[Qemu-devel] [PATCH v3 1/2] move vm_start to cpus.c

[Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>]

This patch:

* moves vm_start to cpus.c .
* exports qemu_vmstop_requested, since it's needed by vm_start .
* extracts vm_prepare_start from vm_start; it does what vm_start did,
  except restarting the cpus. vm_start now calls vm_prepare_start.
* moves the call to qemu_clock_enable away from resume_all_vcpus, and
  add an explicit call to it before each instance of resume_all_vcpus
  in the code.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
---
 cpus.c                     | 44 +++++++++++++++++++++++++++++++++++++++++++-
 hw/i386/kvmvapic.c         |  2 ++
 include/sysemu/cpus.h      |  1 +
 include/sysemu/sysemu.h    |  2 ++
 target-s390x/misc_helper.c |  2 ++
 vl.c                       | 32 +++-----------------------------
 6 files changed, 53 insertions(+), 30 deletions(-)

diff --git a/cpus.c b/cpus.c
index cfd5cdc..34667fa 100644
--- a/cpus.c
+++ b/cpus.c
@@ -1260,7 +1260,6 @@ void resume_all_vcpus(void)
 {
     CPUState *cpu;
 
-    qemu_clock_enable(QEMU_CLOCK_VIRTUAL, true);
     CPU_FOREACH(cpu) {
         cpu_resume(cpu);
     }
@@ -1396,6 +1395,49 @@ int vm_stop(RunState state)
     return do_vm_stop(state);
 }
 
+/**
+ * Prepare for (re)starting the VM.
+ * Returns -1 if the vCPUs are not to be restarted (e.g. if they are already
+ * running or in case of an error condition), 0 otherwise.
+ */
+int vm_prepare_start(void)
+{
+    RunState requested;
+    int res = 0;
+
+    qemu_vmstop_requested(&requested);
+    if (runstate_is_running() && requested == RUN_STATE__MAX) {
+        return -1;
+    }
+
+    /* Ensure that a STOP/RESUME pair of events is emitted if a
+     * vmstop request was pending.  The BLOCK_IO_ERROR event, for
+     * example, according to documentation is always followed by
+     * the STOP event.
+     */
+    if (runstate_is_running()) {
+        qapi_event_send_stop(&error_abort);
+        res = -1;
+    } else {
+        replay_enable_events();
+        cpu_enable_ticks();
+        runstate_set(RUN_STATE_RUNNING);
+        vm_state_notify(1, RUN_STATE_RUNNING);
+    }
+
+    /* XXX: is it ok to send this even before actually resuming the CPUs? */
+    qapi_event_send_resume(&error_abort);
+    return res;
+}
+
+void vm_start(void)
+{
+    if (!vm_prepare_start()) {
+        qemu_clock_enable(QEMU_CLOCK_VIRTUAL, true);
+        resume_all_vcpus();
+    }
+}
+
 /* does a state transition even if the VM is already stopped,
    current state is forgotten forever */
 int vm_stop_force_state(RunState state)
diff --git a/hw/i386/kvmvapic.c b/hw/i386/kvmvapic.c
index 74a549b..3101860 100644
--- a/hw/i386/kvmvapic.c
+++ b/hw/i386/kvmvapic.c
@@ -446,6 +446,7 @@ static void patch_instruction(VAPICROMState *s, X86CPU *cpu, target_ulong ip)
         abort();
     }
 
+    qemu_clock_enable(QEMU_CLOCK_VIRTUAL, true);
     resume_all_vcpus();
 
     if (!kvm_enabled()) {
@@ -686,6 +687,7 @@ static void vapic_write(void *opaque, hwaddr addr, uint64_t data,
             pause_all_vcpus();
             patch_byte(cpu, env->eip - 2, 0x66);
             patch_byte(cpu, env->eip - 1, 0x90);
+            qemu_clock_enable(QEMU_CLOCK_VIRTUAL, true);
             resume_all_vcpus();
         }
 
diff --git a/include/sysemu/cpus.h b/include/sysemu/cpus.h
index 3728a1e..5fa074b 100644
--- a/include/sysemu/cpus.h
+++ b/include/sysemu/cpus.h
@@ -5,6 +5,7 @@
 bool qemu_in_vcpu_thread(void);
 void qemu_init_cpu_loop(void);
 void resume_all_vcpus(void);
+void resume_some_vcpus(CPUState **cpus);
 void pause_all_vcpus(void);
 void cpu_stop_current(void);
 void cpu_ticks_init(void);
diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index 66c6f15..ebe8b76 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -37,6 +37,7 @@ void vm_state_notify(int running, RunState state);
 #define VMRESET_REPORT   true
 
 void vm_start(void);
+int vm_prepare_start(void);
 int vm_stop(RunState state);
 int vm_stop_force_state(RunState state);
 
@@ -60,6 +61,7 @@ void qemu_register_powerdown_notifier(Notifier *notifier);
 void qemu_system_debug_request(void);
 void qemu_system_vmstop_request(RunState reason);
 void qemu_system_vmstop_request_prepare(void);
+bool qemu_vmstop_requested(RunState *r);
 int qemu_shutdown_requested_get(void);
 int qemu_reset_requested_get(void);
 void qemu_system_killed(int signal, pid_t pid);
diff --git a/target-s390x/misc_helper.c b/target-s390x/misc_helper.c
index 4df2ec6..2b74710 100644
--- a/target-s390x/misc_helper.c
+++ b/target-s390x/misc_helper.c
@@ -133,6 +133,7 @@ static int modified_clear_reset(S390CPU *cpu)
     s390_crypto_reset();
     scc->load_normal(CPU(cpu));
     cpu_synchronize_all_post_reset();
+    qemu_clock_enable(QEMU_CLOCK_VIRTUAL, true);
     resume_all_vcpus();
     return 0;
 }
@@ -152,6 +153,7 @@ static int load_normal_reset(S390CPU *cpu)
     scc->initial_cpu_reset(CPU(cpu));
     scc->load_normal(CPU(cpu));
     cpu_synchronize_all_post_reset();
+    qemu_clock_enable(QEMU_CLOCK_VIRTUAL, true);
     resume_all_vcpus();
     return 0;
 }
diff --git a/vl.c b/vl.c
index 4ec8120..e2dbc45 100644
--- a/vl.c
+++ b/vl.c
@@ -746,7 +746,7 @@ StatusInfo *qmp_query_status(Error **errp)
     return info;
 }
 
-static bool qemu_vmstop_requested(RunState *r)
+bool qemu_vmstop_requested(RunState *r)
 {
     qemu_mutex_lock(&vmstop_lock);
     *r = vmstop_requested;
@@ -767,34 +767,6 @@ void qemu_system_vmstop_request(RunState state)
     qemu_notify_event();
 }
 
-void vm_start(void)
-{
-    RunState requested;
-
-    qemu_vmstop_requested(&requested);
-    if (runstate_is_running() && requested == RUN_STATE__MAX) {
-        return;
-    }
-
-    /* Ensure that a STOP/RESUME pair of events is emitted if a
-     * vmstop request was pending.  The BLOCK_IO_ERROR event, for
-     * example, according to documentation is always followed by
-     * the STOP event.
-     */
-    if (runstate_is_running()) {
-        qapi_event_send_stop(&error_abort);
-    } else {
-        replay_enable_events();
-        cpu_enable_ticks();
-        runstate_set(RUN_STATE_RUNNING);
-        vm_state_notify(1, RUN_STATE_RUNNING);
-        resume_all_vcpus();
-    }
-
-    qapi_event_send_resume(&error_abort);
-}
-
-
 /***********************************************************/
 /* real time host monotonic timer */
 
@@ -1914,6 +1886,7 @@ static bool main_loop_should_exit(void)
     if (qemu_reset_requested()) {
         pause_all_vcpus();
         qemu_system_reset(VMRESET_REPORT);
+        qemu_clock_enable(QEMU_CLOCK_VIRTUAL, true);
         resume_all_vcpus();
         if (!runstate_check(RUN_STATE_RUNNING) &&
                 !runstate_check(RUN_STATE_INMIGRATE)) {
@@ -1925,6 +1898,7 @@ static bool main_loop_should_exit(void)
         qemu_system_reset(VMRESET_SILENT);
         notifier_list_notify(&wakeup_notifiers, &wakeup_reason);
         wakeup_reason = QEMU_WAKEUP_REASON_NONE;
+        qemu_clock_enable(QEMU_CLOCK_VIRTUAL, true);
         resume_all_vcpus();
         qapi_event_send_wakeup(&error_abort);
     }
-- 
1.9.1