[PATCH v2 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.

Signed-off-by: Suleiman Souhlal <suleiman@google.com>
---
 include/linux/kvm_host.h |  2 ++
 virt/kvm/kvm_main.c      | 13 +++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index b23c6d48392f7c..8fec37b372d8c0 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2494,4 +2494,6 @@ 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 cb2b78e92910fb..2235933d9247bc 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -5720,6 +5720,15 @@ static void kvm_shutdown(void)
 	on_each_cpu(hardware_disable_nolock, NULL, 1);
 }
 
+static u64 last_suspend;
+static u64 total_suspend_ns;
+
+u64
+kvm_total_suspend_ns(void)
+{
+	return total_suspend_ns;
+}
+
 static int kvm_suspend(void)
 {
 	/*
@@ -5735,6 +5744,8 @@ static int kvm_suspend(void)
 
 	if (kvm_usage_count)
 		hardware_disable_nolock(NULL);
+
+	last_suspend = ktime_get_boottime_ns();
 	return 0;
 }
 
@@ -5745,6 +5756,8 @@ static void kvm_resume(void)
 
 	if (kvm_usage_count)
 		WARN_ON_ONCE(__hardware_enable_nolock());
+
+	total_suspend_ns += ktime_get_boottime_ns() - last_suspend;
 }
 
 static struct syscore_ops kvm_syscore_ops = {
-- 
2.46.0.184.g6999bdac58-goog