[Qemu-devel] [PATCH v3 09/13] tpm: Introduce condition to notify waiters of completed command

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

Introduce a lock and a condition to notify anyone waiting for the completion
of the execution of a TPM command by the backend (thread). The backend
uses the condition to signal anyone waiting for command completion.
We need to place the condition in two locations: one is invoked by the
backend thread, the other by the bottom half thread.
We will use the signaling to wait for command completion before VM
suspend.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
---
 hw/tpm/tpm_tis.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/hw/tpm/tpm_tis.c b/hw/tpm/tpm_tis.c
index 035c6ef..86e9a92 100644
--- a/hw/tpm/tpm_tis.c
+++ b/hw/tpm/tpm_tis.c
@@ -80,6 +80,9 @@ typedef struct TPMState {
     TPMVersion be_tpm_version;
 
     size_t be_buffer_size;
+
+    QemuMutex state_lock;
+    QemuCond cmd_complete;
 } TPMState;
 
 #define TPM(obj) OBJECT_CHECK(TPMState, (obj), TYPE_TPM_TIS)
@@ -405,6 +408,8 @@ static void tpm_tis_request_completed(TPMIf *ti)
         }
     }
 
+    qemu_mutex_lock(&s->state_lock);
+
     tpm_tis_sts_set(&s->loc[locty],
                     TPM_TIS_STS_VALID | TPM_TIS_STS_DATA_AVAILABLE);
     s->loc[locty].state = TPM_TIS_STATE_COMPLETION;
@@ -419,6 +424,10 @@ static void tpm_tis_request_completed(TPMIf *ti)
 
     tpm_tis_raise_irq(s, locty,
                       TPM_TIS_INT_DATA_AVAILABLE | TPM_TIS_INT_STS_VALID);
+
+    /* notify of completed command */
+    qemu_cond_signal(&s->cmd_complete);
+    qemu_mutex_unlock(&s->state_lock);
 }
 
 /*
@@ -1046,6 +1055,9 @@ static void tpm_tis_initfn(Object *obj)
     memory_region_init_io(&s->mmio, OBJECT(s), &tpm_tis_memory_ops,
                           s, "tpm-tis-mmio",
                           TPM_TIS_NUM_LOCALITIES << TPM_TIS_LOCALITY_SHIFT);
+
+    qemu_mutex_init(&s->state_lock);
+    qemu_cond_init(&s->cmd_complete);
 }
 
 static void tpm_tis_class_init(ObjectClass *klass, void *data)
-- 
2.5.5