diff options
Diffstat (limited to 'arch/x86/kvm/i8254.c')
| -rw-r--r-- | arch/x86/kvm/i8254.c | 748 |
1 files changed, 748 insertions, 0 deletions
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c new file mode 100644 index 000000000..a6e218c61 --- /dev/null +++ b/arch/x86/kvm/i8254.c @@ -0,0 +1,748 @@ +/* + * 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 + * Copyright 2009 Red Hat, Inc. and/or its affiliates. + * + * 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 <sheng.yang@intel.com> + * Based on QEMU and Xen. + */ + +#define pr_fmt(fmt) "pit: " fmt + +#include <linux/kvm_host.h> +#include <linux/slab.h> + +#include "ioapic.h" +#include "irq.h" +#include "i8254.h" +#include "x86.h" + +#ifndef CONFIG_X86_64 +#define mod_64(x, y) ((x) - (y) * div64_u64(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 + +static void pit_set_gate(struct kvm_pit *pit, int channel, u32 val) +{ + struct kvm_kpit_channel_state *c = &pit->pit_state.channels[channel]; + + 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; +} + +static int pit_get_gate(struct kvm_pit *pit, int channel) +{ + return pit->pit_state.channels[channel].gate; +} + +static s64 __kpit_elapsed(struct kvm_pit *pit) +{ + s64 elapsed; + ktime_t remaining; + struct kvm_kpit_state *ps = &pit->pit_state; + + if (!ps->period) + return 0; + + /* + * The Counter does not stop when it reaches zero. In + * Modes 0, 1, 4, and 5 the Counter ``wraps around'' to + * the highest count, either FFFF hex for binary counting + * or 9999 for BCD counting, and continues counting. + * Modes 2 and 3 are periodic; the Counter reloads + * itself with the initial count and continues counting + * from there. + */ + remaining = hrtimer_get_remaining(&ps->timer); + elapsed = ps->period - ktime_to_ns(remaining); + + return elapsed; +} + +static s64 kpit_elapsed(struct kvm_pit *pit, struct kvm_kpit_channel_state *c, + int channel) +{ + if (channel == 0) + return __kpit_elapsed(pit); + + return ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time)); +} + +static int pit_get_count(struct kvm_pit *pit, int channel) +{ + struct kvm_kpit_channel_state *c = &pit->pit_state.channels[channel]; + s64 d, t; + int counter; + + t = kpit_elapsed(pit, c, channel); + d = mul_u64_u32_div(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_pit *pit, int channel) +{ + struct kvm_kpit_channel_state *c = &pit->pit_state.channels[channel]; + s64 d, t; + int out; + + t = kpit_elapsed(pit, c, channel); + d = mul_u64_u32_div(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_pit *pit, int channel) +{ + struct kvm_kpit_channel_state *c = &pit->pit_state.channels[channel]; + + if (!c->count_latched) { + c->latched_count = pit_get_count(pit, channel); + c->count_latched = c->rw_mode; + } +} + +static void pit_latch_status(struct kvm_pit *pit, int channel) +{ + struct kvm_kpit_channel_state *c = &pit->pit_state.channels[channel]; + + if (!c->status_latched) { + /* TODO: Return NULL COUNT (bit 6). */ + c->status = ((pit_get_out(pit, channel) << 7) | + (c->rw_mode << 4) | + (c->mode << 1) | + c->bcd); + c->status_latched = 1; + } +} + +static inline struct kvm_pit *pit_state_to_pit(struct kvm_kpit_state *ps) +{ + return container_of(ps, struct kvm_pit, pit_state); +} + +static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian) +{ + struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state, + irq_ack_notifier); + struct kvm_pit *pit = pit_state_to_pit(ps); + + atomic_set(&ps->irq_ack, 1); + /* irq_ack should be set before pending is read. Order accesses with + * inc(pending) in pit_timer_fn and xchg(irq_ack, 0) in pit_do_work. + */ + smp_mb(); + if (atomic_dec_if_positive(&ps->pending) > 0) + kthread_queue_work(pit->worker, &pit->expired); +} + +void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu) +{ + struct kvm_pit *pit = vcpu->kvm->arch.vpit; + struct hrtimer *timer; + + if (!kvm_vcpu_is_bsp(vcpu) || !pit) + return; + + timer = &pit->pit_state.timer; + mutex_lock(&pit->pit_state.lock); + if (hrtimer_cancel(timer)) + hrtimer_start_expires(timer, HRTIMER_MODE_ABS); + mutex_unlock(&pit->pit_state.lock); +} + +static void destroy_pit_timer(struct kvm_pit *pit) +{ + hrtimer_cancel(&pit->pit_state.timer); + kthread_flush_work(&pit->expired); +} + +static void pit_do_work(struct kthread_work *work) +{ + struct kvm_pit *pit = container_of(work, struct kvm_pit, expired); + struct kvm *kvm = pit->kvm; + struct kvm_vcpu *vcpu; + int i; + struct kvm_kpit_state *ps = &pit->pit_state; + + if (atomic_read(&ps->reinject) && !atomic_xchg(&ps->irq_ack, 0)) + return; + + kvm_set_irq(kvm, pit->irq_source_id, 0, 1, false); + kvm_set_irq(kvm, pit->irq_source_id, 0, 0, false); + + /* + * Provides NMI watchdog support via Virtual Wire mode. + * The route is: PIT -> LVT0 in NMI mode. + * + * Note: Our Virtual Wire implementation does not follow + * the MP specification. We propagate a PIT interrupt to all + * VCPUs and only when LVT0 is in NMI mode. The interrupt can + * also be simultaneously delivered through PIC and IOAPIC. + */ + if (atomic_read(&kvm->arch.vapics_in_nmi_mode) > 0) + kvm_for_each_vcpu(i, vcpu, kvm) + kvm_apic_nmi_wd_deliver(vcpu); +} + +static enum hrtimer_restart pit_timer_fn(struct hrtimer *data) +{ + struct kvm_kpit_state *ps = container_of(data, struct kvm_kpit_state, timer); + struct kvm_pit *pt = pit_state_to_pit(ps); + + if (atomic_read(&ps->reinject)) + atomic_inc(&ps->pending); + + kthread_queue_work(pt->worker, &pt->expired); + + if (ps->is_periodic) { + hrtimer_add_expires_ns(&ps->timer, ps->period); + return HRTIMER_RESTART; + } else + return HRTIMER_NORESTART; +} + +static inline void kvm_pit_reset_reinject(struct kvm_pit *pit) +{ + atomic_set(&pit->pit_state.pending, 0); + atomic_set(&pit->pit_state.irq_ack, 1); +} + +void kvm_pit_set_reinject(struct kvm_pit *pit, bool reinject) +{ + struct kvm_kpit_state *ps = &pit->pit_state; + struct kvm *kvm = pit->kvm; + + if (atomic_read(&ps->reinject) == reinject) + return; + + /* + * AMD SVM AVIC accelerates EOI write and does not trap. + * This cause in-kernel PIT re-inject mode to fail + * since it checks ps->irq_ack before kvm_set_irq() + * and relies on the ack notifier to timely queue + * the pt->worker work iterm and reinject the missed tick. + * So, deactivate APICv when PIT is in reinject mode. + */ + if (reinject) { + kvm_request_apicv_update(kvm, false, + APICV_INHIBIT_REASON_PIT_REINJ); + /* The initial state is preserved while ps->reinject == 0. */ + kvm_pit_reset_reinject(pit); + kvm_register_irq_ack_notifier(kvm, &ps->irq_ack_notifier); + kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier); + } else { + kvm_request_apicv_update(kvm, true, + APICV_INHIBIT_REASON_PIT_REINJ); + kvm_unregister_irq_ack_notifier(kvm, &ps->irq_ack_notifier); + kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier); + } + + atomic_set(&ps->reinject, reinject); +} + +static void create_pit_timer(struct kvm_pit *pit, u32 val, int is_period) +{ + struct kvm_kpit_state *ps = &pit->pit_state; + struct kvm *kvm = pit->kvm; + s64 interval; + + if (!ioapic_in_kernel(kvm) || + ps->flags & KVM_PIT_FLAGS_HPET_LEGACY) + return; + + interval = mul_u64_u32_div(val, NSEC_PER_SEC, KVM_PIT_FREQ); + + pr_debug("create pit timer, interval is %llu nsec\n", interval); + + /* TODO The new value only affected after the retriggered */ + hrtimer_cancel(&ps->timer); + kthread_flush_work(&pit->expired); + ps->period = interval; + ps->is_periodic = is_period; + + kvm_pit_reset_reinject(pit); + + /* + * Do not allow the guest to program periodic timers with small + * interval, since the hrtimers are not throttled by the host + * scheduler. + */ + if (ps->is_periodic) { + s64 min_period = min_timer_period_us * 1000LL; + + if (ps->period < min_period) { + pr_info_ratelimited( + "kvm: requested %lld ns " + "i8254 timer period limited to %lld ns\n", + ps->period, min_period); + ps->period = min_period; + } + } + + hrtimer_start(&ps->timer, ktime_add_ns(ktime_get(), interval), + HRTIMER_MODE_ABS); +} + +static void pit_load_count(struct kvm_pit *pit, int channel, u32 val) +{ + struct kvm_kpit_state *ps = &pit->pit_state; + + pr_debug("load_count val is %u, channel is %d\n", val, channel); + + /* + * The largest possible initial count is 0; this is equivalent + * to 216 for binary counting and 104 for BCD counting. + */ + if (val == 0) + val = 0x10000; + + ps->channels[channel].count = val; + + if (channel != 0) { + ps->channels[channel].count_load_time = ktime_get(); + return; + } + + /* Two types of timer + * mode 1 is one shot, mode 2 is period, otherwise del timer */ + switch (ps->channels[0].mode) { + case 0: + case 1: + /* FIXME: enhance mode 4 precision */ + case 4: + create_pit_timer(pit, val, 0); + break; + case 2: + case 3: + create_pit_timer(pit, val, 1); + break; + default: + destroy_pit_timer(pit); + } +} + +void kvm_pit_load_count(struct kvm_pit *pit, int channel, u32 val, + int hpet_legacy_start) +{ + u8 saved_mode; + + WARN_ON_ONCE(!mutex_is_locked(&pit->pit_state.lock)); + + if (hpet_legacy_start) { + /* save existing mode for later reenablement */ + WARN_ON(channel != 0); + saved_mode = pit->pit_state.channels[0].mode; + pit->pit_state.channels[0].mode = 0xff; /* disable timer */ + pit_load_count(pit, channel, val); + pit->pit_state.channels[0].mode = saved_mode; + } else { + pit_load_count(pit, channel, val); + } +} + +static inline struct kvm_pit *dev_to_pit(struct kvm_io_device *dev) +{ + return container_of(dev, struct kvm_pit, dev); +} + +static inline struct kvm_pit *speaker_to_pit(struct kvm_io_device *dev) +{ + return container_of(dev, struct kvm_pit, speaker_dev); +} + +static inline int pit_in_range(gpa_t addr) +{ + return ((addr >= KVM_PIT_BASE_ADDRESS) && + (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH)); +} + +static int pit_ioport_write(struct kvm_vcpu *vcpu, + struct kvm_io_device *this, + gpa_t addr, int len, const void *data) +{ + struct kvm_pit *pit = dev_to_pit(this); + struct kvm_kpit_state *pit_state = &pit->pit_state; + int channel, access; + struct kvm_kpit_channel_state *s; + u32 val = *(u32 *) data; + if (!pit_in_range(addr)) + return -EOPNOTSUPP; + + val &= 0xff; + addr &= KVM_PIT_CHANNEL_MASK; + + mutex_lock(&pit_state->lock); + + if (val != 0) + pr_debug("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++) { + if (val & (2 << channel)) { + if (!(val & 0x20)) + pit_latch_count(pit, channel); + if (!(val & 0x10)) + pit_latch_status(pit, channel); + } + } + } else { + /* Select Counter <channel>. */ + s = &pit_state->channels[channel]; + access = (val >> 4) & KVM_PIT_CHANNEL_MASK; + if (access == 0) { + pit_latch_count(pit, 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(pit, addr, val); + break; + case RW_STATE_MSB: + pit_load_count(pit, 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(pit, addr, s->write_latch | (val << 8)); + s->write_state = RW_STATE_WORD0; + break; + } + } + + mutex_unlock(&pit_state->lock); + return 0; +} + +static int pit_ioport_read(struct kvm_vcpu *vcpu, + struct kvm_io_device *this, + gpa_t addr, int len, void *data) +{ + struct kvm_pit *pit = dev_to_pit(this); + struct kvm_kpit_state *pit_state = &pit->pit_state; + int ret, count; + struct kvm_kpit_channel_state *s; + if (!pit_in_range(addr)) + return -EOPNOTSUPP; + + addr &= KVM_PIT_CHANNEL_MASK; + if (addr == 3) + return 0; + + 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(pit, addr); + ret = count & 0xff; + break; + case RW_STATE_MSB: + count = pit_get_count(pit, addr); + ret = (count >> 8) & 0xff; + break; + case RW_STATE_WORD0: + count = pit_get_count(pit, addr); + ret = count & 0xff; + s->read_state = RW_STATE_WORD1; + break; + case RW_STATE_WORD1: + count = pit_get_count(pit, 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); + return 0; +} + +static int speaker_ioport_write(struct kvm_vcpu *vcpu, + struct kvm_io_device *this, + gpa_t addr, int len, const void *data) +{ + struct kvm_pit *pit = speaker_to_pit(this); + struct kvm_kpit_state *pit_state = &pit->pit_state; + u32 val = *(u32 *) data; + if (addr != KVM_SPEAKER_BASE_ADDRESS) + return -EOPNOTSUPP; + + mutex_lock(&pit_state->lock); + pit_state->speaker_data_on = (val >> 1) & 1; + pit_set_gate(pit, 2, val & 1); + mutex_unlock(&pit_state->lock); + return 0; +} + +static int speaker_ioport_read(struct kvm_vcpu *vcpu, + struct kvm_io_device *this, + gpa_t addr, int len, void *data) +{ + struct kvm_pit *pit = speaker_to_pit(this); + struct kvm_kpit_state *pit_state = &pit->pit_state; + unsigned int refresh_clock; + int ret; + if (addr != KVM_SPEAKER_BASE_ADDRESS) + return -EOPNOTSUPP; + + /* 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(pit, 2) | + (pit_get_out(pit, 2) << 5) | (refresh_clock << 4)); + if (len > sizeof(ret)) + len = sizeof(ret); + memcpy(data, (char *)&ret, len); + mutex_unlock(&pit_state->lock); + return 0; +} + +static void kvm_pit_reset(struct kvm_pit *pit) +{ + int i; + struct kvm_kpit_channel_state *c; + + pit->pit_state.flags = 0; + for (i = 0; i < 3; i++) { + c = &pit->pit_state.channels[i]; + c->mode = 0xff; + c->gate = (i != 2); + pit_load_count(pit, i, 0); + } + + kvm_pit_reset_reinject(pit); +} + +static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask) +{ + struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier); + + if (!mask) + kvm_pit_reset_reinject(pit); +} + +static const struct kvm_io_device_ops pit_dev_ops = { + .read = pit_ioport_read, + .write = pit_ioport_write, +}; + +static const struct kvm_io_device_ops speaker_dev_ops = { + .read = speaker_ioport_read, + .write = speaker_ioport_write, +}; + +struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags) +{ + struct kvm_pit *pit; + struct kvm_kpit_state *pit_state; + struct pid *pid; + pid_t pid_nr; + int ret; + + pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL_ACCOUNT); + if (!pit) + return NULL; + + pit->irq_source_id = kvm_request_irq_source_id(kvm); + if (pit->irq_source_id < 0) + goto fail_request; + + mutex_init(&pit->pit_state.lock); + + pid = get_pid(task_tgid(current)); + pid_nr = pid_vnr(pid); + put_pid(pid); + + pit->worker = kthread_create_worker(0, "kvm-pit/%d", pid_nr); + if (IS_ERR(pit->worker)) + goto fail_kthread; + + kthread_init_work(&pit->expired, pit_do_work); + + pit->kvm = kvm; + + pit_state = &pit->pit_state; + hrtimer_init(&pit_state->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); + pit_state->timer.function = pit_timer_fn; + + pit_state->irq_ack_notifier.gsi = 0; + pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq; + pit->mask_notifier.func = pit_mask_notifer; + + kvm_pit_reset(pit); + + kvm_pit_set_reinject(pit, true); + + mutex_lock(&kvm->slots_lock); + kvm_iodevice_init(&pit->dev, &pit_dev_ops); + ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, KVM_PIT_BASE_ADDRESS, + KVM_PIT_MEM_LENGTH, &pit->dev); + if (ret < 0) + goto fail_register_pit; + + if (flags & KVM_PIT_SPEAKER_DUMMY) { + kvm_iodevice_init(&pit->speaker_dev, &speaker_dev_ops); + ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, + KVM_SPEAKER_BASE_ADDRESS, 4, + &pit->speaker_dev); + if (ret < 0) + goto fail_register_speaker; + } + mutex_unlock(&kvm->slots_lock); + + return pit; + +fail_register_speaker: + kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev); +fail_register_pit: + mutex_unlock(&kvm->slots_lock); + kvm_pit_set_reinject(pit, false); + kthread_destroy_worker(pit->worker); +fail_kthread: + kvm_free_irq_source_id(kvm, pit->irq_source_id); +fail_request: + kfree(pit); + return NULL; +} + +void kvm_free_pit(struct kvm *kvm) +{ + struct kvm_pit *pit = kvm->arch.vpit; + + if (pit) { + mutex_lock(&kvm->slots_lock); + kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev); + kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->speaker_dev); + mutex_unlock(&kvm->slots_lock); + kvm_pit_set_reinject(pit, false); + hrtimer_cancel(&pit->pit_state.timer); + kthread_destroy_worker(pit->worker); + kvm_free_irq_source_id(kvm, pit->irq_source_id); + kfree(pit); + } +} |