1 files changed, 360 insertions, 0 deletions

diff --git a/kernel/virt/kvm/arm/arch_timer.c b/kernel/virt/kvm/arm/arch_timer.c
new file mode 100644
index 000000000..98c95f2fc
--- /dev/null
+++ b/kernel/virt/kvm/arm/arch_timer.c
@@ -0,0 +1,360 @@
+/*
+ * 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;
+
+	timer->cntv_ctl |= ARCH_TIMER_CTRL_IT_MASK;
+	ret = kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
+				  timer->irq->irq,
+				  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))
+		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);
+}
+
+void kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu,
+			  const struct kvm_irq_level *irq)
+{
+	struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
+
+	/*
+	 * 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;
+}
+
+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);
+}
+
+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();
+}