[Qemu-devel] [PATCH v2 2/7] tpm: Introduce condition in TPM backend for notification

[Stefan Berger <stefanb@linux.vnet.ibm.com>]

TPM backends will suspend independently of the frontends. Also
here we need to be able to wait for the TPM command to have been
completely processed.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
---
 backends/tpm.c               | 19 +++++++++++++++++++
 include/sysemu/tpm_backend.h | 14 ++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/backends/tpm.c b/backends/tpm.c
index 7777467..2f60166 100644
--- a/backends/tpm.c
+++ b/backends/tpm.c
@@ -20,6 +20,14 @@
 #include "qemu/thread.h"
 #include "qemu/main-loop.h"
 
+void tpm_backend_cmd_completed(TPMBackend *s)
+{
+    qemu_mutex_lock(&s->state_lock);
+    s->tpm_busy = false;
+    qemu_cond_signal(&s->cmd_complete);
+    qemu_mutex_unlock(&s->state_lock);
+}
+
 static void tpm_backend_request_completed_bh(void *opaque)
 {
     TPMBackend *s = TPM_BACKEND(opaque);
@@ -36,6 +44,9 @@ static void tpm_backend_worker_thread(gpointer data, gpointer user_data)
     k->handle_request(s, (TPMBackendCmd *)data);
 
     qemu_bh_schedule(s->bh);
+
+    /* result delivered */
+    tpm_backend_cmd_completed(s);
 }
 
 static void tpm_backend_thread_end(TPMBackend *s)
@@ -64,6 +75,10 @@ int tpm_backend_init(TPMBackend *s, TPMIf *tpmif, Error **errp)
     object_ref(OBJECT(tpmif));
 
     s->had_startup_error = false;
+    s->tpm_busy = false;
+
+    qemu_mutex_init(&s->state_lock);
+    qemu_cond_init(&s->cmd_complete);
 
     return 0;
 }
@@ -93,6 +108,10 @@ bool tpm_backend_had_startup_error(TPMBackend *s)
 
 void tpm_backend_deliver_request(TPMBackend *s, TPMBackendCmd *cmd)
 {
+    qemu_mutex_lock(&s->state_lock);
+    s->tpm_busy = true;
+    qemu_mutex_unlock(&s->state_lock);
+
     g_thread_pool_push(s->thread_pool, cmd, NULL);
 }
 
diff --git a/include/sysemu/tpm_backend.h b/include/sysemu/tpm_backend.h
index d02067e..e08c51d 100644
--- a/include/sysemu/tpm_backend.h
+++ b/include/sysemu/tpm_backend.h
@@ -19,6 +19,7 @@
 #include "qemu/option.h"
 #include "sysemu/tpm.h"
 #include "hw/tpm/tpm_int.h"
+#include "qemu/thread.h"
 
 #define TYPE_TPM_BACKEND "tpm-backend"
 #define TPM_BACKEND(obj) \
@@ -54,6 +55,10 @@ struct TPMBackend {
     char *id;
 
     QLIST_ENTRY(TPMBackend) list;
+
+    QemuMutex state_lock;
+    QemuCond cmd_complete; /* signaled once tpm_busy is false */
+    bool tpm_busy;
 };
 
 struct TPMBackendClass {
@@ -193,6 +198,15 @@ TPMVersion tpm_backend_get_tpm_version(TPMBackend *s);
  */
 TPMInfo *tpm_backend_query_tpm(TPMBackend *s);
 
+/**
+ * tpm_backend_cmd_completed:
+ * @s: the backend
+ *
+ * Mark the backend as not busy and notify anyone interested
+ * in the state changed
+ */
+void tpm_backend_cmd_completed(TPMBackend *s);
+
 TPMBackend *qemu_find_tpm_be(const char *id);
 
 void tpm_register_model(enum TpmModel model);
-- 
2.5.5