[Qemu-devel] [patch 10/10] qemu: basic kvm iothread support

[Marcelo Tosatti]

Allow the iothread to run while vcpu is in guest mode. To be tuned
with SMP support.

Signed-off-by: Marcelo Tosatti <address@hidden>

Index: trunk/kvm-all.c
===================================================================
--- trunk.orig/kvm-all.c
+++ trunk/kvm-all.c
@@ -451,6 +451,7 @@ int kvm_cpu_exec(CPUState *env)
 
     do {
         kvm_arch_pre_run(env, run);
+        kvm_pre_run(env);
 
         if (env->exit_request) {
             dprintf("interrupt exit requested\n");
@@ -459,6 +460,7 @@ int kvm_cpu_exec(CPUState *env)
         }
 
         ret = kvm_vcpu_ioctl(env, KVM_RUN, 0);
+        kvm_post_run(env);
         kvm_arch_post_run(env, run);
 
         if (ret == -EINTR || ret == -EAGAIN) {
Index: trunk/kvm.h
===================================================================
--- trunk.orig/kvm.h
+++ trunk/kvm.h
@@ -27,6 +27,10 @@ extern int kvm_allowed;
 
 struct kvm_run;
 
+/* main loop interface, vl.c */
+void kvm_pre_run(CPUState *env);
+void kvm_post_run(CPUState *env);
+
 /* external API */
 
 int kvm_init(int smp_cpus);
Index: trunk/target-i386/helper.c
===================================================================
--- trunk.orig/target-i386/helper.c
+++ trunk/target-i386/helper.c
@@ -1668,9 +1668,6 @@ CPUX86State *cpu_x86_init(const char *cp
 #ifdef USE_KQEMU
     kqemu_init(env);
 #endif
-    if (kvm_enabled())
-        kvm_init_vcpu(env);
-
     qemu_init_vcpu(env);
 
     return env;
Index: trunk/target-ppc/helper.c
===================================================================
--- trunk.orig/target-ppc/helper.c
+++ trunk/target-ppc/helper.c
@@ -2829,8 +2829,6 @@ CPUPPCState *cpu_ppc_init (const char *c
     cpu_ppc_register_internal(env, def);
     cpu_ppc_reset(env);
 
-    if (kvm_enabled())
-        kvm_init_vcpu(env);
     qemu_init_vcpu(env);
 
     return env;
Index: trunk/vl.c
===================================================================
--- trunk.orig/vl.c
+++ trunk/vl.c
@@ -3842,6 +3842,8 @@ void qemu_cpu_kick(void *_env)
 {
     CPUState *env = _env;
     qemu_cond_broadcast(env->halt_cond);
+    if (kvm_enabled())
+        qemu_thread_signal(env->thread, SIGUSR1);
 }
 
 int qemu_cpu_self(void *env)
@@ -3902,6 +3904,16 @@ static void qemu_signal_lock(unsigned in
     qemu_mutex_unlock(&qemu_fair_mutex);
 }
 
+static void qemu_mutex_lock_iothread(void)
+{
+    if (kvm_enabled()) {
+        qemu_mutex_lock(&qemu_fair_mutex);
+        qemu_mutex_lock(&qemu_global_mutex);
+        qemu_mutex_unlock(&qemu_fair_mutex);
+    } else
+        qemu_signal_lock(100);
+}
+
 static int all_vcpus_paused(void)
 {
     CPUState *penv = first_cpu;
@@ -3998,7 +4010,7 @@ void main_loop_wait(int timeout)
      */
     qemu_mutex_unlock(&qemu_global_mutex);
     ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv);
-    qemu_signal_lock(100);
+    qemu_mutex_lock_iothread();
     if (ret > 0) {
         IOHandlerRecord **pioh;
 
@@ -4206,9 +4218,8 @@ static void *cpu_main_loop(void *arg)
     return NULL;
 }
 
-void qemu_init_vcpu(void *_env)
+static void tcg_init_vcpu(CPUState *env)
 {
-    CPUState *env = _env;
     /* share a single thread for all cpus with TCG */
     if (!tcg_cpu_thread) {
         env->thread = qemu_mallocz(sizeof(QemuThread));
@@ -4225,6 +4236,39 @@ void qemu_init_vcpu(void *_env)
     }
 }
 
+static void kvm_start_vcpu(CPUState *env)
+{
+    kvm_init_vcpu(env);
+    env->thread = qemu_mallocz(sizeof(QemuThread));
+    env->halt_cond = qemu_mallocz(sizeof(QemuCond));
+    qemu_cond_init(env->halt_cond);
+    qemu_thread_create(env->thread, cpu_main_loop, env);
+    while (env->created == 0)
+        qemu_cond_timedwait(&qemu_cpu_cond, &qemu_global_mutex, 100);
+}
+
+void kvm_pre_run(CPUState *env)
+{
+    cpu_single_env = NULL;
+    qemu_mutex_unlock(&qemu_global_mutex);
+}
+
+void kvm_post_run(CPUState *env)
+{
+    qemu_mutex_lock(&qemu_global_mutex);
+    cpu_single_env = env;
+}
+
+void qemu_init_vcpu(void *_env)
+{
+    CPUState *env = _env;
+
+    if (kvm_enabled())
+        kvm_start_vcpu(env);
+    else
+        tcg_init_vcpu(env);
+}
+
 static void qemu_init_state(void)
 {
     qemu_cond_init(&qemu_pause_cond);