[Qemu-devel] [RFC PATCH 3/4] 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               | 16 ++++++++++++++++
 hw/tpm/tpm_emulator.c        |  3 +++
 include/sysemu/tpm_backend.h | 14 ++++++++++++++
 3 files changed, 33 insertions(+)

diff --git a/backends/tpm.c b/backends/tpm.c
index 37c84b7..334836b 100644
--- a/backends/tpm.c
+++ b/backends/tpm.c
@@ -52,10 +52,22 @@ int tpm_backend_init(TPMBackend *s, TPMState *state,
     s->tpm_state = state;
     s->recv_data_callback = datacb;
     s->had_startup_error = false;
+    s->tpm_busy = false;
+
+    qemu_mutex_init(&s->state_lock);
+    qemu_cond_init(&s->cmd_complete);
 
     return k->ops->init ? k->ops->init(s) : 0;
 }
 
+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);
+}
+
 int tpm_backend_startup_tpm(TPMBackend *s)
 {
     int res = 0;
@@ -82,6 +94,10 @@ bool tpm_backend_had_startup_error(TPMBackend *s)
 
 void tpm_backend_deliver_request(TPMBackend *s)
 {
+    qemu_mutex_lock(&s->state_lock);
+    s->tpm_busy = true;
+    qemu_mutex_unlock(&s->state_lock);
+
     g_thread_pool_push(s->thread_pool, (gpointer)TPM_BACKEND_CMD_PROCESS_CMD,
                        NULL);
 }
diff --git a/hw/tpm/tpm_emulator.c b/hw/tpm/tpm_emulator.c
index 95e1e04..556b8c8 100644
--- a/hw/tpm/tpm_emulator.c
+++ b/hw/tpm/tpm_emulator.c
@@ -200,6 +200,9 @@ static void tpm_emulator_handle_request(TPMBackend *tb, TPMBackendCmd cmd)
         tb->recv_data_callback(tb->tpm_state, tb->tpm_state->locty_number,
                                selftest_done);
 
+        /* result delivered */
+        tpm_backend_cmd_completed(tb);
+
         break;
     case TPM_BACKEND_CMD_INIT:
     case TPM_BACKEND_CMD_END:
diff --git a/include/sysemu/tpm_backend.h b/include/sysemu/tpm_backend.h
index 2c798a1..cdc4742 100644
--- a/include/sysemu/tpm_backend.h
+++ b/include/sysemu/tpm_backend.h
@@ -18,6 +18,7 @@
 #include "qapi-types.h"
 #include "qemu/option.h"
 #include "sysemu/tpm.h"
+#include "qemu/thread.h"
 
 #define TYPE_TPM_BACKEND "tpm-backend"
 #define TPM_BACKEND(obj) \
@@ -54,6 +55,10 @@ struct TPMBackend {
     enum TpmModel fe_model;
 
     QLIST_ENTRY(TPMBackend) list;
+
+    QemuMutex state_lock;
+    QemuCond cmd_complete; /* signaled once tpm_busy is false */
+    bool tpm_busy;
 };
 
 struct TPMBackendClass {
@@ -213,6 +218,15 @@ 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(const char *id);
 
 const TPMDriverOps *tpm_get_backend_driver(const char *type);
-- 
2.5.5