Marc Zyngier | 53e7240 | 2013-01-23 13:21:58 -0500 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2012 ARM Ltd. |
| 3 | * Author: Marc Zyngier <marc.zyngier@arm.com> |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License version 2 as |
| 7 | * published by the Free Software Foundation. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with this program; if not, write to the Free Software |
| 16 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 17 | */ |
| 18 | |
| 19 | #include <linux/cpu.h> |
| 20 | #include <linux/of_irq.h> |
| 21 | #include <linux/kvm.h> |
| 22 | #include <linux/kvm_host.h> |
| 23 | #include <linux/interrupt.h> |
| 24 | |
Mark Rutland | 372b7c1 | 2013-03-27 15:56:11 +0000 | [diff] [blame] | 25 | #include <clocksource/arm_arch_timer.h> |
Marc Zyngier | 53e7240 | 2013-01-23 13:21:58 -0500 | [diff] [blame] | 26 | #include <asm/arch_timer.h> |
| 27 | |
| 28 | #include <asm/kvm_vgic.h> |
| 29 | #include <asm/kvm_arch_timer.h> |
| 30 | |
| 31 | static struct timecounter *timecounter; |
| 32 | static struct workqueue_struct *wqueue; |
| 33 | static struct kvm_irq_level timer_irq = { |
| 34 | .level = 1, |
| 35 | }; |
| 36 | |
| 37 | static cycle_t kvm_phys_timer_read(void) |
| 38 | { |
| 39 | return timecounter->cc->read(timecounter->cc); |
| 40 | } |
| 41 | |
| 42 | static bool timer_is_armed(struct arch_timer_cpu *timer) |
| 43 | { |
| 44 | return timer->armed; |
| 45 | } |
| 46 | |
| 47 | /* timer_arm: as in "arm the timer", not as in ARM the company */ |
| 48 | static void timer_arm(struct arch_timer_cpu *timer, u64 ns) |
| 49 | { |
| 50 | timer->armed = true; |
| 51 | hrtimer_start(&timer->timer, ktime_add_ns(ktime_get(), ns), |
| 52 | HRTIMER_MODE_ABS); |
| 53 | } |
| 54 | |
| 55 | static void timer_disarm(struct arch_timer_cpu *timer) |
| 56 | { |
| 57 | if (timer_is_armed(timer)) { |
| 58 | hrtimer_cancel(&timer->timer); |
| 59 | cancel_work_sync(&timer->expired); |
| 60 | timer->armed = false; |
| 61 | } |
| 62 | } |
| 63 | |
| 64 | static void kvm_timer_inject_irq(struct kvm_vcpu *vcpu) |
| 65 | { |
| 66 | struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; |
| 67 | |
Mark Rutland | 372b7c1 | 2013-03-27 15:56:11 +0000 | [diff] [blame] | 68 | timer->cntv_ctl |= ARCH_TIMER_CTRL_IT_MASK; |
Marc Zyngier | 53e7240 | 2013-01-23 13:21:58 -0500 | [diff] [blame] | 69 | kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id, |
| 70 | vcpu->arch.timer_cpu.irq->irq, |
| 71 | vcpu->arch.timer_cpu.irq->level); |
| 72 | } |
| 73 | |
| 74 | static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id) |
| 75 | { |
| 76 | struct kvm_vcpu *vcpu = *(struct kvm_vcpu **)dev_id; |
| 77 | |
| 78 | /* |
| 79 | * We disable the timer in the world switch and let it be |
| 80 | * handled by kvm_timer_sync_hwstate(). Getting a timer |
| 81 | * interrupt at this point is a sure sign of some major |
| 82 | * breakage. |
| 83 | */ |
| 84 | pr_warn("Unexpected interrupt %d on vcpu %p\n", irq, vcpu); |
| 85 | return IRQ_HANDLED; |
| 86 | } |
| 87 | |
| 88 | static void kvm_timer_inject_irq_work(struct work_struct *work) |
| 89 | { |
| 90 | struct kvm_vcpu *vcpu; |
| 91 | |
| 92 | vcpu = container_of(work, struct kvm_vcpu, arch.timer_cpu.expired); |
| 93 | vcpu->arch.timer_cpu.armed = false; |
| 94 | kvm_timer_inject_irq(vcpu); |
| 95 | } |
| 96 | |
| 97 | static enum hrtimer_restart kvm_timer_expire(struct hrtimer *hrt) |
| 98 | { |
| 99 | struct arch_timer_cpu *timer; |
| 100 | timer = container_of(hrt, struct arch_timer_cpu, timer); |
| 101 | queue_work(wqueue, &timer->expired); |
| 102 | return HRTIMER_NORESTART; |
| 103 | } |
| 104 | |
| 105 | /** |
| 106 | * kvm_timer_flush_hwstate - prepare to move the virt timer to the cpu |
| 107 | * @vcpu: The vcpu pointer |
| 108 | * |
| 109 | * Disarm any pending soft timers, since the world-switch code will write the |
| 110 | * virtual timer state back to the physical CPU. |
| 111 | */ |
| 112 | void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu) |
| 113 | { |
| 114 | struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; |
| 115 | |
| 116 | /* |
| 117 | * We're about to run this vcpu again, so there is no need to |
| 118 | * keep the background timer running, as we're about to |
| 119 | * populate the CPU timer again. |
| 120 | */ |
| 121 | timer_disarm(timer); |
| 122 | } |
| 123 | |
| 124 | /** |
| 125 | * kvm_timer_sync_hwstate - sync timer state from cpu |
| 126 | * @vcpu: The vcpu pointer |
| 127 | * |
| 128 | * Check if the virtual timer was armed and either schedule a corresponding |
| 129 | * soft timer or inject directly if already expired. |
| 130 | */ |
| 131 | void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu) |
| 132 | { |
| 133 | struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; |
| 134 | cycle_t cval, now; |
| 135 | u64 ns; |
| 136 | |
Mark Rutland | 372b7c1 | 2013-03-27 15:56:11 +0000 | [diff] [blame] | 137 | if ((timer->cntv_ctl & ARCH_TIMER_CTRL_IT_MASK) || |
| 138 | !(timer->cntv_ctl & ARCH_TIMER_CTRL_ENABLE)) |
Marc Zyngier | 53e7240 | 2013-01-23 13:21:58 -0500 | [diff] [blame] | 139 | return; |
| 140 | |
| 141 | cval = timer->cntv_cval; |
| 142 | now = kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff; |
| 143 | |
| 144 | BUG_ON(timer_is_armed(timer)); |
| 145 | |
| 146 | if (cval <= now) { |
| 147 | /* |
| 148 | * Timer has already expired while we were not |
| 149 | * looking. Inject the interrupt and carry on. |
| 150 | */ |
| 151 | kvm_timer_inject_irq(vcpu); |
| 152 | return; |
| 153 | } |
| 154 | |
| 155 | ns = cyclecounter_cyc2ns(timecounter->cc, cval - now); |
| 156 | timer_arm(timer, ns); |
| 157 | } |
| 158 | |
| 159 | void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu) |
| 160 | { |
| 161 | struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; |
| 162 | |
| 163 | INIT_WORK(&timer->expired, kvm_timer_inject_irq_work); |
| 164 | hrtimer_init(&timer->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); |
| 165 | timer->timer.function = kvm_timer_expire; |
| 166 | timer->irq = &timer_irq; |
| 167 | } |
| 168 | |
| 169 | static void kvm_timer_init_interrupt(void *info) |
| 170 | { |
| 171 | enable_percpu_irq(timer_irq.irq, 0); |
| 172 | } |
| 173 | |
| 174 | |
| 175 | static int kvm_timer_cpu_notify(struct notifier_block *self, |
| 176 | unsigned long action, void *cpu) |
| 177 | { |
| 178 | switch (action) { |
| 179 | case CPU_STARTING: |
| 180 | case CPU_STARTING_FROZEN: |
| 181 | kvm_timer_init_interrupt(NULL); |
| 182 | break; |
| 183 | case CPU_DYING: |
| 184 | case CPU_DYING_FROZEN: |
| 185 | disable_percpu_irq(timer_irq.irq); |
| 186 | break; |
| 187 | } |
| 188 | |
| 189 | return NOTIFY_OK; |
| 190 | } |
| 191 | |
| 192 | static struct notifier_block kvm_timer_cpu_nb = { |
| 193 | .notifier_call = kvm_timer_cpu_notify, |
| 194 | }; |
| 195 | |
| 196 | static const struct of_device_id arch_timer_of_match[] = { |
| 197 | { .compatible = "arm,armv7-timer", }, |
| 198 | {}, |
| 199 | }; |
| 200 | |
| 201 | int kvm_timer_hyp_init(void) |
| 202 | { |
| 203 | struct device_node *np; |
| 204 | unsigned int ppi; |
| 205 | int err; |
| 206 | |
| 207 | timecounter = arch_timer_get_timecounter(); |
| 208 | if (!timecounter) |
| 209 | return -ENODEV; |
| 210 | |
| 211 | np = of_find_matching_node(NULL, arch_timer_of_match); |
| 212 | if (!np) { |
| 213 | kvm_err("kvm_arch_timer: can't find DT node\n"); |
| 214 | return -ENODEV; |
| 215 | } |
| 216 | |
| 217 | ppi = irq_of_parse_and_map(np, 2); |
| 218 | if (!ppi) { |
| 219 | kvm_err("kvm_arch_timer: no virtual timer interrupt\n"); |
| 220 | err = -EINVAL; |
| 221 | goto out; |
| 222 | } |
| 223 | |
| 224 | err = request_percpu_irq(ppi, kvm_arch_timer_handler, |
| 225 | "kvm guest timer", kvm_get_running_vcpus()); |
| 226 | if (err) { |
| 227 | kvm_err("kvm_arch_timer: can't request interrupt %d (%d)\n", |
| 228 | ppi, err); |
| 229 | goto out; |
| 230 | } |
| 231 | |
| 232 | timer_irq.irq = ppi; |
| 233 | |
| 234 | err = register_cpu_notifier(&kvm_timer_cpu_nb); |
| 235 | if (err) { |
| 236 | kvm_err("Cannot register timer CPU notifier\n"); |
| 237 | goto out_free; |
| 238 | } |
| 239 | |
| 240 | wqueue = create_singlethread_workqueue("kvm_arch_timer"); |
| 241 | if (!wqueue) { |
| 242 | err = -ENOMEM; |
| 243 | goto out_free; |
| 244 | } |
| 245 | |
| 246 | kvm_info("%s IRQ%d\n", np->name, ppi); |
| 247 | on_each_cpu(kvm_timer_init_interrupt, NULL, 1); |
| 248 | |
| 249 | goto out; |
| 250 | out_free: |
| 251 | free_percpu_irq(ppi, kvm_get_running_vcpus()); |
| 252 | out: |
| 253 | of_node_put(np); |
| 254 | return err; |
| 255 | } |
| 256 | |
| 257 | void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu) |
| 258 | { |
| 259 | struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; |
| 260 | |
| 261 | timer_disarm(timer); |
| 262 | } |
| 263 | |
| 264 | int kvm_timer_init(struct kvm *kvm) |
| 265 | { |
| 266 | if (timecounter && wqueue) { |
| 267 | kvm->arch.timer.cntvoff = kvm_phys_timer_read(); |
| 268 | kvm->arch.timer.enabled = 1; |
| 269 | } |
| 270 | |
| 271 | return 0; |
| 272 | } |