x, level 0x%x, "
+		   "dest_mode 0x%x, delivery_mode 0x%x, vector 0x%x\n",
+		   icr_high, icr_low, short_hand, dest,
+		   trig_mode, level, dest_mode, delivery_mode, vector);
+
+	for (i = 0; i < KVM_MAX_VCPUS; i++) {
+		vcpu = apic->vcpu->kvm->vcpus[i];
+		if (!vcpu)
+			continue;
+
+		if (vcpu->apic &&
+		    apic_match_dest(vcpu, apic, short_hand, dest, dest_mode)) {
+			if (delivery_mode == APIC_DM_LOWEST)
+				set_bit(vcpu->vcpu_id, &lpr_map);
+			else
+				__apic_accept_irq(vcpu->apic, delivery_mode,
+						  vector, level, trig_mode);
+		}
+	}
+
+	if (delivery_mode == APIC_DM_LOWEST) {
+		target = kvm_apic_round_robin(vcpu->kvm, vector, lpr_map);
+		if (target != NULL)
+			__apic_accept_irq(target, delivery_mode,
+					  vector, level, trig_mode);
+	}
+}
+
+static u32 apic_get_tmcct(struct kvm_lapic *apic)
+{
+	u32 counter_passed;
+	ktime_t passed, now = apic->timer.dev.base->get_time();
+	u32 tmcct = apic_get_reg(apic, APIC_TMICT);
+
+	ASSERT(apic != NULL);
+
+	if (unlikely(ktime_to_ns(now) <=
+		ktime_to_ns(apic->timer.last_update))) {
+		/* Wrap around */
+		passed = ktime_add(( {
+				    (ktime_t) {
+				    .tv64 = KTIME_MAX -
+				    (apic->timer.last_update).tv64}; }
+				   ), now);
+		apic_debug("time elapsed\n");
+	} else
+		passed = ktime_sub(now, apic->timer.last_update);
+
+	counter_passed = div64_64(ktime_to_ns(passed),
+				  (APIC_BUS_CYCLE_NS * apic->timer.divide_count));
+	tmcct -= counter_passed;
+
+	if (tmcct <= 0) {
+		if (unlikely(!apic_lvtt_period(apic)))
+			tmcct = 0;
+		else
+			do {
+				tmcct += apic_get_reg(apic, APIC_TMICT);
+			} while (tmcct <= 0);
+	}
+
+	return tmcct;
+}
+
+static u32 __apic_read(struct kvm_lapic *apic, unsigned int offset)
+{
+	u32 val = 0;
+
+	if (offset >= LAPIC_MMIO_LENGTH)
+		return 0;
+
+	switch (offset) {
+	case APIC_ARBPRI:
+		printk(KERN_WARNING "Access APIC ARBPRI register "
+		       "which is for P6\n");
+		break;
+
+	case APIC_TMCCT:	/* Timer CCR */
+		val = apic_get_tmcct(apic);
+		break;
+
+	default:
+		val = apic_get_reg(apic, offset);
+		break;
+	}
+
+	return val;
+}
+
+static void apic_mmio_read(struct kvm_io_device *this,
+			   gpa_t address, int len, void *data)
+{
+	struct kvm_lapic *apic = (struct kvm_lapic *)this->private;
+	unsigned int offset = address - apic->base_address;
+	unsigned char alignment = offset & 0xf;
+	u32 result;
+
+	if ((alignment + len) > 4) {
+		printk(KERN_ERR "KVM_APIC_READ: alignment error %lx %d",
+		       (unsigned long)address, len);
+		return;
+	}
+	result = __apic_read(apic, offset & ~0xf);
+
+	switch (len) {
+	case 1:
+	case 2:
+	case 4:
+		memcpy(data, (char *)&result + alignment, len);
+		break;
+	default:
+		printk(KERN_ERR "Local APIC read with len = %x, "
+		       "should be 1,2, or 4 instead\n", len);
+		break;
+	}
+}
+
+static void update_divide_count(struct kvm_lapic *apic)
+{
+	u32 tmp1, tmp2, tdcr;
+
+	tdcr = apic_get_reg(apic, APIC_TDCR);
+	tmp1 = tdcr & 0xf;
+	tmp2 = ((tmp1 & 0x3) | ((tmp1 & 0x8) >> 1)) + 1;
+	apic->timer.divide_count = 0x1 << (tmp2 & 0x7);
+
+	apic_debug("timer divide count is 0x%x\n",
+				   apic->timer.divide_count);
+}
+
+static void start_apic_timer(struct kvm_lapic *apic)
+{
+	ktime_t now = apic->timer.dev.base->get_time();
+
+	apic->timer.last_update = now;
+
+	apic->timer.period = apic_get_reg(apic, APIC_TMICT) *
+		    APIC_BUS_CYCLE_NS * apic->timer.divide_count;
+	atomic_set(&apic->timer.pending, 0);
+	hrtimer_start(&apic->timer.dev,
+		      ktime_add_ns(now, apic->timer.period),
+		      HRTIMER_MODE_ABS);
+
+	apic_debug("%s: bus cycle is %" PRId64 "ns, now 0x%016"
+			   PRIx64 ", "
+			   "timer initial count 0x%x, period %lldns, "
+			   "expire @ 0x%016" PRIx64 ".\n", __FUNCTION__,
+			   APIC_BUS_CYCLE_NS, ktime_to_ns(now),
+			   apic_get_reg(apic, APIC_TMICT),
+			   apic->timer.period,
+			   ktime_to_ns(ktime_add_ns(now,
+					apic->timer.period)));
+}
+
+static void apic_mmio_write(struct kvm_io_device *this,
+			    gpa_t address, int len, const void *data)
+{
+	struct kvm_lapic *apic = (struct kvm_lapic *)this->private;
+	unsigned int offset = address - apic->base_address;
+	unsigned char alignment = offset & 0xf;
+	u32 val;
+
+	/*
+	 * APIC register must be aligned on 128-bits boundary.
+	 * 32/64/128 bits registers must be accessed thru 32 bits.
+	 * Refer SDM 8.4.1
+	 */
+	if (len != 4 || alignment) {
+		if (printk_ratelimit())
+			printk(KERN_ERR "apic write: bad size=%d %lx\n",
+			       len, (long)address);
+		return;
+	}
+
+	val = *(u32 *) data;
+
+	/* too common printing */
+	if (offset != APIC_EOI)
+		apic_debug("%s: offset 0x%x with length 0x%x, and value is "
+			   "0x%x\n", __FUNCTION__, offset, len, val);
+
+	offset &= 0xff0;
+
+	switch (offset) {
+	case APIC_ID:		/* Local APIC ID */
+		apic_set_reg(apic, APIC_ID, val);
+		break;
+
+	case APIC_TASKPRI:
+		apic_set_tpr(apic, val & 0xff);
+		break;
+
+	case APIC_EOI:
+		apic_set_eoi(apic);
+		break;
+
+	case APIC_LDR:
+		apic_set_reg(apic, APIC_LDR, val & APIC_LDR_MASK);
+		break;
+
+	case APIC_DFR:
+		apic_set_reg(apic, APIC_DFR, val | 0x0FFFFFFF);
+		break;
+
+	case APIC_SPIV:
+		apic_set_reg(apic, APIC_SPIV, val & 0x3ff);
+		if (!(val & APIC_SPIV_APIC_ENABLED)) {
+			int i;
+			u32 lvt_val;
+
+			for (i = 0; i < APIC_LVT_NUM; i++) {
+				lvt_val = apic_get_reg(apic,
+						       APIC_LVTT + 0x10 * i);
+				apic_set_reg(apic, APIC_LVTT + 0x10 * i,
+					     lvt_val | APIC_LVT_MASKED);
+			}
+			atomic_set(&apic->timer.pending, 0);
+
+		}
+		break;
+
+	case APIC_ICR:
+		/* No delay here, so we always clear the pending bit */
+		apic_set_reg(apic, APIC_ICR, val & ~(1 << 12));
+		apic_send_ipi(apic);
+		break;
+
+	case APIC_ICR2:
+		apic_set_reg(apic, APIC_ICR2, val & 0xff000000);
+		break;
+
+	case APIC_LVTT:
+	case APIC_LVTTHMR:
+	case APIC_LVTPC:
+	case APIC_LVT0:
+	case APIC_LVT1:
+	case APIC_LVTERR:
+		/* TODO: Check vector */
+		if (!apic_sw_enabled(apic))
+			val |= APIC_LVT_MASKED;
+
+		val &= apic_lvt_mask[(offset - APIC_LVTT) >> 4];
+		apic_set_reg(apic, offset, val);
+
+		break;
+
+	case APIC_TMICT:
+		hrtimer_cancel(&apic->timer.dev);
+		apic_set_reg(apic, APIC_TMICT, val);
+		start_apic_timer(apic);
+		return;
+
+	case APIC_TDCR:
+		if (val & 4)
+			printk(KERN_ERR "KVM_WRITE:TDCR %x\n", val);
+		apic_set_reg(apic, APIC_TDCR, val);
+		update_divide_count(apic);
+		break;
+
+	default:
+		apic_debug("Local APIC Write to read-only register %x\n",
+			   offset);
+		break;
+	}
+
+}
+
+static int apic_mmio_range(struct kvm_io_device *this, gpa_t addr)
+{
+	struct kvm_lapic *apic = (struct kvm_lapic *)this->private;
+	int ret = 0;
+
+
+	if (apic_hw_enabled(apic) &&
+	    (addr >= apic->base_address) &&
+	    (addr < (apic->base_address + LAPIC_MMIO_LENGTH)))
+		ret = 1;
+
+	return ret;
+}
+
+void kvm_free_apic(struct kvm_lapic *apic)
+{
+	if (!apic)
+		return;
+
+	hrtimer_cancel(&apic->timer.dev);
+
+	if (apic->regs_page) {
+		__free_page(apic->regs_page);
+		apic->regs_page = 0;
+	}
+
+	kfree(apic);
+}
+
+/*
+ *----------------------------------------------------------------------
+ * LAPIC interface
+ *----------------------------------------------------------------------
+ */
+
+void kvm_lapic_set_tpr(struct kvm_vcpu *vcpu, unsigned long cr8)
+{
+	struct kvm_lapic *apic = (struct kvm_lapic *)vcpu->apic;
+
+	if (!apic)
+		return;
+	apic_set_tpr(apic, ((cr8 & 0x0f) << 4));
+}
+
+u64 kvm_lapic_get_cr8(struct kvm_vcpu *vcpu)
+{
+	struct kvm_lapic *apic = (struct kvm_lapic *)vcpu->apic;
+	u64 tpr;
+
+	if (!apic)
+		return 0;
+	tpr = (u64) apic_get_reg(apic, APIC_TASKPRI);
+
+	return (tpr & 0xf0) >> 4;
+}
+
+void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value)
+{
+	struct kvm_lapic *apic = (struct kvm_lapic *)vcpu->apic;
+
+	if (!apic) {
+		value |= MSR_IA32_APICBASE_BSP;
+		vcpu->apic_base = value;
+		return;
+	}
+	if (apic->vcpu->vcpu_id)
+		value &= ~MSR_IA32_APICBASE_BSP;
+
+	vcpu->apic_base = value;
+	apic->base_address = apic->vcpu->apic_base &
+			     MSR_IA32_APICBASE_BASE;
+
+	/* with FSB delivery interrupt, we can restart APIC functionality */
+	apic_debug("apic base msr is 0x%016" PRIx64 ", and base address is "
+		   "0x%lx.\n", apic->apic_base, apic->base_address);
+
+}
+
+u64 kvm_lapic_get_base(struct kvm_vcpu *vcpu)
+{
+	return vcpu->apic_base;
+}
+EXPORT_SYMBOL_GPL(kvm_lapic_get_base);
+
+static void lapic_reset(struct kvm_vcpu *vcpu)
+{
+	struct kvm_lapic *apic;
+	int i;
+
+	apic_debug("%s\n", __FUNCTION__);
+
+	ASSERT(vcpu);
+	apic = vcpu->apic;
+	ASSERT(apic != NULL);
+
+	/* Stop the timer in case it's a reset to an active apic */
+	hrtimer_cancel(&apic->timer.dev);
+
+	apic_set_reg(apic, APIC_ID, vcpu->vcpu_id << 24);
+	apic_set_reg(apic, APIC_LVR, APIC_VERSION);
+
+	for (i = 0; i < APIC_LVT_NUM; i++)
+		apic_set_reg(apic, APIC_LVTT + 0x10 * i, APIC_LVT_MASKED);
+
+	apic_set_reg(apic, APIC_DFR, 0xffffffffU);
+	apic_set_reg(apic, APIC_SPIV, 0xff);
+	apic_set_reg(apic, APIC_TASKPRI, 0);
+	apic_set_reg(apic, APIC_LDR, 0);
+	apic_set_reg(apic, APIC_ESR, 0);
+	apic_set_reg(apic, APIC_ICR, 0);
+	apic_set_reg(apic, APIC_ICR2, 0);
+	apic_set_reg(apic, APIC_TDCR, 0);
+	apic_set_reg(apic, APIC_TMICT, 0);
+	for (i = 0; i < 8; i++) {
+		apic_set_reg(apic, APIC_IRR + 0x10 * i, 0);
+		apic_set_reg(apic, APIC_ISR + 0x10 * i, 0);
+		apic_set_reg(apic, APIC_TMR + 0x10 * i, 0);
+	}
+	apic->timer.divide_count = 0;
+	atomic_set(&apic->timer.pending, 0);
+	if (vcpu->vcpu_id == 0)
+		vcpu->apic_base |= MSR_IA32_APICBASE_BSP;
+	apic_update_ppr(apic);
+
+	apic_debug(KERN_INFO "%s: vcpu=%p, id=%d, base_msr="
+		   "0x%016" PRIx64 ", base_address=0x%0lx.\n", __FUNCTION__,
+		   vcpu, kvm_apic_id(apic),
+		   vcpu->apic_base, apic->base_address);
+}
+
+int kvm_lapic_enabled(struct kvm_vcpu *vcpu)
+{
+	struct kvm_lapic *apic = (struct kvm_lapic *)vcpu->apic;
+	int ret = 0;
+
+	if (!apic)
+		return 0;
+	ret = apic_enabled(apic);
+
+	return ret;
+}
+
+/*
+ *----------------------------------------------------------------------
+ * timer interface
+ *----------------------------------------------------------------------
+ */
+static int __apic_timer_fn(struct kvm_lapic *apic)
+{
+	u32 vector;
+	int result = 0;
+
+	if (unlikely(!apic_enabled(apic) ||
+		     !apic_lvt_enabled(apic, APIC_LVTT))) {
+		apic_debug("%s: time interrupt although apic is down\n",
+			   __FUNCTION__);
+		return 0;
+	}
+
+	vector = apic_lvt_vector(apic, APIC_LVTT);
+	apic->timer.last_update = apic->timer.dev.expires;
+	atomic_inc(&apic->timer.pending);
+	__apic_accept_irq(apic, APIC_DM_FIXED, vector, 1, 0);
+
+	if (apic_lvtt_period(apic)) {
+		u32 offset;
+		u32 tmict = apic_get_reg(apic, APIC_TMICT);
+
+		offset = APIC_BUS_CYCLE_NS * apic->timer.divide_count * tmict;
+
+		result = 1;
+		apic->timer.dev.expires = ktime_add_ns(
+					apic->timer.dev.expires,
+					apic->timer.period);
+	}
+
+	return result;
+}
+
+static enum hrtimer_restart apic_timer_fn(struct hrtimer *data)
+{
+	struct kvm_lapic *apic;
+	int restart_timer = 0;
+
+	apic = container_of(data, struct kvm_lapic, timer.dev);
+
+	restart_timer = __apic_timer_fn(apic);
+
+	if (restart_timer)
+		return HRTIMER_RESTART;
+	else
+		return HRTIMER_NORESTART;
+}
+
+int kvm_create_lapic(struct kvm_vcpu *vcpu)
+{
+	struct kvm_lapic *apic;
+
+	ASSERT(vcpu != NULL);
+	apic_debug("apic_init %d\n", vcpu->vcpu_id);
+
+	apic = kzalloc(sizeof(*apic), GFP_KERNEL);
+	if (!apic)
+		goto nomem;
+
+	vcpu->apic = apic;
+
+	apic->regs_page = alloc_page(GFP_KERNEL);
+	if (apic->regs_page == NULL) {
+		printk(KERN_ERR "malloc apic regs error for vcpu %x\n",
+		       vcpu->vcpu_id);
+		goto nomem;
+	}
+	apic->regs = page_address(apic->regs_page);
+	memset(apic->regs, 0, PAGE_SIZE);
+	apic->vcpu = vcpu;
+
+	hrtimer_init(&apic->timer.dev, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+	apic->timer.dev.function = apic_timer_fn;
+	apic->base_address = APIC_DEFAULT_PHYS_BASE;
+	vcpu->apic_base = APIC_DEFAULT_PHYS_BASE;
+
+	lapic_reset(vcpu);
+	apic->dev.read = apic_mmio_read;
+	apic->dev.write = apic_mmio_write;
+	apic->dev.in_range = apic_mmio_range;
+	apic->dev.private = apic;
+
+	return 0;
+nomem:
+	kvm_free_apic(apic);
+	return -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(kvm_create_lapic);
+
+int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu)
+{
+	struct kvm_lapic *apic = vcpu->apic;
+	int highest_irr;
+
+	if (!apic || !apic_enabled(apic))
+		return -1;
+
+	highest_irr = apic_find_highest_irr(apic);
+	if ((highest_irr == -1) ||
+	    ((highest_irr & 0xF0) <= apic_get_reg(apic, APIC_PROCPRI)))
+		return -1;
+	return highest_irr;
+}
+
+int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu)
+{
+	int vector = kvm_apic_has_interrupt(vcpu);
+	struct kvm_lapic *apic = vcpu->apic;
+
+	if (vector == -1)
+		return -1;
+
+	apic_set_vector(vector, apic->regs + APIC_ISR);
+	apic_update_ppr(apic);
+	apic_clear_irr(vector, apic);
+	return vector;
+}
diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index 57525e7..d576451 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -573,6 +573,12 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id)
 	if (err)
 		goto free_svm;
 
+	if (irqchip_in_kernel(kvm)) {
+		err = kvm_create_lapic(&svm->vcpu);
+		if (err < 0)
+			goto free_svm;
+	}
+
 	page = alloc_page(GFP_KERNEL);
 	if (!page) {
 		err = -ENOMEM;
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 19676b5..c4cc17c 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -2390,6 +2390,12 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
 	if (err)
 		goto free_vcpu;
 
+	if (irqchip_in_kernel(kvm)) {
+		err = kvm_create_lapic(&vmx->vcpu);
+		if (err < 0)
+			goto free_vcpu;
+	}
+
 	vmx->guest_msrs = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!vmx->guest_msrs) {
 		err = -ENOMEM;