KVM: In-kernel PIT model

From af5d9ee2a189c2f0998c5c46d1fcd25c5cb72f8c Mon Sep 17 00:00:00 2001
From: Sheng Yang <[email protected]>
Date: Mon, 28 Jan 2008 05:10:22 +0800
Subject: [PATCH] KVM: In-kernel PIT model

The patch moved PIT from userspace to kernel, and increase the timer accuracy greatly.

---
 arch/x86/kvm/Makefile      |    3 +-
 arch/x86/kvm/i8254.c       |  589 
++++++++++++++++++++++++++++++++++++++++++++
 arch/x86/kvm/i8254.h       |   62 +++++
 arch/x86/kvm/irq.c         |    3 +
 arch/x86/kvm/x86.c         |    9 +
 include/asm-x86/kvm_host.h |    1 +
 include/linux/kvm.h        |    2 +
 7 files changed, 668 insertions(+), 1 deletions(-)
 create mode 100644 arch/x86/kvm/i8254.c
 create mode 100644 arch/x86/kvm/i8254.h

index ffdd0b3..4d0c22e 100644
@@ -6,7 +6,8 @@ common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o 

ioapic.o)

EXTRA_CFLAGS += -Ivirt/kvm -Iarch/x86/kvm

-kvm-objs := $(common-objs) x86.o mmu.o x86_emulate.o i8259.o irq.o lapic.o +kvm-objs := $(common-objs) x86.o mmu.o x86_emulate.o i8259.o irq.o lapic.o \
+ i8254.o
obj-$(CONFIG_KVM) += kvm.o
kvm-intel-objs = vmx.o
obj-$(CONFIG_KVM_INTEL) += kvm-intel.o

new file mode 100644
index 0000000..73b8240
@@ -0,0 +1,589 @@
+/*
+ * 8253/8254 interval timer emulation
+ *
+ * Copyright (c) 2003-2004 Fabrice Bellard
+ * Copyright (c) 2006 Intel Corporation
+ * Copyright (c) 2007 Keir Fraser, XenSource Inc
+ * Copyright (c) 2008 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a 

copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * Authors:
+ * Sheng Yang <[email protected]>
+ * Based on QEMU and Xen.
+ */
+
+#include <linux/kvm_host.h>
+
+#include "i8254.h"
+
+#if 0
+#define pit_debug(fmt, arg...) printk(KERN_WARNING fmt, ##arg) +#else
+#define pit_debug(fmt, arg...)
+#endif
+
+#ifndef CONFIG_X86_64
+#define mod_64(x, y) ((x) - (y) * div64_64(x, y))
+#else
+#define mod_64(x, y) ((x) % (y))
+#endif
+
+#define RW_STATE_LSB 1
+#define RW_STATE_MSB 2
+#define RW_STATE_WORD0 3
+#define RW_STATE_WORD1 4
+
+/* Compute with 96 bit intermediate result: (a*b)/c */
+static u64 muldiv64(u64 a, u32 b, u32 c)
+{
+ union {
+ u64 ll;
+ struct {
+#ifdef WORDS_BIGENDIAN
+ u32 high, low;
+#else
+ u32 low, high;
+#endif
+ } l;
+ } u, res;
+ u64 rl, rh;
+
+ u.ll = a;
+ rl = (u64)u.l.low * (u64)b;
+ rh = (u64)u.l.high * (u64)b;
+ rh += (rl >> 32);
+ res.l.high = div64_64(rh, c);
+ res.l.low = div64_64(((mod_64(rh, c) << 32) + (rl & 0xffffffff)), c);
+ return res.ll;
+}
+
+static void pit_set_gate(struct kvm *kvm, int channel, u32 val) +{
+ struct pit_channel_state *c =
+ &kvm->arch.vpit->pit_state.channels[channel];
+
+ ASSERT(mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
+
+ switch (c->mode) {
+ default:
+ case 0:
+ case 4:
+ /* XXX: just disable/enable counting */
+ break;
+ case 1:
+ case 2:
+ case 3:
+ case 5:
+ /* Restart counting on rising edge. */
+ if (c->gate < val)
+ c->count_load_time = ktime_get();
+ break;
+ }
+
+ c->gate = val;
+}
+
+int pit_get_gate(struct kvm *kvm, int channel)
+{
+ ASSERT(mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
+
+ return kvm->arch.vpit->pit_state.channels[channel].gate;
+}
+
+static int pit_get_count(struct kvm *kvm, int channel)
+{
+ struct pit_channel_state *c =
+ &kvm->arch.vpit->pit_state.channels[channel];
+ s64 d, t;
+ int counter;
+
+ ASSERT(mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
+
+ t = ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));
+ d = muldiv64(t, PIT_FREQ, 1e9);
+
+ switch (c->mode) {
+ case 0:
+ case 1:
+ case 4:
+ case 5:
+ counter = (c->count - d) & 0xffff;
+ break;
+ case 3:
+ /* XXX: may be incorrect for odd counts */
+ counter = c->count - (mod_64((2 * d), c->count));
+ break;
+ default:
+ counter = c->count - mod_64(d, c->count);
+ break;
+ }
+ return counter;
+}
+
+static int pit_get_out(struct kvm *kvm, int channel)
+{
+ struct pit_channel_state *c =
+ &kvm->arch.vpit->pit_state.channels[channel];
+ s64 d, t;
+ int out;
+
+ ASSERT(mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
+
+ t = ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));
+ d = muldiv64(t, PIT_FREQ, 1e9);
+
+ switch (c->mode) {
+ default:
+ case 0:
+ out = (d >= c->count);
+ break;
+ case 1:
+ out = (d < c->count);
+ break;
+ case 2:
+ out = ((mod_64(d, c->count) == 0) && (d != 0));
+ break;
+ case 3:
+ out = (mod_64(d, c->count) < ((c->count + 1) >> 1));
+ break;
+ case 4:
+ case 5:
+ out = (d == c->count);
+ break;
+ }
+
+ return out;
+}
+
+static void pit_latch_count(struct kvm *kvm, int channel)
+{
+ struct pit_channel_state *c =
+ &kvm->arch.vpit->pit_state.channels[channel];
+
+ ASSERT(mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
+
+ if (!c->count_latched) {
+ c->latched_count = pit_get_count(kvm, channel);
+ c->count_latched = c->rw_mode;
+ }
+}
+
+static void pit_latch_status(struct kvm *kvm, int channel)
+{
+ struct pit_channel_state *c =
+ &kvm->arch.vpit->pit_state.channels[channel];
+
+ ASSERT(mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
+
+ if (!c->status_latched) {
+ /* TODO: Return NULL COUNT (bit 6). */
+ c->status = ((pit_get_out(kvm, channel) << 7) |
+ (c->rw_mode << 4) |
+ (c->mode << 1) |
+ c->bcd);
+ c->status_latched = 1;
+ }
+}
+
+int __pit_timer_fn(struct pit_channel_state *pc)
+{
+ struct pit_timer *pt = &pc->pit_timer;
+ struct kvm_vcpu *vcpu0 = pc->pit_state->pit->kvm->vcpus[0];
+
+ atomic_inc(&pt->pending);
+ if (vcpu0 && waitqueue_active(&vcpu0->wq)) {
+ vcpu0->arch.mp_state = VCPU_MP_STATE_RUNNABLE;
+ wake_up_interruptible(&vcpu0->wq);
+ }
+
+ pt->timer.expires = ktime_add_ns(pt->timer.expires, pt->period);
+ pt->scheduled = ktime_to_ns(pt->timer.expires);
+
+ return (pt->period == 0 ? 0 : 1);
+}
+
+static enum hrtimer_restart pit_timer_fn(struct hrtimer *data) +{
+ struct pit_channel_state *pc;
+ int restart_timer = 0;
+
+ pc = container_of(data, struct pit_channel_state, pit_timer.timer);
+
+ restart_timer = __pit_timer_fn(pc);
+
+ if (restart_timer)
+ return HRTIMER_RESTART;
+ else
+ return HRTIMER_NORESTART;
+}
+
+static void destroy_pit_timer(struct pit_channel_state *s)
+{
+ pit_debug("pit: execute del timer!\n");
+ hrtimer_cancel(&s->pit_timer.timer);
+}
+
+static void create_pit_timer(struct pit_channel_state *pc,
+ u32 val, int is_period)
+{
+ s64 interval;
+
+ interval = muldiv64(val, 1e9, PIT_FREQ);
+
+ pit_debug("pit: create pit timer, interval is %llu nsec\n", interval);
+
+ /* TODO The new value only affected after the retriggered */
+ hrtimer_cancel(&pc->pit_timer.timer);
+ pc->pit_timer.period = (is_period == 0) ? 0 : interval;
+ pc->pit_timer.timer.function = pit_timer_fn;
+ atomic_set(&pc->pit_timer.pending, 0);
+
+ hrtimer_start(&pc->pit_timer.timer, ktime_add_ns(ktime_get(), interval),
+ HRTIMER_MODE_ABS);
+}
+
+static void pit_load_count(struct kvm *kvm, int channel, u32 val) +{
+ struct pit_channel_state *s =
+ &kvm->arch.vpit->pit_state.channels[channel];
+
+ ASSERT(mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
+
+ pit_debug("pit: load_count val is %d, channel is %d\n", val, channel);
+
+ if (val == 0)
+ val = 0x10000;
+
+ s->count_load_time = ktime_get();
+ s->count = val;
+
+ if (channel != 0)
+ return;
+
+ /* Two types of timer
+ * mode 1 is one shot, mode 2 is period, otherwise del timer */
+ switch (s->mode) {
+ case 1:
+ create_pit_timer(s, val, 0);
+ break;
+ case 2:
+ create_pit_timer(s, val, 1);
+ break;
+ default:
+ destroy_pit_timer(s);
+ }
+}
+
+static void pit_ioport_write(struct kvm_io_device *this,
+ gpa_t addr, int len, const void *data)
+{
+ struct kvm_pit *pit = (struct kvm_pit *)this->private;
+ struct pit_state *pit_state = &pit->pit_state;
+ struct kvm *kvm = pit->kvm;
+ int channel, access;
+ struct pit_channel_state *s;
+ u32 val = *(u32 *) data;
+
+ val &= 0xff;
+ addr &= 3;
+
+ mutex_lock(&pit_state->lock);
+
+ if (val != 0)
+ pit_debug("pit: write addr is 0x%x, len is %d, val is 0x%x\n",
+ (unsigned int)addr, len, val);
+
+ if (addr == 3) {
+ channel = val >> 6;
+ if (channel == 3) {
+ /* Read-Back Command. */
+ for (channel = 0; channel < 3; channel++) {
+ s = &pit_state->channels[channel];
+ if (val & (2 << channel)) {
+ if (!(val & 0x20))
+ pit_latch_count(kvm, channel);
+ if (!(val & 0x10))
+ pit_latch_status(kvm, channel);
+ }
+ }
+ } else {
+ /* Select Counter <channel>. */
+ s = &pit_state->channels[channel];
+ access = (val >> 4) & 3;
+ if (access == 0) {
+ pit_latch_count(kvm, channel);
+ } else {
+ s->rw_mode = access;
+ s->read_state = access;
+ s->write_state = access;
+ s->mode = (val >> 1) & 7;
+ if (s->mode > 5)
+ s->mode -= 4;
+ s->bcd = val & 1;
+ }
+ }
+ } else {
+ /* Write Count. */
+ s = &pit_state->channels[addr];
+ switch (s->write_state) {
+ default:
+ case RW_STATE_LSB:
+ pit_load_count(kvm, addr, val);
+ break;
+ case RW_STATE_MSB:
+ pit_load_count(kvm, addr, val << 8);
+ break;
+ case RW_STATE_WORD0:
+ s->write_latch = val;
+ s->write_state = RW_STATE_WORD1;
+ break;
+ case RW_STATE_WORD1:
+ pit_load_count(kvm, addr, s->write_latch | (val << 8));
+ s->write_state = RW_STATE_WORD0;
+ break;
+ }
+ }
+
+ mutex_unlock(&pit_state->lock);
+}
+
+static void pit_ioport_read(struct kvm_io_device *this,
+ gpa_t addr, int len, void *data)
+{
+ struct kvm_pit *pit = (struct kvm_pit *)this->private;
+ struct pit_state *pit_state = &pit->pit_state;
+ struct kvm *kvm = pit->kvm;
+ int ret, count;
+ struct pit_channel_state *s;
+
+ addr &= 3;
+ s = &pit_state->channels[addr];
+
+ mutex_lock(&pit_state->lock);
+
+ if (s->status_latched) {
+ s->status_latched = 0;
+ ret = s->status;
+ } else if (s->count_latched) {
+ switch (s->count_latched) {
+ default:
+ case RW_STATE_LSB:
+ ret = s->latched_count & 0xff;
+ s->count_latched = 0;
+ break;
+ case RW_STATE_MSB:
+ ret = s->latched_count >> 8;
+ s->count_latched = 0;
+ break;
+ case RW_STATE_WORD0:
+ ret = s->latched_count & 0xff;
+ s->count_latched = RW_STATE_MSB;
+ break;
+ }
+ } else {
+ switch (s->read_state) {
+ default:
+ case RW_STATE_LSB:
+ count = pit_get_count(kvm, addr);
+ ret = count & 0xff;
+ break;
+ case RW_STATE_MSB:
+ count = pit_get_count(kvm, addr);
+ ret = (count >> 8) & 0xff;
+ break;
+ case RW_STATE_WORD0:
+ count = pit_get_count(kvm, addr);
+ ret = count & 0xff;
+ s->read_state = RW_STATE_WORD1;
+ break;
+ case RW_STATE_WORD1:
+ count = pit_get_count(kvm, addr);
+ ret = (count >> 8) & 0xff;
+ s->read_state = RW_STATE_WORD0;
+ break;
+ }
+ }
+
+ if (len > sizeof(ret))
+ len = sizeof(ret);
+ memcpy(data, (char *)&ret, len);
+
+ mutex_unlock(&pit_state->lock);
+}
+
+static int pit_in_range(struct kvm_io_device *this, gpa_t addr) +{
+ return ((addr >= PIT_BASE_ADDRESS) &&
+ (addr < PIT_BASE_ADDRESS + PIT_MEM_LENGTH));
+}
+
+static void speaker_ioport_write(struct kvm_io_device *this,
+ gpa_t addr, int len, const void *data)
+{
+ struct kvm_pit *pit = (struct kvm_pit *)this->private;
+ struct pit_state *pit_state = &pit->pit_state;
+ struct kvm *kvm = pit->kvm;
+ u32 val = *(u32 *) data;
+
+ mutex_lock(&pit_state->lock);
+ pit_state->speaker_data_on = (val >> 1) & 1;
+ pit_set_gate(kvm, 2, val & 1);
+ mutex_unlock(&pit_state->lock);
+}
+
+static void speaker_ioport_read(struct kvm_io_device *this,
+ gpa_t addr, int len, void *data)
+{
+ struct kvm_pit *pit = (struct kvm_pit *)this->private;
+ struct pit_state *pit_state = &pit->pit_state;
+ struct kvm *kvm = pit->kvm;
+ unsigned int refresh_clock;
+ int ret;
+
+ /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
+ refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
+
+ mutex_lock(&pit_state->lock);
+ ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
+ (pit_get_out(kvm, 2) << 5) | (refresh_clock << 4));
+ if (len > sizeof(ret))
+ len = sizeof(ret);
+ memcpy(data, (char *)&ret, len);
+ mutex_unlock(&pit_state->lock);
+}
+
+static int speaker_in_range(struct kvm_io_device *this, gpa_t addr) +{
+ return (addr == SPEAKER_BASE_ADDRESS);
+}
+
+struct kvm_pit *kvm_create_pit(struct kvm *kvm)
+{
+ int i;
+ struct kvm_pit *pit;
+ struct pit_state *pit_state;
+ struct pit_channel_state *c;
+
+ pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
+ if (!pit)
+ return NULL;
+
+ mutex_init(&pit->pit_state.lock);
+ mutex_lock(&pit->pit_state.lock);
+
+ /* Initialize PIO device */
+ pit->dev.read = pit_ioport_read;
+ pit->dev.write = pit_ioport_write;
+ pit->dev.in_range = pit_in_range;
+ pit->dev.private = pit;
+ kvm_io_bus_register_dev(&kvm->pio_bus, &pit->dev);
+
+ pit->speaker_dev.read = speaker_ioport_read;
+ pit->speaker_dev.write = speaker_ioport_write;
+ pit->speaker_dev.in_range = speaker_in_range;
+ pit->speaker_dev.private = pit;
+ kvm_io_bus_register_dev(&kvm->pio_bus, &pit->speaker_dev);
+
+ kvm->arch.vpit = pit;
+ pit->kvm = kvm;
+
+ pit_state = &pit->pit_state;
+ pit_state->pit = pit;
+ hrtimer_init(&pit_state->channels[0].pit_timer.timer,
+ CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+ atomic_set(&pit_state->channels[0].pit_timer.pending, 0);
+ for (i = 0; i < 3; i++) {
+ c = &pit_state->channels[i];
+ c->pit_state = pit_state;
+ c->mode = 0xff;
+ c->gate = (i != 2);
+ pit_load_count(kvm, i, 0);
+ }
+
+ mutex_unlock(&pit->pit_state.lock);
+
+ atomic_set(&pit->inject_pending, 1);
+
+ return pit;
+}
+
+void kvm_free_pit(struct kvm *kvm)
+{
+ struct hrtimer *timer;
+
+ if (kvm->arch.vpit) {
+ mutex_lock(&kvm->arch.vpit->pit_state.lock);
+ timer = &kvm->arch.vpit->pit_state.channels[0].pit_timer.timer;
+ hrtimer_cancel(timer);
+ mutex_unlock(&kvm->arch.vpit->pit_state.lock);
+ kfree(kvm->arch.vpit);
+ }
+}
+
+void __inject_pit_timer_intr(struct kvm *kvm)
+{
+ mutex_lock(&kvm->lock);
+ kvm_ioapic_set_irq(kvm->arch.vioapic, 0, 1);
+ kvm_ioapic_set_irq(kvm->arch.vioapic, 0, 0);
+ kvm_pic_set_irq(pic_irqchip(kvm), 0, 1);
+ kvm_pic_set_irq(pic_irqchip(kvm), 0, 0);
+ mutex_unlock(&kvm->lock);
+}
+
+void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu)
+{
+ struct kvm_pit *pit = vcpu->kvm->arch.vpit;
+ struct kvm *kvm = vcpu->kvm;
+ struct pit_channel_state *pc;
+ static unsigned long last_injected_time;
+
+ if (vcpu && pit) {
+ pc = &pit->pit_state.channels[0];
+ /* Try to inject pending interrupts when:
+ * 1. Pending exists
+ * 2. Last interrupt was accepted or waited for too long time */
+ if (atomic_read(&pc->pit_timer.pending) &&
+ (atomic_read(&pit->inject_pending) ||
+ (jiffies - last_injected_time >= MAX_PIT_INTR_INTERVAL))) {
+ atomic_set(&pit->inject_pending, 0);
+ __inject_pit_timer_intr(kvm);
+ last_injected_time = jiffies;
+ }
+ }
+}
+
+void kvm_pit_timer_intr_post(struct kvm_vcpu *vcpu, int vec)
+{
+ struct kvm_arch *arch = &vcpu->kvm->arch;
+ struct pit_channel_state *pc;
+
+ if (vcpu && arch->vpit) {
+ pc = &arch->vpit->pit_state.channels[0];
+ if (atomic_read(&pc->pit_timer.pending) &&
+ (((arch->vpic->pics[0].imr & 1) == 0 &&

+		  arch->vpic->pics[0].irq_base == vec) ||
+		  (arch->vioapic->redirtbl[0].fields.vector == vec &&
+		  arch->vioapic->redirtbl[0].fields.mask != 1))) {

+ atomic_set(&arch->vpit->inject_pending, 1);
+ atomic_dec(&pc->pit_timer.pending);
+ pc->count_load_time = ktime_get();
+ }
+ }
+}

index e571475..dbfe21c 100644
@@ -23,6 +23,7 @@
 #include <linux/kvm_host.h>
 
 #include "irq.h"
+#include "i8254.h"
 
 /*
  * check if there is pending interrupt without

@@ -66,6 +67,7 @@ EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
 void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
 {
 	kvm_inject_apic_timer_irqs(vcpu);
+	kvm_inject_pit_timer_irqs(vcpu);
 	/* TODO: PIT, RTC etc. */
 }
 EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs);

@@ -73,6 +75,7 @@ EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs);
 void kvm_timer_intr_post(struct kvm_vcpu *vcpu, int vec)
 {
 	kvm_apic_timer_intr_post(vcpu, vec);
+	kvm_pit_timer_intr_post(vcpu, vec);
 	/* TODO: PIT, RTC etc. */
 }
 EXPORT_SYMBOL_GPL(kvm_timer_intr_post);

index 8f94a0b..0993fad 100644
@@ -18,6 +18,7 @@
 #include "segment_descriptor.h"
 #include "irq.h"
 #include "mmu.h"
+#include "i8254.h"
 
 #include <linux/kvm.h>
 #include <linux/fs.h>

@@ -680,6 +681,7 @@ int kvm_dev_ioctl_check_extension(long ext)
 	case KVM_CAP_USER_MEMORY:
 	case KVM_CAP_SET_TSS_ADDR:
 	case KVM_CAP_EXT_CPUID:
+	case KVM_CAP_PIT:
 		r = 1;
 		break;
 	case KVM_CAP_VAPIC:

@@ -1432,6 +1434,12 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		} else
 			goto out;
 		break;
+	case KVM_CREATE_PIT:
+		r = -ENOMEM;
+		kvm->arch.vpit = kvm_create_pit(kvm);
+		if (kvm->arch.vpit)
+			r = 0;
+		break;
 	case KVM_IRQ_LINE: {
 		struct kvm_irq_level irq_event;
 

@@ -3207,6 +3215,7 @@ static void kvm_free_vcpus(struct kvm *kvm)
 
 void kvm_arch_destroy_vm(struct kvm *kvm)
 {
+	kvm_free_pit(kvm);
 	kfree(kvm->arch.vpic);
 	kfree(kvm->arch.vioapic);
 	kvm_free_vcpus(kvm);

index 67ae307..80b0bfc 100644
@@ -283,6 +283,7 @@ struct kvm_arch{
 	struct list_head active_mmu_pages;
 	struct kvm_pic *vpic;
 	struct kvm_ioapic *vioapic;
+	struct kvm_pit *vpit;
 
 	int round_robin_prev_vcpu;
 	unsigned int tss_addr;

index 4de4fd2..2f18cfe 100644
@@ -232,6 +232,7 @@ struct kvm_vapic_addr {
 #define KVM_CAP_SET_TSS_ADDR 4
 #define KVM_CAP_EXT_CPUID 5
 #define KVM_CAP_VAPIC 6
+#define KVM_CAP_PIT 7
 
 /*
  * ioctls for VM fds

@@ -255,6 +256,7 @@ struct kvm_vapic_addr {
 #define KVM_IRQ_LINE		  _IOW(KVMIO, 0x61, struct kvm_irq_level)
 #define KVM_GET_IRQCHIP		  _IOWR(KVMIO, 0x62, struct kvm_irqchip)
 #define KVM_SET_IRQCHIP		  _IOR(KVMIO,  0x63, struct kvm_irqchip)
+#define KVM_CREATE_PIT		  _IO(KVMIO,  0x64)
 
 /*
  * ioctls for vcpu fds

--
debian.1.5.3.7.1-dirty

From af5d9ee2a189c2f0998c5c46d1fcd25c5cb72f8c Mon Sep 17 00:00:00 2001
From: Sheng Yang <[email protected]>
Date: Mon, 28 Jan 2008 05:10:22 +0800
Subject: [PATCH] KVM: In-kernel PIT model

The patch moved PIT from userspace to kernel, and increase the timer accuracy greatly.

---
 arch/x86/kvm/Makefile      |    3 +-
 arch/x86/kvm/i8254.c       |  589 ++++++++++++++++++++++++++++++++++++++++++++
 arch/x86/kvm/i8254.h       |   62 +++++
 arch/x86/kvm/irq.c         |    3 +
 arch/x86/kvm/x86.c         |    9 +
 include/asm-x86/kvm_host.h |    1 +
 include/linux/kvm.h        |    2 +
 7 files changed, 668 insertions(+), 1 deletions(-)
 create mode 100644 arch/x86/kvm/i8254.c
 create mode 100644 arch/x86/kvm/i8254.h

index ffdd0b3..4d0c22e 100644
@@ -6,7 +6,8 @@ common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o ioapic.o)
 
 EXTRA_CFLAGS += -Ivirt/kvm -Iarch/x86/kvm
 
-kvm-objs := $(common-objs) x86.o mmu.o x86_emulate.o i8259.o irq.o lapic.o
+kvm-objs := $(common-objs) x86.o mmu.o x86_emulate.o i8259.o irq.o lapic.o \
+	i8254.o
 obj-$(CONFIG_KVM) += kvm.o
 kvm-intel-objs = vmx.o
 obj-$(CONFIG_KVM_INTEL) += kvm-intel.o

index e571475..dbfe21c 100644
@@ -23,6 +23,7 @@
 #include <linux/kvm_host.h>
 
 #include "irq.h"
+#include "i8254.h"
 
 /*
  * check if there is pending interrupt without

@@ -66,6 +67,7 @@ EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
 void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
 {
 	kvm_inject_apic_timer_irqs(vcpu);
+	kvm_inject_pit_timer_irqs(vcpu);
 	/* TODO: PIT, RTC etc. */
 }
 EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs);

@@ -73,6 +75,7 @@ EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs);
 void kvm_timer_intr_post(struct kvm_vcpu *vcpu, int vec)
 {
 	kvm_apic_timer_intr_post(vcpu, vec);
+	kvm_pit_timer_intr_post(vcpu, vec);
 	/* TODO: PIT, RTC etc. */
 }
 EXPORT_SYMBOL_GPL(kvm_timer_intr_post);

index 8f94a0b..0993fad 100644
@@ -18,6 +18,7 @@
 #include "segment_descriptor.h"
 #include "irq.h"
 #include "mmu.h"
+#include "i8254.h"
 
 #include <linux/kvm.h>
 #include <linux/fs.h>

@@ -680,6 +681,7 @@ int kvm_dev_ioctl_check_extension(long ext)
 	case KVM_CAP_USER_MEMORY:
 	case KVM_CAP_SET_TSS_ADDR:
 	case KVM_CAP_EXT_CPUID:
+	case KVM_CAP_PIT:
 		r = 1;
 		break;
 	case KVM_CAP_VAPIC:

@@ -1432,6 +1434,12 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		} else
 			goto out;
 		break;
+	case KVM_CREATE_PIT:
+		r = -ENOMEM;
+		kvm->arch.vpit = kvm_create_pit(kvm);
+		if (kvm->arch.vpit)
+			r = 0;
+		break;
 	case KVM_IRQ_LINE: {
 		struct kvm_irq_level irq_event;
 

@@ -3207,6 +3215,7 @@ static void kvm_free_vcpus(struct kvm *kvm)
 
 void kvm_arch_destroy_vm(struct kvm *kvm)
 {
+	kvm_free_pit(kvm);
 	kfree(kvm->arch.vpic);
 	kfree(kvm->arch.vioapic);
 	kvm_free_vcpus(kvm);

index 67ae307..80b0bfc 100644
@@ -283,6 +283,7 @@ struct kvm_arch{
 	struct list_head active_mmu_pages;
 	struct kvm_pic *vpic;
 	struct kvm_ioapic *vioapic;
+	struct kvm_pit *vpit;
 
 	int round_robin_prev_vcpu;
 	unsigned int tss_addr;

index 4de4fd2..2f18cfe 100644
@@ -232,6 +232,7 @@ struct kvm_vapic_addr {
 #define KVM_CAP_SET_TSS_ADDR 4
 #define KVM_CAP_EXT_CPUID 5
 #define KVM_CAP_VAPIC 6
+#define KVM_CAP_PIT 7
 
 /*
  * ioctls for VM fds

@@ -255,6 +256,7 @@ struct kvm_vapic_addr {
 #define KVM_IRQ_LINE		  _IOW(KVMIO, 0x61, struct kvm_irq_level)
 #define KVM_GET_IRQCHIP		  _IOWR(KVMIO, 0x62, struct kvm_irqchip)
 #define KVM_SET_IRQCHIP		  _IOR(KVMIO,  0x63, struct kvm_irqchip)
+#define KVM_CREATE_PIT		  _IO(KVMIO,  0x64)
 
 /*
  * ioctls for vcpu fds

debian.1.5.3.7.1-dirty

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