The commit 317b0a6d8 fixed an issue which caused by the outdated env->tsc
value, but the fix lead to cpu_synchronize_all_states called twice during
live migration. The cpu_synchronize_all_states takes about 300us, which is
a bit expensive.
This patch tries to fix the issue in another way, and there is only one
cpu_synchronize_all_states call during live migration.
Signed-off-by: Liang Li <liang.z...@intel.com>
---
cpus.c | 8 ++++++++
hw/i386/kvm/clock.c | 17 -----------------
2 files changed, 8 insertions(+), 17 deletions(-)
diff --git a/cpus.c b/cpus.c
index c1e74d9..cd5abef 100644
--- a/cpus.c
+++ b/cpus.c
@@ -634,6 +634,14 @@ static int do_vm_stop(RunState state)
pause_all_vcpus();
runstate_set(state);
vm_state_notify(0, state);
+ switch (state) {
+ case RUN_STATE_PAUSED:
+ case RUN_STATE_SUSPENDED:
+ cpu_synchronize_all_states();
+ break;
+ default:
+ break;
+ }
qapi_event_send_stop(&error_abort);
}
diff --git a/hw/i386/kvm/clock.c b/hw/i386/kvm/clock.c
index efdf165..a9db073 100644
--- a/hw/i386/kvm/clock.c
+++ b/hw/i386/kvm/clock.c
@@ -17,7 +17,6 @@
#include "qemu/host-utils.h"
#include "sysemu/sysemu.h"
#include "sysemu/kvm.h"
-#include "sysemu/cpus.h"
#include "hw/sysbus.h"
#include "hw/kvm/clock.h"
@@ -125,22 +124,6 @@ static void kvmclock_vm_state_change(void *opaque, int
running,
return;
}
- cpu_synchronize_all_states();
- /* In theory, the cpu_synchronize_all_states() call above wouldn't
- * affect the rest of the code, as the VCPU state inside CPUState
- * is supposed to always match the VCPU state on the kernel side.
- *
- * In practice, calling cpu_synchronize_state() too soon will load the
- * kernel-side APIC state into X86CPU.apic_state too early, APIC state
- * won't be reloaded later because CPUState.vcpu_dirty==true, and
- * outdated APIC state may be migrated to another host.
- *
- * The real fix would be to make sure outdated APIC state is read
- * from the kernel again when necessary. While this is not fixed, we
- * need the cpu_clean_all_dirty() call below.
- */
- cpu_clean_all_dirty();
-
ret = kvm_vm_ioctl(kvm_state, KVM_GET_CLOCK, &data);
if (ret < 0) {
fprintf(stderr, "KVM_GET_CLOCK failed: %s\n", strerror(ret));
--
1.9.1
