From a29e53e436547408522271bba8f5b3c557c09747 Mon Sep 17 00:00:00 2001
From: Rob Bradford <robert.bradford@intel.com>
Date: Mon, 6 Dec 2021 10:47:29 +0000
Subject: [PATCH] vmm: Move KVM clock saving to common Vm::restore() method

Saving the KVM clock and restoring it is key for correct behaviour of
the VM when doing snapshot/restore or live migration. The clock is
restored to the KVM state as part of the Vm::resume() method prior to
that it must be extracted from the state object and stored for later use
by this method. This change simplifies the extraction and storage part
so that it is done in the same way for both snapshot/restore and live
migration.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>
---
 vmm/src/lib.rs |  4 ----
 vmm/src/vm.rs  | 15 +++++----------
 2 files changed, 5 insertions(+), 14 deletions(-)

diff --git a/vmm/src/lib.rs b/vmm/src/lib.rs
index 696a0cff7..a0d915982 100644
--- a/vmm/src/lib.rs
+++ b/vmm/src/lib.rs
@@ -826,10 +826,6 @@ impl Vmm {
             MigratableError::MigrateReceive(anyhow!("Error deserialising snapshot: {}", e))
         })?;
 
-        #[cfg(all(feature = "kvm", target_arch = "x86_64"))]
-        vm.load_clock_from_snapshot(&snapshot)
-            .map_err(|e| MigratableError::MigrateReceive(anyhow!("Error resume clock: {:?}", e)))?;
-
         // Create VM
         vm.restore(snapshot).map_err(|e| {
             Response::error().write_to(socket).ok();
diff --git a/vmm/src/vm.rs b/vmm/src/vm.rs
index 987d89251..728fbc9e4 100644
--- a/vmm/src/vm.rs
+++ b/vmm/src/vm.rs
@@ -529,9 +529,6 @@ impl Vm {
         reset_evt: EventFd,
         seccomp_action: &SeccompAction,
         hypervisor: Arc<dyn hypervisor::Hypervisor>,
-        #[cfg(all(feature = "kvm", target_arch = "x86_64"))] _saved_clock: Option<
-            hypervisor::ClockData,
-        >,
         activate_evt: EventFd,
         restoring: bool,
     ) -> Result<Self> {
@@ -641,7 +638,7 @@ impl Vm {
             memory_manager,
             vm,
             #[cfg(all(feature = "kvm", target_arch = "x86_64"))]
-            saved_clock: _saved_clock,
+            saved_clock: None,
             #[cfg(any(target_arch = "aarch64", feature = "acpi"))]
             numa_nodes,
             seccomp_action: seccomp_action.clone(),
@@ -792,8 +789,6 @@ impl Vm {
             reset_evt,
             seccomp_action,
             hypervisor,
-            #[cfg(all(feature = "kvm", target_arch = "x86_64"))]
-            None,
             activate_evt,
             false,
         )?;
@@ -865,8 +860,6 @@ impl Vm {
             reset_evt,
             seccomp_action,
             hypervisor,
-            #[cfg(all(feature = "kvm", target_arch = "x86_64"))]
-            vm_snapshot.clock,
             activate_evt,
             true,
         )
@@ -915,8 +908,6 @@ impl Vm {
             reset_evt,
             seccomp_action,
             hypervisor,
-            #[cfg(all(feature = "kvm", target_arch = "x86_64"))]
-            None,
             activate_evt,
             true,
         )
@@ -2508,6 +2499,10 @@ impl Snapshottable for Vm {
             MigratableError::Restore(anyhow!("Could not restore VM state: {:#?}", e))
         })?;
 
+        #[cfg(all(feature = "kvm", target_arch = "x86_64"))]
+        self.load_clock_from_snapshot(&snapshot)
+            .map_err(|e| MigratableError::Restore(anyhow!("Error restoring clock: {:?}", e)))?;
+
         if let Some(memory_manager_snapshot) = snapshot.snapshots.get(MEMORY_MANAGER_SNAPSHOT_ID) {
             self.memory_manager
                 .lock()