[PATCH v3 1/1] hmp: synchronize cpu state for lapic info

[Dongli Zhang]

While the default "info lapic" always synchronizes cpu state ...

mon_get_cpu()
-> mon_get_cpu_sync(mon, true)
   -> cpu_synchronize_state(cpu)
      -> ioctl KVM_GET_LAPIC (taking KVM as example)

... the cpu state is not synchronized when the apic-id is available as
argument.

The cpu state should be synchronized when apic-id is available. Otherwise
the "info lapic <apic-id>" always returns stale data.

Reference:
https://lore.kernel.org/all/20211028155457.967291-19-berrange@redhat.com/

Cc: Joe Jin <joe.jin@oracle.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
---
Changed since v1:
  - I sent out wrong patch version in v1
Changed since v2:
  - Add the Reviewed-by from Daniel and David

 target/i386/monitor.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/target/i386/monitor.c b/target/i386/monitor.c
index 6512846327..d727270fd0 100644
--- a/target/i386/monitor.c
+++ b/target/i386/monitor.c
@@ -28,6 +28,7 @@
 #include "monitor/hmp-target.h"
 #include "monitor/hmp.h"
 #include "qapi/qmp/qdict.h"
+#include "sysemu/hw_accel.h"
 #include "sysemu/kvm.h"
 #include "qapi/error.h"
 #include "qapi/qapi-commands-misc-target.h"
@@ -654,7 +655,11 @@ void hmp_info_local_apic(Monitor *mon, const QDict *qdict)
 
     if (qdict_haskey(qdict, "apic-id")) {
         int id = qdict_get_try_int(qdict, "apic-id", 0);
+
         cs = cpu_by_arch_id(id);
+        if (cs) {
+            cpu_synchronize_state(cs);
+        }
     } else {
         cs = mon_get_cpu(mon);
     }
-- 
2.34.1