[PATCH 1/3] qapi/misc: Fix missed query-iothreads items

[PATCH 1/3] qapi/misc: Fix missed query-iothreads items

[Zhang Chen]

As the struct IOThreadInfo definition:
{ 'struct': 'IOThreadInfo',
  'data': {'id': 'str',
           'thread-id': 'int',
           'poll-max-ns': 'int',
           'poll-grow': 'int',
           'poll-shrink': 'int',
           'aio-max-batch': 'int' } }

Signed-off-by: Zhang Chen <zhangckid@gmail.com>
---
 qapi/misc.json | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/qapi/misc.json b/qapi/misc.json
index 28c641fe2f..6153ed3d04 100644
--- a/qapi/misc.json
+++ b/qapi/misc.json
@@ -117,11 +117,19 @@
 #     <- { "return": [
 #              {
 #                 "id":"iothread0",
-#                 "thread-id":3134
+#                 "thread-id":3134,
+#                 'poll-max-ns':0,
+#                 "poll-grow":0,
+#                 "poll-shrink":0,
+#                 "aio-max-batch":0
 #              },
 #              {
 #                 "id":"iothread1",
-#                 "thread-id":3135
+#                 "thread-id":3135,
+#                 'poll-max-ns':0,
+#                 "poll-grow":0,
+#                 "poll-shrink":0,
+#                 "aio-max-batch":0
 #              }
 #           ]
 #        }
-- 
2.49.0

[PATCH 2/3] iothread: Introduce a new flag to show iothreads attached status

[Zhang Chen]

QEMU Need a flag to show current iothread attached status
when hotplug multi iothreads. For example virtio-blk.

Signed-off-by: Zhang Chen <zhangckid@gmail.com>
---
 include/system/iothread.h | 1 +
 iothread.c                | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/include/system/iothread.h b/include/system/iothread.h
index e26d13c6c7..3d00474523 100644
--- a/include/system/iothread.h
+++ b/include/system/iothread.h
@@ -32,6 +32,7 @@ struct IOThread {
     QemuSemaphore init_done_sem; /* is thread init done? */
     bool stopping;              /* has iothread_stop() been called? */
     bool running;               /* should iothread_run() continue? */
+    bool attached;              /* Whether or not attached to device */
     int thread_id;
 
     /* AioContext poll parameters */
diff --git a/iothread.c b/iothread.c
index caf68e0764..38e38fb44d 100644
--- a/iothread.c
+++ b/iothread.c
@@ -94,6 +94,7 @@ void iothread_stop(IOThread *iothread)
         return;
     }
     iothread->stopping = true;
+    iothread->attached = false;
     aio_bh_schedule_oneshot(iothread->ctx, iothread_stop_bh, iothread);
     qemu_thread_join(&iothread->thread);
 }
@@ -199,6 +200,9 @@ static void iothread_init(EventLoopBase *base, Error **errp)
      */
     iothread_init_gcontext(iothread, thread_name);
 
+    /* Clear iothread attached flag for init gcontext */
+    iothread->attached = false;
+
     iothread_set_aio_context_params(base, &local_error);
     if (local_error) {
         error_propagate(errp, local_error);
@@ -336,6 +340,7 @@ char *iothread_get_id(IOThread *iothread)
 
 AioContext *iothread_get_aio_context(IOThread *iothread)
 {
+    iothread->attached = true;
     return iothread->ctx;
 }
 
-- 
2.49.0

[PATCH 3/3] qapi: Add thread_status flag for iothreads

[Zhang Chen]

The thread_status depends on struct IOThreadInfo's
'attached': 'bool'. Show in the qmp/hmp CMD with
'attached' or 'detached'.

Signed-off-by: Zhang Chen <zhangckid@gmail.com>
---
 iothread.c         | 1 +
 monitor/hmp-cmds.c | 2 ++
 qapi/misc.json     | 6 ++++++
 3 files changed, 9 insertions(+)

diff --git a/iothread.c b/iothread.c
index 38e38fb44d..fb4898e491 100644
--- a/iothread.c
+++ b/iothread.c
@@ -358,6 +358,7 @@ static int query_one_iothread(Object *object, void *opaque)
     info = g_new0(IOThreadInfo, 1);
     info->id = iothread_get_id(iothread);
     info->thread_id = iothread->thread_id;
+    info->attached = iothread->attached;
     info->poll_max_ns = iothread->poll_max_ns;
     info->poll_grow = iothread->poll_grow;
     info->poll_shrink = iothread->poll_shrink;
diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
index 33a88ce205..84b01737cf 100644
--- a/monitor/hmp-cmds.c
+++ b/monitor/hmp-cmds.c
@@ -197,6 +197,8 @@ void hmp_info_iothreads(Monitor *mon, const QDict *qdict)
         value = info->value;
         monitor_printf(mon, "%s:\n", value->id);
         monitor_printf(mon, "  thread_id=%" PRId64 "\n", value->thread_id);
+        monitor_printf(mon, "  thread_status=%s" "\n",
+                       value->attached ? "attached" : "detached");
         monitor_printf(mon, "  poll-max-ns=%" PRId64 "\n", value->poll_max_ns);
         monitor_printf(mon, "  poll-grow=%" PRId64 "\n", value->poll_grow);
         monitor_printf(mon, "  poll-shrink=%" PRId64 "\n", value->poll_shrink);
diff --git a/qapi/misc.json b/qapi/misc.json
index 6153ed3d04..2eea920bd2 100644
--- a/qapi/misc.json
+++ b/qapi/misc.json
@@ -76,6 +76,9 @@
 #
 # @thread-id: ID of the underlying host thread
 #
+# @attached: flag to show current iothread attached status
+#            (since 10.3.0)
+#
 # @poll-max-ns: maximum polling time in ns, 0 means polling is
 #     disabled (since 2.9)
 #
@@ -93,6 +96,7 @@
 { 'struct': 'IOThreadInfo',
   'data': {'id': 'str',
            'thread-id': 'int',
+           'attached': 'bool',
            'poll-max-ns': 'int',
            'poll-grow': 'int',
            'poll-shrink': 'int',
@@ -118,6 +122,7 @@
 #              {
 #                 "id":"iothread0",
 #                 "thread-id":3134,
+#                 'thread_status':"attached",
 #                 'poll-max-ns':0,
 #                 "poll-grow":0,
 #                 "poll-shrink":0,
@@ -126,6 +131,7 @@
 #              {
 #                 "id":"iothread1",
 #                 "thread-id":3135,
+#                 'thread_status':"detached",
 #                 'poll-max-ns':0,
 #                 "poll-grow":0,
 #                 "poll-shrink":0,
-- 
2.49.0

Re: [PATCH 3/3] qapi: Add thread_status flag for iothreads

[Markus Armbruster]

Zhang Chen <zhangckid@gmail.com> writes:

> The thread_status depends on struct IOThreadInfo's
> 'attached': 'bool'. Show in the qmp/hmp CMD with
> 'attached' or 'detached'.
>
> Signed-off-by: Zhang Chen <zhangckid@gmail.com>
> ---
>  iothread.c         | 1 +
>  monitor/hmp-cmds.c | 2 ++
>  qapi/misc.json     | 6 ++++++
>  3 files changed, 9 insertions(+)
>
> diff --git a/iothread.c b/iothread.c
> index 38e38fb44d..fb4898e491 100644
> --- a/iothread.c
> +++ b/iothread.c
> @@ -358,6 +358,7 @@ static int query_one_iothread(Object *object, void *opaque)
>      info = g_new0(IOThreadInfo, 1);
>      info->id = iothread_get_id(iothread);
>      info->thread_id = iothread->thread_id;
> +    info->attached = iothread->attached;
>      info->poll_max_ns = iothread->poll_max_ns;
>      info->poll_grow = iothread->poll_grow;
>      info->poll_shrink = iothread->poll_shrink;
> diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
> index 33a88ce205..84b01737cf 100644
> --- a/monitor/hmp-cmds.c
> +++ b/monitor/hmp-cmds.c
> @@ -197,6 +197,8 @@ void hmp_info_iothreads(Monitor *mon, const QDict *qdict)
>          value = info->value;
>          monitor_printf(mon, "%s:\n", value->id);
>          monitor_printf(mon, "  thread_id=%" PRId64 "\n", value->thread_id);
> +        monitor_printf(mon, "  thread_status=%s" "\n",
> +                       value->attached ? "attached" : "detached");
>          monitor_printf(mon, "  poll-max-ns=%" PRId64 "\n", value->poll_max_ns);
>          monitor_printf(mon, "  poll-grow=%" PRId64 "\n", value->poll_grow);
>          monitor_printf(mon, "  poll-shrink=%" PRId64 "\n", value->poll_shrink);
> diff --git a/qapi/misc.json b/qapi/misc.json
> index 6153ed3d04..2eea920bd2 100644
> --- a/qapi/misc.json
> +++ b/qapi/misc.json
> @@ -76,6 +76,9 @@
>  #
>  # @thread-id: ID of the underlying host thread
>  #
> +# @attached: flag to show current iothread attached status

What does "attached status" actually mean?

> +#            (since 10.3.0)

(since 12.0)

> +#
>  # @poll-max-ns: maximum polling time in ns, 0 means polling is
>  #     disabled (since 2.9)
>  #
> @@ -93,6 +96,7 @@
>  { 'struct': 'IOThreadInfo',
>    'data': {'id': 'str',
>             'thread-id': 'int',
> +           'attached': 'bool',
>             'poll-max-ns': 'int',
>             'poll-grow': 'int',
>             'poll-shrink': 'int',
> @@ -118,6 +122,7 @@
>  #              {
>  #                 "id":"iothread0",
>  #                 "thread-id":3134,
> +#                 'thread_status':"attached",

I believe this is actually

                     "attached": true

and ...

>  #                 'poll-max-ns':0,
>  #                 "poll-grow":0,
>  #                 "poll-shrink":0,
> @@ -126,6 +131,7 @@
>  #              {
>  #                 "id":"iothread1",
>  #                 "thread-id":3135,
> +#                 'thread_status':"detached",

                     "attached": false

Recommend to create example output by running a test instead of making
it up, because making it up likely screws it up :)

>  #                 'poll-max-ns':0,
>  #                 "poll-grow":0,
>  #                 "poll-shrink":0,

Re: [PATCH 3/3] qapi: Add thread_status flag for iothreads

[Zhang Chen]

On Thu, Jan 8, 2026 at 8:12 PM Markus Armbruster <armbru@redhat.com> wrote:
>
> Zhang Chen <zhangckid@gmail.com> writes:
>
> > The thread_status depends on struct IOThreadInfo's
> > 'attached': 'bool'. Show in the qmp/hmp CMD with
> > 'attached' or 'detached'.
> >
> > Signed-off-by: Zhang Chen <zhangckid@gmail.com>
> > ---
> >  iothread.c         | 1 +
> >  monitor/hmp-cmds.c | 2 ++
> >  qapi/misc.json     | 6 ++++++
> >  3 files changed, 9 insertions(+)
> >
> > diff --git a/iothread.c b/iothread.c
> > index 38e38fb44d..fb4898e491 100644
> > --- a/iothread.c
> > +++ b/iothread.c
> > @@ -358,6 +358,7 @@ static int query_one_iothread(Object *object, void *opaque)
> >      info = g_new0(IOThreadInfo, 1);
> >      info->id = iothread_get_id(iothread);
> >      info->thread_id = iothread->thread_id;
> > +    info->attached = iothread->attached;
> >      info->poll_max_ns = iothread->poll_max_ns;
> >      info->poll_grow = iothread->poll_grow;
> >      info->poll_shrink = iothread->poll_shrink;
> > diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
> > index 33a88ce205..84b01737cf 100644
> > --- a/monitor/hmp-cmds.c
> > +++ b/monitor/hmp-cmds.c
> > @@ -197,6 +197,8 @@ void hmp_info_iothreads(Monitor *mon, const QDict *qdict)
> >          value = info->value;
> >          monitor_printf(mon, "%s:\n", value->id);
> >          monitor_printf(mon, "  thread_id=%" PRId64 "\n", value->thread_id);
> > +        monitor_printf(mon, "  thread_status=%s" "\n",
> > +                       value->attached ? "attached" : "detached");
> >          monitor_printf(mon, "  poll-max-ns=%" PRId64 "\n", value->poll_max_ns);
> >          monitor_printf(mon, "  poll-grow=%" PRId64 "\n", value->poll_grow);
> >          monitor_printf(mon, "  poll-shrink=%" PRId64 "\n", value->poll_shrink);
> > diff --git a/qapi/misc.json b/qapi/misc.json
> > index 6153ed3d04..2eea920bd2 100644
> > --- a/qapi/misc.json
> > +++ b/qapi/misc.json
> > @@ -76,6 +76,9 @@
> >  #
> >  # @thread-id: ID of the underlying host thread
> >  #
> > +# @attached: flag to show current iothread attached status
>
> What does "attached status" actually mean?

This flag means weather the "-object iothread" already been used by a
real device.
In hotplug scenario, user can add multiple "-object iothread" and
multiple devices (like virtio-blk).
When user hotunplug the devices can keep the iothreads as a thread
pool, following the new
hotplug devices can attach to the released iothread.

>
> > +#            (since 10.3.0)
>
> (since 12.0)

OK.

>
> > +#
> >  # @poll-max-ns: maximum polling time in ns, 0 means polling is
> >  #     disabled (since 2.9)
> >  #
> > @@ -93,6 +96,7 @@
> >  { 'struct': 'IOThreadInfo',
> >    'data': {'id': 'str',
> >             'thread-id': 'int',
> > +           'attached': 'bool',
> >             'poll-max-ns': 'int',
> >             'poll-grow': 'int',
> >             'poll-shrink': 'int',
> > @@ -118,6 +122,7 @@
> >  #              {
> >  #                 "id":"iothread0",
> >  #                 "thread-id":3134,
> > +#                 'thread_status':"attached",
>
> I believe this is actually
>
>                      "attached": true
>
> and ...

No, I changed it here for readability:
> > +        monitor_printf(mon, "  thread_status=%s" "\n",
> > +                       value->attached ? "attached" : "detached");

But if you think ""attached": true" is more direct way, I can change
it next version.

>
> >  #                 'poll-max-ns':0,
> >  #                 "poll-grow":0,
> >  #                 "poll-shrink":0,
> > @@ -126,6 +131,7 @@
> >  #              {
> >  #                 "id":"iothread1",
> >  #                 "thread-id":3135,
> > +#                 'thread_status':"detached",
>
>                      "attached": false
>
> Recommend to create example output by running a test instead of making
> it up, because making it up likely screws it up :)

Uh.... This output print is the real test in my machine, maybe you
missed the previous description.

Thanks
Chen

>
> >  #                 'poll-max-ns':0,
> >  #                 "poll-grow":0,
> >  #                 "poll-shrink":0,
>

Re: [PATCH 3/3] qapi: Add thread_status flag for iothreads

[Zhang Chen]

On Fri, Jan 9, 2026 at 11:11 AM Zhang Chen <zhangckid@gmail.com> wrote:
>
> On Thu, Jan 8, 2026 at 8:12 PM Markus Armbruster <armbru@redhat.com> wrote:
> >
> > Zhang Chen <zhangckid@gmail.com> writes:
> >
> > > The thread_status depends on struct IOThreadInfo's
> > > 'attached': 'bool'. Show in the qmp/hmp CMD with
> > > 'attached' or 'detached'.
> > >
> > > Signed-off-by: Zhang Chen <zhangckid@gmail.com>
> > > ---
> > >  iothread.c         | 1 +
> > >  monitor/hmp-cmds.c | 2 ++
> > >  qapi/misc.json     | 6 ++++++
> > >  3 files changed, 9 insertions(+)
> > >
> > > diff --git a/iothread.c b/iothread.c
> > > index 38e38fb44d..fb4898e491 100644
> > > --- a/iothread.c
> > > +++ b/iothread.c
> > > @@ -358,6 +358,7 @@ static int query_one_iothread(Object *object, void *opaque)
> > >      info = g_new0(IOThreadInfo, 1);
> > >      info->id = iothread_get_id(iothread);
> > >      info->thread_id = iothread->thread_id;
> > > +    info->attached = iothread->attached;
> > >      info->poll_max_ns = iothread->poll_max_ns;
> > >      info->poll_grow = iothread->poll_grow;
> > >      info->poll_shrink = iothread->poll_shrink;
> > > diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
> > > index 33a88ce205..84b01737cf 100644
> > > --- a/monitor/hmp-cmds.c
> > > +++ b/monitor/hmp-cmds.c
> > > @@ -197,6 +197,8 @@ void hmp_info_iothreads(Monitor *mon, const QDict *qdict)
> > >          value = info->value;
> > >          monitor_printf(mon, "%s:\n", value->id);
> > >          monitor_printf(mon, "  thread_id=%" PRId64 "\n", value->thread_id);
> > > +        monitor_printf(mon, "  thread_status=%s" "\n",
> > > +                       value->attached ? "attached" : "detached");
> > >          monitor_printf(mon, "  poll-max-ns=%" PRId64 "\n", value->poll_max_ns);
> > >          monitor_printf(mon, "  poll-grow=%" PRId64 "\n", value->poll_grow);
> > >          monitor_printf(mon, "  poll-shrink=%" PRId64 "\n", value->poll_shrink);
> > > diff --git a/qapi/misc.json b/qapi/misc.json
> > > index 6153ed3d04..2eea920bd2 100644
> > > --- a/qapi/misc.json
> > > +++ b/qapi/misc.json
> > > @@ -76,6 +76,9 @@
> > >  #
> > >  # @thread-id: ID of the underlying host thread
> > >  #
> > > +# @attached: flag to show current iothread attached status
> >
> > What does "attached status" actually mean?
>
> This flag means weather the "-object iothread" already been used by a
> real device.
> In hotplug scenario, user can add multiple "-object iothread" and
> multiple devices (like virtio-blk).
> When user hotunplug the devices can keep the iothreads as a thread
> pool, following the new
> hotplug devices can attach to the released iothread.
>
> >
> > > +#            (since 10.3.0)
> >
> > (since 12.0)
>
> OK.
>
> >
> > > +#
> > >  # @poll-max-ns: maximum polling time in ns, 0 means polling is
> > >  #     disabled (since 2.9)
> > >  #
> > > @@ -93,6 +96,7 @@
> > >  { 'struct': 'IOThreadInfo',
> > >    'data': {'id': 'str',
> > >             'thread-id': 'int',
> > > +           'attached': 'bool',
> > >             'poll-max-ns': 'int',
> > >             'poll-grow': 'int',
> > >             'poll-shrink': 'int',
> > > @@ -118,6 +122,7 @@
> > >  #              {
> > >  #                 "id":"iothread0",
> > >  #                 "thread-id":3134,
> > > +#                 'thread_status':"attached",
> >
> > I believe this is actually
> >
> >                      "attached": true
> >
> > and ...
>
> No, I changed it here for readability:
> > > +        monitor_printf(mon, "  thread_status=%s" "\n",
> > > +                       value->attached ? "attached" : "detached");
>
> But if you think ""attached": true" is more direct way, I can change
> it next version.

If no other comments, I will keep this part and update to version 2
for this series.

Thanks
Chen

>
> >
> > >  #                 'poll-max-ns':0,
> > >  #                 "poll-grow":0,
> > >  #                 "poll-shrink":0,
> > > @@ -126,6 +131,7 @@
> > >  #              {
> > >  #                 "id":"iothread1",
> > >  #                 "thread-id":3135,
> > > +#                 'thread_status':"detached",
> >
> >                      "attached": false
> >
> > Recommend to create example output by running a test instead of making
> > it up, because making it up likely screws it up :)
>
> Uh.... This output print is the real test in my machine, maybe you
> missed the previous description.
>
> Thanks
> Chen
>
> >
> > >  #                 'poll-max-ns':0,
> > >  #                 "poll-grow":0,
> > >  #                 "poll-shrink":0,
> >

Re: [PATCH 3/3] qapi: Add thread_status flag for iothreads

[Markus Armbruster]

Zhang Chen <zhangckid@gmail.com> writes:

> On Thu, Jan 8, 2026 at 8:12 PM Markus Armbruster <armbru@redhat.com> wrote:
>>
>> Zhang Chen <zhangckid@gmail.com> writes:
>>
>> > The thread_status depends on struct IOThreadInfo's
>> > 'attached': 'bool'. Show in the qmp/hmp CMD with
>> > 'attached' or 'detached'.
>> >
>> > Signed-off-by: Zhang Chen <zhangckid@gmail.com>
>> > ---
>> >  iothread.c         | 1 +
>> >  monitor/hmp-cmds.c | 2 ++
>> >  qapi/misc.json     | 6 ++++++
>> >  3 files changed, 9 insertions(+)
>> >
>> > diff --git a/iothread.c b/iothread.c
>> > index 38e38fb44d..fb4898e491 100644
>> > --- a/iothread.c
>> > +++ b/iothread.c
>> > @@ -358,6 +358,7 @@ static int query_one_iothread(Object *object, void *opaque)
>> >      info = g_new0(IOThreadInfo, 1);
>> >      info->id = iothread_get_id(iothread);
>> >      info->thread_id = iothread->thread_id;
>> > +    info->attached = iothread->attached;
>> >      info->poll_max_ns = iothread->poll_max_ns;
>> >      info->poll_grow = iothread->poll_grow;
>> >      info->poll_shrink = iothread->poll_shrink;
>> > diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
>> > index 33a88ce205..84b01737cf 100644
>> > --- a/monitor/hmp-cmds.c
>> > +++ b/monitor/hmp-cmds.c
>> > @@ -197,6 +197,8 @@ void hmp_info_iothreads(Monitor *mon, const QDict *qdict)
>> >          value = info->value;
>> >          monitor_printf(mon, "%s:\n", value->id);
>> >          monitor_printf(mon, "  thread_id=%" PRId64 "\n", value->thread_id);
>> > +        monitor_printf(mon, "  thread_status=%s" "\n",
>> > +                       value->attached ? "attached" : "detached");
>> >          monitor_printf(mon, "  poll-max-ns=%" PRId64 "\n", value->poll_max_ns);
>> >          monitor_printf(mon, "  poll-grow=%" PRId64 "\n", value->poll_grow);
>> >          monitor_printf(mon, "  poll-shrink=%" PRId64 "\n", value->poll_shrink);
>> > diff --git a/qapi/misc.json b/qapi/misc.json
>> > index 6153ed3d04..2eea920bd2 100644
>> > --- a/qapi/misc.json
>> > +++ b/qapi/misc.json
>> > @@ -76,6 +76,9 @@
>> >  #
>> >  # @thread-id: ID of the underlying host thread
>> >  #
>> > +# @attached: flag to show current iothread attached status
>>
>> What does "attached status" actually mean?
>
> This flag means weather the "-object iothread" already been used by a
> real device.
> In hotplug scenario, user can add multiple "-object iothread" and
> multiple devices (like virtio-blk).
> When user hotunplug the devices can keep the iothreads as a thread
> pool, following the new
> hotplug devices can attach to the released iothread.

Why would a management application or human user want to know this?

The answer should lead us to better doc text.

>>
>> > +#            (since 10.3.0)
>>
>> (since 12.0)
>
> OK.
>
>>
>> > +#
>> >  # @poll-max-ns: maximum polling time in ns, 0 means polling is
>> >  #     disabled (since 2.9)
>> >  #
>> > @@ -93,6 +96,7 @@
>> >  { 'struct': 'IOThreadInfo',
>> >    'data': {'id': 'str',
>> >             'thread-id': 'int',
>> > +           'attached': 'bool',
>> >             'poll-max-ns': 'int',
>> >             'poll-grow': 'int',
>> >             'poll-shrink': 'int',
>> > @@ -118,6 +122,7 @@
>> >  #              {
>> >  #                 "id":"iothread0",
>> >  #                 "thread-id":3134,
>> > +#                 'thread_status':"attached",
>>
>> I believe this is actually
>>
>>                      "attached": true
>>
>> and ...
>
> No, I changed it here for readability:
>
>> > +        monitor_printf(mon, "  thread_status=%s" "\n",
>> > +                       value->attached ? "attached" : "detached");
>
> But if you think ""attached": true" is more direct way, I can change
> it next version.

The example in the doc comment shows QMP.  Here's what I see in QMP:

    $ qemu-system-x86_64 -S -display none -qmp stdio -object iothread,id=iot0 -name debug-threads=on
    {"QMP": {"version": {"qemu": {"micro": 50, "minor": 2, "major": 10}, "package": "v10.2.0-521-g05115811fa"}, "capabilities": ["oob"]}}
    {"execute": "qmp_capabilities", "arguments": {"enable": ["oob"]}}
    {"return": {}}
    {"execute": "query-iothreads"}
    {"return": [{"attached": false, "poll-shrink": 0, "thread-id": 4031494, "aio-max-batch": 0, "poll-grow": 0, "poll-max-ns": 32768, "id": "iot0"}]}

This shows "attached": false, not 'thread_status': "attached".

The code you showed applies to HMP:

    $ qemu-system-x86_64 -S -display none -monitor stdio -object iothread,id=iot0 -name debug-threads=on
    QEMU 10.2.50 monitor - type 'help' for more information
    (qemu) info iothreads
    iot0:
      thread_id=4032011
      thread_status=detached
      poll-max-ns=32768
      poll-grow=0
      poll-shrink=0
      aio-max-batch=0

thread_status=detached might be slightly more readable than
attached=false, but it could also be confusing to people working with
both HMP and QMP.  I'd avoid the difference between the two.

>>
>> >  #                 'poll-max-ns':0,
>> >  #                 "poll-grow":0,
>> >  #                 "poll-shrink":0,
>> > @@ -126,6 +131,7 @@
>> >  #              {
>> >  #                 "id":"iothread1",
>> >  #                 "thread-id":3135,
>> > +#                 'thread_status':"detached",
>>
>>                      "attached": false
>>
>> Recommend to create example output by running a test instead of making
>> it up, because making it up likely screws it up :)
>
> Uh.... This output print is the real test in my machine, maybe you
> missed the previous description.

I can't see how QMP could possibly show 'thread_status':"detached:.

>
> Thanks
> Chen
>
>>
>> >  #                 'poll-max-ns':0,
>> >  #                 "poll-grow":0,
>> >  #                 "poll-shrink":0,
>>

Re: [PATCH 3/3] qapi: Add thread_status flag for iothreads

[Zhang Chen]

On Fri, Jan 16, 2026 at 4:18 PM Markus Armbruster <armbru@redhat.com> wrote:
>
> Zhang Chen <zhangckid@gmail.com> writes:
>
> > On Thu, Jan 8, 2026 at 8:12 PM Markus Armbruster <armbru@redhat.com> wrote:
> >>
> >> Zhang Chen <zhangckid@gmail.com> writes:
> >>
> >> > The thread_status depends on struct IOThreadInfo's
> >> > 'attached': 'bool'. Show in the qmp/hmp CMD with
> >> > 'attached' or 'detached'.
> >> >
> >> > Signed-off-by: Zhang Chen <zhangckid@gmail.com>
> >> > ---
> >> >  iothread.c         | 1 +
> >> >  monitor/hmp-cmds.c | 2 ++
> >> >  qapi/misc.json     | 6 ++++++
> >> >  3 files changed, 9 insertions(+)
> >> >
> >> > diff --git a/iothread.c b/iothread.c
> >> > index 38e38fb44d..fb4898e491 100644
> >> > --- a/iothread.c
> >> > +++ b/iothread.c
> >> > @@ -358,6 +358,7 @@ static int query_one_iothread(Object *object, void *opaque)
> >> >      info = g_new0(IOThreadInfo, 1);
> >> >      info->id = iothread_get_id(iothread);
> >> >      info->thread_id = iothread->thread_id;
> >> > +    info->attached = iothread->attached;
> >> >      info->poll_max_ns = iothread->poll_max_ns;
> >> >      info->poll_grow = iothread->poll_grow;
> >> >      info->poll_shrink = iothread->poll_shrink;
> >> > diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
> >> > index 33a88ce205..84b01737cf 100644
> >> > --- a/monitor/hmp-cmds.c
> >> > +++ b/monitor/hmp-cmds.c
> >> > @@ -197,6 +197,8 @@ void hmp_info_iothreads(Monitor *mon, const QDict *qdict)
> >> >          value = info->value;
> >> >          monitor_printf(mon, "%s:\n", value->id);
> >> >          monitor_printf(mon, "  thread_id=%" PRId64 "\n", value->thread_id);
> >> > +        monitor_printf(mon, "  thread_status=%s" "\n",
> >> > +                       value->attached ? "attached" : "detached");
> >> >          monitor_printf(mon, "  poll-max-ns=%" PRId64 "\n", value->poll_max_ns);
> >> >          monitor_printf(mon, "  poll-grow=%" PRId64 "\n", value->poll_grow);
> >> >          monitor_printf(mon, "  poll-shrink=%" PRId64 "\n", value->poll_shrink);
> >> > diff --git a/qapi/misc.json b/qapi/misc.json
> >> > index 6153ed3d04..2eea920bd2 100644
> >> > --- a/qapi/misc.json
> >> > +++ b/qapi/misc.json
> >> > @@ -76,6 +76,9 @@
> >> >  #
> >> >  # @thread-id: ID of the underlying host thread
> >> >  #
> >> > +# @attached: flag to show current iothread attached status
> >>
> >> What does "attached status" actually mean?
> >
> > This flag means weather the "-object iothread" already been used by a
> > real device.
> > In hotplug scenario, user can add multiple "-object iothread" and
> > multiple devices (like virtio-blk).
> > When user hotunplug the devices can keep the iothreads as a thread
> > pool, following the new
> > hotplug devices can attach to the released iothread.
>
> Why would a management application or human user want to know this?

Because some usercases already been changed.
This demand comes from Cloud Native ecosystem.
User want to manage resources more flexible like containers (Kata container).
The real workload maybe changed(runc) in the VM without VM reboot,
It may need hotplug/unplug different multi disks with multi iothreads to meet
high level scheduler's needs(like K8s).


>
> The answer should lead us to better doc text.
>

OK, I will add it in next version.

> >>
> >> > +#            (since 10.3.0)
> >>
> >> (since 12.0)
> >
> > OK.
> >
> >>
> >> > +#
> >> >  # @poll-max-ns: maximum polling time in ns, 0 means polling is
> >> >  #     disabled (since 2.9)
> >> >  #
> >> > @@ -93,6 +96,7 @@
> >> >  { 'struct': 'IOThreadInfo',
> >> >    'data': {'id': 'str',
> >> >             'thread-id': 'int',
> >> > +           'attached': 'bool',
> >> >             'poll-max-ns': 'int',
> >> >             'poll-grow': 'int',
> >> >             'poll-shrink': 'int',
> >> > @@ -118,6 +122,7 @@
> >> >  #              {
> >> >  #                 "id":"iothread0",
> >> >  #                 "thread-id":3134,
> >> > +#                 'thread_status':"attached",
> >>
> >> I believe this is actually
> >>
> >>                      "attached": true
> >>
> >> and ...
> >
> > No, I changed it here for readability:
> >
> >> > +        monitor_printf(mon, "  thread_status=%s" "\n",
> >> > +                       value->attached ? "attached" : "detached");
> >
> > But if you think ""attached": true" is more direct way, I can change
> > it next version.
>
> The example in the doc comment shows QMP.  Here's what I see in QMP:
>
>     $ qemu-system-x86_64 -S -display none -qmp stdio -object iothread,id=iot0 -name debug-threads=on
>     {"QMP": {"version": {"qemu": {"micro": 50, "minor": 2, "major": 10}, "package": "v10.2.0-521-g05115811fa"}, "capabilities": ["oob"]}}
>     {"execute": "qmp_capabilities", "arguments": {"enable": ["oob"]}}
>     {"return": {}}
>     {"execute": "query-iothreads"}
>     {"return": [{"attached": false, "poll-shrink": 0, "thread-id": 4031494, "aio-max-batch": 0, "poll-grow": 0, "poll-max-ns": 32768, "id": "iot0"}]}
>
> This shows "attached": false, not 'thread_status': "attached".
>
> The code you showed applies to HMP:
>
>     $ qemu-system-x86_64 -S -display none -monitor stdio -object iothread,id=iot0 -name debug-threads=on
>     QEMU 10.2.50 monitor - type 'help' for more information
>     (qemu) info iothreads
>     iot0:
>       thread_id=4032011
>       thread_status=detached
>       poll-max-ns=32768
>       poll-grow=0
>       poll-shrink=0
>       aio-max-batch=0
>
> thread_status=detached might be slightly more readable than
> attached=false, but it could also be confusing to people working with
> both HMP and QMP.  I'd avoid the difference between the two.

Make sense, I will change it to ""attached": false" style next version.

Thanks
Chen

>
> >>
> >> >  #                 'poll-max-ns':0,
> >> >  #                 "poll-grow":0,
> >> >  #                 "poll-shrink":0,
> >> > @@ -126,6 +131,7 @@
> >> >  #              {
> >> >  #                 "id":"iothread1",
> >> >  #                 "thread-id":3135,
> >> > +#                 'thread_status':"detached",
> >>
> >>                      "attached": false
> >>
> >> Recommend to create example output by running a test instead of making
> >> it up, because making it up likely screws it up :)
> >
> > Uh.... This output print is the real test in my machine, maybe you
> > missed the previous description.
>
> I can't see how QMP could possibly show 'thread_status':"detached:.
>
> >
> > Thanks
> > Chen
> >
> >>
> >> >  #                 'poll-max-ns':0,
> >> >  #                 "poll-grow":0,
> >> >  #                 "poll-shrink":0,
> >>
>

Re: [PATCH 3/3] qapi: Add thread_status flag for iothreads

[Markus Armbruster]

Zhang Chen <zhangckid@gmail.com> writes:

> On Fri, Jan 16, 2026 at 4:18 PM Markus Armbruster <armbru@redhat.com> wrote:
>>
>> Zhang Chen <zhangckid@gmail.com> writes:
>>
>> > On Thu, Jan 8, 2026 at 8:12 PM Markus Armbruster <armbru@redhat.com> wrote:
>> >>
>> >> Zhang Chen <zhangckid@gmail.com> writes:
>> >>
>> >> > The thread_status depends on struct IOThreadInfo's
>> >> > 'attached': 'bool'. Show in the qmp/hmp CMD with
>> >> > 'attached' or 'detached'.
>> >> >
>> >> > Signed-off-by: Zhang Chen <zhangckid@gmail.com>
>> >> > ---
>> >> >  iothread.c         | 1 +
>> >> >  monitor/hmp-cmds.c | 2 ++
>> >> >  qapi/misc.json     | 6 ++++++
>> >> >  3 files changed, 9 insertions(+)
>> >> >
>> >> > diff --git a/iothread.c b/iothread.c
>> >> > index 38e38fb44d..fb4898e491 100644
>> >> > --- a/iothread.c
>> >> > +++ b/iothread.c
>> >> > @@ -358,6 +358,7 @@ static int query_one_iothread(Object *object, void *opaque)
>> >> >      info = g_new0(IOThreadInfo, 1);
>> >> >      info->id = iothread_get_id(iothread);
>> >> >      info->thread_id = iothread->thread_id;
>> >> > +    info->attached = iothread->attached;
>> >> >      info->poll_max_ns = iothread->poll_max_ns;
>> >> >      info->poll_grow = iothread->poll_grow;
>> >> >      info->poll_shrink = iothread->poll_shrink;
>> >> > diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
>> >> > index 33a88ce205..84b01737cf 100644
>> >> > --- a/monitor/hmp-cmds.c
>> >> > +++ b/monitor/hmp-cmds.c
>> >> > @@ -197,6 +197,8 @@ void hmp_info_iothreads(Monitor *mon, const QDict *qdict)
>> >> >          value = info->value;
>> >> >          monitor_printf(mon, "%s:\n", value->id);
>> >> >          monitor_printf(mon, "  thread_id=%" PRId64 "\n", value->thread_id);
>> >> > +        monitor_printf(mon, "  thread_status=%s" "\n",
>> >> > +                       value->attached ? "attached" : "detached");
>> >> >          monitor_printf(mon, "  poll-max-ns=%" PRId64 "\n", value->poll_max_ns);
>> >> >          monitor_printf(mon, "  poll-grow=%" PRId64 "\n", value->poll_grow);
>> >> >          monitor_printf(mon, "  poll-shrink=%" PRId64 "\n", value->poll_shrink);
>> >> > diff --git a/qapi/misc.json b/qapi/misc.json
>> >> > index 6153ed3d04..2eea920bd2 100644
>> >> > --- a/qapi/misc.json
>> >> > +++ b/qapi/misc.json
>> >> > @@ -76,6 +76,9 @@
>> >> >  #
>> >> >  # @thread-id: ID of the underlying host thread
>> >> >  #
>> >> > +# @attached: flag to show current iothread attached status
>> >>
>> >> What does "attached status" actually mean?
>> >
>> > This flag means weather the "-object iothread" already been used by a
>> > real device.
>> > In hotplug scenario, user can add multiple "-object iothread" and
>> > multiple devices (like virtio-blk).
>> > When user hotunplug the devices can keep the iothreads as a thread
>> > pool, following the new
>> > hotplug devices can attach to the released iothread.
>>
>> Why would a management application or human user want to know this?
>
> Because some usercases already been changed.
> This demand comes from Cloud Native ecosystem.
> User want to manage resources more flexible like containers (Kata container).
> The real workload maybe changed(runc) in the VM without VM reboot,
> It may need hotplug/unplug different multi disks with multi iothreads to meet
> high level scheduler's needs(like K8s).

In your v2, you added a (broken) PATCH 4 that describes @attached as
follows:

    The ``attached`` parameter is a flag to show whether the iothread
    is attached to an actual device(for example virtio-blk). In hotplug
    scenario, user can add multiple "-object iothread" and multiple
    devices (like virtio-blk). When user hotunplug the devices can keep
    the iothreads as a thread pool, following the new hotplug devices can
    attach to the released iothread.

Should this information go into the QAPI schema, too?

>> The answer should lead us to better doc text.
>>
>
> OK, I will add it in next version.

[...]

Re: [PATCH 1/3] qapi/misc: Fix missed query-iothreads items

[Markus Armbruster]

Zhang Chen <zhangckid@gmail.com> writes:

> As the struct IOThreadInfo definition:
> { 'struct': 'IOThreadInfo',
>   'data': {'id': 'str',
>            'thread-id': 'int',
>            'poll-max-ns': 'int',
>            'poll-grow': 'int',
>            'poll-shrink': 'int',
>            'aio-max-batch': 'int' } }

Suggest:

  The example is incomplete: it misses members @poll-max-ns, @poll-grow,
  @poll-shrink, @aio-max-batch.  Messed up in commit 5fc00480ab1
  (monitor: add poll-* properties into query-iothreads result) and
  commit 1793ad0247c (iothread: add aio-max-batch parameter).

  Cc: qemu-stable@nongnu.org

> Signed-off-by: Zhang Chen <zhangckid@gmail.com>
> ---
>  qapi/misc.json | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/qapi/misc.json b/qapi/misc.json
> index 28c641fe2f..6153ed3d04 100644
> --- a/qapi/misc.json
> +++ b/qapi/misc.json
> @@ -117,11 +117,19 @@
>  #     <- { "return": [
>  #              {
>  #                 "id":"iothread0",
> -#                 "thread-id":3134
> +#                 "thread-id":3134,
> +#                 'poll-max-ns':0,

Double quotes, please.

The default value appears to be 32768.  Maybe show that?

> +#                 "poll-grow":0,
> +#                 "poll-shrink":0,
> +#                 "aio-max-batch":0
>  #              },
>  #              {
>  #                 "id":"iothread1",
> -#                 "thread-id":3135
> +#                 "thread-id":3135,
> +#                 'poll-max-ns':0,

Likewise.

> +#                 "poll-grow":0,
> +#                 "poll-shrink":0,
> +#                 "aio-max-batch":0
>  #              }
>  #           ]
>  #        }

Re: [PATCH 1/3] qapi/misc: Fix missed query-iothreads items

[Zhang Chen]

On Thu, Jan 8, 2026 at 8:06 PM Markus Armbruster <armbru@redhat.com> wrote:
>
> Zhang Chen <zhangckid@gmail.com> writes:
>
> > As the struct IOThreadInfo definition:
> > { 'struct': 'IOThreadInfo',
> >   'data': {'id': 'str',
> >            'thread-id': 'int',
> >            'poll-max-ns': 'int',
> >            'poll-grow': 'int',
> >            'poll-shrink': 'int',
> >            'aio-max-batch': 'int' } }
>
> Suggest:
>
>   The example is incomplete: it misses members @poll-max-ns, @poll-grow,
>   @poll-shrink, @aio-max-batch.  Messed up in commit 5fc00480ab1
>   (monitor: add poll-* properties into query-iothreads result) and
>   commit 1793ad0247c (iothread: add aio-max-batch parameter).
>
>   Cc: qemu-stable@nongnu.org

Nice description! I will rewrite the commit log next version.

>
> > Signed-off-by: Zhang Chen <zhangckid@gmail.com>
> > ---
> >  qapi/misc.json | 12 ++++++++++--
> >  1 file changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/qapi/misc.json b/qapi/misc.json
> > index 28c641fe2f..6153ed3d04 100644
> > --- a/qapi/misc.json
> > +++ b/qapi/misc.json
> > @@ -117,11 +117,19 @@
> >  #     <- { "return": [
> >  #              {
> >  #                 "id":"iothread0",
> > -#                 "thread-id":3134
> > +#                 "thread-id":3134,
> > +#                 'poll-max-ns':0,
>
> Double quotes, please.
>
> The default value appears to be 32768.  Maybe show that?

Good catch, will fix it next version.


>
> > +#                 "poll-grow":0,
> > +#                 "poll-shrink":0,
> > +#                 "aio-max-batch":0
> >  #              },
> >  #              {
> >  #                 "id":"iothread1",
> > -#                 "thread-id":3135
> > +#                 "thread-id":3135,
> > +#                 'poll-max-ns':0,
>
> Likewise.

Yes.

Thanks
Chen

>
> > +#                 "poll-grow":0,
> > +#                 "poll-shrink":0,
> > +#                 "aio-max-batch":0
> >  #              }
> >  #           ]
> >  #        }
>