[PATCH v3 1/3] kvm: Introduce kvm_total_suspend_ns().

[Suleiman Souhlal <suleiman@google.com>]

It returns the cumulative nanoseconds that the host has been suspended.
It is intended to be used for reporting host suspend time to the guest.

Change-Id: I8f644c9fbdb2c48d2c99dd9efaa5c85a83a14c2a
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
---
 include/linux/kvm_host.h |  2 ++
 virt/kvm/kvm_main.c      | 26 ++++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 401439bb21e3e6..cf926168b30820 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2553,4 +2553,6 @@ long kvm_arch_vcpu_pre_fault_memory(struct kvm_vcpu *vcpu,
 				    struct kvm_pre_fault_memory *range);
 #endif
 
+u64 kvm_total_suspend_ns(void);
+
 #endif
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index de2c11dae23163..d5ae237df76d0d 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -889,13 +889,39 @@ static int kvm_init_mmu_notifier(struct kvm *kvm)
 
 #endif /* CONFIG_KVM_GENERIC_MMU_NOTIFIER */
 
+static u64 last_suspend;
+static u64 total_suspend_ns;
+
+u64 kvm_total_suspend_ns(void)
+{
+	return total_suspend_ns;
+}
+
+
 #ifdef CONFIG_HAVE_KVM_PM_NOTIFIER
+static int kvm_pm_notifier(struct kvm *kvm, unsigned long state)
+{
+	switch (state) {
+	case PM_HIBERNATION_PREPARE:
+	case PM_SUSPEND_PREPARE:
+		last_suspend = ktime_get_boottime_ns();
+	case PM_POST_HIBERNATION:
+	case PM_POST_SUSPEND:
+		total_suspend_ns += ktime_get_boottime_ns() - last_suspend;
+	}
+
+	return NOTIFY_DONE;
+}
+
 static int kvm_pm_notifier_call(struct notifier_block *bl,
 				unsigned long state,
 				void *unused)
 {
 	struct kvm *kvm = container_of(bl, struct kvm, pm_notifier);
 
+	if (kvm_pm_notifier(kvm, state) != NOTIFY_DONE)
+		return NOTIFY_BAD;
+
 	return kvm_arch_pm_notifier(kvm, state);
 }
 
-- 
2.47.1.613.gc27f4b7a9f-goog