| /* |
| * Copyright (C) 2012 ARM Ltd. |
| * Author: Marc Zyngier <marc.zyngier@arm.com> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| */ |
| |
| #include <linux/cpu.h> |
| #include <linux/of_irq.h> |
| #include <linux/kvm.h> |
| #include <linux/kvm_host.h> |
| #include <linux/interrupt.h> |
| |
| #include <clocksource/arm_arch_timer.h> |
| #include <asm/arch_timer.h> |
| |
| #include <kvm/arm_vgic.h> |
| #include <kvm/arm_arch_timer.h> |
| |
| static struct timecounter *timecounter; |
| static struct workqueue_struct *wqueue; |
| static unsigned int host_vtimer_irq; |
| |
| static cycle_t kvm_phys_timer_read(void) |
| { |
| return timecounter->cc->read(timecounter->cc); |
| } |
| |
| static bool timer_is_armed(struct arch_timer_cpu *timer) |
| { |
| return timer->armed; |
| } |
| |
| /* timer_arm: as in "arm the timer", not as in ARM the company */ |
| static void timer_arm(struct arch_timer_cpu *timer, u64 ns) |
| { |
| timer->armed = true; |
| hrtimer_start(&timer->timer, ktime_add_ns(ktime_get(), ns), |
| HRTIMER_MODE_ABS); |
| } |
| |
| static void timer_disarm(struct arch_timer_cpu *timer) |
| { |
| if (timer_is_armed(timer)) { |
| hrtimer_cancel(&timer->timer); |
| cancel_work_sync(&timer->expired); |
| timer->armed = false; |
| } |
| } |
| |
| static void kvm_timer_inject_irq(struct kvm_vcpu *vcpu) |
| { |
| int ret; |
| struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; |
| |
| kvm_vgic_set_phys_irq_active(timer->map, true); |
| ret = kvm_vgic_inject_mapped_irq(vcpu->kvm, vcpu->vcpu_id, |
| timer->map, |
| timer->irq->level); |
| WARN_ON(ret); |
| } |
| |
| static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id) |
| { |
| struct kvm_vcpu *vcpu = *(struct kvm_vcpu **)dev_id; |
| |
| /* |
| * We disable the timer in the world switch and let it be |
| * handled by kvm_timer_sync_hwstate(). Getting a timer |
| * interrupt at this point is a sure sign of some major |
| * breakage. |
| */ |
| pr_warn("Unexpected interrupt %d on vcpu %p\n", irq, vcpu); |
| return IRQ_HANDLED; |
| } |
| |
| /* |
| * Work function for handling the backup timer that we schedule when a vcpu is |
| * no longer running, but had a timer programmed to fire in the future. |
| */ |
| static void kvm_timer_inject_irq_work(struct work_struct *work) |
| { |
| struct kvm_vcpu *vcpu; |
| |
| vcpu = container_of(work, struct kvm_vcpu, arch.timer_cpu.expired); |
| vcpu->arch.timer_cpu.armed = false; |
| |
| /* |
| * If the vcpu is blocked we want to wake it up so that it will see |
| * the timer has expired when entering the guest. |
| */ |
| kvm_vcpu_kick(vcpu); |
| } |
| |
| static enum hrtimer_restart kvm_timer_expire(struct hrtimer *hrt) |
| { |
| struct arch_timer_cpu *timer; |
| timer = container_of(hrt, struct arch_timer_cpu, timer); |
| queue_work(wqueue, &timer->expired); |
| return HRTIMER_NORESTART; |
| } |
| |
| bool kvm_timer_should_fire(struct kvm_vcpu *vcpu) |
| { |
| struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; |
| cycle_t cval, now; |
| |
| if ((timer->cntv_ctl & ARCH_TIMER_CTRL_IT_MASK) || |
| !(timer->cntv_ctl & ARCH_TIMER_CTRL_ENABLE) || |
| kvm_vgic_get_phys_irq_active(timer->map)) |
| return false; |
| |
| cval = timer->cntv_cval; |
| now = kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff; |
| |
| return cval <= now; |
| } |
| |
| /** |
| * kvm_timer_flush_hwstate - prepare to move the virt timer to the cpu |
| * @vcpu: The vcpu pointer |
| * |
| * Disarm any pending soft timers, since the world-switch code will write the |
| * virtual timer state back to the physical CPU. |
| */ |
| void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu) |
| { |
| struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; |
| |
| /* |
| * We're about to run this vcpu again, so there is no need to |
| * keep the background timer running, as we're about to |
| * populate the CPU timer again. |
| */ |
| timer_disarm(timer); |
| |
| /* |
| * If the timer expired while we were not scheduled, now is the time |
| * to inject it. |
| */ |
| if (kvm_timer_should_fire(vcpu)) |
| kvm_timer_inject_irq(vcpu); |
| } |
| |
| /** |
| * kvm_timer_sync_hwstate - sync timer state from cpu |
| * @vcpu: The vcpu pointer |
| * |
| * Check if the virtual timer was armed and either schedule a corresponding |
| * soft timer or inject directly if already expired. |
| */ |
| void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu) |
| { |
| struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; |
| cycle_t cval, now; |
| u64 ns; |
| |
| BUG_ON(timer_is_armed(timer)); |
| |
| if (kvm_timer_should_fire(vcpu)) { |
| /* |
| * Timer has already expired while we were not |
| * looking. Inject the interrupt and carry on. |
| */ |
| kvm_timer_inject_irq(vcpu); |
| return; |
| } |
| |
| cval = timer->cntv_cval; |
| now = kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff; |
| |
| ns = cyclecounter_cyc2ns(timecounter->cc, cval - now, timecounter->mask, |
| &timecounter->frac); |
| timer_arm(timer, ns); |
| } |
| |
| int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu, |
| const struct kvm_irq_level *irq) |
| { |
| struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; |
| struct irq_phys_map *map; |
| |
| /* |
| * The vcpu timer irq number cannot be determined in |
| * kvm_timer_vcpu_init() because it is called much before |
| * kvm_vcpu_set_target(). To handle this, we determine |
| * vcpu timer irq number when the vcpu is reset. |
| */ |
| timer->irq = irq; |
| |
| /* |
| * Tell the VGIC that the virtual interrupt is tied to a |
| * physical interrupt. We do that once per VCPU. |
| */ |
| map = kvm_vgic_map_phys_irq(vcpu, irq->irq, host_vtimer_irq); |
| if (WARN_ON(IS_ERR(map))) |
| return PTR_ERR(map); |
| |
| timer->map = map; |
| return 0; |
| } |
| |
| void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu) |
| { |
| struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; |
| |
| INIT_WORK(&timer->expired, kvm_timer_inject_irq_work); |
| hrtimer_init(&timer->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); |
| timer->timer.function = kvm_timer_expire; |
| } |
| |
| static void kvm_timer_init_interrupt(void *info) |
| { |
| enable_percpu_irq(host_vtimer_irq, 0); |
| } |
| |
| int kvm_arm_timer_set_reg(struct kvm_vcpu *vcpu, u64 regid, u64 value) |
| { |
| struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; |
| |
| switch (regid) { |
| case KVM_REG_ARM_TIMER_CTL: |
| timer->cntv_ctl = value; |
| break; |
| case KVM_REG_ARM_TIMER_CNT: |
| vcpu->kvm->arch.timer.cntvoff = kvm_phys_timer_read() - value; |
| break; |
| case KVM_REG_ARM_TIMER_CVAL: |
| timer->cntv_cval = value; |
| break; |
| default: |
| return -1; |
| } |
| return 0; |
| } |
| |
| u64 kvm_arm_timer_get_reg(struct kvm_vcpu *vcpu, u64 regid) |
| { |
| struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; |
| |
| switch (regid) { |
| case KVM_REG_ARM_TIMER_CTL: |
| return timer->cntv_ctl; |
| case KVM_REG_ARM_TIMER_CNT: |
| return kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff; |
| case KVM_REG_ARM_TIMER_CVAL: |
| return timer->cntv_cval; |
| } |
| return (u64)-1; |
| } |
| |
| static int kvm_timer_cpu_notify(struct notifier_block *self, |
| unsigned long action, void *cpu) |
| { |
| switch (action) { |
| case CPU_STARTING: |
| case CPU_STARTING_FROZEN: |
| kvm_timer_init_interrupt(NULL); |
| break; |
| case CPU_DYING: |
| case CPU_DYING_FROZEN: |
| disable_percpu_irq(host_vtimer_irq); |
| break; |
| } |
| |
| return NOTIFY_OK; |
| } |
| |
| static struct notifier_block kvm_timer_cpu_nb = { |
| .notifier_call = kvm_timer_cpu_notify, |
| }; |
| |
| static const struct of_device_id arch_timer_of_match[] = { |
| { .compatible = "arm,armv7-timer", }, |
| { .compatible = "arm,armv8-timer", }, |
| {}, |
| }; |
| |
| int kvm_timer_hyp_init(void) |
| { |
| struct device_node *np; |
| unsigned int ppi; |
| int err; |
| |
| timecounter = arch_timer_get_timecounter(); |
| if (!timecounter) |
| return -ENODEV; |
| |
| np = of_find_matching_node(NULL, arch_timer_of_match); |
| if (!np) { |
| kvm_err("kvm_arch_timer: can't find DT node\n"); |
| return -ENODEV; |
| } |
| |
| ppi = irq_of_parse_and_map(np, 2); |
| if (!ppi) { |
| kvm_err("kvm_arch_timer: no virtual timer interrupt\n"); |
| err = -EINVAL; |
| goto out; |
| } |
| |
| err = request_percpu_irq(ppi, kvm_arch_timer_handler, |
| "kvm guest timer", kvm_get_running_vcpus()); |
| if (err) { |
| kvm_err("kvm_arch_timer: can't request interrupt %d (%d)\n", |
| ppi, err); |
| goto out; |
| } |
| |
| host_vtimer_irq = ppi; |
| |
| err = __register_cpu_notifier(&kvm_timer_cpu_nb); |
| if (err) { |
| kvm_err("Cannot register timer CPU notifier\n"); |
| goto out_free; |
| } |
| |
| wqueue = create_singlethread_workqueue("kvm_arch_timer"); |
| if (!wqueue) { |
| err = -ENOMEM; |
| goto out_free; |
| } |
| |
| kvm_info("%s IRQ%d\n", np->name, ppi); |
| on_each_cpu(kvm_timer_init_interrupt, NULL, 1); |
| |
| goto out; |
| out_free: |
| free_percpu_irq(ppi, kvm_get_running_vcpus()); |
| out: |
| of_node_put(np); |
| return err; |
| } |
| |
| void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu) |
| { |
| struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; |
| |
| timer_disarm(timer); |
| if (timer->map) |
| kvm_vgic_unmap_phys_irq(vcpu, timer->map); |
| } |
| |
| void kvm_timer_enable(struct kvm *kvm) |
| { |
| if (kvm->arch.timer.enabled) |
| return; |
| |
| /* |
| * There is a potential race here between VCPUs starting for the first |
| * time, which may be enabling the timer multiple times. That doesn't |
| * hurt though, because we're just setting a variable to the same |
| * variable that it already was. The important thing is that all |
| * VCPUs have the enabled variable set, before entering the guest, if |
| * the arch timers are enabled. |
| */ |
| if (timecounter && wqueue) |
| kvm->arch.timer.enabled = 1; |
| } |
| |
| void kvm_timer_init(struct kvm *kvm) |
| { |
| kvm->arch.timer.cntvoff = kvm_phys_timer_read(); |
| } |