[Qemu-devel] [PATCH v3 00/12] pc: Support firmware configuration with -blockdev

[Qemu-devel] [PATCH v3 00/12] pc: Support firmware configuration with -blockdev

[Markus Armbruster]

Based-on: <20190308094610.21210-1-armbru@redhat.com>

v3:
* PATCH 05: Commit message tidied up [Philippe, László]
* PATCH 06: Comment tidied up [checkpatch]
* PATCH 12: Comment polish [László]

v2:
* PATCH 05,06: New [Philippe]
* PATCH 07: Old PATCH 5 rebased onto new patches, with new comment
  [Philippe]
* PATCH 08+10: New, factored out of old PATCH 6 [by Philippe]
* PATCH 09: New [by Philippe]
* PATCH 11: Remainder of old PATCH 6, with FIXME resolved, literal
  4096 de-duplicated [László], extraneous error check deleted
  [László], and comment typos fixed
* PATCH 12: New

Markus Armbruster (9):
  qdev: Fix latent bug with compat_props and onboard devices
  qom: Move compat_props machinery from qdev to QOM
  vl: Fix latent bug with -global and onboard devices
  sysbus: Fix latent bug with onboard devices
  vl: Improve legibility of BlockdevOptions queue
  vl: Factor configure_blockdev() out of main()
  vl: Create block backends before setting machine properties
  pc: Support firmware configuration with -blockdev
  docs/interop/firmware.json: Prefer -machine to if=pflash

Philippe Mathieu-Daudé (3):
  pflash_cfi01: Add pflash_cfi01_get_blk() helper
  pc_sysfw: Remove unused PcSysFwDevice
  pc_sysfw: Pass PCMachineState to pc_system_firmware_init()

 accel/accel.c              |   1 +
 docs/interop/firmware.json |  20 ++-
 hw/block/pflash_cfi01.c    |   5 +
 hw/core/qdev.c             |  21 +---
 hw/core/sysbus.c           |   3 -
 hw/i386/pc.c               |   4 +-
 hw/i386/pc_sysfw.c         | 249 ++++++++++++++++++++++++-------------
 include/hw/block/flash.h   |   1 +
 include/hw/i386/pc.h       |   6 +-
 include/hw/qdev-core.h     |   2 -
 include/qom/object.h       |   3 +
 qom/object.c               |  39 ++++++
 vl.c                       | 125 ++++++++++---------
 13 files changed, 303 insertions(+), 176 deletions(-)

-- 
2.17.2

[Qemu-devel] [PATCH v3 01/12] qdev: Fix latent bug with compat_props and onboard devices

[Markus Armbruster]

Compatibility properties started life as a qdev property thing: we
supported them only for qdev properties, and implemented them with the
machinery backing command line option -global.

Recent commit fa0cb34d221 put them to use (tacitly) with memory
backend objects (subtypes of TYPE_MEMORY_BACKEND).  To make that
possible, we first moved the work of applying them from the -global
machinery into TYPE_DEVICE's .instance_post_init() method
device_post_init(), in commits ea9ce8934c5 and b66bbee39f6, then made
it available to TYPE_MEMORY_BACKEND's .instance_post_init() method
host_memory_backend_post_init() as object_apply_compat_props(), in
commit 1c3994f6d2a.

Note the code smell: we now have function name starting with object_
in hw/core/qdev.c.  It has to be there rather than in qom/, because it
calls qdev_get_machine() to find the current accelerator's and
machine's compat_props.

Turns out calling qdev_get_machine() there is problematic.  If we
qdev_create() from a machine's .instance_init() method, we call
device_post_init() and thus qdev_get_machine() before main() can
create "/machine" in QOM.  qdev_get_machine() tries to get it with
container_get(), which "helpfully" creates it as "container" object,
and returns that.  object_apply_compat_props() tries to paper over the
problem by doing nothing when the value of qdev_get_machine() isn't a
TYPE_MACHINE.  But the damage is done already: when main() later
attempts to create the real "/machine", it fails with "attempt to add
duplicate property 'machine' to object (type 'container')", and
aborts.

Since no machine .instance_init() calls qdev_create() so far, the bug
is latent.  But since I want to do that, I get to fix the bug first.

Observe that object_apply_compat_props() doesn't actually need the
MachineState, only its the compat_props member of its MachineClass and
AccelClass.  This permits a simple fix: register MachineClass and
AccelClass compat_props with the object_apply_compat_props() machinery
right after these classes get selected.

This is actually similar to how things worked before commits
ea9ce8934c5 and b66bbee39f6, except we now register much earlier.  The
old code registered them only after the machine's .instance_init()
ran, which would've broken compatibility properties for any devices
created there.

Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 accel/accel.c          |  1 +
 hw/core/qdev.c         | 48 ++++++++++++++++++++++++++++++++----------
 include/hw/qdev-core.h |  2 ++
 vl.c                   |  1 +
 4 files changed, 41 insertions(+), 11 deletions(-)

diff --git a/accel/accel.c b/accel/accel.c
index 68b6d56323..4a1670e404 100644
--- a/accel/accel.c
+++ b/accel/accel.c
@@ -66,6 +66,7 @@ static int accel_init_machine(AccelClass *acc, MachineState *ms)
         *(acc->allowed) = false;
         object_unref(OBJECT(accel));
     }
+    object_set_accelerator_compat_props(acc->compat_props);
     return ret;
 }
 
diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index 512ce7ca7a..4f3200d54b 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -978,25 +978,51 @@ static void device_initfn(Object *obj)
     QLIST_INIT(&dev->gpios);
 }
 
+/*
+ * Global property defaults
+ * Slot 0: accelerator's global property defaults
+ * Slot 1: machine's global property defaults
+ * Each is a GPtrArray of of GlobalProperty.
+ * Applied in order, later entries override earlier ones.
+ */
+static GPtrArray *object_compat_props[2];
+
+/*
+ * Set machine's global property defaults to @compat_props.
+ * May be called at most once.
+ */
+void object_set_machine_compat_props(GPtrArray *compat_props)
+{
+    assert(!object_compat_props[1]);
+    object_compat_props[1] = compat_props;
+}
+
+/*
+ * Set accelerator's global property defaults to @compat_props.
+ * May be called at most once.
+ */
+void object_set_accelerator_compat_props(GPtrArray *compat_props)
+{
+    assert(!object_compat_props[0]);
+    object_compat_props[0] = compat_props;
+}
+
 void object_apply_compat_props(Object *obj)
 {
-    if (object_dynamic_cast(qdev_get_machine(), TYPE_MACHINE)) {
-        MachineState *m = MACHINE(qdev_get_machine());
-        MachineClass *mc = MACHINE_GET_CLASS(m);
+    int i;
 
-        if (m->accelerator) {
-            AccelClass *ac = ACCEL_GET_CLASS(m->accelerator);
-
-            if (ac->compat_props) {
-                object_apply_global_props(obj, ac->compat_props, &error_abort);
-            }
-        }
-        object_apply_global_props(obj, mc->compat_props, &error_abort);
+    for (i = 0; i < ARRAY_SIZE(object_compat_props); i++) {
+        object_apply_global_props(obj, object_compat_props[i],
+                                  &error_abort);
     }
 }
 
 static void device_post_init(Object *obj)
 {
+    /*
+     * Note: ordered so that the user's global properties take
+     * precedence.
+     */
     object_apply_compat_props(obj);
     qdev_prop_set_globals(DEVICE(obj));
 }
diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
index 17f09aac72..aa8a3ea782 100644
--- a/include/hw/qdev-core.h
+++ b/include/hw/qdev-core.h
@@ -431,6 +431,8 @@ const char *qdev_fw_name(DeviceState *dev);
 
 Object *qdev_get_machine(void);
 
+void object_set_machine_compat_props(GPtrArray *compat_props);
+void object_set_accelerator_compat_props(GPtrArray *compat_props);
 void object_apply_compat_props(Object *obj);
 
 /* FIXME: make this a link<> */
diff --git a/vl.c b/vl.c
index 4c5cc0d8ad..712b92d707 100644
--- a/vl.c
+++ b/vl.c
@@ -3955,6 +3955,7 @@ int main(int argc, char **argv, char **envp)
     configure_rtc(qemu_find_opts_singleton("rtc"));
 
     machine_class = select_machine();
+    object_set_machine_compat_props(machine_class->compat_props);
 
     set_memory_options(&ram_slots, &maxram_size, machine_class);
 
-- 
2.17.2

[Qemu-devel] [PATCH v3 02/12] qom: Move compat_props machinery from qdev to QOM

[Markus Armbruster]

See the previous commit for rationale.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 hw/core/qdev.c         | 39 ---------------------------------------
 include/hw/qdev-core.h |  4 ----
 include/qom/object.h   |  3 +++
 qom/object.c           | 39 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 42 insertions(+), 43 deletions(-)

diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index 4f3200d54b..f9b6efe509 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -978,45 +978,6 @@ static void device_initfn(Object *obj)
     QLIST_INIT(&dev->gpios);
 }
 
-/*
- * Global property defaults
- * Slot 0: accelerator's global property defaults
- * Slot 1: machine's global property defaults
- * Each is a GPtrArray of of GlobalProperty.
- * Applied in order, later entries override earlier ones.
- */
-static GPtrArray *object_compat_props[2];
-
-/*
- * Set machine's global property defaults to @compat_props.
- * May be called at most once.
- */
-void object_set_machine_compat_props(GPtrArray *compat_props)
-{
-    assert(!object_compat_props[1]);
-    object_compat_props[1] = compat_props;
-}
-
-/*
- * Set accelerator's global property defaults to @compat_props.
- * May be called at most once.
- */
-void object_set_accelerator_compat_props(GPtrArray *compat_props)
-{
-    assert(!object_compat_props[0]);
-    object_compat_props[0] = compat_props;
-}
-
-void object_apply_compat_props(Object *obj)
-{
-    int i;
-
-    for (i = 0; i < ARRAY_SIZE(object_compat_props); i++) {
-        object_apply_global_props(obj, object_compat_props[i],
-                                  &error_abort);
-    }
-}
-
 static void device_post_init(Object *obj)
 {
     /*
diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
index aa8a3ea782..33ed3b8dde 100644
--- a/include/hw/qdev-core.h
+++ b/include/hw/qdev-core.h
@@ -431,10 +431,6 @@ const char *qdev_fw_name(DeviceState *dev);
 
 Object *qdev_get_machine(void);
 
-void object_set_machine_compat_props(GPtrArray *compat_props);
-void object_set_accelerator_compat_props(GPtrArray *compat_props);
-void object_apply_compat_props(Object *obj);
-
 /* FIXME: make this a link<> */
 void qdev_set_parent_bus(DeviceState *dev, BusState *bus);
 
diff --git a/include/qom/object.h b/include/qom/object.h
index e0262962b5..288cdddf44 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -677,6 +677,9 @@ Object *object_new_with_propv(const char *typename,
 
 void object_apply_global_props(Object *obj, const GPtrArray *props,
                                Error **errp);
+void object_set_machine_compat_props(GPtrArray *compat_props);
+void object_set_accelerator_compat_props(GPtrArray *compat_props);
+void object_apply_compat_props(Object *obj);
 
 /**
  * object_set_props:
diff --git a/qom/object.c b/qom/object.c
index 05a8567041..e3206d6799 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -408,6 +408,45 @@ void object_apply_global_props(Object *obj, const GPtrArray *props, Error **errp
     }
 }
 
+/*
+ * Global property defaults
+ * Slot 0: accelerator's global property defaults
+ * Slot 1: machine's global property defaults
+ * Each is a GPtrArray of of GlobalProperty.
+ * Applied in order, later entries override earlier ones.
+ */
+static GPtrArray *object_compat_props[2];
+
+/*
+ * Set machine's global property defaults to @compat_props.
+ * May be called at most once.
+ */
+void object_set_machine_compat_props(GPtrArray *compat_props)
+{
+    assert(!object_compat_props[1]);
+    object_compat_props[1] = compat_props;
+}
+
+/*
+ * Set accelerator's global property defaults to @compat_props.
+ * May be called at most once.
+ */
+void object_set_accelerator_compat_props(GPtrArray *compat_props)
+{
+    assert(!object_compat_props[0]);
+    object_compat_props[0] = compat_props;
+}
+
+void object_apply_compat_props(Object *obj)
+{
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(object_compat_props); i++) {
+        object_apply_global_props(obj, object_compat_props[i],
+                                  &error_abort);
+    }
+}
+
 static void object_initialize_with_type(void *data, size_t size, TypeImpl *type)
 {
     Object *obj = data;
-- 
2.17.2

[Qemu-devel] [PATCH v3 03/12] vl: Fix latent bug with -global and onboard devices

[Markus Armbruster]

main() registers the user's -global only after we create the machine
object, i.e. too late for devices created in the machine's
.instance_init().

Fortunately, we know the bug is only latent: the commit before
previous fixed a bug that would've crashed any attempt to create a
device in an .instance_init().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 vl.c | 19 ++-----------------
 1 file changed, 2 insertions(+), 17 deletions(-)

diff --git a/vl.c b/vl.c
index 712b92d707..b6368662e0 100644
--- a/vl.c
+++ b/vl.c
@@ -2939,17 +2939,6 @@ static void user_register_global_props(void)
                       global_init_func, NULL, NULL);
 }
 
-/*
- * Note: we should see that these properties are actually having a
- * priority: accel < machine < user. This means e.g. when user
- * specifies something in "-global", it'll always be used with highest
- * priority than either machine/accelerator compat properties.
- */
-static void register_global_properties(MachineState *ms)
-{
-    user_register_global_props();
-}
-
 int main(int argc, char **argv, char **envp)
 {
     int i;
@@ -3944,6 +3933,8 @@ int main(int argc, char **argv, char **envp)
      */
     loc_set_none();
 
+    user_register_global_props();
+
     replay_configure(icount_opts);
 
     if (incoming && !preconfig_exit_requested) {
@@ -4252,12 +4243,6 @@ int main(int argc, char **argv, char **envp)
                      machine_class->name, machine_class->deprecation_reason);
     }
 
-    /*
-     * Register all the global properties, including accel properties,
-     * machine properties, and user-specified ones.
-     */
-    register_global_properties(current_machine);
-
     /*
      * Migration object can only be created after global properties
      * are applied correctly.
-- 
2.17.2

[Qemu-devel] [PATCH v3 04/12] sysbus: Fix latent bug with onboard devices

[Markus Armbruster]

The first call of sysbus_get_default() creates the main system bus and
stores it in QOM as "/machine/unattached/sysbus".  This must not
happen before main() creates "/machine", or else container_get() would
"helpfully" create it as "container" object, and the real creation of
"/machine" would later abort with "attempt to add duplicate property
'machine' to object (type 'container')".  Has been that way ever since
we wired up busses in QOM (commit f968fc6892d, v1.2.0).

I believe the bug is latent.  I got it to bite by trying to
qdev_create() a sysbus device from a machine's .instance_init()
method.

The fix is obvious: store the main system bus in QOM right after
creating "/machine".

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
---
 hw/core/sysbus.c | 3 ---
 vl.c             | 4 ++++
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/hw/core/sysbus.c b/hw/core/sysbus.c
index 9f9edbcab9..307cf90a51 100644
--- a/hw/core/sysbus.c
+++ b/hw/core/sysbus.c
@@ -357,9 +357,6 @@ static void main_system_bus_create(void)
     qbus_create_inplace(main_system_bus, system_bus_info.instance_size,
                         TYPE_SYSTEM_BUS, NULL, "main-system-bus");
     OBJECT(main_system_bus)->free = g_free;
-    object_property_add_child(container_get(qdev_get_machine(),
-                                            "/unattached"),
-                              "sysbus", OBJECT(main_system_bus), NULL);
 }
 
 BusState *sysbus_get_default(void)
diff --git a/vl.c b/vl.c
index b6368662e0..c38739e34c 100644
--- a/vl.c
+++ b/vl.c
@@ -3991,6 +3991,10 @@ int main(int argc, char **argv, char **envp)
     }
     object_property_add_child(object_get_root(), "machine",
                               OBJECT(current_machine), &error_abort);
+    object_property_add_child(container_get(OBJECT(current_machine),
+                                            "/unattached"),
+                              "sysbus", OBJECT(sysbus_get_default()),
+                              NULL);
 
     if (machine_class->minimum_page_bits) {
         if (!set_preferred_target_page_bits(machine_class->minimum_page_bits)) {
-- 
2.17.2

[Qemu-devel] [PATCH v3 05/12] vl: Improve legibility of BlockdevOptions queue

[Markus Armbruster]

Give the queue head type a name: BlockdevOptionsQueue.

Rename the queue entry type from BlockdevOptions_queue to
BlockdevOptionsQueueEntry.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 vl.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/vl.c b/vl.c
index c38739e34c..3045ab0df3 100644
--- a/vl.c
+++ b/vl.c
@@ -1193,6 +1193,14 @@ static void default_drive(int enable, int snapshot, BlockInterfaceType type,
 
 }
 
+typedef struct BlockdevOptionsQueueEntry {
+    BlockdevOptions *bdo;
+    Location loc;
+    QSIMPLEQ_ENTRY(BlockdevOptionsQueueEntry) entry;
+} BlockdevOptionsQueueEntry;
+
+typedef QSIMPLEQ_HEAD(, BlockdevOptionsQueueEntry) BlockdevOptionsQueue;
+
 static QemuOptsList qemu_smp_opts = {
     .name = "smp-opts",
     .implied_opt_name = "cpus",
@@ -2973,13 +2981,7 @@ int main(int argc, char **argv, char **envp)
     Error *err = NULL;
     bool list_data_dirs = false;
     char *dir, **dirs;
-    typedef struct BlockdevOptions_queue {
-        BlockdevOptions *bdo;
-        Location loc;
-        QSIMPLEQ_ENTRY(BlockdevOptions_queue) entry;
-    } BlockdevOptions_queue;
-    QSIMPLEQ_HEAD(, BlockdevOptions_queue) bdo_queue
-        = QSIMPLEQ_HEAD_INITIALIZER(bdo_queue);
+    BlockdevOptionsQueue bdo_queue = QSIMPLEQ_HEAD_INITIALIZER(bdo_queue);
 
     module_call_init(MODULE_INIT_TRACE);
 
@@ -3103,12 +3105,12 @@ int main(int argc, char **argv, char **envp)
             case QEMU_OPTION_blockdev:
                 {
                     Visitor *v;
-                    BlockdevOptions_queue *bdo;
+                    BlockdevOptionsQueueEntry *bdo;
 
                     v = qobject_input_visitor_new_str(optarg, "driver",
                                                       &error_fatal);
 
-                    bdo = g_new(BlockdevOptions_queue, 1);
+                    bdo = g_new(BlockdevOptionsQueueEntry, 1);
                     visit_type_BlockdevOptions(v, NULL, &bdo->bdo,
                                                &error_fatal);
                     visit_free(v);
@@ -4368,7 +4370,7 @@ int main(int argc, char **argv, char **envp)
 
     /* open the virtual block devices */
     while (!QSIMPLEQ_EMPTY(&bdo_queue)) {
-        BlockdevOptions_queue *bdo = QSIMPLEQ_FIRST(&bdo_queue);
+        BlockdevOptionsQueueEntry *bdo = QSIMPLEQ_FIRST(&bdo_queue);
 
         QSIMPLEQ_REMOVE_HEAD(&bdo_queue, entry);
         loc_push_restore(&bdo->loc);
-- 
2.17.2

Re: [Qemu-devel] [PATCH v3 05/12] vl: Improve legibility of BlockdevOptions queue

[Philippe Mathieu-Daudé]

On 3/8/19 2:14 PM, Markus Armbruster wrote:
> Give the queue head type a name: BlockdevOptionsQueue.
> 
> Rename the queue entry type from BlockdevOptions_queue to
> BlockdevOptionsQueueEntry.
> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> ---
>  vl.c | 22 ++++++++++++----------
>  1 file changed, 12 insertions(+), 10 deletions(-)
> 
> diff --git a/vl.c b/vl.c
> index c38739e34c..3045ab0df3 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -1193,6 +1193,14 @@ static void default_drive(int enable, int snapshot, BlockInterfaceType type,
>  
>  }
>  
> +typedef struct BlockdevOptionsQueueEntry {
> +    BlockdevOptions *bdo;
> +    Location loc;
> +    QSIMPLEQ_ENTRY(BlockdevOptionsQueueEntry) entry;
> +} BlockdevOptionsQueueEntry;
> +
> +typedef QSIMPLEQ_HEAD(, BlockdevOptionsQueueEntry) BlockdevOptionsQueue;
> +
>  static QemuOptsList qemu_smp_opts = {
>      .name = "smp-opts",
>      .implied_opt_name = "cpus",
> @@ -2973,13 +2981,7 @@ int main(int argc, char **argv, char **envp)
>      Error *err = NULL;
>      bool list_data_dirs = false;
>      char *dir, **dirs;
> -    typedef struct BlockdevOptions_queue {
> -        BlockdevOptions *bdo;
> -        Location loc;
> -        QSIMPLEQ_ENTRY(BlockdevOptions_queue) entry;
> -    } BlockdevOptions_queue;
> -    QSIMPLEQ_HEAD(, BlockdevOptions_queue) bdo_queue
> -        = QSIMPLEQ_HEAD_INITIALIZER(bdo_queue);
> +    BlockdevOptionsQueue bdo_queue = QSIMPLEQ_HEAD_INITIALIZER(bdo_queue);
>  
>      module_call_init(MODULE_INIT_TRACE);
>  
> @@ -3103,12 +3105,12 @@ int main(int argc, char **argv, char **envp)
>              case QEMU_OPTION_blockdev:
>                  {
>                      Visitor *v;
> -                    BlockdevOptions_queue *bdo;
> +                    BlockdevOptionsQueueEntry *bdo;
>  
>                      v = qobject_input_visitor_new_str(optarg, "driver",
>                                                        &error_fatal);
>  
> -                    bdo = g_new(BlockdevOptions_queue, 1);
> +                    bdo = g_new(BlockdevOptionsQueueEntry, 1);
>                      visit_type_BlockdevOptions(v, NULL, &bdo->bdo,
>                                                 &error_fatal);
>                      visit_free(v);
> @@ -4368,7 +4370,7 @@ int main(int argc, char **argv, char **envp)
>  
>      /* open the virtual block devices */
>      while (!QSIMPLEQ_EMPTY(&bdo_queue)) {
> -        BlockdevOptions_queue *bdo = QSIMPLEQ_FIRST(&bdo_queue);
> +        BlockdevOptionsQueueEntry *bdo = QSIMPLEQ_FIRST(&bdo_queue);
>  
>          QSIMPLEQ_REMOVE_HEAD(&bdo_queue, entry);
>          loc_push_restore(&bdo->loc);
> 

Re: [Qemu-devel] [PATCH v3 05/12] vl: Improve legibility of BlockdevOptions queue

[Paolo Bonzini]

On 08/03/19 14:14, Markus Armbruster wrote:
> Give the queue head type a name: BlockdevOptionsQueue.

No particular need for this, but no huge objections either.

> Rename the queue entry type from BlockdevOptions_queue to
> BlockdevOptionsQueueEntry.

This is welcome. ;)

Paolo

[Qemu-devel] [PATCH v3 06/12] vl: Factor configure_blockdev() out of main()

[Markus Armbruster]

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 vl.c | 74 ++++++++++++++++++++++++++++++++++--------------------------
 1 file changed, 42 insertions(+), 32 deletions(-)

diff --git a/vl.c b/vl.c
index 3045ab0df3..573de5ec4a 100644
--- a/vl.c
+++ b/vl.c
@@ -1201,6 +1201,47 @@ typedef struct BlockdevOptionsQueueEntry {
 
 typedef QSIMPLEQ_HEAD(, BlockdevOptionsQueueEntry) BlockdevOptionsQueue;
 
+static void configure_blockdev(BlockdevOptionsQueue *bdo_queue,
+                               MachineClass *machine_class, int snapshot)
+{
+    /*
+     * If the currently selected machine wishes to override the
+     * units-per-bus property of its default HBA interface type, do so
+     * now.
+     */
+    if (machine_class->units_per_default_bus) {
+        override_max_devs(machine_class->block_default_type,
+                          machine_class->units_per_default_bus);
+    }
+
+    /* open the virtual block devices */
+    while (!QSIMPLEQ_EMPTY(bdo_queue)) {
+        BlockdevOptionsQueueEntry *bdo = QSIMPLEQ_FIRST(bdo_queue);
+
+        QSIMPLEQ_REMOVE_HEAD(bdo_queue, entry);
+        loc_push_restore(&bdo->loc);
+        qmp_blockdev_add(bdo->bdo, &error_fatal);
+        loc_pop(&bdo->loc);
+        qapi_free_BlockdevOptions(bdo->bdo);
+        g_free(bdo);
+    }
+    if (snapshot || replay_mode != REPLAY_MODE_NONE) {
+        qemu_opts_foreach(qemu_find_opts("drive"), drive_enable_snapshot,
+                          NULL, NULL);
+    }
+    if (qemu_opts_foreach(qemu_find_opts("drive"), drive_init_func,
+                          &machine_class->block_default_type, &error_fatal)) {
+        /* We printed help */
+        exit(0);
+    }
+
+    default_drive(default_cdrom, snapshot, machine_class->block_default_type, 2,
+                  CDROM_OPTS);
+    default_drive(default_floppy, snapshot, IF_FLOPPY, 0, FD_OPTS);
+    default_drive(default_sdcard, snapshot, IF_SD, 0, SD_OPTS);
+
+}
+
 static QemuOptsList qemu_smp_opts = {
     .name = "smp-opts",
     .implied_opt_name = "cpus",
@@ -4361,38 +4402,7 @@ int main(int argc, char **argv, char **envp)
     ram_mig_init();
     dirty_bitmap_mig_init();
 
-    /* If the currently selected machine wishes to override the units-per-bus
-     * property of its default HBA interface type, do so now. */
-    if (machine_class->units_per_default_bus) {
-        override_max_devs(machine_class->block_default_type,
-                          machine_class->units_per_default_bus);
-    }
-
-    /* open the virtual block devices */
-    while (!QSIMPLEQ_EMPTY(&bdo_queue)) {
-        BlockdevOptionsQueueEntry *bdo = QSIMPLEQ_FIRST(&bdo_queue);
-
-        QSIMPLEQ_REMOVE_HEAD(&bdo_queue, entry);
-        loc_push_restore(&bdo->loc);
-        qmp_blockdev_add(bdo->bdo, &error_fatal);
-        loc_pop(&bdo->loc);
-        qapi_free_BlockdevOptions(bdo->bdo);
-        g_free(bdo);
-    }
-    if (snapshot || replay_mode != REPLAY_MODE_NONE) {
-        qemu_opts_foreach(qemu_find_opts("drive"), drive_enable_snapshot,
-                          NULL, NULL);
-    }
-    if (qemu_opts_foreach(qemu_find_opts("drive"), drive_init_func,
-                          &machine_class->block_default_type, &error_fatal)) {
-        /* We printed help */
-        exit(0);
-    }
-
-    default_drive(default_cdrom, snapshot, machine_class->block_default_type, 2,
-                  CDROM_OPTS);
-    default_drive(default_floppy, snapshot, IF_FLOPPY, 0, FD_OPTS);
-    default_drive(default_sdcard, snapshot, IF_SD, 0, SD_OPTS);
+    configure_blockdev(&bdo_queue, machine_class, snapshot);
 
     qemu_opts_foreach(qemu_find_opts("mon"),
                       mon_init_func, NULL, &error_fatal);
-- 
2.17.2

Re: [Qemu-devel] [PATCH v3 06/12] vl: Factor configure_blockdev() out of main()

[Paolo Bonzini]

On 08/03/19 14:14, Markus Armbruster wrote:
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>  vl.c | 74 ++++++++++++++++++++++++++++++++++--------------------------
>  1 file changed, 42 insertions(+), 32 deletions(-)
> 
> diff --git a/vl.c b/vl.c
> index 3045ab0df3..573de5ec4a 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -1201,6 +1201,47 @@ typedef struct BlockdevOptionsQueueEntry {
>  
>  typedef QSIMPLEQ_HEAD(, BlockdevOptionsQueueEntry) BlockdevOptionsQueue;
>  
> +static void configure_blockdev(BlockdevOptionsQueue *bdo_queue,

Aha. :)

Paolo

> +                               MachineClass *machine_class, int snapshot)
> +{
> +    /*
> +     * If the currently selected machine wishes to override the
> +     * units-per-bus property of its default HBA interface type, do so
> +     * now.
> +     */
> +    if (machine_class->units_per_default_bus) {
> +        override_max_devs(machine_class->block_default_type,
> +                          machine_class->units_per_default_bus);
> +    }
> +
> +    /* open the virtual block devices */
> +    while (!QSIMPLEQ_EMPTY(bdo_queue)) {
> +        BlockdevOptionsQueueEntry *bdo = QSIMPLEQ_FIRST(bdo_queue);
> +
> +        QSIMPLEQ_REMOVE_HEAD(bdo_queue, entry);
> +        loc_push_restore(&bdo->loc);
> +        qmp_blockdev_add(bdo->bdo, &error_fatal);
> +        loc_pop(&bdo->loc);
> +        qapi_free_BlockdevOptions(bdo->bdo);
> +        g_free(bdo);
> +    }
> +    if (snapshot || replay_mode != REPLAY_MODE_NONE) {
> +        qemu_opts_foreach(qemu_find_opts("drive"), drive_enable_snapshot,
> +                          NULL, NULL);
> +    }
> +    if (qemu_opts_foreach(qemu_find_opts("drive"), drive_init_func,
> +                          &machine_class->block_default_type, &error_fatal)) {
> +        /* We printed help */
> +        exit(0);
> +    }
> +
> +    default_drive(default_cdrom, snapshot, machine_class->block_default_type, 2,
> +                  CDROM_OPTS);
> +    default_drive(default_floppy, snapshot, IF_FLOPPY, 0, FD_OPTS);
> +    default_drive(default_sdcard, snapshot, IF_SD, 0, SD_OPTS);
> +
> +}
> +
>  static QemuOptsList qemu_smp_opts = {
>      .name = "smp-opts",
>      .implied_opt_name = "cpus",
> @@ -4361,38 +4402,7 @@ int main(int argc, char **argv, char **envp)
>      ram_mig_init();
>      dirty_bitmap_mig_init();
>  
> -    /* If the currently selected machine wishes to override the units-per-bus
> -     * property of its default HBA interface type, do so now. */
> -    if (machine_class->units_per_default_bus) {
> -        override_max_devs(machine_class->block_default_type,
> -                          machine_class->units_per_default_bus);
> -    }
> -
> -    /* open the virtual block devices */
> -    while (!QSIMPLEQ_EMPTY(&bdo_queue)) {
> -        BlockdevOptionsQueueEntry *bdo = QSIMPLEQ_FIRST(&bdo_queue);
> -
> -        QSIMPLEQ_REMOVE_HEAD(&bdo_queue, entry);
> -        loc_push_restore(&bdo->loc);
> -        qmp_blockdev_add(bdo->bdo, &error_fatal);
> -        loc_pop(&bdo->loc);
> -        qapi_free_BlockdevOptions(bdo->bdo);
> -        g_free(bdo);
> -    }
> -    if (snapshot || replay_mode != REPLAY_MODE_NONE) {
> -        qemu_opts_foreach(qemu_find_opts("drive"), drive_enable_snapshot,
> -                          NULL, NULL);
> -    }
> -    if (qemu_opts_foreach(qemu_find_opts("drive"), drive_init_func,
> -                          &machine_class->block_default_type, &error_fatal)) {
> -        /* We printed help */
> -        exit(0);
> -    }
> -
> -    default_drive(default_cdrom, snapshot, machine_class->block_default_type, 2,
> -                  CDROM_OPTS);
> -    default_drive(default_floppy, snapshot, IF_FLOPPY, 0, FD_OPTS);
> -    default_drive(default_sdcard, snapshot, IF_SD, 0, SD_OPTS);
> +    configure_blockdev(&bdo_queue, machine_class, snapshot);
>  
>      qemu_opts_foreach(qemu_find_opts("mon"),
>                        mon_init_func, NULL, &error_fatal);
> 

[Qemu-devel] [PATCH v3 07/12] vl: Create block backends before setting machine properties

[Markus Armbruster]

qemu-system-FOO's main() acts on command line arguments in its own
idiosyncratic order.  There's not much method to its madness.
Whenever we find a case where one kind of command line argument needs
to refer to something created for another kind later, we rejigger the
order.

Block devices get created long after machine properties get processed.
Therefore, block device machine properties can be created, but not
set.  No such properties exist.  But the next commit will create some.
Time to rejigger again: create block devices earlier.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 vl.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/vl.c b/vl.c
index 573de5ec4a..58e05b296f 100644
--- a/vl.c
+++ b/vl.c
@@ -4276,6 +4276,13 @@ int main(int argc, char **argv, char **envp)
         exit(0);
     }
 
+    /*
+     * Note: we need to create block backends before
+     * machine_set_property(), so machine properties can refer to
+     * them.
+     */
+    configure_blockdev(&bdo_queue, machine_class, snapshot);
+
     machine_opts = qemu_get_machine_opts();
     qemu_opt_foreach(machine_opts, machine_set_property, current_machine,
                      &error_fatal);
@@ -4402,8 +4409,6 @@ int main(int argc, char **argv, char **envp)
     ram_mig_init();
     dirty_bitmap_mig_init();
 
-    configure_blockdev(&bdo_queue, machine_class, snapshot);
-
     qemu_opts_foreach(qemu_find_opts("mon"),
                       mon_init_func, NULL, &error_fatal);
 
-- 
2.17.2

[Qemu-devel] [PATCH v3 08/12] pflash_cfi01: Add pflash_cfi01_get_blk() helper

[Markus Armbruster]

From: Philippe Mathieu-Daudé <philmd@redhat.com>

Add an helper to access the opaque struct PFlashCFI01.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
---
 hw/block/pflash_cfi01.c  | 5 +++++
 include/hw/block/flash.h | 1 +
 2 files changed, 6 insertions(+)

diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
index 9d1c356eb6..125f70b8e4 100644
--- a/hw/block/pflash_cfi01.c
+++ b/hw/block/pflash_cfi01.c
@@ -967,6 +967,11 @@ PFlashCFI01 *pflash_cfi01_register(hwaddr base,
     return PFLASH_CFI01(dev);
 }
 
+BlockBackend *pflash_cfi01_get_blk(PFlashCFI01 *fl)
+{
+    return fl->blk;
+}
+
 MemoryRegion *pflash_cfi01_get_memory(PFlashCFI01 *fl)
 {
     return &fl->mem;
diff --git a/include/hw/block/flash.h b/include/hw/block/flash.h
index 914932eaec..a0f488732a 100644
--- a/include/hw/block/flash.h
+++ b/include/hw/block/flash.h
@@ -22,6 +22,7 @@ PFlashCFI01 *pflash_cfi01_register(hwaddr base,
                                    uint16_t id0, uint16_t id1,
                                    uint16_t id2, uint16_t id3,
                                    int be);
+BlockBackend *pflash_cfi01_get_blk(PFlashCFI01 *fl);
 MemoryRegion *pflash_cfi01_get_memory(PFlashCFI01 *fl);
 
 /* pflash_cfi02.c */
-- 
2.17.2

[Qemu-devel] [PATCH v3 09/12] pc_sysfw: Remove unused PcSysFwDevice

[Markus Armbruster]

From: Philippe Mathieu-Daudé <philmd@redhat.com>

This structure is not used since commit 6dd2a5c98a.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 hw/i386/pc_sysfw.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
index 34727c5b1f..46b87afe23 100644
--- a/hw/i386/pc_sysfw.c
+++ b/hw/i386/pc_sysfw.c
@@ -40,11 +40,6 @@
 
 #define BIOS_FILENAME "bios.bin"
 
-typedef struct PcSysFwDevice {
-    SysBusDevice busdev;
-    uint8_t isapc_ram_fw;
-} PcSysFwDevice;
-
 static void pc_isa_bios_init(MemoryRegion *rom_memory,
                              MemoryRegion *flash_mem,
                              int ram_size)
-- 
2.17.2

[Qemu-devel] [PATCH v3 10/12] pc_sysfw: Pass PCMachineState to pc_system_firmware_init()

[Markus Armbruster]

From: Philippe Mathieu-Daudé <philmd@redhat.com>

pc_system_firmware_init() parameter @isapc_ram_fw is PCMachineState
member pci_enabled negated.  The next commit will need more of
PCMachineState.  To prepare for that, pass a PCMachineState *, and
drop the now redundant parameter @isapc_ram_fw.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
---
 hw/i386/pc.c         | 2 +-
 hw/i386/pc_sysfw.c   | 5 ++++-
 include/hw/i386/pc.h | 3 +--
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 42128183e9..b2947e433b 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1803,7 +1803,7 @@ void pc_memory_init(PCMachineState *pcms,
     }
 
     /* Initialize PC system firmware */
-    pc_system_firmware_init(rom_memory, !pcmc->pci_enabled);
+    pc_system_firmware_init(pcms, rom_memory);
 
     option_rom_mr = g_malloc(sizeof(*option_rom_mr));
     memory_region_init_ram(option_rom_mr, NULL, "pc.rom", PC_ROM_SIZE,
diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
index 46b87afe23..785123252c 100644
--- a/hw/i386/pc_sysfw.c
+++ b/hw/i386/pc_sysfw.c
@@ -231,8 +231,11 @@ static void old_pc_system_rom_init(MemoryRegion *rom_memory, bool isapc_ram_fw)
                                 bios);
 }
 
-void pc_system_firmware_init(MemoryRegion *rom_memory, bool isapc_ram_fw)
+void pc_system_firmware_init(PCMachineState *pcms,
+                             MemoryRegion *rom_memory)
 {
+    PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
+    bool isapc_ram_fw = !pcmc->pci_enabled;
     DriveInfo *pflash_drv;
 
     pflash_drv = drive_get(IF_PFLASH, 0, 0);
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 54222a202d..4f5ed7cefc 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -277,8 +277,7 @@ extern PCIDevice *piix4_dev;
 int piix4_init(PCIBus *bus, ISABus **isa_bus, int devfn);
 
 /* pc_sysfw.c */
-void pc_system_firmware_init(MemoryRegion *rom_memory,
-                             bool isapc_ram_fw);
+void pc_system_firmware_init(PCMachineState *pcms, MemoryRegion *rom_memory);
 
 /* acpi-build.c */
 void pc_madt_cpu_entry(AcpiDeviceIf *adev, int uid,
-- 
2.17.2

[Qemu-devel] [PATCH v3 11/12] pc: Support firmware configuration with -blockdev

[Markus Armbruster]

The PC machines put firmware in ROM by default.  To get it put into
flash memory (required by OVMF), you have to use -drive
if=pflash,unit=0,... and optionally -drive if=pflash,unit=1,...

Why two -drive?  This permits setting up one part of the flash memory
read-only, and the other part read/write.  Below the hood, it creates
two separate flash devices, because we were too lazy to improve our
flash device models to support sector protection.

The problem at hand is to do the same with -blockdev somehow, as one
more step towards deprecating -drive.

Mapping -drive if=none,... to -blockdev is a solved problem.  With
if=T other than if=none, -drive additionally configures a block device
frontend.  For non-onboard devices, that part maps to -device.  Also a
solved problem.  For onboard devices such as PC flash memory, we have
an unsolved problem.

This is actually an instance of a wider problem: our general device
configuration interface doesn't cover onboard devices.  Instead, we
have a zoo of ad hoc interfaces that are much more limited.  Some of
them we'd rather deprecate (-drive, -net), but can't until we have
suitable replacements.

Sadly, I can't attack the wider problem today.  So back to the narrow
problem.

My first idea was to reduce it to its solved buddy by using pluggable
instead of onboard devices for the flash memory.  Workable, but it
requires some extra smarts in firmware descriptors and libvirt.  Paolo
had an idea that is simpler for libvirt: keep the devices onboard, and
add machine properties for their block backends.

The implementation is less than straightforward, I'm afraid.

First, block backend properties are *qdev* properties.  Machines can't
have those, as they're not devices.  I could duplicate these qdev
properties as QOM properties, but I hate that.

More seriously, the properties do not belong to the machine, they
belong to the onboard flash devices.  Adding them to the machine would
then require bad magic to somehow transfer them to the flash devices.
Fortunately, QOM provides the means to handle exactly this case: add
alias properties to the machine that forward to the onboard devices'
properties.

Properties need to be created in .instance_init() methods.  For PC
machines, that's pc_machine_initfn().  To make alias properties work,
we need to create the onboard flash devices there, too.  Requires
several bug fixes, in the previous commits.  We also have to realize
the devices.  More on that below.

If the user sets pflash0, firmware resides in flash memory.
pc_system_firmware_init() maps and realizes the flash devices.

Else, firmware resides in ROM.  The onboard flash devices aren't used
then.  pc_system_firmware_init() destroys them unrealized, along with
the alias properties.

The existing code to pick up drives defined with -drive if=pflash is
replaced by code to desugar into the machine properties.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
---
 hw/i386/pc.c         |   2 +
 hw/i386/pc_sysfw.c   | 243 ++++++++++++++++++++++++++++---------------
 include/hw/i386/pc.h |   3 +
 3 files changed, 166 insertions(+), 82 deletions(-)

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index b2947e433b..7e7f4cbfb4 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -2643,6 +2643,8 @@ static void pc_machine_initfn(Object *obj)
     pcms->smbus_enabled = true;
     pcms->sata_enabled = true;
     pcms->pit_enabled = true;
+
+    pc_system_flash_create(pcms);
 }
 
 static void pc_machine_reset(void)
diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
index 785123252c..ccf2221acb 100644
--- a/hw/i386/pc_sysfw.c
+++ b/hw/i386/pc_sysfw.c
@@ -40,6 +40,17 @@
 
 #define BIOS_FILENAME "bios.bin"
 
+/*
+ * We don't have a theoretically justifiable exact lower bound on the base
+ * address of any flash mapping. In practice, the IO-APIC MMIO range is
+ * [0xFEE00000..0xFEE01000] -- see IO_APIC_DEFAULT_ADDRESS --, leaving free
+ * only 18MB-4KB below 4G. For now, restrict the cumulative mapping to 8MB in
+ * size.
+ */
+#define FLASH_SIZE_LIMIT (8 * MiB)
+
+#define FLASH_SECTOR_SIZE 4096
+
 static void pc_isa_bios_init(MemoryRegion *rom_memory,
                              MemoryRegion *flash_mem,
                              int ram_size)
@@ -71,96 +82,128 @@ static void pc_isa_bios_init(MemoryRegion *rom_memory,
     memory_region_set_readonly(isa_bios, true);
 }
 
-#define FLASH_MAP_UNIT_MAX 2
+static PFlashCFI01 *pc_pflash_create(const char *name)
+{
+    DeviceState *dev = qdev_create(NULL, TYPE_PFLASH_CFI01);
 
-/* We don't have a theoretically justifiable exact lower bound on the base
- * address of any flash mapping. In practice, the IO-APIC MMIO range is
- * [0xFEE00000..0xFEE01000[ -- see IO_APIC_DEFAULT_ADDRESS --, leaving free
- * only 18MB-4KB below 4G. For now, restrict the cumulative mapping to 8MB in
- * size.
- */
-#define FLASH_MAP_BASE_MIN ((hwaddr)(4 * GiB - 8 * MiB))
+    qdev_prop_set_uint64(dev, "sector-length", FLASH_SECTOR_SIZE);
+    qdev_prop_set_uint8(dev, "width", 1);
+    qdev_prop_set_string(dev, "name", name);
+    return PFLASH_CFI01(dev);
+}
 
-/* This function maps flash drives from 4G downward, in order of their unit
- * numbers. The mapping starts at unit#0, with unit number increments of 1, and
- * stops before the first missing flash drive, or before
- * unit#FLASH_MAP_UNIT_MAX, whichever is reached first.
- *
- * Addressing within one flash drive is of course not reversed.
- *
- * An error message is printed and the process exits if:
- * - the size of the backing file for a flash drive is non-positive, or not a
- *   multiple of the required sector size, or
- * - the current mapping's base address would fall below FLASH_MAP_BASE_MIN.
+void pc_system_flash_create(PCMachineState *pcms)
+{
+    PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
+
+    if (pcmc->pci_enabled) {
+        pcms->flash[0] = pc_pflash_create("system.flash0");
+        pcms->flash[1] = pc_pflash_create("system.flash1");
+        object_property_add_alias(OBJECT(pcms), "pflash0",
+                                  OBJECT(pcms->flash[0]), "drive",
+                                  &error_abort);
+        object_property_add_alias(OBJECT(pcms), "pflash1",
+                                  OBJECT(pcms->flash[1]), "drive",
+                                  &error_abort);
+    }
+}
+
+static void pc_system_flash_cleanup_unused(PCMachineState *pcms)
+{
+    char *prop_name;
+    int i;
+    Object *dev_obj;
+
+    assert(PC_MACHINE_GET_CLASS(pcms)->pci_enabled);
+
+    for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
+        dev_obj = OBJECT(pcms->flash[i]);
+        if (!object_property_get_bool(dev_obj, "realized", &error_abort)) {
+            prop_name = g_strdup_printf("pflash%d", i);
+            object_property_del(OBJECT(pcms), prop_name, &error_abort);
+            g_free(prop_name);
+            /*
+             * Delete @dev_obj.  Straight object_unref() is wrong,
+             * since it leaves dangling references in the parent bus
+             * behind.  object_unparent() doesn't work, either: since
+             * @dev_obj hasn't been realized, dev_obj->parent is null,
+             * and object_unparent() does nothing.  DeviceClass method
+             * device_unparent() works, but we have to take a
+             * temporary reference, or else device_unparent() commits
+             * a use-after-free error.
+             */
+            object_ref(dev_obj);
+            object_get_class(dev_obj)->unparent(dev_obj);
+            object_unref(dev_obj);
+            pcms->flash[i] = NULL;
+        }
+    }
+}
+
+/*
+ * Map the pcms->flash[] from 4GiB downward, and realize.
+ * Map them in descending order, i.e. pcms->flash[0] at the top,
+ * without gaps.
+ * Stop at the first pcms->flash[0] lacking a block backend.
+ * Set each flash's size from its block backend.  Fatal error if the
+ * size isn't a non-zero multiple of 4KiB, or the total size exceeds
+ * FLASH_SIZE_LIMIT.
  *
- * The drive with unit#0 (if available) is mapped at the highest address, and
- * it is passed to pc_isa_bios_init(). Merging several drives for isa-bios is
+ * If pcms->flash[0] has a block backend, its memory is passed to
+ * pc_isa_bios_init().  Merging several flash devices for isa-bios is
  * not supported.
  */
-static void pc_system_flash_init(MemoryRegion *rom_memory)
+static void pc_system_flash_map(PCMachineState *pcms,
+                                MemoryRegion *rom_memory)
 {
-    int unit;
-    DriveInfo *pflash_drv;
+    hwaddr total_size = 0;
+    int i;
     BlockBackend *blk;
     int64_t size;
-    char *fatal_errmsg = NULL;
-    hwaddr phys_addr = 0x100000000ULL;
-    uint32_t sector_size = 4096;
     PFlashCFI01 *system_flash;
     MemoryRegion *flash_mem;
-    char name[64];
     void *flash_ptr;
     int ret, flash_size;
 
-    for (unit = 0;
-         (unit < FLASH_MAP_UNIT_MAX &&
-          (pflash_drv = drive_get(IF_PFLASH, 0, unit)) != NULL);
-         ++unit) {
-        blk = blk_by_legacy_dinfo(pflash_drv);
+    assert(PC_MACHINE_GET_CLASS(pcms)->pci_enabled);
+
+    for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
+        system_flash = pcms->flash[i];
+        blk = pflash_cfi01_get_blk(system_flash);
+        if (!blk) {
+            break;
+        }
         size = blk_getlength(blk);
         if (size < 0) {
-            fatal_errmsg = g_strdup_printf("failed to get backing file size");
-        } else if (size == 0) {
-            fatal_errmsg = g_strdup_printf("PC system firmware (pflash) "
-                               "cannot have zero size");
-        } else if ((size % sector_size) != 0) {
-            fatal_errmsg = g_strdup_printf("PC system firmware (pflash) "
-                               "must be a multiple of 0x%x", sector_size);
-        } else if (phys_addr < size || phys_addr - size < FLASH_MAP_BASE_MIN) {
-            fatal_errmsg = g_strdup_printf("oversized backing file, pflash "
-                               "segments cannot be mapped under "
-                               TARGET_FMT_plx, FLASH_MAP_BASE_MIN);
+            error_report("can't get size of block device %s: %s",
+                         blk_name(blk), strerror(-size));
+            exit(1);
         }
-        if (fatal_errmsg != NULL) {
-            Location loc;
-
-            /* push a new, "none" location on the location stack; overwrite its
-             * contents with the location saved in the option; print the error
-             * (includes location); pop the top
-             */
-            loc_push_none(&loc);
-            if (pflash_drv->opts != NULL) {
-                qemu_opts_loc_restore(pflash_drv->opts);
-            }
-            error_report("%s", fatal_errmsg);
-            loc_pop(&loc);
-            g_free(fatal_errmsg);
+        if (size == 0 || size % FLASH_SECTOR_SIZE != 0) {
+            error_report("system firmware block device %s has invalid size "
+                         "%" PRId64,
+                         blk_name(blk), size);
+            info_report("its size must be a non-zero multiple of 0x%x",
+                        FLASH_SECTOR_SIZE);
+            exit(1);
+        }
+        if ((hwaddr)size != size
+            || total_size > HWADDR_MAX - size
+            || total_size + size > FLASH_SIZE_LIMIT) {
+            error_report("combined size of system firmware exceeds "
+                         "%" PRIu64 " bytes",
+                         FLASH_SIZE_LIMIT);
             exit(1);
         }
 
-        phys_addr -= size;
+        total_size += size;
+        qdev_prop_set_uint32(DEVICE(system_flash), "num-blocks",
+                             size / FLASH_SECTOR_SIZE);
+        qdev_init_nofail(DEVICE(system_flash));
+        sysbus_mmio_map(SYS_BUS_DEVICE(system_flash), 0,
+                        0x100000000ULL - total_size);
 
-        /* pflash_cfi01_register() creates a deep copy of the name */
-        snprintf(name, sizeof name, "system.flash%d", unit);
-        system_flash = pflash_cfi01_register(phys_addr, name,
-                                             size, blk, sector_size,
-                                             1      /* width */,
-                                             0x0000 /* id0 */,
-                                             0x0000 /* id1 */,
-                                             0x0000 /* id2 */,
-                                             0x0000 /* id3 */,
-                                             0      /* be */);
-        if (unit == 0) {
+        if (i == 0) {
             flash_mem = pflash_cfi01_get_memory(system_flash);
             pc_isa_bios_init(rom_memory, flash_mem, size);
 
@@ -235,23 +278,59 @@ void pc_system_firmware_init(PCMachineState *pcms,
                              MemoryRegion *rom_memory)
 {
     PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
-    bool isapc_ram_fw = !pcmc->pci_enabled;
+    int i;
     DriveInfo *pflash_drv;
+    BlockBackend *pflash_blk[ARRAY_SIZE(pcms->flash)];
+    Location loc;
 
-    pflash_drv = drive_get(IF_PFLASH, 0, 0);
-
-    if (isapc_ram_fw || pflash_drv == NULL) {
-        /* When a pflash drive is not found, use rom-mode */
-        old_pc_system_rom_init(rom_memory, isapc_ram_fw);
+    if (!pcmc->pci_enabled) {
+        old_pc_system_rom_init(rom_memory, true);
         return;
     }
 
-    if (kvm_enabled() && !kvm_readonly_mem_enabled()) {
-        /* Older KVM cannot execute from device memory. So, flash memory
-         * cannot be used unless the readonly memory kvm capability is present. */
-        fprintf(stderr, "qemu: pflash with kvm requires KVM readonly memory support\n");
-        exit(1);
+    /* Map legacy -drive if=pflash to machine properties */
+    for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
+        pflash_blk[i] = pflash_cfi01_get_blk(pcms->flash[i]);
+        pflash_drv = drive_get(IF_PFLASH, 0, i);
+        if (!pflash_drv) {
+            continue;
+        }
+        loc_push_none(&loc);
+        qemu_opts_loc_restore(pflash_drv->opts);
+        if (pflash_blk[i]) {
+            error_report("clashes with -machine");
+            exit(1);
+        }
+        pflash_blk[i] = blk_by_legacy_dinfo(pflash_drv);
+        qdev_prop_set_drive(DEVICE(pcms->flash[i]),
+                            "drive", pflash_blk[i], &error_fatal);
+        loc_pop(&loc);
     }
 
-    pc_system_flash_init(rom_memory);
+    /* Reject gaps */
+    for (i = 1; i < ARRAY_SIZE(pcms->flash); i++) {
+        if (pflash_blk[i] && !pflash_blk[i - 1]) {
+            error_report("pflash%d requires pflash%d", i, i - 1);
+            exit(1);
+        }
+    }
+
+    if (!pflash_blk[0]) {
+        /* Machine property pflash0 not set, use ROM mode */
+        old_pc_system_rom_init(rom_memory, false);
+    } else {
+        if (kvm_enabled() && !kvm_readonly_mem_enabled()) {
+            /*
+             * Older KVM cannot execute from device memory. So, flash
+             * memory cannot be used unless the readonly memory kvm
+             * capability is present.
+             */
+            error_report("pflash with kvm requires KVM readonly memory support");
+            exit(1);
+        }
+
+        pc_system_flash_map(pcms, rom_memory);
+    }
+
+    pc_system_flash_cleanup_unused(pcms);
 }
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 4f5ed7cefc..276ff15d4d 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -6,6 +6,7 @@
 #include "hw/boards.h"
 #include "hw/isa/isa.h"
 #include "hw/block/fdc.h"
+#include "hw/block/flash.h"
 #include "net/net.h"
 #include "hw/i386/ioapic.h"
 
@@ -39,6 +40,7 @@ struct PCMachineState {
     PCIBus *bus;
     FWCfgState *fw_cfg;
     qemu_irq *gsi;
+    PFlashCFI01 *flash[2];
 
     /* Configuration options: */
     uint64_t max_ram_below_4g;
@@ -277,6 +279,7 @@ extern PCIDevice *piix4_dev;
 int piix4_init(PCIBus *bus, ISABus **isa_bus, int devfn);
 
 /* pc_sysfw.c */
+void pc_system_flash_create(PCMachineState *pcms);
 void pc_system_firmware_init(PCMachineState *pcms, MemoryRegion *rom_memory);
 
 /* acpi-build.c */
-- 
2.17.2

Re: [Qemu-devel] [PATCH v3 11/12] pc: Support firmware configuration with -blockdev

[Paolo Bonzini]

On 08/03/19 14:14, Markus Armbruster wrote:
> The PC machines put firmware in ROM by default.  To get it put into
> flash memory (required by OVMF), you have to use -drive
> if=pflash,unit=0,... and optionally -drive if=pflash,unit=1,...
> 
> Why two -drive?  This permits setting up one part of the flash memory
> read-only, and the other part read/write.  Below the hood, it creates
> two separate flash devices, because we were too lazy to improve our
> flash device models to support sector protection.

Not just that, it avoids the need to "upgrade the firmware" of old
virtual machines.  Instead, you just need to upgrade the files on the
host and restart QEMU, just like with non-UEFI firmware.

> This is actually an instance of a wider problem: our general device
> configuration interface doesn't cover onboard devices.  Instead, we
> have a zoo of ad hoc interfaces that are much more limited.  Some of
> them we'd rather deprecate (-drive, -net), but can't until we have
> suitable replacements.

-net already has a better replacement, -nic, which is basically "like
-netdev but also tell board creation code about it".  I suppose you'd
prefer that it were also accessible as "-netdev ...,id=foo -machine
net0=foo"?

> +static void pc_system_flash_cleanup_unused(PCMachineState *pcms)
> +{
> +    char *prop_name;
> +    int i;
> +    Object *dev_obj;
> +
> +    assert(PC_MACHINE_GET_CLASS(pcms)->pci_enabled);
> +
> +    for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
> +        dev_obj = OBJECT(pcms->flash[i]);
> +        if (!object_property_get_bool(dev_obj, "realized", &error_abort)) {
> +            prop_name = g_strdup_printf("pflash%d", i);
> +            object_property_del(OBJECT(pcms), prop_name, &error_abort);

Why didn't this already call object->class->unparent?

> +            g_free(prop_name);
> +            /*
> +             * Delete @dev_obj.  Straight object_unref() is wrong,
> +             * since it leaves dangling references in the parent bus
> +             * behind.  object_unparent() doesn't work, either: since
> +             * @dev_obj hasn't been realized, dev_obj->parent is null,
> +             * and object_unparent() does nothing.

Does it work if you add the device yourself as a child of /machine,
instead of relying on /machine/unattached?

>   DeviceClass method
> +             * device_unparent() works, but we have to take a
> +             * temporary reference, or else device_unparent() commits
> +             * a use-after-free error.
> +             */
> +            object_ref(dev_obj);
> +            object_get_class(dev_obj)->unparent(dev_obj);
> +            object_unref(dev_obj);
> +            pcms->flash[i] = NULL;
> +        }

Paolo

> +    }
> +}
> +
> +/*
> + * Map the pcms->flash[] from 4GiB downward, and realize.
> + * Map them in descending order, i.e. pcms->flash[0] at the top,
> + * without gaps.
> + * Stop at the first pcms->flash[0] lacking a block backend.
> + * Set each flash's size from its block backend.  Fatal error if the
> + * size isn't a non-zero multiple of 4KiB, or the total size exceeds
> + * FLASH_SIZE_LIMIT.
>   *
> - * The drive with unit#0 (if available) is mapped at the highest address, and
> - * it is passed to pc_isa_bios_init(). Merging several drives for isa-bios is
> + * If pcms->flash[0] has a block backend, its memory is passed to
> + * pc_isa_bios_init().  Merging several flash devices for isa-bios is
>   * not supported.
>   */
> -static void pc_system_flash_init(MemoryRegion *rom_memory)
> +static void pc_system_flash_map(PCMachineState *pcms,
> +                                MemoryRegion *rom_memory)
>  {
> -    int unit;
> -    DriveInfo *pflash_drv;
> +    hwaddr total_size = 0;
> +    int i;
>      BlockBackend *blk;
>      int64_t size;
> -    char *fatal_errmsg = NULL;
> -    hwaddr phys_addr = 0x100000000ULL;
> -    uint32_t sector_size = 4096;
>      PFlashCFI01 *system_flash;
>      MemoryRegion *flash_mem;
> -    char name[64];
>      void *flash_ptr;
>      int ret, flash_size;
>  
> -    for (unit = 0;
> -         (unit < FLASH_MAP_UNIT_MAX &&
> -          (pflash_drv = drive_get(IF_PFLASH, 0, unit)) != NULL);
> -         ++unit) {
> -        blk = blk_by_legacy_dinfo(pflash_drv);
> +    assert(PC_MACHINE_GET_CLASS(pcms)->pci_enabled);
> +
> +    for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
> +        system_flash = pcms->flash[i];
> +        blk = pflash_cfi01_get_blk(system_flash);
> +        if (!blk) {
> +            break;
> +        }
>          size = blk_getlength(blk);
>          if (size < 0) {
> -            fatal_errmsg = g_strdup_printf("failed to get backing file size");
> -        } else if (size == 0) {
> -            fatal_errmsg = g_strdup_printf("PC system firmware (pflash) "
> -                               "cannot have zero size");
> -        } else if ((size % sector_size) != 0) {
> -            fatal_errmsg = g_strdup_printf("PC system firmware (pflash) "
> -                               "must be a multiple of 0x%x", sector_size);
> -        } else if (phys_addr < size || phys_addr - size < FLASH_MAP_BASE_MIN) {
> -            fatal_errmsg = g_strdup_printf("oversized backing file, pflash "
> -                               "segments cannot be mapped under "
> -                               TARGET_FMT_plx, FLASH_MAP_BASE_MIN);
> +            error_report("can't get size of block device %s: %s",
> +                         blk_name(blk), strerror(-size));
> +            exit(1);
>          }
> -        if (fatal_errmsg != NULL) {
> -            Location loc;
> -
> -            /* push a new, "none" location on the location stack; overwrite its
> -             * contents with the location saved in the option; print the error
> -             * (includes location); pop the top
> -             */
> -            loc_push_none(&loc);
> -            if (pflash_drv->opts != NULL) {
> -                qemu_opts_loc_restore(pflash_drv->opts);
> -            }
> -            error_report("%s", fatal_errmsg);
> -            loc_pop(&loc);
> -            g_free(fatal_errmsg);
> +        if (size == 0 || size % FLASH_SECTOR_SIZE != 0) {
> +            error_report("system firmware block device %s has invalid size "
> +                         "%" PRId64,
> +                         blk_name(blk), size);
> +            info_report("its size must be a non-zero multiple of 0x%x",
> +                        FLASH_SECTOR_SIZE);
> +            exit(1);
> +        }
> +        if ((hwaddr)size != size
> +            || total_size > HWADDR_MAX - size
> +            || total_size + size > FLASH_SIZE_LIMIT) {
> +            error_report("combined size of system firmware exceeds "
> +                         "%" PRIu64 " bytes",
> +                         FLASH_SIZE_LIMIT);
>              exit(1);
>          }
>  
> -        phys_addr -= size;
> +        total_size += size;
> +        qdev_prop_set_uint32(DEVICE(system_flash), "num-blocks",
> +                             size / FLASH_SECTOR_SIZE);
> +        qdev_init_nofail(DEVICE(system_flash));
> +        sysbus_mmio_map(SYS_BUS_DEVICE(system_flash), 0,
> +                        0x100000000ULL - total_size);
>  
> -        /* pflash_cfi01_register() creates a deep copy of the name */
> -        snprintf(name, sizeof name, "system.flash%d", unit);
> -        system_flash = pflash_cfi01_register(phys_addr, name,
> -                                             size, blk, sector_size,
> -                                             1      /* width */,
> -                                             0x0000 /* id0 */,
> -                                             0x0000 /* id1 */,
> -                                             0x0000 /* id2 */,
> -                                             0x0000 /* id3 */,
> -                                             0      /* be */);
> -        if (unit == 0) {
> +        if (i == 0) {
>              flash_mem = pflash_cfi01_get_memory(system_flash);
>              pc_isa_bios_init(rom_memory, flash_mem, size);
>  
> @@ -235,23 +278,59 @@ void pc_system_firmware_init(PCMachineState *pcms,
>                               MemoryRegion *rom_memory)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
> -    bool isapc_ram_fw = !pcmc->pci_enabled;
> +    int i;
>      DriveInfo *pflash_drv;
> +    BlockBackend *pflash_blk[ARRAY_SIZE(pcms->flash)];
> +    Location loc;
>  
> -    pflash_drv = drive_get(IF_PFLASH, 0, 0);
> -
> -    if (isapc_ram_fw || pflash_drv == NULL) {
> -        /* When a pflash drive is not found, use rom-mode */
> -        old_pc_system_rom_init(rom_memory, isapc_ram_fw);
> +    if (!pcmc->pci_enabled) {
> +        old_pc_system_rom_init(rom_memory, true);
>          return;
>      }
>  
> -    if (kvm_enabled() && !kvm_readonly_mem_enabled()) {
> -        /* Older KVM cannot execute from device memory. So, flash memory
> -         * cannot be used unless the readonly memory kvm capability is present. */
> -        fprintf(stderr, "qemu: pflash with kvm requires KVM readonly memory support\n");
> -        exit(1);
> +    /* Map legacy -drive if=pflash to machine properties */
> +    for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
> +        pflash_blk[i] = pflash_cfi01_get_blk(pcms->flash[i]);
> +        pflash_drv = drive_get(IF_PFLASH, 0, i);
> +        if (!pflash_drv) {
> +            continue;
> +        }
> +        loc_push_none(&loc);
> +        qemu_opts_loc_restore(pflash_drv->opts);
> +        if (pflash_blk[i]) {
> +            error_report("clashes with -machine");
> +            exit(1);
> +        }
> +        pflash_blk[i] = blk_by_legacy_dinfo(pflash_drv);
> +        qdev_prop_set_drive(DEVICE(pcms->flash[i]),
> +                            "drive", pflash_blk[i], &error_fatal);
> +        loc_pop(&loc);
>      }
>  
> -    pc_system_flash_init(rom_memory);
> +    /* Reject gaps */
> +    for (i = 1; i < ARRAY_SIZE(pcms->flash); i++) {
> +        if (pflash_blk[i] && !pflash_blk[i - 1]) {
> +            error_report("pflash%d requires pflash%d", i, i - 1);
> +            exit(1);
> +        }
> +    }
> +
> +    if (!pflash_blk[0]) {
> +        /* Machine property pflash0 not set, use ROM mode */
> +        old_pc_system_rom_init(rom_memory, false);
> +    } else {
> +        if (kvm_enabled() && !kvm_readonly_mem_enabled()) {
> +            /*
> +             * Older KVM cannot execute from device memory. So, flash
> +             * memory cannot be used unless the readonly memory kvm
> +             * capability is present.
> +             */
> +            error_report("pflash with kvm requires KVM readonly memory support");
> +            exit(1);
> +        }
> +
> +        pc_system_flash_map(pcms, rom_memory);
> +    }
> +
> +    pc_system_flash_cleanup_unused(pcms);
>  }
> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index 4f5ed7cefc..276ff15d4d 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -6,6 +6,7 @@
>  #include "hw/boards.h"
>  #include "hw/isa/isa.h"
>  #include "hw/block/fdc.h"
> +#include "hw/block/flash.h"
>  #include "net/net.h"
>  #include "hw/i386/ioapic.h"
>  
> @@ -39,6 +40,7 @@ struct PCMachineState {
>      PCIBus *bus;
>      FWCfgState *fw_cfg;
>      qemu_irq *gsi;
> +    PFlashCFI01 *flash[2];
>  
>      /* Configuration options: */
>      uint64_t max_ram_below_4g;
> @@ -277,6 +279,7 @@ extern PCIDevice *piix4_dev;
>  int piix4_init(PCIBus *bus, ISABus **isa_bus, int devfn);
>  
>  /* pc_sysfw.c */
> +void pc_system_flash_create(PCMachineState *pcms);
>  void pc_system_firmware_init(PCMachineState *pcms, MemoryRegion *rom_memory);
>  
>  /* acpi-build.c */
> 

Re: [Qemu-devel] [PATCH v3 11/12] pc: Support firmware configuration with -blockdev

[Markus Armbruster]

Paolo Bonzini <pbonzini@redhat.com> writes:

> On 08/03/19 14:14, Markus Armbruster wrote:
>> The PC machines put firmware in ROM by default.  To get it put into
>> flash memory (required by OVMF), you have to use -drive
>> if=pflash,unit=0,... and optionally -drive if=pflash,unit=1,...
>> 
>> Why two -drive?  This permits setting up one part of the flash memory
>> read-only, and the other part read/write.  Below the hood, it creates
>> two separate flash devices, because we were too lazy to improve our
>> flash device models to support sector protection.
>
> Not just that, it avoids the need to "upgrade the firmware" of old
> virtual machines.  Instead, you just need to upgrade the files on the
> host and restart QEMU, just like with non-UEFI firmware.

True.  I'll insert "It also makes upgrading firmware on the host
easier."

>> This is actually an instance of a wider problem: our general device
>> configuration interface doesn't cover onboard devices.  Instead, we
>> have a zoo of ad hoc interfaces that are much more limited.  Some of
>> them we'd rather deprecate (-drive, -net), but can't until we have
>> suitable replacements.
>
> -net already has a better replacement, -nic, which is basically "like
> -netdev but also tell board creation code about it".  I suppose you'd
> prefer that it were also accessible as "-netdev ...,id=foo -machine
> net0=foo"?

I got confused.  Or rather, my mind was stuck in the past.  Along with
parts of our UI, to be frank.  Yes, -net already has suitable
replacements (-nic and -netdev hubport).  We've kept around -net anyway.
If this situation confuses me, chances are it confuses users, too.  I
think we should deprecate it.

I'll drop -net from my parenthesis.

Restoring a bit more quoted material for later:

   +void pc_system_flash_create(PCMachineState *pcms)
   +{
   +    PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
   +
   +    if (pcmc->pci_enabled) {
   +        pcms->flash[0] = pc_pflash_create("system.flash0");
   +        pcms->flash[1] = pc_pflash_create("system.flash1");
   +        object_property_add_alias(OBJECT(pcms), "pflash0",
   +                                  OBJECT(pcms->flash[0]), "drive",
   +                                  &error_abort);
   +        object_property_add_alias(OBJECT(pcms), "pflash1",
   +                                  OBJECT(pcms->flash[1]), "drive",
   +                                  &error_abort);
   +    }
   +}
   +
>> +static void pc_system_flash_cleanup_unused(PCMachineState *pcms)
>> +{
>> +    char *prop_name;
>> +    int i;
>> +    Object *dev_obj;
>> +
>> +    assert(PC_MACHINE_GET_CLASS(pcms)->pci_enabled);
>> +
>> +    for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
>> +        dev_obj = OBJECT(pcms->flash[i]);
>> +        if (!object_property_get_bool(dev_obj, "realized", &error_abort)) {
>> +            prop_name = g_strdup_printf("pflash%d", i);
>> +            object_property_del(OBJECT(pcms), prop_name, &error_abort);
>
> Why didn't this already call object->class->unparent?

Let's see...

    void object_property_del(Object *obj, const char *name, Error **errp)
    {
        ObjectProperty *prop = g_hash_table_lookup(obj->properties, name);

        if (!prop) {
            error_setg(errp, "Property '.%s' not found", name);
            return;
        }

        if (prop->release) {
            prop->release(obj, name, prop->opaque);
        }
        g_hash_table_remove(obj->properties, name);
    }

The only thing that could possibly call object->class->unparent() is
prop->release().  In gdb:

    (gdb) p *prop
    $1 = {name = 0x555556a4aa20 "pflash0", type = 0x555556a4aa40 "str", 
      description = 0x555556a4aa80 "Node name or ID of a block device to use as a backend", get = 0x555555d02734 <property_get_alias>, 
      set = 0x555555d0277a <property_set_alias>, 
      resolve = 0x555555d027c0 <property_resolve_alias>, 
      release = 0x555555d027f8 <property_release_alias>, opaque = 0x555556a4a990}

property_release_alias() doesn't:

    static void property_release_alias(Object *obj, const char *name, void *opaque)
    {
        AliasProperty *prop = opaque;

        g_free(prop->target_name);
        g_free(prop);
    }

Remember, the machine property is merely an alias that forwards to the
pflash device's property.

>> +            g_free(prop_name);
>> +            /*
>> +             * Delete @dev_obj.  Straight object_unref() is wrong,
>> +             * since it leaves dangling references in the parent bus
>> +             * behind.  object_unparent() doesn't work, either: since
>> +             * @dev_obj hasn't been realized, dev_obj->parent is null,
>> +             * and object_unparent() does nothing.
>
> Does it work if you add the device yourself as a child of /machine,
> instead of relying on /machine/unattached?

I figure you're suggesting something like this incremental patch:

   diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
   index ccf2221acb..9d3a80c51a 100644
   --- a/hw/i386/pc_sysfw.c
   +++ b/hw/i386/pc_sysfw.c
   @@ -99,6 +99,10 @@ void pc_system_flash_create(PCMachineState *pcms)
        if (pcmc->pci_enabled) {
            pcms->flash[0] = pc_pflash_create("system.flash0");
            pcms->flash[1] = pc_pflash_create("system.flash1");
   +        object_property_add_child(OBJECT(pcms), "pfl0",
   +                                  OBJECT(pcms->flash[0]), &error_abort);
   +        object_property_add_child(OBJECT(pcms), "pfl1",
   +                                  OBJECT(pcms->flash[1]), &error_abort);
            object_property_add_alias(OBJECT(pcms), "pflash0",
                                      OBJECT(pcms->flash[0]), "drive",
                                      &error_abort);
   @@ -122,19 +126,7 @@ static void pc_system_flash_cleanup_unused(PCMachineState *pcms)
                prop_name = g_strdup_printf("pflash%d", i);
                object_property_del(OBJECT(pcms), prop_name, &error_abort);
                g_free(prop_name);
   -            /*
   -             * Delete @dev_obj.  Straight object_unref() is wrong,
   -             * since it leaves dangling references in the parent bus
   -             * behind.  object_unparent() doesn't work, either: since
   -             * @dev_obj hasn't been realized, dev_obj->parent is null,
   -             * and object_unparent() does nothing.  DeviceClass method
   -             * device_unparent() works, but we have to take a
   -             * temporary reference, or else device_unparent() commits
   -             * a use-after-free error.
   -             */
   -            object_ref(dev_obj);
   -            object_get_class(dev_obj)->unparent(dev_obj);
   -            object_unref(dev_obj);
   +            object_unparent(dev_obj);
                pcms->flash[i] = NULL;
            }
        }

Passes "make check" and "info qtree" looks good both with and without
-machine pflash0,...

I'm not exactly happy with "pfl0" and "pfl1".  Got a favorite color for
my bikeshed?

>>   DeviceClass method
>> +             * device_unparent() works, but we have to take a
>> +             * temporary reference, or else device_unparent() commits
>> +             * a use-after-free error.
>> +             */
>> +            object_ref(dev_obj);
>> +            object_get_class(dev_obj)->unparent(dev_obj);
>> +            object_unref(dev_obj);
>> +            pcms->flash[i] = NULL;
>> +        }
>
> Paolo

Thank you!

[...]

Re: [Qemu-devel] [PATCH v3 11/12] pc: Support firmware configuration with -blockdev

[Paolo Bonzini]

On 11/03/19 16:42, Markus Armbruster wrote:
>> Does it work if you add the device yourself as a child of /machine,
>> instead of relying on /machine/unattached?
> 
> I figure you're suggesting something like this incremental patch:

Yes.

> Passes "make check" and "info qtree" looks good both with and without
> -machine pflash0,...
> 
> I'm not exactly happy with "pfl0" and "pfl1".  Got a favorite color for
> my bikeshed?

"pflash[0]" and "pflash[1]"?

Paolo

Re: [Qemu-devel] [PATCH v3 11/12] pc: Support firmware configuration with -blockdev

[Philippe Mathieu-Daudé]

Le lun. 11 mars 2019 17:02, Markus Armbruster <armbru@redhat.com> a écrit :

> Paolo Bonzini <pbonzini@redhat.com> writes:
>
> > On 08/03/19 14:14, Markus Armbruster wrote:
> >> The PC machines put firmware in ROM by default.  To get it put into
> >> flash memory (required by OVMF), you have to use -drive
> >> if=pflash,unit=0,... and optionally -drive if=pflash,unit=1,...
> >>
> >> Why two -drive?  This permits setting up one part of the flash memory
> >> read-only, and the other part read/write.  Below the hood, it creates
> >> two separate flash devices, because we were too lazy to improve our
> >> flash device models to support sector protection.
> >
> > Not just that, it avoids the need to "upgrade the firmware" of old
> > virtual machines.  Instead, you just need to upgrade the files on the
> > host and restart QEMU, just like with non-UEFI firmware.
>
> True.  I'll insert "It also makes upgrading firmware on the host
> easier."
>
> >> This is actually an instance of a wider problem: our general device
> >> configuration interface doesn't cover onboard devices.  Instead, we
> >> have a zoo of ad hoc interfaces that are much more limited.  Some of
> >> them we'd rather deprecate (-drive, -net), but can't until we have
> >> suitable replacements.
> >
> > -net already has a better replacement, -nic, which is basically "like
> > -netdev but also tell board creation code about it".  I suppose you'd
> > prefer that it were also accessible as "-netdev ...,id=foo -machine
> > net0=foo"?
>
> I got confused.  Or rather, my mind was stuck in the past.  Along with
> parts of our UI, to be frank.  Yes, -net already has suitable
> replacements (-nic and -netdev hubport).  We've kept around -net anyway.
> If this situation confuses me, chances are it confuses users, too.  I
> think we should deprecate it.
>
> I'll drop -net from my parenthesis.
>
> Restoring a bit more quoted material for later:
>
>    +void pc_system_flash_create(PCMachineState *pcms)
>    +{
>    +    PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
>    +
>    +    if (pcmc->pci_enabled) {
>    +        pcms->flash[0] = pc_pflash_create("system.flash0");
>    +        pcms->flash[1] = pc_pflash_create("system.flash1");
>    +        object_property_add_alias(OBJECT(pcms), "pflash0",
>    +                                  OBJECT(pcms->flash[0]), "drive",
>    +                                  &error_abort);
>    +        object_property_add_alias(OBJECT(pcms), "pflash1",
>    +                                  OBJECT(pcms->flash[1]), "drive",
>    +                                  &error_abort);
>    +    }
>    +}
>    +
> >> +static void pc_system_flash_cleanup_unused(PCMachineState *pcms)
> >> +{
> >> +    char *prop_name;
> >> +    int i;
> >> +    Object *dev_obj;
> >> +
> >> +    assert(PC_MACHINE_GET_CLASS(pcms)->pci_enabled);
> >> +
> >> +    for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
> >> +        dev_obj = OBJECT(pcms->flash[i]);
> >> +        if (!object_property_get_bool(dev_obj, "realized",
> &error_abort)) {
> >> +            prop_name = g_strdup_printf("pflash%d", i);
> >> +            object_property_del(OBJECT(pcms), prop_name, &error_abort);
> >
> > Why didn't this already call object->class->unparent?
>
> Let's see...
>
>     void object_property_del(Object *obj, const char *name, Error **errp)
>     {
>         ObjectProperty *prop = g_hash_table_lookup(obj->properties, name);
>
>         if (!prop) {
>             error_setg(errp, "Property '.%s' not found", name);
>             return;
>         }
>
>         if (prop->release) {
>             prop->release(obj, name, prop->opaque);
>         }
>         g_hash_table_remove(obj->properties, name);
>     }
>
> The only thing that could possibly call object->class->unparent() is
> prop->release().  In gdb:
>
>     (gdb) p *prop
>     $1 = {name = 0x555556a4aa20 "pflash0", type = 0x555556a4aa40 "str",
>       description = 0x555556a4aa80 "Node name or ID of a block device to
> use as a backend", get = 0x555555d02734 <property_get_alias>,
>       set = 0x555555d0277a <property_set_alias>,
>       resolve = 0x555555d027c0 <property_resolve_alias>,
>       release = 0x555555d027f8 <property_release_alias>, opaque =
> 0x555556a4a990}
>
> property_release_alias() doesn't:
>
>     static void property_release_alias(Object *obj, const char *name, void
> *opaque)
>     {
>         AliasProperty *prop = opaque;
>
>         g_free(prop->target_name);
>         g_free(prop);
>     }
>
> Remember, the machine property is merely an alias that forwards to the
> pflash device's property.
>
> >> +            g_free(prop_name);
> >> +            /*
> >> +             * Delete @dev_obj.  Straight object_unref() is wrong,
> >> +             * since it leaves dangling references in the parent bus
> >> +             * behind.  object_unparent() doesn't work, either: since
> >> +             * @dev_obj hasn't been realized, dev_obj->parent is null,
> >> +             * and object_unparent() does nothing.
> >
> > Does it work if you add the device yourself as a child of /machine,
> > instead of relying on /machine/unattached?
>
> I figure you're suggesting something like this incremental patch:
>
>    diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
>    index ccf2221acb..9d3a80c51a 100644
>    --- a/hw/i386/pc_sysfw.c
>    +++ b/hw/i386/pc_sysfw.c
>    @@ -99,6 +99,10 @@ void pc_system_flash_create(PCMachineState *pcms)
>         if (pcmc->pci_enabled) {
>             pcms->flash[0] = pc_pflash_create("system.flash0");
>             pcms->flash[1] = pc_pflash_create("system.flash1");
>    +        object_property_add_child(OBJECT(pcms), "pfl0",
>    +                                  OBJECT(pcms->flash[0]),
> &error_abort);
>    +        object_property_add_child(OBJECT(pcms), "pfl1",
>    +                                  OBJECT(pcms->flash[1]),
> &error_abort);
>             object_property_add_alias(OBJECT(pcms), "pflash0",
>                                       OBJECT(pcms->flash[0]), "drive",
>                                       &error_abort);
>    @@ -122,19 +126,7 @@ static void
> pc_system_flash_cleanup_unused(PCMachineState *pcms)
>                 prop_name = g_strdup_printf("pflash%d", i);
>                 object_property_del(OBJECT(pcms), prop_name, &error_abort);
>                 g_free(prop_name);
>    -            /*
>    -             * Delete @dev_obj.  Straight object_unref() is wrong,
>    -             * since it leaves dangling references in the parent bus
>    -             * behind.  object_unparent() doesn't work, either: since
>    -             * @dev_obj hasn't been realized, dev_obj->parent is null,
>    -             * and object_unparent() does nothing.  DeviceClass method
>    -             * device_unparent() works, but we have to take a
>    -             * temporary reference, or else device_unparent() commits
>    -             * a use-after-free error.
>    -             */
>    -            object_ref(dev_obj);
>    -            object_get_class(dev_obj)->unparent(dev_obj);
>    -            object_unref(dev_obj);
>    +            object_unparent(dev_obj);
>                 pcms->flash[i] = NULL;
>             }
>         }
>
> Passes "make check" and "info qtree" looks good both with and without
> -machine pflash0,...
>
> I'm not exactly happy with "pfl0" and "pfl1".  Got a favorite color for
> my bikeshed?
>

ovmf_code & ovmf_vars?

>
> >>   DeviceClass method
> >> +             * device_unparent() works, but we have to take a
> >> +             * temporary reference, or else device_unparent() commits
> >> +             * a use-after-free error.
> >> +             */
> >> +            object_ref(dev_obj);
> >> +            object_get_class(dev_obj)->unparent(dev_obj);
> >> +            object_unref(dev_obj);
> >> +            pcms->flash[i] = NULL;
> >> +        }
> >
> > Paolo
>
> Thank you!
>
> [...]
>
>

Re: [Qemu-devel] [PATCH v3 11/12] pc: Support firmware configuration with -blockdev

[Markus Armbruster]

Philippe Mathieu-Daudé <f4bug@amsat.org> writes:

> Le lun. 11 mars 2019 17:02, Markus Armbruster <armbru@redhat.com> a écrit :
>
>> Paolo Bonzini <pbonzini@redhat.com> writes:
[...]
>> > Does it work if you add the device yourself as a child of /machine,
>> > instead of relying on /machine/unattached?
>>
>> I figure you're suggesting something like this incremental patch:
>>
>>    diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
>>    index ccf2221acb..9d3a80c51a 100644
>>    --- a/hw/i386/pc_sysfw.c
>>    +++ b/hw/i386/pc_sysfw.c
>>    @@ -99,6 +99,10 @@ void pc_system_flash_create(PCMachineState *pcms)
>>         if (pcmc->pci_enabled) {
>>             pcms->flash[0] = pc_pflash_create("system.flash0");
>>             pcms->flash[1] = pc_pflash_create("system.flash1");
>>    +        object_property_add_child(OBJECT(pcms), "pfl0",
>>    +                                  OBJECT(pcms->flash[0]),
>> &error_abort);
>>    +        object_property_add_child(OBJECT(pcms), "pfl1",
>>    +                                  OBJECT(pcms->flash[1]),
>> &error_abort);
>>             object_property_add_alias(OBJECT(pcms), "pflash0",
>>                                       OBJECT(pcms->flash[0]), "drive",
>>                                       &error_abort);
>>    @@ -122,19 +126,7 @@ static void
>> pc_system_flash_cleanup_unused(PCMachineState *pcms)
>>                 prop_name = g_strdup_printf("pflash%d", i);
>>                 object_property_del(OBJECT(pcms), prop_name, &error_abort);
>>                 g_free(prop_name);
>>    -            /*
>>    -             * Delete @dev_obj.  Straight object_unref() is wrong,
>>    -             * since it leaves dangling references in the parent bus
>>    -             * behind.  object_unparent() doesn't work, either: since
>>    -             * @dev_obj hasn't been realized, dev_obj->parent is null,
>>    -             * and object_unparent() does nothing.  DeviceClass method
>>    -             * device_unparent() works, but we have to take a
>>    -             * temporary reference, or else device_unparent() commits
>>    -             * a use-after-free error.
>>    -             */
>>    -            object_ref(dev_obj);
>>    -            object_get_class(dev_obj)->unparent(dev_obj);
>>    -            object_unref(dev_obj);
>>    +            object_unparent(dev_obj);
>>                 pcms->flash[i] = NULL;
>>             }
>>         }
>>
>> Passes "make check" and "info qtree" looks good both with and without
>> -machine pflash0,...
>>
>> I'm not exactly happy with "pfl0" and "pfl1".  Got a favorite color for
>> my bikeshed?
>>
>
> ovmf_code & ovmf_vars?

Tempting, since we use these guys only for OVMF so far.  However, we
could also use them for SeaBIOS[*], or whatever other firmware comes up.

[...]


[*] See also
Subject: Re: Configuring pflash devices for OVMF firmware
Message-ID: <9c4e222f-3941-426e-3195-5598b2af1501@redhat.com>
https://lists.nongnu.org/archive/html/qemu-devel/2019-01/msg08145.html

[Qemu-devel] [PATCH v3 12/12] docs/interop/firmware.json: Prefer -machine to if=pflash

[Markus Armbruster]

The previous commit added a way to configure firmware with -blockdev
rather than -drive if=pflash.  Document it as the preferred way.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 docs/interop/firmware.json | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/docs/interop/firmware.json b/docs/interop/firmware.json
index 28f9bc1591..ff8c2ce5f2 100644
--- a/docs/interop/firmware.json
+++ b/docs/interop/firmware.json
@@ -212,9 +212,13 @@
 #
 # @executable: Identifies the firmware executable. The firmware
 #              executable may be shared by multiple virtual machine
-#              definitions. The corresponding QEMU command line option
-#              is "-drive
-#              if=pflash,unit=0,readonly=on,file=@executable.@filename,format=@executable.@format".
+#              definitions. The preferred corresponding QEMU command
+#              line options are
+#                  -drive if=none,id=pflash0,readonly=on,file=@executable.@filename,format=@executable.@format
+#                  -machine pflash0=pflash0
+#              or equivalent -blockdev instead of -drive.
+#              With QEMU versions older than 4.0, you have to use
+#                  -drive if=pflash,unit=0,readonly=on,file=@executable.@filename,format=@executable.@format
 #
 # @nvram-template: Identifies the NVRAM template compatible with
 #                  @executable. Management software instantiates an
@@ -225,9 +229,13 @@
 #                  individual copies of it are. An NVRAM file is
 #                  typically used for persistently storing the
 #                  non-volatile UEFI variables of a virtual machine
-#                  definition. The corresponding QEMU command line
-#                  option is "-drive
-#                  if=pflash,unit=1,readonly=off,file=FILENAME_OF_PRIVATE_NVRAM_FILE,format=@nvram-template.@format".
+#                  definition. The preferred corresponding QEMU
+#                  command line options are
+#                      -drive if=none,id=pflash1,readonly=off,file=FILENAME_OF_PRIVATE_NVRAM_FILE,format=@nvram-template.@format
+#                      -machine pflash1=pflash1
+#                  or equivalent -blockdev instead of -drive.
+#                  With QEMU versions older than 4.0, you have to use
+#                      -drive if=pflash,unit=1,readonly=off,file=FILENAME_OF_PRIVATE_NVRAM_FILE,format=@nvram-template.@format
 #
 # Since: 3.0
 ##
-- 
2.17.2

Re: [Qemu-devel] [PATCH v3 12/12] docs/interop/firmware.json: Prefer -machine to if=pflash

[Laszlo Ersek]

On 03/08/19 14:14, Markus Armbruster wrote:
> The previous commit added a way to configure firmware with -blockdev
> rather than -drive if=pflash.  Document it as the preferred way.
> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---
>  docs/interop/firmware.json | 20 ++++++++++++++------
>  1 file changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/docs/interop/firmware.json b/docs/interop/firmware.json
> index 28f9bc1591..ff8c2ce5f2 100644
> --- a/docs/interop/firmware.json
> +++ b/docs/interop/firmware.json
> @@ -212,9 +212,13 @@
>  #
>  # @executable: Identifies the firmware executable. The firmware
>  #              executable may be shared by multiple virtual machine
> -#              definitions. The corresponding QEMU command line option
> -#              is "-drive
> -#              if=pflash,unit=0,readonly=on,file=@executable.@filename,format=@executable.@format".
> +#              definitions. The preferred corresponding QEMU command
> +#              line options are
> +#                  -drive if=none,id=pflash0,readonly=on,file=@executable.@filename,format=@executable.@format
> +#                  -machine pflash0=pflash0
> +#              or equivalent -blockdev instead of -drive.
> +#              With QEMU versions older than 4.0, you have to use
> +#                  -drive if=pflash,unit=0,readonly=on,file=@executable.@filename,format=@executable.@format
>  #
>  # @nvram-template: Identifies the NVRAM template compatible with
>  #                  @executable. Management software instantiates an
> @@ -225,9 +229,13 @@
>  #                  individual copies of it are. An NVRAM file is
>  #                  typically used for persistently storing the
>  #                  non-volatile UEFI variables of a virtual machine
> -#                  definition. The corresponding QEMU command line
> -#                  option is "-drive
> -#                  if=pflash,unit=1,readonly=off,file=FILENAME_OF_PRIVATE_NVRAM_FILE,format=@nvram-template.@format".
> +#                  definition. The preferred corresponding QEMU
> +#                  command line options are
> +#                      -drive if=none,id=pflash1,readonly=off,file=FILENAME_OF_PRIVATE_NVRAM_FILE,format=@nvram-template.@format
> +#                      -machine pflash1=pflash1
> +#                  or equivalent -blockdev instead of -drive.
> +#                  With QEMU versions older than 4.0, you have to use
> +#                      -drive if=pflash,unit=1,readonly=off,file=FILENAME_OF_PRIVATE_NVRAM_FILE,format=@nvram-template.@format
>  #
>  # Since: 3.0
>  ##
> 

Awesome.

Reviewed-by: Laszlo Ersek <lersek@redhat.com>

Thanks!
Laszlo

Re: [Qemu-devel] [PATCH v3 00/12] pc: Support firmware configuration with -blockdev

[Michael S. Tsirkin]

On Fri, Mar 08, 2019 at 02:14:33PM +0100, Markus Armbruster wrote:
> Based-on: <20190308094610.21210-1-armbru@redhat.com>
> 
> v3:
> * PATCH 05: Commit message tidied up [Philippe, László]
> * PATCH 06: Comment tidied up [checkpatch]
> * PATCH 12: Comment polish [László]
> 
> v2:
> * PATCH 05,06: New [Philippe]
> * PATCH 07: Old PATCH 5 rebased onto new patches, with new comment
>   [Philippe]
> * PATCH 08+10: New, factored out of old PATCH 6 [by Philippe]
> * PATCH 09: New [by Philippe]
> * PATCH 11: Remainder of old PATCH 6, with FIXME resolved, literal
>   4096 de-duplicated [László], extraneous error check deleted
>   [László], and comment typos fixed
> * PATCH 12: New
> 
> Markus Armbruster (9):
>   qdev: Fix latent bug with compat_props and onboard devices
>   qom: Move compat_props machinery from qdev to QOM
>   vl: Fix latent bug with -global and onboard devices
>   sysbus: Fix latent bug with onboard devices
>   vl: Improve legibility of BlockdevOptions queue
>   vl: Factor configure_blockdev() out of main()
>   vl: Create block backends before setting machine properties
>   pc: Support firmware configuration with -blockdev
>   docs/interop/firmware.json: Prefer -machine to if=pflash
> 
> Philippe Mathieu-Daudé (3):
>   pflash_cfi01: Add pflash_cfi01_get_blk() helper
>   pc_sysfw: Remove unused PcSysFwDevice
>   pc_sysfw: Pass PCMachineState to pc_system_firmware_init()

OK looks good to me.

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

Paolo will you be merging this?


>  accel/accel.c              |   1 +
>  docs/interop/firmware.json |  20 ++-
>  hw/block/pflash_cfi01.c    |   5 +
>  hw/core/qdev.c             |  21 +---
>  hw/core/sysbus.c           |   3 -
>  hw/i386/pc.c               |   4 +-
>  hw/i386/pc_sysfw.c         | 249 ++++++++++++++++++++++++-------------
>  include/hw/block/flash.h   |   1 +
>  include/hw/i386/pc.h       |   6 +-
>  include/hw/qdev-core.h     |   2 -
>  include/qom/object.h       |   3 +
>  qom/object.c               |  39 ++++++
>  vl.c                       | 125 ++++++++++---------
>  13 files changed, 303 insertions(+), 176 deletions(-)
> 
> -- 
> 2.17.2

Re: [Qemu-devel] [PATCH v3 00/12] pc: Support firmware configuration with -blockdev

[Markus Armbruster]

"Michael S. Tsirkin" <mst@redhat.com> writes:

> On Fri, Mar 08, 2019 at 02:14:33PM +0100, Markus Armbruster wrote:
>> Based-on: <20190308094610.21210-1-armbru@redhat.com>
>> 
>> v3:
>> * PATCH 05: Commit message tidied up [Philippe, László]
>> * PATCH 06: Comment tidied up [checkpatch]
>> * PATCH 12: Comment polish [László]
>> 
>> v2:
>> * PATCH 05,06: New [Philippe]
>> * PATCH 07: Old PATCH 5 rebased onto new patches, with new comment
>>   [Philippe]
>> * PATCH 08+10: New, factored out of old PATCH 6 [by Philippe]
>> * PATCH 09: New [by Philippe]
>> * PATCH 11: Remainder of old PATCH 6, with FIXME resolved, literal
>>   4096 de-duplicated [László], extraneous error check deleted
>>   [László], and comment typos fixed
>> * PATCH 12: New
>> 
>> Markus Armbruster (9):
>>   qdev: Fix latent bug with compat_props and onboard devices
>>   qom: Move compat_props machinery from qdev to QOM
>>   vl: Fix latent bug with -global and onboard devices
>>   sysbus: Fix latent bug with onboard devices
>>   vl: Improve legibility of BlockdevOptions queue
>>   vl: Factor configure_blockdev() out of main()
>>   vl: Create block backends before setting machine properties
>>   pc: Support firmware configuration with -blockdev
>>   docs/interop/firmware.json: Prefer -machine to if=pflash
>> 
>> Philippe Mathieu-Daudé (3):
>>   pflash_cfi01: Add pflash_cfi01_get_blk() helper
>>   pc_sysfw: Remove unused PcSysFwDevice
>>   pc_sysfw: Pass PCMachineState to pc_system_firmware_init()
>
> OK looks good to me.
>
> Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

Thanks!

> Paolo will you be merging this?

Alternatively, I can do the pull request myself.  Paolo, would you like
me to?

[Qemu-devel] [PATCH v4 11/12] pc: Support firmware configuration with -blockdev

[Markus Armbruster]

The PC machines put firmware in ROM by default.  To get it put into
flash memory (required by OVMF), you have to use -drive
if=pflash,unit=0,... and optionally -drive if=pflash,unit=1,...

Why two -drive?  This permits setting up one part of the flash memory
read-only, and the other part read/write.  It also makes upgrading
firmware on the host easier.  Below the hood, it creates two separate
flash devices, because we were too lazy to improve our flash device
models to support sector protection.

The problem at hand is to do the same with -blockdev somehow, as one
more step towards deprecating -drive.

Mapping -drive if=none,... to -blockdev is a solved problem.  With
if=T other than if=none, -drive additionally configures a block device
frontend.  For non-onboard devices, that part maps to -device.  Also a
solved problem.  For onboard devices such as PC flash memory, we have
an unsolved problem.

This is actually an instance of a wider problem: our general device
configuration interface doesn't cover onboard devices.  Instead, we have
a zoo of ad hoc interfaces that are much more limited.  One of them is
-drive, which we'd rather deprecate, but can't until we have suitable
replacements for all its uses.

Sadly, I can't attack the wider problem today.  So back to the narrow
problem.

My first idea was to reduce it to its solved buddy by using pluggable
instead of onboard devices for the flash memory.  Workable, but it
requires some extra smarts in firmware descriptors and libvirt.  Paolo
had an idea that is simpler for libvirt: keep the devices onboard, and
add machine properties for their block backends.

The implementation is less than straightforward, I'm afraid.

First, block backend properties are *qdev* properties.  Machines can't
have those, as they're not devices.  I could duplicate these qdev
properties as QOM properties, but I hate that.

More seriously, the properties do not belong to the machine, they
belong to the onboard flash devices.  Adding them to the machine would
then require bad magic to somehow transfer them to the flash devices.
Fortunately, QOM provides the means to handle exactly this case: add
alias properties to the machine that forward to the onboard devices'
properties.

Properties need to be created in .instance_init() methods.  For PC
machines, that's pc_machine_initfn().  To make alias properties work,
we need to create the onboard flash devices there, too.  Requires
several bug fixes, in the previous commits.  We also have to realize
the devices.  More on that below.

If the user sets pflash0, firmware resides in flash memory.
pc_system_firmware_init() maps and realizes the flash devices.

Else, firmware resides in ROM.  The onboard flash devices aren't used
then.  pc_system_firmware_init() destroys them unrealized, along with
the alias properties.

The existing code to pick up drives defined with -drive if=pflash is
replaced by code to desugar into the machine properties.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
---
 hw/i386/pc.c         |   2 +
 hw/i386/pc_sysfw.c   | 233 ++++++++++++++++++++++++++++---------------
 include/hw/i386/pc.h |   3 +
 3 files changed, 156 insertions(+), 82 deletions(-)

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index b2947e433b..7e7f4cbfb4 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -2643,6 +2643,8 @@ static void pc_machine_initfn(Object *obj)
     pcms->smbus_enabled = true;
     pcms->sata_enabled = true;
     pcms->pit_enabled = true;
+
+    pc_system_flash_create(pcms);
 }
 
 static void pc_machine_reset(void)
diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
index 785123252c..c628540774 100644
--- a/hw/i386/pc_sysfw.c
+++ b/hw/i386/pc_sysfw.c
@@ -40,6 +40,17 @@
 
 #define BIOS_FILENAME "bios.bin"
 
+/*
+ * We don't have a theoretically justifiable exact lower bound on the base
+ * address of any flash mapping. In practice, the IO-APIC MMIO range is
+ * [0xFEE00000..0xFEE01000] -- see IO_APIC_DEFAULT_ADDRESS --, leaving free
+ * only 18MB-4KB below 4G. For now, restrict the cumulative mapping to 8MB in
+ * size.
+ */
+#define FLASH_SIZE_LIMIT (8 * MiB)
+
+#define FLASH_SECTOR_SIZE 4096
+
 static void pc_isa_bios_init(MemoryRegion *rom_memory,
                              MemoryRegion *flash_mem,
                              int ram_size)
@@ -71,96 +82,118 @@ static void pc_isa_bios_init(MemoryRegion *rom_memory,
     memory_region_set_readonly(isa_bios, true);
 }
 
-#define FLASH_MAP_UNIT_MAX 2
+static PFlashCFI01 *pc_pflash_create(PCMachineState *pcms,
+                                     const char *name,
+                                     const char *alias_prop_name)
+{
+    DeviceState *dev = qdev_create(NULL, TYPE_PFLASH_CFI01);
 
-/* We don't have a theoretically justifiable exact lower bound on the base
- * address of any flash mapping. In practice, the IO-APIC MMIO range is
- * [0xFEE00000..0xFEE01000[ -- see IO_APIC_DEFAULT_ADDRESS --, leaving free
- * only 18MB-4KB below 4G. For now, restrict the cumulative mapping to 8MB in
- * size.
- */
-#define FLASH_MAP_BASE_MIN ((hwaddr)(4 * GiB - 8 * MiB))
+    qdev_prop_set_uint64(dev, "sector-length", FLASH_SECTOR_SIZE);
+    qdev_prop_set_uint8(dev, "width", 1);
+    qdev_prop_set_string(dev, "name", name);
+    object_property_add_child(OBJECT(pcms), name, OBJECT(dev),
+                              &error_abort);
+    object_property_add_alias(OBJECT(pcms), alias_prop_name,
+                              OBJECT(dev), "drive", &error_abort);
+    return PFLASH_CFI01(dev);
+}
 
-/* This function maps flash drives from 4G downward, in order of their unit
- * numbers. The mapping starts at unit#0, with unit number increments of 1, and
- * stops before the first missing flash drive, or before
- * unit#FLASH_MAP_UNIT_MAX, whichever is reached first.
- *
- * Addressing within one flash drive is of course not reversed.
- *
- * An error message is printed and the process exits if:
- * - the size of the backing file for a flash drive is non-positive, or not a
- *   multiple of the required sector size, or
- * - the current mapping's base address would fall below FLASH_MAP_BASE_MIN.
+void pc_system_flash_create(PCMachineState *pcms)
+{
+    PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
+
+    if (pcmc->pci_enabled) {
+        pcms->flash[0] = pc_pflash_create(pcms, "system.flash0",
+                                          "pflash0");
+        pcms->flash[1] = pc_pflash_create(pcms, "system.flash1",
+                                          "pflash1");
+    }
+}
+
+static void pc_system_flash_cleanup_unused(PCMachineState *pcms)
+{
+    char *prop_name;
+    int i;
+    Object *dev_obj;
+
+    assert(PC_MACHINE_GET_CLASS(pcms)->pci_enabled);
+
+    for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
+        dev_obj = OBJECT(pcms->flash[i]);
+        if (!object_property_get_bool(dev_obj, "realized", &error_abort)) {
+            prop_name = g_strdup_printf("pflash%d", i);
+            object_property_del(OBJECT(pcms), prop_name, &error_abort);
+            g_free(prop_name);
+            object_unparent(dev_obj);
+            pcms->flash[i] = NULL;
+        }
+    }
+}
+
+/*
+ * Map the pcms->flash[] from 4GiB downward, and realize.
+ * Map them in descending order, i.e. pcms->flash[0] at the top,
+ * without gaps.
+ * Stop at the first pcms->flash[0] lacking a block backend.
+ * Set each flash's size from its block backend.  Fatal error if the
+ * size isn't a non-zero multiple of 4KiB, or the total size exceeds
+ * FLASH_SIZE_LIMIT.
  *
- * The drive with unit#0 (if available) is mapped at the highest address, and
- * it is passed to pc_isa_bios_init(). Merging several drives for isa-bios is
+ * If pcms->flash[0] has a block backend, its memory is passed to
+ * pc_isa_bios_init().  Merging several flash devices for isa-bios is
  * not supported.
  */
-static void pc_system_flash_init(MemoryRegion *rom_memory)
+static void pc_system_flash_map(PCMachineState *pcms,
+                                MemoryRegion *rom_memory)
 {
-    int unit;
-    DriveInfo *pflash_drv;
+    hwaddr total_size = 0;
+    int i;
     BlockBackend *blk;
     int64_t size;
-    char *fatal_errmsg = NULL;
-    hwaddr phys_addr = 0x100000000ULL;
-    uint32_t sector_size = 4096;
     PFlashCFI01 *system_flash;
     MemoryRegion *flash_mem;
-    char name[64];
     void *flash_ptr;
     int ret, flash_size;
 
-    for (unit = 0;
-         (unit < FLASH_MAP_UNIT_MAX &&
-          (pflash_drv = drive_get(IF_PFLASH, 0, unit)) != NULL);
-         ++unit) {
-        blk = blk_by_legacy_dinfo(pflash_drv);
+    assert(PC_MACHINE_GET_CLASS(pcms)->pci_enabled);
+
+    for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
+        system_flash = pcms->flash[i];
+        blk = pflash_cfi01_get_blk(system_flash);
+        if (!blk) {
+            break;
+        }
         size = blk_getlength(blk);
         if (size < 0) {
-            fatal_errmsg = g_strdup_printf("failed to get backing file size");
-        } else if (size == 0) {
-            fatal_errmsg = g_strdup_printf("PC system firmware (pflash) "
-                               "cannot have zero size");
-        } else if ((size % sector_size) != 0) {
-            fatal_errmsg = g_strdup_printf("PC system firmware (pflash) "
-                               "must be a multiple of 0x%x", sector_size);
-        } else if (phys_addr < size || phys_addr - size < FLASH_MAP_BASE_MIN) {
-            fatal_errmsg = g_strdup_printf("oversized backing file, pflash "
-                               "segments cannot be mapped under "
-                               TARGET_FMT_plx, FLASH_MAP_BASE_MIN);
+            error_report("can't get size of block device %s: %s",
+                         blk_name(blk), strerror(-size));
+            exit(1);
         }
-        if (fatal_errmsg != NULL) {
-            Location loc;
-
-            /* push a new, "none" location on the location stack; overwrite its
-             * contents with the location saved in the option; print the error
-             * (includes location); pop the top
-             */
-            loc_push_none(&loc);
-            if (pflash_drv->opts != NULL) {
-                qemu_opts_loc_restore(pflash_drv->opts);
-            }
-            error_report("%s", fatal_errmsg);
-            loc_pop(&loc);
-            g_free(fatal_errmsg);
+        if (size == 0 || size % FLASH_SECTOR_SIZE != 0) {
+            error_report("system firmware block device %s has invalid size "
+                         "%" PRId64,
+                         blk_name(blk), size);
+            info_report("its size must be a non-zero multiple of 0x%x",
+                        FLASH_SECTOR_SIZE);
+            exit(1);
+        }
+        if ((hwaddr)size != size
+            || total_size > HWADDR_MAX - size
+            || total_size + size > FLASH_SIZE_LIMIT) {
+            error_report("combined size of system firmware exceeds "
+                         "%" PRIu64 " bytes",
+                         FLASH_SIZE_LIMIT);
             exit(1);
         }
 
-        phys_addr -= size;
+        total_size += size;
+        qdev_prop_set_uint32(DEVICE(system_flash), "num-blocks",
+                             size / FLASH_SECTOR_SIZE);
+        qdev_init_nofail(DEVICE(system_flash));
+        sysbus_mmio_map(SYS_BUS_DEVICE(system_flash), 0,
+                        0x100000000ULL - total_size);
 
-        /* pflash_cfi01_register() creates a deep copy of the name */
-        snprintf(name, sizeof name, "system.flash%d", unit);
-        system_flash = pflash_cfi01_register(phys_addr, name,
-                                             size, blk, sector_size,
-                                             1      /* width */,
-                                             0x0000 /* id0 */,
-                                             0x0000 /* id1 */,
-                                             0x0000 /* id2 */,
-                                             0x0000 /* id3 */,
-                                             0      /* be */);
-        if (unit == 0) {
+        if (i == 0) {
             flash_mem = pflash_cfi01_get_memory(system_flash);
             pc_isa_bios_init(rom_memory, flash_mem, size);
 
@@ -235,23 +268,59 @@ void pc_system_firmware_init(PCMachineState *pcms,
                              MemoryRegion *rom_memory)
 {
     PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
-    bool isapc_ram_fw = !pcmc->pci_enabled;
+    int i;
     DriveInfo *pflash_drv;
+    BlockBackend *pflash_blk[ARRAY_SIZE(pcms->flash)];
+    Location loc;
 
-    pflash_drv = drive_get(IF_PFLASH, 0, 0);
-
-    if (isapc_ram_fw || pflash_drv == NULL) {
-        /* When a pflash drive is not found, use rom-mode */
-        old_pc_system_rom_init(rom_memory, isapc_ram_fw);
+    if (!pcmc->pci_enabled) {
+        old_pc_system_rom_init(rom_memory, true);
         return;
     }
 
-    if (kvm_enabled() && !kvm_readonly_mem_enabled()) {
-        /* Older KVM cannot execute from device memory. So, flash memory
-         * cannot be used unless the readonly memory kvm capability is present. */
-        fprintf(stderr, "qemu: pflash with kvm requires KVM readonly memory support\n");
-        exit(1);
+    /* Map legacy -drive if=pflash to machine properties */
+    for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
+        pflash_blk[i] = pflash_cfi01_get_blk(pcms->flash[i]);
+        pflash_drv = drive_get(IF_PFLASH, 0, i);
+        if (!pflash_drv) {
+            continue;
+        }
+        loc_push_none(&loc);
+        qemu_opts_loc_restore(pflash_drv->opts);
+        if (pflash_blk[i]) {
+            error_report("clashes with -machine");
+            exit(1);
+        }
+        pflash_blk[i] = blk_by_legacy_dinfo(pflash_drv);
+        qdev_prop_set_drive(DEVICE(pcms->flash[i]),
+                            "drive", pflash_blk[i], &error_fatal);
+        loc_pop(&loc);
     }
 
-    pc_system_flash_init(rom_memory);
+    /* Reject gaps */
+    for (i = 1; i < ARRAY_SIZE(pcms->flash); i++) {
+        if (pflash_blk[i] && !pflash_blk[i - 1]) {
+            error_report("pflash%d requires pflash%d", i, i - 1);
+            exit(1);
+        }
+    }
+
+    if (!pflash_blk[0]) {
+        /* Machine property pflash0 not set, use ROM mode */
+        old_pc_system_rom_init(rom_memory, false);
+    } else {
+        if (kvm_enabled() && !kvm_readonly_mem_enabled()) {
+            /*
+             * Older KVM cannot execute from device memory. So, flash
+             * memory cannot be used unless the readonly memory kvm
+             * capability is present.
+             */
+            error_report("pflash with kvm requires KVM readonly memory support");
+            exit(1);
+        }
+
+        pc_system_flash_map(pcms, rom_memory);
+    }
+
+    pc_system_flash_cleanup_unused(pcms);
 }
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 4f5ed7cefc..276ff15d4d 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -6,6 +6,7 @@
 #include "hw/boards.h"
 #include "hw/isa/isa.h"
 #include "hw/block/fdc.h"
+#include "hw/block/flash.h"
 #include "net/net.h"
 #include "hw/i386/ioapic.h"
 
@@ -39,6 +40,7 @@ struct PCMachineState {
     PCIBus *bus;
     FWCfgState *fw_cfg;
     qemu_irq *gsi;
+    PFlashCFI01 *flash[2];
 
     /* Configuration options: */
     uint64_t max_ram_below_4g;
@@ -277,6 +279,7 @@ extern PCIDevice *piix4_dev;
 int piix4_init(PCIBus *bus, ISABus **isa_bus, int devfn);
 
 /* pc_sysfw.c */
+void pc_system_flash_create(PCMachineState *pcms);
 void pc_system_firmware_init(PCMachineState *pcms, MemoryRegion *rom_memory);
 
 /* acpi-build.c */
-- 
2.17.2

Re: [Qemu-devel] [PATCH v4 11/12] pc: Support firmware configuration with -blockdev

[Markus Armbruster]

Incremental diff since v3:

diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
index ccf2221acb..c628540774 100644
--- a/hw/i386/pc_sysfw.c
+++ b/hw/i386/pc_sysfw.c
@@ -82,13 +82,19 @@ static void pc_isa_bios_init(MemoryRegion *rom_memory,
     memory_region_set_readonly(isa_bios, true);
 }
 
-static PFlashCFI01 *pc_pflash_create(const char *name)
+static PFlashCFI01 *pc_pflash_create(PCMachineState *pcms,
+                                     const char *name,
+                                     const char *alias_prop_name)
 {
     DeviceState *dev = qdev_create(NULL, TYPE_PFLASH_CFI01);
 
     qdev_prop_set_uint64(dev, "sector-length", FLASH_SECTOR_SIZE);
     qdev_prop_set_uint8(dev, "width", 1);
     qdev_prop_set_string(dev, "name", name);
+    object_property_add_child(OBJECT(pcms), name, OBJECT(dev),
+                              &error_abort);
+    object_property_add_alias(OBJECT(pcms), alias_prop_name,
+                              OBJECT(dev), "drive", &error_abort);
     return PFLASH_CFI01(dev);
 }
 
@@ -97,14 +103,10 @@ void pc_system_flash_create(PCMachineState *pcms)
     PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
 
     if (pcmc->pci_enabled) {
-        pcms->flash[0] = pc_pflash_create("system.flash0");
-        pcms->flash[1] = pc_pflash_create("system.flash1");
-        object_property_add_alias(OBJECT(pcms), "pflash0",
-                                  OBJECT(pcms->flash[0]), "drive",
-                                  &error_abort);
-        object_property_add_alias(OBJECT(pcms), "pflash1",
-                                  OBJECT(pcms->flash[1]), "drive",
-                                  &error_abort);
+        pcms->flash[0] = pc_pflash_create(pcms, "system.flash0",
+                                          "pflash0");
+        pcms->flash[1] = pc_pflash_create(pcms, "system.flash1",
+                                          "pflash1");
     }
 }
 
@@ -122,19 +124,7 @@ static void pc_system_flash_cleanup_unused(PCMachineState *pcms)
             prop_name = g_strdup_printf("pflash%d", i);
             object_property_del(OBJECT(pcms), prop_name, &error_abort);
             g_free(prop_name);
-            /*
-             * Delete @dev_obj.  Straight object_unref() is wrong,
-             * since it leaves dangling references in the parent bus
-             * behind.  object_unparent() doesn't work, either: since
-             * @dev_obj hasn't been realized, dev_obj->parent is null,
-             * and object_unparent() does nothing.  DeviceClass method
-             * device_unparent() works, but we have to take a
-             * temporary reference, or else device_unparent() commits
-             * a use-after-free error.
-             */
-            object_ref(dev_obj);
-            object_get_class(dev_obj)->unparent(dev_obj);
-            object_unref(dev_obj);
+            object_unparent(dev_obj);
             pcms->flash[i] = NULL;
         }
     }

Re: [Qemu-devel] [PATCH v4 11/12] pc: Support firmware configuration with -blockdev

[Paolo Bonzini]

On 11/03/19 18:42, Markus Armbruster wrote:
> Incremental diff since v3:

Ack, thanks.

Paolo

> diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
> index ccf2221acb..c628540774 100644
> --- a/hw/i386/pc_sysfw.c
> +++ b/hw/i386/pc_sysfw.c
> @@ -82,13 +82,19 @@ static void pc_isa_bios_init(MemoryRegion *rom_memory,
>      memory_region_set_readonly(isa_bios, true);
>  }
>  
> -static PFlashCFI01 *pc_pflash_create(const char *name)
> +static PFlashCFI01 *pc_pflash_create(PCMachineState *pcms,
> +                                     const char *name,
> +                                     const char *alias_prop_name)
>  {
>      DeviceState *dev = qdev_create(NULL, TYPE_PFLASH_CFI01);
>  
>      qdev_prop_set_uint64(dev, "sector-length", FLASH_SECTOR_SIZE);
>      qdev_prop_set_uint8(dev, "width", 1);
>      qdev_prop_set_string(dev, "name", name);
> +    object_property_add_child(OBJECT(pcms), name, OBJECT(dev),
> +                              &error_abort);
> +    object_property_add_alias(OBJECT(pcms), alias_prop_name,
> +                              OBJECT(dev), "drive", &error_abort);
>      return PFLASH_CFI01(dev);
>  }
>  
> @@ -97,14 +103,10 @@ void pc_system_flash_create(PCMachineState *pcms)
>      PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
>  
>      if (pcmc->pci_enabled) {
> -        pcms->flash[0] = pc_pflash_create("system.flash0");
> -        pcms->flash[1] = pc_pflash_create("system.flash1");
> -        object_property_add_alias(OBJECT(pcms), "pflash0",
> -                                  OBJECT(pcms->flash[0]), "drive",
> -                                  &error_abort);
> -        object_property_add_alias(OBJECT(pcms), "pflash1",
> -                                  OBJECT(pcms->flash[1]), "drive",
> -                                  &error_abort);
> +        pcms->flash[0] = pc_pflash_create(pcms, "system.flash0",
> +                                          "pflash0");
> +        pcms->flash[1] = pc_pflash_create(pcms, "system.flash1",
> +                                          "pflash1");
>      }
>  }
>  
> @@ -122,19 +124,7 @@ static void pc_system_flash_cleanup_unused(PCMachineState *pcms)
>              prop_name = g_strdup_printf("pflash%d", i);
>              object_property_del(OBJECT(pcms), prop_name, &error_abort);
>              g_free(prop_name);
> -            /*
> -             * Delete @dev_obj.  Straight object_unref() is wrong,
> -             * since it leaves dangling references in the parent bus
> -             * behind.  object_unparent() doesn't work, either: since
> -             * @dev_obj hasn't been realized, dev_obj->parent is null,
> -             * and object_unparent() does nothing.  DeviceClass method
> -             * device_unparent() works, but we have to take a
> -             * temporary reference, or else device_unparent() commits
> -             * a use-after-free error.
> -             */
> -            object_ref(dev_obj);
> -            object_get_class(dev_obj)->unparent(dev_obj);
> -            object_unref(dev_obj);
> +            object_unparent(dev_obj);
>              pcms->flash[i] = NULL;
>          }
>      }
>