From 7837699fa6d7adf81f26ab73a5f6897ea1ab9d6a Mon Sep 17 00:00:00 2001 From: Sheng Yang Date: Mon, 28 Jan 2008 05:10:22 +0800 Subject: KVM: In kernel PIT model The patch moves the PIT model from userspace to kernel, and increases the timer accuracy greatly. [marcelo: make last_injected_time per-guest] Signed-off-by: Sheng Yang Signed-off-by: Marcelo Tosatti Tested-and-Acked-by: Alex Davis Signed-off-by: Avi Kivity --- arch/x86/kvm/i8254.c | 586 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 586 insertions(+) create mode 100644 arch/x86/kvm/i8254.c (limited to 'arch/x86/kvm/i8254.c') diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c new file mode 100644 index 000000000000..c7435093bbee --- /dev/null +++ b/arch/x86/kvm/i8254.c @@ -0,0 +1,586 @@ +/* + * 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 + * Based on QEMU and Xen. + */ + +#include + +#include "irq.h" +#include "i8254.h" + +#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 { + u32 low, high; + } 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 kvm_kpit_channel_state *c = + &kvm->arch.vpit->pit_state.channels[channel]; + + WARN_ON(!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) +{ + WARN_ON(!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 kvm_kpit_channel_state *c = + &kvm->arch.vpit->pit_state.channels[channel]; + s64 d, t; + int counter; + + WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock)); + + t = ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time)); + d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC); + + 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 kvm_kpit_channel_state *c = + &kvm->arch.vpit->pit_state.channels[channel]; + s64 d, t; + int out; + + WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock)); + + t = ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time)); + d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC); + + 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 kvm_kpit_channel_state *c = + &kvm->arch.vpit->pit_state.channels[channel]; + + WARN_ON(!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 kvm_kpit_channel_state *c = + &kvm->arch.vpit->pit_state.channels[channel]; + + WARN_ON(!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 kvm_kpit_state *ps) +{ + struct kvm_vcpu *vcpu0 = ps->pit->kvm->vcpus[0]; + struct kvm_kpit_timer *pt = &ps->pit_timer; + + atomic_inc(&pt->pending); + smp_mb__after_atomic_inc(); + /* FIXME: handle case where the guest is in guest mode */ + 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 kvm_kpit_state *ps; + int restart_timer = 0; + + ps = container_of(data, struct kvm_kpit_state, pit_timer.timer); + + restart_timer = __pit_timer_fn(ps); + + if (restart_timer) + return HRTIMER_RESTART; + else + return HRTIMER_NORESTART; +} + +static void destroy_pit_timer(struct kvm_kpit_timer *pt) +{ + pr_debug("pit: execute del timer!\n"); + hrtimer_cancel(&pt->timer); +} + +static void create_pit_timer(struct kvm_kpit_timer *pt, u32 val, int is_period) +{ + s64 interval; + + interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ); + + pr_debug("pit: create pit timer, interval is %llu nsec\n", interval); + + /* TODO The new value only affected after the retriggered */ + hrtimer_cancel(&pt->timer); + pt->period = (is_period == 0) ? 0 : interval; + pt->timer.function = pit_timer_fn; + atomic_set(&pt->pending, 0); + + hrtimer_start(&pt->timer, ktime_add_ns(ktime_get(), interval), + HRTIMER_MODE_ABS); +} + +static void pit_load_count(struct kvm *kvm, int channel, u32 val) +{ + struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state; + + WARN_ON(!mutex_is_locked(&ps->lock)); + + pr_debug("pit: load_count val is %d, channel is %d\n", val, channel); + + /* + * Though spec said the state of 8254 is undefined after power-up, + * seems some tricky OS like Windows XP depends on IRQ0 interrupt + * when booting up. + * So here setting initialize rate for it, and not a specific number + */ + if (val == 0) + val = 0x10000; + + ps->channels[channel].count_load_time = ktime_get(); + ps->channels[channel].count = val; + + if (channel != 0) + return; + + /* Two types of timer + * mode 1 is one shot, mode 2 is period, otherwise del timer */ + switch (ps->channels[0].mode) { + case 1: + create_pit_timer(&ps->pit_timer, val, 0); + break; + case 2: + create_pit_timer(&ps->pit_timer, val, 1); + break; + default: + destroy_pit_timer(&ps->pit_timer); + } +} + +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 kvm_kpit_state *pit_state = &pit->pit_state; + struct kvm *kvm = pit->kvm; + int channel, access; + struct kvm_kpit_channel_state *s; + u32 val = *(u32 *) data; + + val &= 0xff; + addr &= KVM_PIT_CHANNEL_MASK; + + mutex_lock(&pit_state->lock); + + if (val != 0) + pr_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 . */ + s = &pit_state->channels[channel]; + access = (val >> 4) & KVM_PIT_CHANNEL_MASK; + 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 kvm_kpit_state *pit_state = &pit->pit_state; + struct kvm *kvm = pit->kvm; + int ret, count; + struct kvm_kpit_channel_state *s; + + addr &= KVM_PIT_CHANNEL_MASK; + 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 >= KVM_PIT_BASE_ADDRESS) && + (addr < KVM_PIT_BASE_ADDRESS + KVM_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 kvm_kpit_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 kvm_kpit_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 == KVM_SPEAKER_BASE_ADDRESS); +} + +struct kvm_pit *kvm_create_pit(struct kvm *kvm) +{ + int i; + struct kvm_pit *pit; + struct kvm_kpit_state *pit_state; + struct kvm_kpit_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->pit_timer.timer, + CLOCK_MONOTONIC, HRTIMER_MODE_ABS); + atomic_set(&pit_state->pit_timer.pending, 0); + for (i = 0; i < 3; i++) { + c = &pit_state->channels[i]; + c->mode = 0xff; + c->gate = (i != 2); + pit_load_count(kvm, i, 0); + } + + mutex_unlock(&pit->pit_state.lock); + + pit->pit_state.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.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 kvm_kpit_state *ps; + + if (vcpu && pit) { + ps = &pit->pit_state; + + /* Try to inject pending interrupts when: + * 1. Pending exists + * 2. Last interrupt was accepted or waited for too long time*/ + if (atomic_read(&ps->pit_timer.pending) && + (ps->inject_pending || + (jiffies - ps->last_injected_time + >= KVM_MAX_PIT_INTR_INTERVAL))) { + ps->inject_pending = 0; + __inject_pit_timer_intr(kvm); + ps->last_injected_time = jiffies; + } + } +} + +void kvm_pit_timer_intr_post(struct kvm_vcpu *vcpu, int vec) +{ + struct kvm_arch *arch = &vcpu->kvm->arch; + struct kvm_kpit_state *ps; + + if (vcpu && arch->vpit) { + ps = &arch->vpit->pit_state; + if (atomic_read(&ps->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))) { + ps->inject_pending = 1; + atomic_dec(&ps->pit_timer.pending); + ps->channels[0].count_load_time = ktime_get(); + } + } +} -- cgit v1.2.3