[PATCH 0/6] single-binary: deduplicate target_info()

[PATCH 0/6] single-binary: deduplicate target_info()

[Pierrick Bouvier]

We are getting close to be able to link several targets in a single QEMU system
binary, and the last obstacle on the road is to embed several TargetInfo in the
same binary. The end result of this series is to have a single definition for
target_info symbol.

This series adds TargetInfo types in QOM, and retrieve them dynamically(). At
the moment, we don't deal yet with multiple TargetInfo selection, but install
all that is needed to be able to do it easily.

Because TargetInfo data is set through class_init, it creates an issue at
startup, where we may try to instantiate additional (unrelated) types just to
retrieve the list of "target-info-X" types. Those other types class_init may be
using target information, to add target specific properties for instance.
This issue has been fixed by adding a new object_class_get_list_by_name_prefix
that does not force instantiation of all QOM types, but only those matching a
specific pattern. This way, we first initialize and retrieve target-info types
before others.

An alternative would be to leave all this out of QOM, and use startup
initializer to add them in a single list. However, because all the single-binary
work has been using QOM where possible, it would be really sad to not use it for
this final step. Comments are welcome!

Finally, sticking to our promise not create a special "single-binary
configuration", the goal is to use the *exact* same codepath for normal binaries
also. It means that even for existing system binaries, the goal will be to use
QOM to retrieve current target, even if there is only one.

Pierrick Bouvier (6):
  target-info: extract target_info() definition in target-info-init.h
  target-info: introduce TargetInfo in QOM
  system/vl: initialize QOM first
  qom/object: add object_class_get_list_by_name_prefix
  target-info-qom: detect target from QOM
  target-info: replace target_info() in system-mode

 configs/targets/aarch64-softmmu.c |  6 +--
 configs/targets/arm-softmmu.c     |  6 +--
 include/qemu/target-info-init.h   | 63 +++++++++++++++++++++++++++++++
 include/qemu/target-info-qom.h    | 25 ++++++++++++
 include/qom/object.h              | 13 +++++++
 qom/object.c                      | 40 ++++++++++++++++++++
 system/runstate.c                 |  1 -
 system/vl.c                       |  5 +++
 target-info-qom.c                 | 32 ++++++++++++++++
 target-info-stub.c                |  6 +--
 10 files changed, 184 insertions(+), 13 deletions(-)
 create mode 100644 include/qemu/target-info-init.h
 create mode 100644 include/qemu/target-info-qom.h

-- 
2.43.0

[PATCH 1/6] target-info: extract target_info() definition in target-info-init.h

[Pierrick Bouvier]

This allows us to prepare next commits, which will introduce qom
registration for system mode.

Signed-off-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
---
 configs/targets/aarch64-softmmu.c |  6 ++----
 configs/targets/arm-softmmu.c     |  6 ++----
 include/qemu/target-info-init.h   | 20 ++++++++++++++++++++
 target-info-stub.c                |  6 ++----
 4 files changed, 26 insertions(+), 12 deletions(-)
 create mode 100644 include/qemu/target-info-init.h

diff --git a/configs/targets/aarch64-softmmu.c b/configs/targets/aarch64-softmmu.c
index 82ccb575759..75d95b0e743 100644
--- a/configs/targets/aarch64-softmmu.c
+++ b/configs/targets/aarch64-softmmu.c
@@ -8,6 +8,7 @@
 
 #include "qemu/osdep.h"
 #include "qemu/target-info-impl.h"
+#include "qemu/target-info-init.h"
 #include "hw/arm/machines-qom.h"
 #include "target/arm/cpu-qom.h"
 #include "target/arm/cpu-param.h"
@@ -23,7 +24,4 @@ static const TargetInfo target_info_aarch64_system = {
     .page_bits_init = TARGET_PAGE_BITS_LEGACY,
 };
 
-const TargetInfo *target_info(void)
-{
-    return &target_info_aarch64_system;
-}
+target_info_init(target_info_aarch64_system)
diff --git a/configs/targets/arm-softmmu.c b/configs/targets/arm-softmmu.c
index 18940e51e55..73546fa5737 100644
--- a/configs/targets/arm-softmmu.c
+++ b/configs/targets/arm-softmmu.c
@@ -8,6 +8,7 @@
 
 #include "qemu/osdep.h"
 #include "qemu/target-info-impl.h"
+#include "qemu/target-info-init.h"
 #include "hw/arm/machines-qom.h"
 #include "target/arm/cpu-qom.h"
 #include "target/arm/cpu-param.h"
@@ -23,7 +24,4 @@ static const TargetInfo target_info_arm_system = {
     .page_bits_init = TARGET_PAGE_BITS_LEGACY,
 };
 
-const TargetInfo *target_info(void)
-{
-    return &target_info_arm_system;
-}
+target_info_init(target_info_arm_system)
diff --git a/include/qemu/target-info-init.h b/include/qemu/target-info-init.h
new file mode 100644
index 00000000000..9be06d8523a
--- /dev/null
+++ b/include/qemu/target-info-init.h
@@ -0,0 +1,20 @@
+/*
+ * QEMU target info initialization
+ *
+ * Copyright (c) Qualcomm
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * This file is included by each file defining a TargetInfo structure and is
+ * responsible for registering it.
+ */
+
+#ifndef TARGET_INFO_DEF_H
+
+#define target_info_init(ti_var)        \
+const TargetInfo *target_info(void)     \
+{                                       \
+    return &ti_var;                     \
+}
+
+#endif /* TARGET_INFO_DEF_H */
diff --git a/target-info-stub.c b/target-info-stub.c
index f5896a72621..af7cdc5e67a 100644
--- a/target-info-stub.c
+++ b/target-info-stub.c
@@ -9,6 +9,7 @@
 #include "qemu/osdep.h"
 #include "qemu/target-info.h"
 #include "qemu/target-info-impl.h"
+#include "qemu/target-info-init.h"
 #include "hw/core/boards.h"
 #include "cpu.h"
 #include "exec/page-vary.h"
@@ -40,7 +41,4 @@ static const TargetInfo target_info_stub = {
 #endif
 };
 
-const TargetInfo *target_info(void)
-{
-    return &target_info_stub;
-}
+target_info_init(target_info_stub)
-- 
2.43.0

[PATCH 2/6] target-info: introduce TargetInfo in QOM

[Pierrick Bouvier]

For the single-binary, we want to be able to retrieve at runtime the
current target among the different ones available.
A consequence is that we can't rely on existing target_info() definition
since it will create a conflict once more than one target is available.

To solve this, we add TargetInfo in QOM, with this hierarchy.
We define one class "target-info-X" per target, that inherits from
abstract class "target-info". Using concrete vs abstract class ensure we
can easily filter "target-info-X" from all QOM types.
Associated TargetInfo is directly set through class initialization,
without relying on any instance.

For user mode, we simply define target_info() like it was done
previously. In this patch, we keep the same definition for system-mode
also, and it will be replaced in next commits.

Signed-off-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
---
 include/qemu/target-info-init.h | 48 +++++++++++++++++++++++++++++++++
 include/qemu/target-info-qom.h  | 23 ++++++++++++++++
 target-info-qom.c               | 10 +++++++
 3 files changed, 81 insertions(+)
 create mode 100644 include/qemu/target-info-qom.h

diff --git a/include/qemu/target-info-init.h b/include/qemu/target-info-init.h
index 9be06d8523a..f3cea985540 100644
--- a/include/qemu/target-info-init.h
+++ b/include/qemu/target-info-init.h
@@ -11,10 +11,58 @@
 
 #ifndef TARGET_INFO_DEF_H
 
+#ifdef CONFIG_USER_ONLY
+
+/*
+ * User mode does not support multiple targets in the same binary, so just
+ * define target_info().
+ */
 #define target_info_init(ti_var)        \
 const TargetInfo *target_info(void)     \
 {                                       \
     return &ti_var;                     \
 }
 
+#else /* CONFIG_USER_ONLY */
+
+#include "qemu/target-info-qom.h"
+#include "qom/object.h"
+
+#define TYPE_TARGET_INFO_TARGET TYPE_TARGET_INFO"-"TARGET_NAME
+
+typedef struct TargetInfoQomTarget {
+    TargetInfoQom parent;
+} TargetInfoQomTarget;
+
+typedef struct TargetInfoQomTargetClass {
+    TargetInfoQomClass parent_class;
+} TargetInfoQomTargetClass;
+
+OBJECT_DECLARE_TYPE(TargetInfoQomTarget, TargetInfoQomTargetClass, TARGET_INFO_TARGET)
+
+#define target_info_init(ti_var)                                            \
+const TargetInfo *target_info(void)                                         \
+{                                                                           \
+    return &ti_var;                                                         \
+}                                                                           \
+                                                                            \
+static void target_info_qom_class_init(ObjectClass *oc, const void * data)  \
+{                                                                           \
+    TargetInfoQomTargetClass *klass = TARGET_INFO_TARGET_CLASS(oc);         \
+    klass->parent_class.target_info = &ti_var;                              \
+}                                                                           \
+                                                                            \
+static const TypeInfo target_info_qom_target_type_info[] = {                \
+{                                                                           \
+    .name = TYPE_TARGET_INFO_TARGET,                                        \
+    .parent = TYPE_TARGET_INFO,                                             \
+    .instance_size = sizeof(TargetInfoQomTarget),                           \
+    .class_size = sizeof(TargetInfoQomTargetClass),                         \
+    .class_init = target_info_qom_class_init,                               \
+    .abstract = false,                                                      \
+} };                                                                        \
+DEFINE_TYPES(target_info_qom_target_type_info)
+
+#endif /* CONFIG_USER_ONLY */
+
 #endif /* TARGET_INFO_DEF_H */
diff --git a/include/qemu/target-info-qom.h b/include/qemu/target-info-qom.h
new file mode 100644
index 00000000000..db069db718a
--- /dev/null
+++ b/include/qemu/target-info-qom.h
@@ -0,0 +1,23 @@
+/*
+ * QEMU target info QOM types
+ *
+ * Copyright (c) Qualcomm
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/target-info-impl.h"
+#include "qom/object.h"
+
+#define TYPE_TARGET_INFO "target-info"
+
+typedef struct TargetInfoQom {
+    Object parent_obj;
+} TargetInfoQom;
+
+typedef struct TargetInfoQomClass {
+    ObjectClass parent_class;
+    const TargetInfo *target_info;
+} TargetInfoQomClass;
+
+OBJECT_DECLARE_TYPE(TargetInfoQom, TargetInfoQomClass, TARGET_INFO)
diff --git a/target-info-qom.c b/target-info-qom.c
index 7fd58d24818..5ce29f80301 100644
--- a/target-info-qom.c
+++ b/target-info-qom.c
@@ -7,10 +7,20 @@
  */
 
 #include "qemu/osdep.h"
+#include "qapi/error.h"
 #include "qom/object.h"
+#include "qemu/target-info-impl.h"
+#include "qemu/target-info-qom.h"
 #include "hw/arm/machines-qom.h"
 
 static const TypeInfo target_info_types[] = {
+    {
+        .name = TYPE_TARGET_INFO,
+        .parent = TYPE_OBJECT,
+        .instance_size = sizeof(TargetInfoQom),
+        .class_size = sizeof(TargetInfoQomClass),
+        .abstract = true,
+    },
     {
         .name           = TYPE_TARGET_ARM_MACHINE,
         .parent         = TYPE_INTERFACE,
-- 
2.43.0

[PATCH 3/6] system/vl: initialize QOM first

[Pierrick Bouvier]

We will introduce detection of target from QOM, so we need to make sure
QOM is initialized first.

Signed-off-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
---
 system/runstate.c | 1 -
 system/vl.c       | 3 +++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/system/runstate.c b/system/runstate.c
index 770253b467b..c8e92f8a603 100644
--- a/system/runstate.c
+++ b/system/runstate.c
@@ -981,7 +981,6 @@ void qemu_init_subsystems(void)
 
     atexit(qemu_run_exit_notifiers);
 
-    module_call_init(MODULE_INIT_QOM);
     module_call_init(MODULE_INIT_MIGRATION);
 
     runstate_init();
diff --git a/system/vl.c b/system/vl.c
index 0e1fc217b4f..b4a5ea6f857 100644
--- a/system/vl.c
+++ b/system/vl.c
@@ -2889,6 +2889,9 @@ void qemu_init(int argc, char **argv)
     os_setup_limits();
 
     module_init_info(qemu_modinfo);
+    /* We need to initialize QOM first to detect target */
+    module_call_init(MODULE_INIT_QOM);
+
     module_allow_arch(target_name());
 
     qemu_init_subsystems();
-- 
2.43.0

[PATCH 4/6] qom/object: add object_class_get_list_by_name_prefix

[Pierrick Bouvier]

The existing object_class_get_list forces an initialization of all QOM
types, which triggers call to class_init for all types.
This function checks type name before initializing it.

Next commit will query list of target-info QOM types. However, some
existing classes already rely on target detection to add conditional
properties. Thus, we need to be able to initialize only target-info
types first.

Signed-off-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
---
 include/qom/object.h | 13 +++++++++++++
 qom/object.c         | 40 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+)

diff --git a/include/qom/object.h b/include/qom/object.h
index 510885218ba..a6d7b3874a7 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -1033,6 +1033,19 @@ GSList *object_class_get_list(const char *implements_type,
 GSList *object_class_get_list_sorted(const char *implements_type,
                               bool include_abstract);
 
+/**
+ * object_class_get_list:
+ * @name_prefix: Name prefix for type to filter for.
+ * @include_abstract: Whether to include abstract classes.
+ *
+ * To the opposite of object_class_get_list, only matching types are
+ * initialized.
+ *
+ * Returns: A singly-linked list of the classes in reverse hashtable order.
+ */
+GSList *object_class_get_list_by_name_prefix(const char *name_prefix,
+                                             bool include_abstract);
+
 /**
  * object_ref:
  * @obj: the object
diff --git a/qom/object.c b/qom/object.c
index f981e270440..14527108a2e 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -1062,6 +1062,30 @@ static void object_class_foreach_tramp(gpointer key, gpointer value,
     data->fn(k, data->opaque);
 }
 
+static void object_class_foreach_match_name_prefix(gpointer key, gpointer value,
+                                                   gpointer opaque)
+{
+    OCFData *data = opaque;
+    TypeImpl *type = value;
+    ObjectClass *k;
+
+    const char *name_prefix = data->implements_type;
+    size_t prefix_len = name_prefix ? strlen(name_prefix) : 0;
+
+    if (strncmp(type->name, name_prefix, prefix_len)) {
+        return;
+    }
+
+    type_initialize(type);
+    k = type->class;
+
+    if (!data->include_abstract && type->abstract) {
+        return;
+    }
+
+    data->fn(k, data->opaque);
+}
+
 void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
                           const char *implements_type, bool include_abstract,
                           void *opaque)
@@ -1131,6 +1155,22 @@ GSList *object_class_get_list(const char *implements_type,
     return list;
 }
 
+GSList *object_class_get_list_by_name_prefix(const char *name_prefix,
+                                             bool include_abstract)
+{
+    GSList *list = NULL;
+
+    OCFData data = { object_class_get_list_tramp,
+                     name_prefix, include_abstract, &list };
+
+    enumerating_types = true;
+    g_hash_table_foreach(type_table_get(),
+                         object_class_foreach_match_name_prefix,
+                         &data);
+    enumerating_types = false;
+    return list;
+}
+
 static gint object_class_cmp(gconstpointer a, gconstpointer b, gpointer d)
 {
     return g_ascii_strcasecmp(object_class_get_name((ObjectClass *)a),
-- 
2.43.0

[PATCH 5/6] target-info-qom: detect target from QOM

[Pierrick Bouvier]

For now, we expect only one target to be available at runtime. This will
change with the single-binary and we'll detect which one to use
dynamically.

Signed-off-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
---
 include/qemu/target-info-qom.h |  2 ++
 system/vl.c                    |  2 ++
 target-info-qom.c              | 17 +++++++++++++++++
 3 files changed, 21 insertions(+)

diff --git a/include/qemu/target-info-qom.h b/include/qemu/target-info-qom.h
index db069db718a..9549465aa64 100644
--- a/include/qemu/target-info-qom.h
+++ b/include/qemu/target-info-qom.h
@@ -21,3 +21,5 @@ typedef struct TargetInfoQomClass {
 } TargetInfoQomClass;
 
 OBJECT_DECLARE_TYPE(TargetInfoQom, TargetInfoQomClass, TARGET_INFO)
+
+void target_info_qom_set_target(void);
diff --git a/system/vl.c b/system/vl.c
index b4a5ea6f857..96a03ff2ff7 100644
--- a/system/vl.c
+++ b/system/vl.c
@@ -28,6 +28,7 @@
 #include "qemu/units.h"
 #include "qemu/module.h"
 #include "qemu/target-info.h"
+#include "qemu/target-info-qom.h"
 #include "exec/cpu-common.h"
 #include "exec/page-vary.h"
 #include "hw/core/qdev-properties.h"
@@ -2891,6 +2892,7 @@ void qemu_init(int argc, char **argv)
     module_init_info(qemu_modinfo);
     /* We need to initialize QOM first to detect target */
     module_call_init(MODULE_INIT_QOM);
+    target_info_qom_set_target();
 
     module_allow_arch(target_name());
 
diff --git a/target-info-qom.c b/target-info-qom.c
index 5ce29f80301..748fdd5a8fb 100644
--- a/target-info-qom.c
+++ b/target-info-qom.c
@@ -32,3 +32,20 @@ static const TypeInfo target_info_types[] = {
 };
 
 DEFINE_TYPES(target_info_types)
+
+static const TargetInfo *target_info_ptr;
+
+void target_info_qom_set_target(void)
+{
+    g_autoptr(GSList) targets =
+        object_class_get_list_by_name_prefix(TYPE_TARGET_INFO, false);
+
+    size_t num_found = g_slist_length(targets);
+    if (num_found != 1) {
+        error_setg(&error_fatal, num_found == 0 ?
+                                 "no target-info is available" :
+                                 "more than one target-info is available");
+    }
+
+    target_info_ptr = TARGET_INFO_CLASS(targets->data)->target_info;
+}
-- 
2.43.0

[PATCH 6/6] target-info: replace target_info() in system-mode

[Pierrick Bouvier]

We now can use TargetInfo information available from QOM, and remove
duplicated target_info() symbol.

Signed-off-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
---
 include/qemu/target-info-init.h | 5 -----
 target-info-qom.c               | 5 +++++
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/qemu/target-info-init.h b/include/qemu/target-info-init.h
index f3cea985540..51aa9419e88 100644
--- a/include/qemu/target-info-init.h
+++ b/include/qemu/target-info-init.h
@@ -41,11 +41,6 @@ typedef struct TargetInfoQomTargetClass {
 OBJECT_DECLARE_TYPE(TargetInfoQomTarget, TargetInfoQomTargetClass, TARGET_INFO_TARGET)
 
 #define target_info_init(ti_var)                                            \
-const TargetInfo *target_info(void)                                         \
-{                                                                           \
-    return &ti_var;                                                         \
-}                                                                           \
-                                                                            \
 static void target_info_qom_class_init(ObjectClass *oc, const void * data)  \
 {                                                                           \
     TargetInfoQomTargetClass *klass = TARGET_INFO_TARGET_CLASS(oc);         \
diff --git a/target-info-qom.c b/target-info-qom.c
index 748fdd5a8fb..feba764a6bc 100644
--- a/target-info-qom.c
+++ b/target-info-qom.c
@@ -35,6 +35,11 @@ DEFINE_TYPES(target_info_types)
 
 static const TargetInfo *target_info_ptr;
 
+const TargetInfo *target_info(void)
+{
+    return target_info_ptr;
+}
+
 void target_info_qom_set_target(void)
 {
     g_autoptr(GSList) targets =
-- 
2.43.0

Re: [PATCH 2/6] target-info: introduce TargetInfo in QOM

[marcandre.lureau]

On Tue, 28 Apr 2026 16:45:15 -0700, Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com> wrote:
> diff --git a/include/qemu/target-info-qom.h b/include/qemu/target-info-qom.h
> new file mode 100644
> index 00000000000..db069db718a
> --- /dev/null
> +++ b/include/qemu/target-info-qom.h
> @@ -0,0 +1,23 @@
> +/*
> + * QEMU target info QOM types
> + *
> + * Copyright (c) Qualcomm
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +
> +#include "qemu/target-info-impl.h"
> +#include "qom/object.h"

Missing include guard. Add:

  #ifndef QEMU_TARGET_INFO_QOM_H
  #define QEMU_TARGET_INFO_QOM_H

before the includes, and a matching #endif at the end.

-- 
Marc-André Lureau <marcandre.lureau@redhat.com>

Re: [PATCH 3/6] system/vl: initialize QOM first

[marcandre.lureau]

On Tue, 28 Apr 2026 16:45:16 -0700, Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com> wrote:
> diff --git a/system/vl.c b/system/vl.c
> index 0e1fc217b4f..b4a5ea6f857 100644
> --- a/system/vl.c
> +++ b/system/vl.c
> @@ -2889,6 +2889,9 @@ void qemu_init(int argc, char **argv)
>      os_setup_limits();
>  
>      module_init_info(qemu_modinfo);
> +    /* We need to initialize QOM first to detect target */
> +    module_call_init(MODULE_INIT_QOM);
> +
>      module_allow_arch(target_name());

This change is not trivial. By moving the call here, we lose the
initializations from qemu_init_subsystems(). Verifying that all
type_init() code is safe to run without it is a tedious task. It might
be better to introduce a new MODULE_INIT_TARGET_INFO instead

-- 
Marc-André Lureau <marcandre.lureau@redhat.com>

Re: [PATCH 4/6] qom/object: add object_class_get_list_by_name_prefix

[marcandre.lureau]

On Tue, 28 Apr 2026 16:45:17 -0700, Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com> wrote:
> diff --git a/include/qom/object.h b/include/qom/object.h
> index 510885218ba..a6d7b3874a7 100644
> --- a/include/qom/object.h
> +++ b/include/qom/object.h
> @@ -1033,6 +1033,19 @@ GSList *object_class_get_list(const char *implements_type,
>  GSList *object_class_get_list_sorted(const char *implements_type,
>                                bool include_abstract);
>  
> +/**
> + * object_class_get_list:

Should be "object_class_get_list_by_name_prefix:".

> + * @name_prefix: Name prefix for type to filter for.
> + * @include_abstract: Whether to include abstract classes.
> + *
> + * To the opposite of object_class_get_list, only matching types are

Suggest "Unlike object_class_get_list,"

>
> diff --git a/qom/object.c b/qom/object.c
> index f981e270440..14527108a2e 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -1062,6 +1062,30 @@ static void object_class_foreach_tramp(gpointer key, gpointer value,
>      data->fn(k, data->opaque);
>  }
>  
> +static void object_class_foreach_match_name_prefix(gpointer key, gpointer value,
> +                                                   gpointer opaque)
> +{
> +    OCFData *data = opaque;
> +    TypeImpl *type = value;
> +    ObjectClass *k;
> +
> +    const char *name_prefix = data->implements_type;

Perhaps the "implements_type" field should be renamed.

> [ ... skip 11 lines ... ]
> +    }
> +
> +    data->fn(k, data->opaque);
> +}
> +
>  void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),

I wonder if we introduce MODULE_INIT_TARGET_INFO, is this all needed?
since only TargetInfo types would be registered..

Suggest: "Unlike object_class_get_list,"

Suggest: "Unlike object_class_get_list,"

-- 
Marc-André Lureau <marcandre.lureau@redhat.com>

Re: [PATCH 6/6] target-info: replace target_info() in system-mode

[marcandre.lureau]

On Tue, 28 Apr 2026 16:45:19 -0700, Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com> wrote:
> We now can use TargetInfo information available from QOM, and remove
> duplicated target_info() symbol.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

-- 
Marc-André Lureau <marcandre.lureau@redhat.com>

Re: [PATCH 1/6] target-info: extract target_info() definition in target-info-init.h

[marcandre.lureau]

On Tue, 28 Apr 2026 16:45:14 -0700, Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com> wrote:
> This allows us to prepare next commits, which will introduce qom
> registration for system mode.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

-- 
Marc-André Lureau <marcandre.lureau@redhat.com>

Re: [PATCH 5/6] target-info-qom: detect target from QOM

[marcandre.lureau]

On Tue, 28 Apr 2026 16:45:18 -0700, Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com> wrote:
> For now, we expect only one target to be available at runtime. This will
> change with the single-binary and we'll detect which one to use
> dynamically.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

-- 
Marc-André Lureau <marcandre.lureau@redhat.com>

Re: [PATCH 3/6] system/vl: initialize QOM first

[Daniel P. Berrangé]

On Wed, Apr 29, 2026 at 12:36:03PM +0400, marcandre.lureau@redhat.com wrote:
> On Tue, 28 Apr 2026 16:45:16 -0700, Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com> wrote:
> > diff --git a/system/vl.c b/system/vl.c
> > index 0e1fc217b4f..b4a5ea6f857 100644
> > --- a/system/vl.c
> > +++ b/system/vl.c
> > @@ -2889,6 +2889,9 @@ void qemu_init(int argc, char **argv)
> >      os_setup_limits();
> >  
> >      module_init_info(qemu_modinfo);
> > +    /* We need to initialize QOM first to detect target */
> > +    module_call_init(MODULE_INIT_QOM);
> > +
> >      module_allow_arch(target_name());
> 
> This change is not trivial. By moving the call here, we lose the
> initializations from qemu_init_subsystems(). Verifying that all
> type_init() code is safe to run without it is a tedious task. It might
> be better to introduce a new MODULE_INIT_TARGET_INFO instead

I'd be inclined to have a MODULE_INIT_QOM_EARLY, along with a
type_init_early(), so we're not presuming target info is the only
use case for earlier init.

Regards,
Daniel

Re: [PATCH 4/6] qom/object: add object_class_get_list_by_name_prefix

[Daniel P. Berrangé]

On Wed, Apr 29, 2026 at 12:36:03PM +0400, marcandre.lureau@redhat.com wrote:
> On Tue, 28 Apr 2026 16:45:17 -0700, Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com> wrote:
> > diff --git a/include/qom/object.h b/include/qom/object.h
> > index 510885218ba..a6d7b3874a7 100644
> > --- a/include/qom/object.h
> > +++ b/include/qom/object.h
> > @@ -1033,6 +1033,19 @@ GSList *object_class_get_list(const char *implements_type,
> >  GSList *object_class_get_list_sorted(const char *implements_type,
> >                                bool include_abstract);
> >  
> > +/**
> > + * object_class_get_list:
> 
> Should be "object_class_get_list_by_name_prefix:".
> 
> > + * @name_prefix: Name prefix for type to filter for.
> > + * @include_abstract: Whether to include abstract classes.
> > + *
> > + * To the opposite of object_class_get_list, only matching types are
> 
> Suggest "Unlike object_class_get_list,"
> 
> >
> > diff --git a/qom/object.c b/qom/object.c
> > index f981e270440..14527108a2e 100644
> > --- a/qom/object.c
> > +++ b/qom/object.c
> > @@ -1062,6 +1062,30 @@ static void object_class_foreach_tramp(gpointer key, gpointer value,
> >      data->fn(k, data->opaque);
> >  }
> >  
> > +static void object_class_foreach_match_name_prefix(gpointer key, gpointer value,
> > +                                                   gpointer opaque)
> > +{
> > +    OCFData *data = opaque;
> > +    TypeImpl *type = value;
> > +    ObjectClass *k;
> > +
> > +    const char *name_prefix = data->implements_type;
> 
> Perhaps the "implements_type" field should be renamed.
> 
> > [ ... skip 11 lines ... ]
> > +    }
> > +
> > +    data->fn(k, data->opaque);
> > +}
> > +
> >  void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
> 
> I wonder if we introduce MODULE_INIT_TARGET_INFO, is this all needed?
> since only TargetInfo types would be registered..

Yeah, i feel like this patch should be redundant if we provide  a
separate initializer for early types to get registered.

Daniel

Re: [PATCH 2/6] target-info: introduce TargetInfo in QOM

[Pierrick Bouvier]

On 4/29/2026 1:36 AM, marcandre.lureau@redhat.com wrote:
> On Tue, 28 Apr 2026 16:45:15 -0700, Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com> wrote:
>> diff --git a/include/qemu/target-info-qom.h b/include/qemu/target-info-qom.h
>> new file mode 100644
>> index 00000000000..db069db718a
>> --- /dev/null
>> +++ b/include/qemu/target-info-qom.h
>> @@ -0,0 +1,23 @@
>> +/*
>> + * QEMU target info QOM types
>> + *
>> + * Copyright (c) Qualcomm
>> + *
>> + * SPDX-License-Identifier: GPL-2.0-or-later
>> + */
>> +
>> +#include "qemu/target-info-impl.h"
>> +#include "qom/object.h"
> 
> Missing include guard. Add:
> 
>   #ifndef QEMU_TARGET_INFO_QOM_H
>   #define QEMU_TARGET_INFO_QOM_H
> 
> before the includes, and a matching #endif at the end.
> 

Oops indeed. I'll add it thanks.

Re: [PATCH 4/6] qom/object: add object_class_get_list_by_name_prefix

[Pierrick Bouvier]

On 4/29/2026 1:48 AM, Daniel P. Berrangé wrote:
> On Wed, Apr 29, 2026 at 12:36:03PM +0400, marcandre.lureau@redhat.com wrote:
>> On Tue, 28 Apr 2026 16:45:17 -0700, Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com> wrote:
>>> diff --git a/include/qom/object.h b/include/qom/object.h
>>> index 510885218ba..a6d7b3874a7 100644
>>> --- a/include/qom/object.h
>>> +++ b/include/qom/object.h
>>> @@ -1033,6 +1033,19 @@ GSList *object_class_get_list(const char *implements_type,
>>>  GSList *object_class_get_list_sorted(const char *implements_type,
>>>                                bool include_abstract);
>>>  
>>> +/**
>>> + * object_class_get_list:
>>
>> Should be "object_class_get_list_by_name_prefix:".
>>
>>> + * @name_prefix: Name prefix for type to filter for.
>>> + * @include_abstract: Whether to include abstract classes.
>>> + *
>>> + * To the opposite of object_class_get_list, only matching types are
>>
>> Suggest "Unlike object_class_get_list,"
>>
>>>
>>> diff --git a/qom/object.c b/qom/object.c
>>> index f981e270440..14527108a2e 100644
>>> --- a/qom/object.c
>>> +++ b/qom/object.c
>>> @@ -1062,6 +1062,30 @@ static void object_class_foreach_tramp(gpointer key, gpointer value,
>>>      data->fn(k, data->opaque);
>>>  }
>>>  
>>> +static void object_class_foreach_match_name_prefix(gpointer key, gpointer value,
>>> +                                                   gpointer opaque)
>>> +{
>>> +    OCFData *data = opaque;
>>> +    TypeImpl *type = value;
>>> +    ObjectClass *k;
>>> +
>>> +    const char *name_prefix = data->implements_type;
>>
>> Perhaps the "implements_type" field should be renamed.
>>
>>> [ ... skip 11 lines ... ]
>>> +    }
>>> +
>>> +    data->fn(k, data->opaque);
>>> +}
>>> +
>>>  void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
>>
>> I wonder if we introduce MODULE_INIT_TARGET_INFO, is this all needed?
>> since only TargetInfo types would be registered..
> 
> Yeah, i feel like this patch should be redundant if we provide  a
> separate initializer for early types to get registered.
>

You're both right, this patch is not necessary anymore.
Since only target-info QOM types are registered after this step, we can
safely call object_class_get_list.

> Daniel
> 

Regards,
Pierrick

Re: [PATCH 3/6] system/vl: initialize QOM first

[Pierrick Bouvier]

On 4/29/2026 1:46 AM, Daniel P. Berrangé wrote:
> On Wed, Apr 29, 2026 at 12:36:03PM +0400, marcandre.lureau@redhat.com wrote:
>> On Tue, 28 Apr 2026 16:45:16 -0700, Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com> wrote:
>>> diff --git a/system/vl.c b/system/vl.c
>>> index 0e1fc217b4f..b4a5ea6f857 100644
>>> --- a/system/vl.c
>>> +++ b/system/vl.c
>>> @@ -2889,6 +2889,9 @@ void qemu_init(int argc, char **argv)
>>>      os_setup_limits();
>>>  
>>>      module_init_info(qemu_modinfo);
>>> +    /* We need to initialize QOM first to detect target */
>>> +    module_call_init(MODULE_INIT_QOM);
>>> +
>>>      module_allow_arch(target_name());
>>
>> This change is not trivial. By moving the call here, we lose the
>> initializations from qemu_init_subsystems(). Verifying that all
>> type_init() code is safe to run without it is a tedious task. It might
>> be better to introduce a new MODULE_INIT_TARGET_INFO instead
>

That seems like the right approach, thanks!

> I'd be inclined to have a MODULE_INIT_QOM_EARLY, along with a
> type_init_early(), so we're not presuming target info is the only
> use case for earlier init.
>

I feel that if we need such behavior, we can introduce another step when
needed. For the current scenario, it's really target-info vs all other
types, so it makes sense to reflect that in the name. Thus I would
prefer to follow Daniel naming for this one, if it works for you.

> Regards,
> Daniel
> 

Thanks,
Pierrick

Re: [PATCH 0/6] single-binary: deduplicate target_info()

[Pierrick Bouvier]

On 4/28/2026 4:45 PM, Pierrick Bouvier wrote:
> We are getting close to be able to link several targets in a single QEMU system
> binary, and the last obstacle on the road is to embed several TargetInfo in the
> same binary. The end result of this series is to have a single definition for
> target_info symbol.
> 
> This series adds TargetInfo types in QOM, and retrieve them dynamically(). At
> the moment, we don't deal yet with multiple TargetInfo selection, but install
> all that is needed to be able to do it easily.
> 
> Because TargetInfo data is set through class_init, it creates an issue at
> startup, where we may try to instantiate additional (unrelated) types just to
> retrieve the list of "target-info-X" types. Those other types class_init may be
> using target information, to add target specific properties for instance.
> This issue has been fixed by adding a new object_class_get_list_by_name_prefix
> that does not force instantiation of all QOM types, but only those matching a
> specific pattern. This way, we first initialize and retrieve target-info types
> before others.
> 
> An alternative would be to leave all this out of QOM, and use startup
> initializer to add them in a single list. However, because all the single-binary
> work has been using QOM where possible, it would be really sad to not use it for
> this final step. Comments are welcome!
> 
> Finally, sticking to our promise not create a special "single-binary
> configuration", the goal is to use the *exact* same codepath for normal binaries
> also. It means that even for existing system binaries, the goal will be to use
> QOM to retrieve current target, even if there is only one.
> 
> Pierrick Bouvier (6):
>   target-info: extract target_info() definition in target-info-init.h
>   target-info: introduce TargetInfo in QOM
>   system/vl: initialize QOM first
>   qom/object: add object_class_get_list_by_name_prefix
>   target-info-qom: detect target from QOM
>   target-info: replace target_info() in system-mode
> 
>  configs/targets/aarch64-softmmu.c |  6 +--
>  configs/targets/arm-softmmu.c     |  6 +--
>  include/qemu/target-info-init.h   | 63 +++++++++++++++++++++++++++++++
>  include/qemu/target-info-qom.h    | 25 ++++++++++++
>  include/qom/object.h              | 13 +++++++
>  qom/object.c                      | 40 ++++++++++++++++++++
>  system/runstate.c                 |  1 -
>  system/vl.c                       |  5 +++
>  target-info-qom.c                 | 32 ++++++++++++++++
>  target-info-stub.c                |  6 +--
>  10 files changed, 184 insertions(+), 13 deletions(-)
>  create mode 100644 include/qemu/target-info-init.h
>  create mode 100644 include/qemu/target-info-qom.h
> 

Sent v2:
20260430035626.3511676-1-pierrick.bouvier@oss.qualcomm.com

Regards,
Pierrick