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

Suleiman Souhlal
2025-01-07T04:26:03Z

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