[Qemu-devel] [PATCH v2 5/7] tmp backend: Add new api to read backend tpm options

[Amarnath Valluri]

TPM configuration options are backend implementation details and shall not be
part of base TPMBackend object, and these shall not be accessed directly outside
of the class, hence added a new tpm backend api, tpm_backend_get_tpm_options()
to read the backend configured options.

Added new method, get_tpm_options() to TPMDriverOps., which shall be implemented
by the derived classes to return configured tpm options.

Made TPMPassthroughOptions type inherited from newly defined TPMOptions base 
type.
The TPMOptions base type is intentionally left empty and supposed to be
inherited by all backend implementations to define their tpm configuration
options.

Signed-off-by: Amarnath Valluri <address@hidden>
---
 backends/tpm.c               | 12 ++++++----
 hw/tpm/tpm_passthrough.c     | 55 +++++++++++++++++++++++++++++++++++---------
 include/sysemu/tpm_backend.h | 15 ++++++++++--
 qapi-schema.json             | 14 +++++++++--
 tpm.c                        | 13 ++---------
 5 files changed, 78 insertions(+), 31 deletions(-)

diff --git a/backends/tpm.c b/backends/tpm.c
index 0bdc5af..98aafd8 100644
--- a/backends/tpm.c
+++ b/backends/tpm.c
@@ -153,6 +153,13 @@ TPMVersion tpm_backend_get_tpm_version(TPMBackend *s)
     return k->ops->get_tpm_version(s);
 }
 
+TPMOptions *tpm_backend_get_tpm_options(TPMBackend *s)
+{
+    TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
+
+    return k->ops->get_tpm_options ? k->ops->get_tpm_options(s) : NULL;
+}
+
 static bool tpm_backend_prop_get_opened(Object *obj, Error **errp)
 {
     TPMBackend *s = TPM_BACKEND(obj);
@@ -205,9 +212,6 @@ static void tpm_backend_instance_init(Object *obj)
     s->tpm_state = NULL;
     s->thread_pool = NULL;
     s->recv_data_callback = NULL;
-    s->path = NULL;
-    s->cancel_path = NULL;
-
 }
 
 static void tpm_backend_instance_finalize(Object *obj)
@@ -215,8 +219,6 @@ static void tpm_backend_instance_finalize(Object *obj)
     TPMBackend *s = TPM_BACKEND(obj);
 
     g_free(s->id);
-    g_free(s->path);
-    g_free(s->cancel_path);
     tpm_backend_thread_end(s);
 }
 
diff --git a/hw/tpm/tpm_passthrough.c b/hw/tpm/tpm_passthrough.c
index 5b3bf1c..fce1163 100644
--- a/hw/tpm/tpm_passthrough.c
+++ b/hw/tpm/tpm_passthrough.c
@@ -50,6 +50,7 @@
 struct TPMPassthruState {
     TPMBackend parent;
 
+    TPMPassthroughOptions ops;
     char *tpm_dev;
     int tpm_fd;
     bool tpm_executing;
@@ -314,15 +315,14 @@ static TPMVersion 
tpm_passthrough_get_tpm_version(TPMBackend *tb)
  * in Documentation/ABI/stable/sysfs-class-tpm.
  * From /dev/tpm0 create /sys/class/misc/tpm0/device/cancel
  */
-static int tpm_passthrough_open_sysfs_cancel(TPMBackend *tb)
+static int tpm_passthrough_open_sysfs_cancel(TPMPassthruState *tpm_pt)
 {
-    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
     int fd = -1;
     char *dev;
     char path[PATH_MAX];
 
-    if (tb->cancel_path) {
-        fd = qemu_open(tb->cancel_path, O_WRONLY);
+    if (tpm_pt->ops.cancel_path) {
+        fd = qemu_open(tpm_pt->ops.cancel_path, O_WRONLY);
         if (fd < 0) {
             error_report("Could not open TPM cancel path : %s",
                          strerror(errno));
@@ -337,7 +337,7 @@ static int tpm_passthrough_open_sysfs_cancel(TPMBackend *tb)
                      dev) < sizeof(path)) {
             fd = qemu_open(path, O_WRONLY);
             if (fd >= 0) {
-                tb->cancel_path = g_strdup(path);
+                tpm_pt->ops.cancel_path = g_strdup(path);
             } else {
                 error_report("tpm_passthrough: Could not open TPM cancel "
                              "path %s : %s", path, strerror(errno));
@@ -357,17 +357,24 @@ static int tpm_passthrough_handle_device_opts(QemuOpts 
*opts, TPMBackend *tb)
     const char *value;
 
     value = qemu_opt_get(opts, "cancel-path");
-    tb->cancel_path = g_strdup(value);
+    if (value) {
+        tpm_pt->ops.cancel_path = g_strdup(value);
+        tpm_pt->ops.has_cancel_path = true;
+    } else {
+        tpm_pt->ops.has_cancel_path = false;
+    }
 
     value = qemu_opt_get(opts, "path");
     if (!value) {
         value = TPM_PASSTHROUGH_DEFAULT_DEVICE;
+        tpm_pt->ops.has_path = false;
+    } else {
+        tpm_pt->ops.has_path = true;
     }
 
+    tpm_pt->ops.path = g_strdup(value);
     tpm_pt->tpm_dev = g_strdup(value);
 
-    tb->path = g_strdup(tpm_pt->tpm_dev);
-
     tpm_pt->tpm_fd = qemu_open(tpm_pt->tpm_dev, O_RDWR);
     if (tpm_pt->tpm_fd < 0) {
         error_report("Cannot access TPM device using '%s': %s",
@@ -388,8 +395,8 @@ static int tpm_passthrough_handle_device_opts(QemuOpts 
*opts, TPMBackend *tb)
     tpm_pt->tpm_fd = -1;
 
  err_free_parameters:
-    g_free(tb->path);
-    tb->path = NULL;
+    g_free(tpm_pt->ops.path);
+    tpm_pt->ops.path = NULL;
 
     g_free(tpm_pt->tpm_dev);
     tpm_pt->tpm_dev = NULL;
@@ -409,7 +416,7 @@ static TPMBackend *tpm_passthrough_create(QemuOpts *opts, 
const char *id)
         goto err_exit;
     }
 
-    tpm_pt->cancel_fd = tpm_passthrough_open_sysfs_cancel(tb);
+    tpm_pt->cancel_fd = tpm_passthrough_open_sysfs_cancel(tpm_pt);
     if (tpm_pt->cancel_fd < 0) {
         goto err_exit;
     }
@@ -430,9 +437,34 @@ static void tpm_passthrough_destroy(TPMBackend *tb)
 
     qemu_close(tpm_pt->tpm_fd);
     qemu_close(tpm_pt->cancel_fd);
+
+    g_free(tpm_pt->ops.path);
+    g_free(tpm_pt->ops.cancel_path);
     g_free(tpm_pt->tpm_dev);
 }
 
+static TPMOptions *tpm_passthrough_get_tpm_options(TPMBackend *tb)
+{
+    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
+    TPMPassthroughOptions *ops = g_new0(TPMPassthroughOptions, 1);
+
+    if (!ops) {
+        return NULL;
+    }
+
+    if (tpm_pt->ops.has_path) {
+        ops->has_path = true;
+        ops->path = g_strdup(tpm_pt->ops.path);
+    }
+
+    if (tpm_pt->ops.has_cancel_path) {
+        ops->has_cancel_path = true;
+        ops->cancel_path = g_strdup(tpm_pt->ops.cancel_path);
+    }
+
+    return (TPMOptions *)ops;
+}
+
 static const QemuOptDesc tpm_passthrough_cmdline_opts[] = {
     TPM_STANDARD_CMDLINE_OPTS,
     {
@@ -461,6 +493,7 @@ static const TPMDriverOps tpm_passthrough_driver = {
     .get_tpm_established_flag = tpm_passthrough_get_tpm_established_flag,
     .reset_tpm_established_flag = tpm_passthrough_reset_tpm_established_flag,
     .get_tpm_version          = tpm_passthrough_get_tpm_version,
+    .get_tpm_options          = tpm_passthrough_get_tpm_options,
 };
 
 static void tpm_passthrough_inst_init(Object *obj)
diff --git a/include/sysemu/tpm_backend.h b/include/sysemu/tpm_backend.h
index 98b6112..82348a3 100644
--- a/include/sysemu/tpm_backend.h
+++ b/include/sysemu/tpm_backend.h
@@ -41,10 +41,9 @@ struct TPMBackend {
     GThreadPool *thread_pool;
     TPMRecvDataCB *recv_data_callback;
 
+    /* <public> */
     char *id;
     enum TpmModel fe_model;
-    char *path;
-    char *cancel_path;
 
     QLIST_ENTRY(TPMBackend) list;
 };
@@ -81,6 +80,8 @@ struct TPMDriverOps {
     int (*reset_tpm_established_flag)(TPMBackend *t, uint8_t locty);
 
     TPMVersion (*get_tpm_version)(TPMBackend *t);
+
+    TPMOptions* (*get_tpm_options)(TPMBackend *t);
 };
 
 
@@ -213,6 +214,16 @@ void tpm_backend_open(TPMBackend *s, Error **errp);
  */
 TPMVersion tpm_backend_get_tpm_version(TPMBackend *s);
 
+/**
+ * tpm_backend_get_tpm_options:
+ * @s: the backend
+ *
+ * Get the backend configuration options
+ *
+ * Returns newly allocated TPMOptions
+ */
+TPMOptions *tpm_backend_get_tpm_options(TPMBackend *s);
+
 TPMBackend *qemu_find_tpm(const char *id);
 
 const TPMDriverOps *tpm_get_backend_driver(const char *type);
diff --git a/qapi-schema.json b/qapi-schema.json
index b921994..2953cbc 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -5140,6 +5140,16 @@
 { 'command': 'query-tpm-types', 'returns': ['TpmType'] }
 
 ##
+# @TPMOptions:
+#
+# Base type for TPM options
+#
+# Since: 2.10
+##
+{ 'struct': 'TPMOptions',
+  'data': { } }
+
+##
 # @TPMPassthroughOptions:
 #
 # Information about the TPM passthrough type
@@ -5151,8 +5161,8 @@
 #
 # Since: 1.5
 ##
-{ 'struct': 'TPMPassthroughOptions', 'data': { '*path' : 'str',
-                                             '*cancel-path' : 'str'} }
+{ 'struct': 'TPMPassthroughOptions', 'base': 'TPMOptions',
+  'data': { '*path' : 'str', '*cancel-path' : 'str'} }
 
 ##
 # @TpmTypeOptions:
diff --git a/tpm.c b/tpm.c
index 0ee021a..c221000 100644
--- a/tpm.c
+++ b/tpm.c
@@ -252,7 +252,6 @@ static const TPMDriverOps *tpm_driver_find_by_type(enum 
TpmType type)
 static TPMInfo *qmp_query_tpm_inst(TPMBackend *drv)
 {
     TPMInfo *res = g_new0(TPMInfo, 1);
-    TPMPassthroughOptions *tpo;
 
     res->id = g_strdup(drv->id);
     res->model = drv->fe_model;
@@ -261,16 +260,8 @@ static TPMInfo *qmp_query_tpm_inst(TPMBackend *drv)
     switch (tpm_backend_get_type(drv)) {
     case TPM_TYPE_PASSTHROUGH:
         res->options->type = TPM_TYPE_OPTIONS_KIND_PASSTHROUGH;
-        tpo = g_new0(TPMPassthroughOptions, 1);
-        res->options->u.passthrough.data = tpo;
-        if (drv->path) {
-            tpo->path = g_strdup(drv->path);
-            tpo->has_path = true;
-        }
-        if (drv->cancel_path) {
-            tpo->cancel_path = g_strdup(drv->cancel_path);
-            tpo->has_cancel_path = true;
-        }
+        res->options->u.passthrough.data =
+            (TPMPassthroughOptions *)tpm_backend_get_tpm_options(drv);
         break;
     case TPM_TYPE__MAX:
         break;
-- 
2.7.4