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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/x86/kvm/i8254.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/kvm/i8254.c')
-rw-r--r--arch/x86/kvm/i8254.c751
1 files changed, 751 insertions, 0 deletions
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
new file mode 100644
index 000000000..e0a7a0e7a
--- /dev/null
+++ b/arch/x86/kvm/i8254.c
@@ -0,0 +1,751 @@
+/*
+ * 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;
+
+ /* Somewhat arbitrarily make vcpu0 the owner of the PIT. */
+ if (vcpu->vcpu_id || !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;
+ unsigned long 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_set_apicv_inhibit(kvm, 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_clear_apicv_inhibit(kvm, 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);
+ if (val & (1 << 1))
+ pit_state->flags |= KVM_PIT_FLAGS_SPEAKER_DATA_ON;
+ else
+ pit_state->flags &= ~KVM_PIT_FLAGS_SPEAKER_DATA_ON;
+ 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->flags & KVM_PIT_FLAGS_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);
+ }
+}