tpm-be: call request_completed() out of thread

Lift from the backend implementation the responsability to call the
request_completed() callback outside of thread context. This also
simplify frontend/interface work, as they no longer need to care
whether the callback is called from a different thread.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>

backends/tpm.c

@@ -18,14 +18,25 @@
 #include "qapi/qmp/qerror.h"
 #include "sysemu/tpm.h"
 #include "qemu/thread.h"
+#include "qemu/main-loop.h"
+
+static void tpm_backend_request_completed_bh(void *opaque)
+{
+    TPMBackend *s = TPM_BACKEND(opaque);
+    TPMIfClass *tic = TPM_IF_GET_CLASS(s->tpmif);
+
+    tic->request_completed(s->tpmif);
+}
 
 static void tpm_backend_worker_thread(gpointer data, gpointer user_data)
 {
     TPMBackend *s = TPM_BACKEND(user_data);
-    TPMBackendClass *k  = TPM_BACKEND_GET_CLASS(s);
+    TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
 
     assert(k->handle_request != NULL);
     k->handle_request(s, (TPMBackendCmd *)data);
+
+    qemu_bh_schedule(s->bh);
 }
 
 static void tpm_backend_thread_end(TPMBackend *s)
@@ -193,6 +204,7 @@ static void tpm_backend_instance_init(Object *obj)
                              tpm_backend_prop_set_opened,
                              NULL);
     s->fe_model = -1;
+    s->bh = qemu_bh_new(tpm_backend_request_completed_bh, s);
 }
 
 static void tpm_backend_instance_finalize(Object *obj)
@@ -202,6 +214,7 @@ static void tpm_backend_instance_finalize(Object *obj)
     object_unref(OBJECT(s->tpmif));
     g_free(s->id);
     tpm_backend_thread_end(s);
+    qemu_bh_delete(s->bh);
 }
 
 static const TypeInfo tpm_backend_info = {

hw/tpm/tpm_emulator.c

@@ -186,7 +186,6 @@ static int tpm_emulator_set_locality(TPMEmulator *tpm_emu, uint8_t locty_number,
 static void tpm_emulator_handle_request(TPMBackend *tb, TPMBackendCmd *cmd)
 {
     TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
-    TPMIfClass *tic = TPM_IF_GET_CLASS(tb->tpmif);
     Error *err = NULL;
 
     DPRINTF("processing TPM command");
@@ -201,7 +200,6 @@ static void tpm_emulator_handle_request(TPMBackend *tb, TPMBackendCmd *cmd)
         goto error;
     }
 
-    tic->request_completed(tb->tpmif);
     return;
 
 error:

hw/tpm/tpm_passthrough.c

@@ -139,14 +139,11 @@ err_exit:
 static void tpm_passthrough_handle_request(TPMBackend *tb, TPMBackendCmd *cmd)
 {
     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
-    TPMIfClass *tic = TPM_IF_GET_CLASS(tb->tpmif);
 
     DPRINTF("tpm_passthrough: processing command %p\n", cmd);
 
     tpm_passthrough_unix_tx_bufs(tpm_pt, cmd->in, cmd->in_len,
                                  cmd->out, cmd->out_len, &cmd->selftest_done);
-
-    tic->request_completed(tb->tpmif);
 }
 
 static void tpm_passthrough_reset(TPMBackend *tb)

hw/tpm/tpm_tis.c

@@ -76,7 +76,6 @@ typedef struct TPMState {
     ISADevice busdev;
     MemoryRegion mmio;
 
-    QEMUBH *bh;
     uint32_t offset;
     uint8_t buf[TPM_TIS_BUFFER_MAX];
 
@@ -410,10 +409,20 @@ static void tpm_tis_prep_abort(TPMState *s, uint8_t locty, uint8_t newlocty)
     tpm_tis_abort(s, locty);
 }
 
-static void tpm_tis_receive_bh(void *opaque)
+/*
+ * Callback from the TPM to indicate that the response was received.
+ */
+static void tpm_tis_request_completed(TPMIf *ti)
 {
-    TPMState *s = opaque;
+    TPMState *s = TPM(ti);
     uint8_t locty = s->cmd.locty;
+    uint8_t l;
+
+    if (s->cmd.selftest_done) {
+        for (l = 0; l < TPM_TIS_NUM_LOCALITIES; l++) {
+            s->loc[locty].sts |= TPM_TIS_STS_SELFTEST_DONE;
+        }
+    }
 
     tpm_tis_sts_set(&s->loc[locty],
                     TPM_TIS_STS_VALID | TPM_TIS_STS_DATA_AVAILABLE);
@@ -431,23 +440,6 @@ static void tpm_tis_receive_bh(void *opaque)
                       TPM_TIS_INT_DATA_AVAILABLE | TPM_TIS_INT_STS_VALID);
 }
 
-static void tpm_tis_request_completed(TPMIf *ti)
-{
-    TPMState *s = TPM(ti);
-
-    bool is_selftest_done = s->cmd.selftest_done;
-    uint8_t locty = s->cmd.locty;
-    uint8_t l;
-
-    if (is_selftest_done) {
-        for (l = 0; l < TPM_TIS_NUM_LOCALITIES; l++) {
-            s->loc[locty].sts |= TPM_TIS_STS_SELFTEST_DONE;
-        }
-    }
-
-    qemu_bh_schedule(s->bh);
-}
-
 /*
  * Read a byte of response data
  */
@@ -1094,8 +1086,6 @@ static void tpm_tis_realizefn(DeviceState *dev, Error **errp)
         return;
     }
 
-    s->bh = qemu_bh_new(tpm_tis_receive_bh, s);
-
     isa_init_irq(&s->busdev, &s->irq, s->irq_num);
 
     memory_region_add_subregion(isa_address_space(ISA_DEVICE(dev)),

include/sysemu/tpm.h

@@ -40,7 +40,6 @@ typedef struct TPMIf {
 typedef struct TPMIfClass {
     InterfaceClass parent_class;
 
-    /* run in thread pool by backend */
     void (*request_completed)(TPMIf *obj);
 } TPMIfClass;
 

include/sysemu/tpm_backend.h

@@ -47,6 +47,7 @@ struct TPMBackend {
     bool opened;
     GThreadPool *thread_pool;
     bool had_startup_error;
+    QEMUBH *bh;
 
     /* <public> */
     char *id;