We can inject a timer interrupt into the guest as a result of
three possible events:
- The virtual timer interrupt has fired while we were still
executing the guest
- The timer interrupt hasn't fired, but it expired while we
were doing the world switch
- A hrtimer we programmed earlier has fired
Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
---
arch/arm/include/asm/kvm_arch_timer.h | 34 ++++++-
arch/arm/kvm/timer.c | 164 +++++++++++++++++++++++++++++++++
2 files changed, 197 insertions(+), 1 deletion(-)
create mode 100644 arch/arm/kvm/timer.c
diff --git a/arch/arm/include/asm/kvm_arch_timer.h b/arch/arm/include/asm/kvm_arch_timer.h
index 491e336..191c541 100644
--- a/arch/arm/include/asm/kvm_arch_timer.h
+++ b/arch/arm/include/asm/kvm_arch_timer.h
@@ -1,13 +1,45 @@
#ifndef __ASM_ARM_KVM_ARCH_TIMER_H
#define __ASM_ARM_KVM_ARCH_TIMER_H
+#include <linux/clocksource.h>
+#include <linux/hrtimer.h>
+#include <linux/workqueue.h>
+
struct arch_timer_kvm {
+#ifdef CONFIG_KVM_ARM_TIMER
+ bool enabled;
+ union {
+ cycle_t cntvoff;
+ struct {
+ u32 cntvoff_high; /* Restored only */
+ u32 cntvoff_low; /* Restored only */
+ } cntvoff32;
+ };
+#endif
};
struct arch_timer_cpu {
+#ifdef CONFIG_KVM_ARM_TIMER
+ struct hrtimer timer;
+ struct work_struct expired;
+ cycle_t cval;
+ bool armed;
+
+ /* Registers */
+ u32 cntv_ctl; /* Saved/restored */
+ u32 cntv_cval_high; /* Saved/restored */
+ u32 cntv_cval_low; /* Saved/restored */
+#endif
};
-#ifndef CONFIG_KVM_ARM_TIMER
+#ifdef CONFIG_KVM_ARM_TIMER
+int kvm_timer_hyp_init(void);
+int kvm_timer_init(struct kvm *kvm);
+void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu);
+void kvm_timer_sync_to_cpu(struct kvm_vcpu *vcpu);
+void kvm_timer_sync_from_cpu(struct kvm_vcpu *vcpu);
+void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu);
+#else
static inline int kvm_timer_hyp_init(void)
{
return 0;
diff --git a/arch/arm/kvm/timer.c b/arch/arm/kvm/timer.c
new file mode 100644
index 0000000..8642b4c
--- /dev/null
+++ b/arch/arm/kvm/timer.c
@@ -0,0 +1,164 @@
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ * Author: Marc Zyngier <marc.zyngier at 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/kvm.h>
+#include <linux/kvm_host.h>
+#include <linux/interrupt.h>
+
+#include <asm/arch_timer.h>
+
+#include <asm/kvm_vgic.h>
+#include <asm/kvm_arch_timer.h>
+
+static const struct kvm_irq_level virt_timer_ppi = {
+ .irq = 27, /* A7/A15 specific */
+ .level = 1,
+};
+
+static struct timecounter *timecounter;
+static struct workqueue_struct *wqueue;
+
+static cycle_t kvm_phys_timer_read(void)
+{
+ return timecounter->cc->read(timecounter->cc);
+}
+
+static void kvm_timer_inject_irq(struct kvm_vcpu *vcpu)
+{
+ struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
+
+ timer->cntv_ctl |= 1 << 1; /* Mask the interrupt in the guest */
+ kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id, &virt_timer_ppi);
+}
+
+static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id)
+{
+ struct kvm_vcpu *vcpu = kvm_arm_get_running_vcpu();
+
+ if (WARN_ON(!vcpu))
+ return IRQ_NONE;
+
+ kvm_timer_inject_irq(vcpu);
+ return IRQ_HANDLED;
+}
+
+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;
+ kvm_timer_inject_irq(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;
+}
+
+void kvm_timer_sync_to_cpu(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.
+ */
+ if (timer->armed) {
+ hrtimer_cancel(&timer->timer);
+ cancel_work_sync(&timer->expired);
+ timer->armed = false;
+ }
+}
+
+void kvm_timer_sync_from_cpu(struct kvm_vcpu *vcpu)
+{
+ struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
+ cycle_t cval, now;
+ u64 ns;
+
+ /* Check if the timer is enabled and unmasked first */
+ if ((timer->cntv_ctl & 3) != 1)
+ return;
+
+ cval = ((cycle_t)timer->cntv_cval_high << 32) | timer->cntv_cval_low;
+ now = kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
+
+ BUG_ON(timer->armed);
+
+ if (cval <= now) {
+ /*
+ * Timer has already expired while we were not
+ * looking. Inject the interrupt and carry on.
+ */
+ kvm_timer_inject_irq(vcpu);
+ return;
+ }
+
+ timer->cval = cval;
+ timer->armed = true;
+ ns = cyclecounter_cyc2ns(timecounter->cc, cval - now);
+ hrtimer_start(&timer->timer, ktime_add_ns(ktime_get(), ns),
+ HRTIMER_MODE_ABS);
+}
+
+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;
+}
+
+int kvm_timer_hyp_init(void)
+{
+ timecounter = arch_timer_get_timecounter();
+ if (!timecounter)
+ return -ENODEV;
+
+ wqueue = create_singlethread_workqueue("kvm_arch_timer");
+ if (!wqueue)
+ return -ENOMEM;
+
+ arch_timer_switch_to_phys(kvm_arch_timer_handler);
+ return 0;
+}
+
+void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu)
+{
+ struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
+
+ hrtimer_cancel(&timer->timer);
+ cancel_work_sync(&timer->expired);
+}
+
+int kvm_timer_init(struct kvm *kvm)
+{
+#if 0
+ kvm->arch.timer.cntvoff = kvm_phys_timer_read();
+#endif
+ if (timecounter && wqueue)
+ kvm->arch.timer.enabled = 1;
+
+ return 0;
+}
--
1.7.10.3
