KVM: In-kernel PIT model

From 56a50952929f9a7e78fc3ec812dd4550c623b956 Mon Sep 17 00:00:00 2001
From: Sheng Yang <[email protected]>
Date: Mon, 21 Jan 2008 16:42:37 +0800
Subject: [PATCH] KVM: In-kernel PIT model

---
 arch/x86/kvm/Makefile      |    3 +-
 arch/x86/kvm/i8254.c       |  589 
++++++++++++++++++++++++++++++++++++++++++++
 arch/x86/kvm/i8254.h       |   60 +++++
 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, 666 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..f5b53a5
@@ -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]>
+ * Port from QEMU and Xen.
+ */
+
+#include <linux/kvm_host.h>
+
+#include "i8254.h"
+
+#define pit_debug(fmt, arg...) printk(KERN_WARNING fmt, ##arg) +/* #define pit_debug(fmt, arg...) */
+
+#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 PITChannelState *c =
+ &kvm->arch.vpit->pit_state.channels[channel];
+ struct kvm_vcpu *vcpu = kvm->vcpus[0];
+
+ 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)
+ kvm_get_msr(vcpu, MSR_IA32_TIME_STAMP_COUNTER,
+ &c->count_load_time);
+ 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 PITChannelState *c =
+ &kvm->arch.vpit->pit_state.channels[channel];
+ struct kvm_vcpu *vcpu = kvm->vcpus[0];
+ u64 d, t;
+ int counter;
+
+ ASSERT(mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
+
+ kvm_get_msr(vcpu, MSR_IA32_TIME_STAMP_COUNTER, &t);
+ d = muldiv64(t - c->count_load_time, PIT_FREQ, cpu_khz * 1000);
+
+ 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 PITChannelState *c =
+ &kvm->arch.vpit->pit_state.channels[channel];
+ struct kvm_vcpu *vcpu = kvm->vcpus[0];
+ u64 d, t;
+ int out;
+
+ ASSERT(mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
+
+ kvm_get_msr(vcpu, MSR_IA32_TIME_STAMP_COUNTER, &t);
+ d = muldiv64(t - c->count_load_time, PIT_FREQ, cpu_khz * 1000);
+
+ 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 PITChannelState *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 PITChannelState *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 PITChannelState *pc)
+{
+ struct PITTimer *pt = &pc->pit_timer;
+ struct kvm_vcpu *vcpu0 = pc->pit_state->pit->kvm->vcpus[0];
+
+ atomic_inc(&pt->pending);
+ if (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 PITChannelState *pc;
+ int restart_timer = 0;
+
+ pc = container_of(data, struct PITChannelState, 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 PITChannelState *s)
+{
+ pit_debug("pit: execute del timer!\n");
+ hrtimer_cancel(&s->pit_timer.timer);
+}
+
+static void create_pit_timer(struct PITChannelState *pc, u32 val, int is_period)
+{
+ s64 interval;
+ ktime_t now = pc->pit_timer.timer.base->get_time();
+
+ interval = muldiv64(val, 1e9, PIT_FREQ);
+
+ pit_debug("pit: create pit timer, interval is %llu\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(now, interval),
+ HRTIMER_MODE_ABS);
+}
+
+static void pit_load_count(struct kvm *kvm, int channel, u32 val) +{
+ u64 t;
+ struct PITChannelState *s =
+ &kvm->arch.vpit->pit_state.channels[channel];
+ struct kvm_vcpu *vcpu = kvm->vcpus[0];
+
+ 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;
+
+ if (vcpu == NULL) {
+ pit_debug("pit: load host tsc instead of guest\n");
+ rdtscll(t);
+ } else
+ kvm_get_msr(vcpu, MSR_IA32_TIME_STAMP_COUNTER, &t);
+ s->count_load_time = t;
+ 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 PITState *pit_state = &pit->pit_state;
+ struct kvm *kvm = pit->kvm;
+ int channel, access;
+ struct PITChannelState *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 PITState *pit_state = &pit->pit_state;
+ struct kvm *kvm = pit->kvm;
+ int ret, count;
+ struct PITChannelState *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 PITState *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 PITState *pit_state = &pit->pit_state;
+ struct kvm *kvm = pit->kvm;
+ struct kvm_vcpu *vcpu = kvm->vcpus[0];
+ unsigned int refresh_clock;
+ int ret;
+ u64 t;
+
+ kvm_get_msr(vcpu, MSR_IA32_TIME_STAMP_COUNTER, &t);
+ refresh_clock = ((unsigned int)t >> 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 PITState *pit_state;
+ struct PITChannelState *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);
+
+ 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);
+ }
+}
+
+int __inject_pit_timer_irq(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);
+
+ return 1;
+}
+
+void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu)
+{
+ struct kvm_pit *pit = vcpu->kvm->arch.vpit;
+ struct PITChannelState *pc;
+
+ if (pit) {
+ pc = &pit->pit_state.channels[0];
+ if (atomic_read(&pc->pit_timer.pending))
+ __inject_pit_timer_irq(vcpu->kvm);
+ }
+}
+
+void kvm_pit_timer_intr_post(struct kvm_vcpu *vcpu, int vec)
+{
+ struct kvm_pit *pit = vcpu->kvm->arch.vpit;
+ struct PITChannelState *pc;
+
+ if (pit) {
+ pc = &pit->pit_state.channels[0];
+ if (atomic_read(&pc->pit_timer.pending) &&
+ (((vcpu->kvm->arch.vpic->pics[0].imr & 1) == 0 &&
+ vcpu->kvm->arch.vpic->pics[0].irq_base == vec) ||
+ vcpu->kvm->arch.vioapic->redirtbl[0].fields.vector == vec)) {
+ atomic_dec(&pc->pit_timer.pending);
+ kvm_get_msr(vcpu, MSR_IA32_TIME_STAMP_COUNTER,
+ &pc->count_load_time);
+ }
+ }
+}

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 d6db0de..66dbdd5 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 56a50952929f9a7e78fc3ec812dd4550c623b956 Mon Sep 17 00:00:00 2001
From: Sheng Yang <[email protected]>
Date: Mon, 21 Jan 2008 16:42:37 +0800
Subject: [PATCH] KVM: In-kernel PIT model

---
 arch/x86/kvm/Makefile      |    3 +-
 arch/x86/kvm/i8254.c       |  589 ++++++++++++++++++++++++++++++++++++++++++++
 arch/x86/kvm/i8254.h       |   60 +++++
 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, 666 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 d6db0de..66dbdd5 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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Certainly an ioctl() to configure the PIT can be added. I think that we can leave that to a later patch though.

error compiling committee.c: too many arguments to function


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I would rather stuff these parameters into KVM_CREATE_PIT right from the beginning than later breaking the kernel/user ABI or adding a clumsy KVM_CREATE_PIT_SPECIAL_EXTENDED_VERSION. :->

Jan

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Binary compatibility is only guaranteed between released kernel versions; development versions might have changes.

error compiling committee.c: too many arguments to function


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It should also not be common among all archs. On s390 we have CPU timer, which is way superior to PIT (clock cycle granularity, no vmexit to set it up or deliver the irq, no hypervisor support needed because it works transparent).

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Yeah, I also checked IA64 side, and it didn't got PIT too. So I put it in x86 directory.

Thanks
Yang, Sheng

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The direct reason is we using TSC as the reference of pit count_load_time. I think the only alternative is using host ACPI PM timer. But it will wrapped soon...

I think the cpu frequency scaling will affect TSC, though cpu_khz would be changed along with it.

I don't think so. kvm_get_msr() with TSC only read guest tsc, which is indentity for the domain, not specific for vcpu. And I indicated vcpu0 as vcpu(though won't be refered). But I may do it more clear in the future.

Sure.

Thanks
Yang, Sheng

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It breaks the calculation, though.

I suggest moving to the Linux clock API (which is in nanoseconds).

guest_read_tsc() uses vmcs_readl() which implicitly refers to the current vcpu. So you don't actually read vcpu0 tsc.

error compiling committee.c: too many arguments to function


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I updated patch using ktime_get() (Is it too heavy?).

And currently all the muldiv64() is used to divide 1e9, which can be insteaded by ">> 30" approximately. What's your opinion?

But I found just now that the patch would break SMP on pae host(guest hang, so does the old one)... Don't got clue...

--
From f61536abab1d4821c027b9645655c717a90093e7 Mon Sep 17 00:00:00 2001
From: Sheng Yang <[email protected]>
Date: Mon, 21 Jan 2008 16:42:37 +0800
Subject: [PATCH] KVM: In-kernel PIT model

---
 arch/x86/kvm/Makefile      |    3 +-
 arch/x86/kvm/i8254.c       |  575 
++++++++++++++++++++++++++++++++++++++++++++
 arch/x86/kvm/i8254.h       |   60 +++++
 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, 652 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..4f1a54a
@@ -0,0 +1,575 @@
+/*
+ * 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"
+
+#define pit_debug(fmt, arg...) printk(KERN_WARNING fmt, ##arg) +/* #define pit_debug(fmt, arg...) */
+
+#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 (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;
+ ktime_t now = pc->pit_timer.timer.base->get_time();
+
+ interval = muldiv64(val, 1e9, PIT_FREQ);
+
+ pit_debug("pit: create pit timer, interval is %llu usec\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(now, 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);
+
+ 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);
+ }
+}
+
+int __inject_pit_timer_irq(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);
+
+ return 1;
+}
+
+void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu)
+{
+ struct kvm_pit *pit = vcpu->kvm->arch.vpit;
+ struct pit_channel_state *pc;
+
+ if (pit) {
+ pc = &pit->pit_state.channels[0];
+ if (atomic_read(&pc->pit_timer.pending))
+ __inject_pit_timer_irq(vcpu->kvm);
+ }
+}
+
+void kvm_pit_timer_intr_post(struct kvm_vcpu *vcpu, int vec)
+{
+ struct kvm_pit *pit = vcpu->kvm->arch.vpit;
+ struct pit_channel_state *pc;
+
+ if (pit) {
+ pc = &pit->pit_state.channels[0];
+ if (atomic_read(&pc->pit_timer.pending) &&
+ (((vcpu->kvm->arch.vpic->pics[0].imr & 1) == 0 &&
+ vcpu->kvm->arch.vpic->pics[0].irq_base == vec) ||
+ vcpu->kvm->arch.vioapic->redirtbl[0].fields.vector == vec)) {
+ 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 d6db0de..66dbdd5 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 f61536abab1d4821c027b9645655c717a90093e7 Mon Sep 17 00:00:00 2001
From: Sheng Yang <[email protected]>
Date: Mon, 21 Jan 2008 16:42:37 +0800
Subject: [PATCH] KVM: In-kernel PIT model

---
 arch/x86/kvm/Makefile      |    3 +-
 arch/x86/kvm/i8254.c       |  575 ++++++++++++++++++++++++++++++++++++++++++++
 arch/x86/kvm/i8254.h       |   60 +++++
 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, 652 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 d6db0de..66dbdd5 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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Shouldn't be. At least on modern hosts.

Accuracy is more important. And modern processors eat 64-bit divides for breakfast, they're certainly much less expensive than vmexits.

Any sufficiently difficult bug is indistinguishable from a feature.


-------------------------------------------------------------------------
This SF.net email is sponsored by: Microsoft
Defy all challenges. Microsoft(R) Visual Studio 2008.
http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/