From 641565ba90a36e4135a1e1427ea815b243b0e11a Mon Sep 17 00:00:00 2001
From: Yaniv Kamay <yaniv@qumranet.com>
Date: Thu, 19 Mar 2009 00:02:14 +0200
Subject: [PATCH 1/2] kvm: qemu: stop/start cpus before/after devices

Stop cpus before devices when stopping the VM, start cpus after devices
when starting VM.  Otherwise a vcpu could access a stopped device.

(cherry-picked from commit 4e9b07f80709ed62ced04f9988a55e340ada3e39)

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Bugzilla: 492355
RH-Upstream-status: pending
Acked-by: Dor Laor <dlaor@redhat.com>
Acked-with-reservation-by: Juan Quintela <quintela@redhat.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
---
 qemu/qemu-kvm.c |   19 +++++--------------
 qemu/qemu-kvm.h |    3 +++
 qemu/vl.c       |    6 ++++++
 3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/qemu/qemu-kvm.c b/qemu/qemu-kvm.c
index 8c75579..18c5258 100644
--- a/qemu/qemu-kvm.c
+++ b/qemu/qemu-kvm.c
@@ -292,7 +292,7 @@ static int all_threads_paused(void)
     return 1;
 }
 
-static void pause_all_threads(void)
+void qemu_kvm_pause_all_threads(void)
 {
     CPUState *penv = first_cpu;
 
@@ -312,7 +312,7 @@ static void pause_all_threads(void)
 	qemu_cond_wait(&qemu_pause_cond);
 }
 
-static void resume_all_threads(void)
+void qemu_kvm_resume_all_threads(void)
 {
     CPUState *penv = first_cpu;
 
@@ -326,14 +326,6 @@ static void resume_all_threads(void)
     }
 }
 
-static void kvm_vm_state_change_handler(void *context, int running)
-{
-    if (running)
-	resume_all_threads();
-    else
-	pause_all_threads();
-}
-
 static void update_regs_for_sipi(CPUState *env)
 {
     kvm_arch_update_regs_for_sipi(env);
@@ -378,7 +370,7 @@ void qemu_kvm_system_reset(void)
 {
     CPUState *penv = first_cpu;
 
-    pause_all_threads();
+    qemu_kvm_pause_all_threads();
 
     qemu_system_reset();
 
@@ -387,7 +379,7 @@ void qemu_kvm_system_reset(void)
         penv = (CPUState *)penv->next_cpu;
     }
 
-    resume_all_threads();
+    qemu_kvm_resume_all_threads();
 }
 
 static int kvm_main_loop_cpu(CPUState *env)
@@ -473,7 +465,6 @@ int kvm_init_ap(void)
 #ifdef TARGET_I386
     kvm_tpr_opt_setup();
 #endif
-    qemu_add_vm_change_state_handler(kvm_vm_state_change_handler, NULL);
 
     signal(SIG_IPI, sig_ipi_handler);
     return 0;
@@ -617,7 +608,7 @@ int kvm_main_loop(void)
 #endif
     }
 
-    pause_all_threads();
+    qemu_kvm_pause_all_threads();
     pthread_mutex_unlock(&qemu_mutex);
 
     return 0;
diff --git a/qemu/qemu-kvm.h b/qemu/qemu-kvm.h
index 8795362..050e6e9 100644
--- a/qemu/qemu-kvm.h
+++ b/qemu/qemu-kvm.h
@@ -121,6 +121,9 @@ int qemu_kvm_unregister_coalesced_mmio(target_phys_addr_t addr,
 
 void qemu_kvm_system_reset_request(void);
 
+void qemu_kvm_pause_all_threads(void);
+void qemu_kvm_resume_all_threads(void);
+
 int kvm_coalesce_mmio_region(target_phys_addr_t start, ram_addr_t size);
 int kvm_uncoalesce_mmio_region(target_phys_addr_t start, ram_addr_t size);
 
diff --git a/qemu/vl.c b/qemu/vl.c
index b2bb644..ca8e68e 100644
--- a/qemu/vl.c
+++ b/qemu/vl.c
@@ -3611,6 +3611,9 @@ void vm_start(void)
         cpu_enable_ticks();
         vm_running = 1;
         vm_state_notify(1);
+        if (kvm_enabled()) {
+            qemu_kvm_resume_all_threads();
+        }
         qemu_rearm_alarm_timer(alarm_timer);
     }
 }
@@ -3625,6 +3628,9 @@ void vm_stop(int reason)
                 vm_stop_cb(vm_stop_opaque, reason);
             }
         }
+        if (kvm_enabled()) {
+            qemu_kvm_pause_all_threads();
+        }
         vm_state_notify(0);
     }
 }
-- 
1.6.1