3 files changed, 39 insertions, 10 deletions

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 9a5f057a97a3..e98370cd9969 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -266,7 +266,7 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 
 int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
 {
-        return 0;
+        return kvm_timer_should_fire(vcpu);
 }
 
 int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index a74e4c2bf188..e5966758c093 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -67,4 +67,6 @@ void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu);
 u64 kvm_arm_timer_get_reg(struct kvm_vcpu *, u64 regid);
 int kvm_arm_timer_set_reg(struct kvm_vcpu *, u64 regid, u64 value);
 
+bool kvm_timer_should_fire(struct kvm_vcpu *vcpu);
+
 #endif
diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
index 6e54f3542126..98c95f2fcba4 100644
--- a/virt/kvm/arm/arch_timer.c
+++ b/virt/kvm/arm/arch_timer.c
@@ -85,13 +85,22 @@ static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id)
         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;
-        kvm_timer_inject_irq(vcpu);
+
+        /*
+         * 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)
@@ -102,6 +111,21 @@ static enum hrtimer_restart kvm_timer_expire(struct hrtimer *hrt)
         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
@@ -119,6 +143,13 @@ void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu)
          * 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);
 }
 
 /**
@@ -134,16 +165,9 @@ void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu)
         cycle_t cval, now;
         u64 ns;
 
-        if ((timer->cntv_ctl & ARCH_TIMER_CTRL_IT_MASK) ||
-                !(timer->cntv_ctl & ARCH_TIMER_CTRL_ENABLE))
-                return;
-
-        cval = timer->cntv_cval;
-        now = kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
-
         BUG_ON(timer_is_armed(timer));
 
-        if (cval <= now) {
+        if (kvm_timer_should_fire(vcpu)) {
                 /*
                  * Timer has already expired while we were not
                  * looking. Inject the interrupt and carry on.
@@ -152,6 +176,9 @@ void kvm_timer_sync_hwstate(struct kvm_vcpu *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);