Re: [Qemu-devel] [PATCH 1/2] do proper cpu_self check

Re: [Qemu-devel] [PATCH 1/2] do proper cpu_self check

[Glauber Costa]

On Tue, Sep 8, 2009 at 5:13 PM, Glauber Costa<glommer@redhat.com> wrote:
> From: Glauber Costa <glommer@mothafucka.localdomain>

I've obviously sent this from the wrong address.
Just ignore it.

[Qemu-devel] [PATCH 1/2] do proper cpu_self check

[Glauber Costa]

From: Glauber Costa <glommer@mothafucka.localdomain>

Currently, our check for qemu_cpu_self only checks if there is a cpu
currently in execution (represented by cpu_single_env being set). While
this might be okay for tcg, it is certainly not okay for kvm, since multiple
cpus might be executing.

Instead, I propose we use pthread primitives to test if the caller thread is
the same as env->thread.

For tcg, it will have the same semantics as before, since all CPUStates will
point to the same thread, and we'll only have one in execution at a time.

Signed-off-by: Glauber Costa <glommer@mothafucka.localdomain>
---
 vl.c |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/vl.c b/vl.c
index a894285..604e996 100644
--- a/vl.c
+++ b/vl.c
@@ -3803,9 +3803,14 @@ void qemu_cpu_kick(void *_env)
         qemu_thread_signal(env->thread, SIGUSR1);
 }
 
-int qemu_cpu_self(void *env)
+int qemu_cpu_self(void *_env)
 {
-    return (cpu_single_env != NULL);
+    CPUState *env = _env;
+    QemuThread this;
+
+    qemu_thread_self(&this);
+
+    return qemu_thread_equal(&this, env->thread);
 }
 
 static void cpu_signal(int sig)
-- 
1.6.2.5

[Qemu-devel] [PATCH 1/2] do proper cpu_self check

[Glauber Costa]

Currently, our check for qemu_cpu_self only checks if there is a cpu
currently in execution (represented by cpu_single_env being set). While
this might be okay for tcg, it is certainly not okay for kvm, since multiple
cpus might be executing.

Instead, I propose we use pthread primitives to test if the caller thread is
the same as env->thread.

For tcg, it will have the same semantics as before, since all CPUStates will
point to the same thread, and we'll only have one in execution at a time.

Signed-off-by: Glauber Costa <glommer@redhat.com>
---
 vl.c |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/vl.c b/vl.c
index a894285..604e996 100644
--- a/vl.c
+++ b/vl.c
@@ -3803,9 +3803,14 @@ void qemu_cpu_kick(void *_env)
         qemu_thread_signal(env->thread, SIGUSR1);
 }
 
-int qemu_cpu_self(void *env)
+int qemu_cpu_self(void *_env)
 {
-    return (cpu_single_env != NULL);
+    CPUState *env = _env;
+    QemuThread this;
+
+    qemu_thread_self(&this);
+
+    return qemu_thread_equal(&this, env->thread);
 }
 
 static void cpu_signal(int sig)
-- 
1.6.2.5