qdev: add DEFINE_PROP_TPMBE

A property to lookup a tpm backend.
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NStefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: NStefan Berger <stefanb@linux.vnet.ibm.com>

hw/core/qdev-properties-system.c

@@ -21,6 +21,7 @@
 #include "net/hub.h"
 #include "qapi/visitor.h"
 #include "chardev/char-fe.h"
+#include "sysemu/tpm_backend.h"
 #include "sysemu/iothread.h"
 
 static void get_pointer(Object *obj, Visitor *v, Property *prop,
@@ -236,6 +237,69 @@ const PropertyInfo qdev_prop_chr = {
     .release = release_chr,
 };
 
+/* --- character device --- */
+
+static void get_tpm(Object *obj, Visitor *v, const char *name, void *opaque,
+                    Error **errp)
+{
+    DeviceState *dev = DEVICE(obj);
+    TPMBackend **be = qdev_get_prop_ptr(dev, opaque);
+    char *p;
+
+    p = g_strdup(*be ? (*be)->id : "");
+    visit_type_str(v, name, &p, errp);
+    g_free(p);
+}
+
+static void set_tpm(Object *obj, Visitor *v, const char *name, void *opaque,
+                    Error **errp)
+{
+    DeviceState *dev = DEVICE(obj);
+    Error *local_err = NULL;
+    Property *prop = opaque;
+    TPMBackend *s, **be = qdev_get_prop_ptr(dev, prop);
+    char *str;
+
+    if (dev->realized) {
+        qdev_prop_set_after_realize(dev, name, errp);
+        return;
+    }
+
+    visit_type_str(v, name, &str, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
+    s = qemu_find_tpm_be(str);
+    if (s == NULL) {
+        error_setg(errp, "Property '%s.%s' can't find value '%s'",
+                   object_get_typename(obj), prop->name, str);
+    } else if (tpm_backend_init(s, TPM_IF(obj), errp) == 0) {
+        *be = s; /* weak reference, avoid cyclic ref */
+    }
+    g_free(str);
+}
+
+static void release_tpm(Object *obj, const char *name, void *opaque)
+{
+    DeviceState *dev = DEVICE(obj);
+    Property *prop = opaque;
+    TPMBackend **be = qdev_get_prop_ptr(dev, prop);
+
+    if (*be) {
+        tpm_backend_reset(*be);
+    }
+}
+
+const PropertyInfo qdev_prop_tpm = {
+    .name  = "str",
+    .description = "ID of a tpm to use as a backend",
+    .get   = get_tpm,
+    .set   = set_tpm,
+    .release = release_tpm,
+};
+
 /* --- netdev device --- */
 static void get_netdev(Object *obj, Visitor *v, const char *name,
                        void *opaque, Error **errp)

include/hw/qdev-properties.h

@@ -17,6 +17,7 @@ extern const PropertyInfo qdev_prop_int64;
 extern const PropertyInfo qdev_prop_size;
 extern const PropertyInfo qdev_prop_string;
 extern const PropertyInfo qdev_prop_chr;
+extern const PropertyInfo qdev_prop_tpm;
 extern const PropertyInfo qdev_prop_ptr;
 extern const PropertyInfo qdev_prop_macaddr;
 extern const PropertyInfo qdev_prop_on_off_auto;
@@ -186,6 +187,8 @@ extern const PropertyInfo qdev_prop_link;
 
 #define DEFINE_PROP_CHR(_n, _s, _f)             \
     DEFINE_PROP(_n, _s, _f, qdev_prop_chr, CharBackend)
+#define DEFINE_PROP_TPMBE(_n, _s, _f)                     \
+    DEFINE_PROP(_n, _s, _f, qdev_prop_tpm, TPMBackend *)
 #define DEFINE_PROP_STRING(_n, _s, _f)             \
     DEFINE_PROP(_n, _s, _f, qdev_prop_string, char*)
 #define DEFINE_PROP_NETDEV(_n, _s, _f)             \