monitor/hmp: schedule qemu_chr_fe_accept_input() after read

[PATCH] monitor/hmp: schedule qemu_chr_fe_accept_input() after read

Posted by Volker Rümelin 2 years, 9 months ago

Since commit 584af1f1d9 (ui/gtk: add a keyboard fifo to the VTE
consoles) a GTK VTE console chardev backend relies on the
connected chardev frontend to call qemu_chr_fe_accept_input()
whenever it can receive new characters. The HMP monitor doesn't
do this. It only schedules a call to qemu_chr_fe_accept_input()
after it handled a HMP command in monitor_command_cb().

This is a problem if you paste a few characters into the GTK
monitor console. Even entering a UTF-8 multibyte character leads
to the same problem.

Schedule a call to qemu_chr_fe_accept_input() after handling the
received bytes to fix the HMP monitor.

Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
---
 monitor/hmp.c              |  1 +
 monitor/monitor-internal.h |  1 +
 monitor/monitor.c          | 19 +++++++++++++++++--
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/monitor/hmp.c b/monitor/hmp.c
index d50c3124e1..470f56a71d 100644
--- a/monitor/hmp.c
+++ b/monitor/hmp.c
@@ -1349,6 +1349,7 @@ static void monitor_read(void *opaque, const uint8_t *buf, int size)
         for (i = 0; i < size; i++) {
             readline_handle_byte(mon->rs, buf[i]);
         }
+        monitor_accept_input(&mon->common);
     } else {
         if (size == 0 || buf[size - 1] != 0) {
             monitor_printf(&mon->common, "corrupted command\n");
diff --git a/monitor/monitor-internal.h b/monitor/monitor-internal.h
index 9c3a09cb01..af33c3c617 100644
--- a/monitor/monitor-internal.h
+++ b/monitor/monitor-internal.h
@@ -170,6 +170,7 @@ int monitor_puts(Monitor *mon, const char *str);
 void monitor_data_init(Monitor *mon, bool is_qmp, bool skip_flush,
                        bool use_io_thread);
 void monitor_data_destroy(Monitor *mon);
+void monitor_accept_input(Monitor *mon);
 int monitor_can_read(void *opaque);
 void monitor_list_append(Monitor *mon);
 void monitor_fdsets_cleanup(void);
diff --git a/monitor/monitor.c b/monitor/monitor.c
index 46a171bca6..8e3cf4ad98 100644
--- a/monitor/monitor.c
+++ b/monitor/monitor.c
@@ -519,13 +519,28 @@ int monitor_suspend(Monitor *mon)
     return 0;
 }
 
-static void monitor_accept_input(void *opaque)
+static void monitor_accept_input_bh(void *opaque)
 {
     Monitor *mon = opaque;
 
     qemu_chr_fe_accept_input(&mon->chr);
 }
 
+void monitor_accept_input(Monitor *mon)
+{
+    if (!qatomic_mb_read(&mon->suspend_cnt)) {
+        AioContext *ctx;
+
+        if (mon->use_io_thread) {
+            ctx = iothread_get_aio_context(mon_iothread);
+        } else {
+            ctx = qemu_get_aio_context();
+        }
+
+        aio_bh_schedule_oneshot(ctx, monitor_accept_input_bh, mon);
+    }
+}
+
 void monitor_resume(Monitor *mon)
 {
     if (monitor_is_hmp_non_interactive(mon)) {
@@ -547,7 +562,7 @@ void monitor_resume(Monitor *mon)
             readline_show_prompt(hmp_mon->rs);
         }
 
-        aio_bh_schedule_oneshot(ctx, monitor_accept_input, mon);
+        aio_bh_schedule_oneshot(ctx, monitor_accept_input_bh, mon);
     }
 
     trace_monitor_suspend(mon, -1);
-- 
2.26.2

Re: [PATCH] monitor/hmp: schedule qemu_chr_fe_accept_input() after read

Posted by Marc-André Lureau 2 years, 9 months ago

Hi Volker

On Sat, Aug 7, 2021 at 11:32 PM Volker Rümelin <vr_qemu@t-online.de> wrote:

> Since commit 584af1f1d9 (ui/gtk: add a keyboard fifo to the VTE
> consoles) a GTK VTE console chardev backend relies on the
> connected chardev frontend to call qemu_chr_fe_accept_input()
> whenever it can receive new characters. The HMP monitor doesn't
> do this. It only schedules a call to qemu_chr_fe_accept_input()
> after it handled a HMP command in monitor_command_cb().
>
> This is a problem if you paste a few characters into the GTK
> monitor console. Even entering a UTF-8 multibyte character leads
> to the same problem.
>
> Schedule a call to qemu_chr_fe_accept_input() after handling the
> received bytes to fix the HMP monitor.
>
> Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
>

Wouldn't it work to make gd_vc_send_chars() write in a loop (until it
fails)?

If not, I think monitor/qmp.c should be adjusted too.

---
>  monitor/hmp.c              |  1 +
>  monitor/monitor-internal.h |  1 +
>  monitor/monitor.c          | 19 +++++++++++++++++--
>  3 files changed, 19 insertions(+), 2 deletions(-)
>
> diff --git a/monitor/hmp.c b/monitor/hmp.c
> index d50c3124e1..470f56a71d 100644
> --- a/monitor/hmp.c
> +++ b/monitor/hmp.c
> @@ -1349,6 +1349,7 @@ static void monitor_read(void *opaque, const uint8_t
> *buf, int size)
>          for (i = 0; i < size; i++) {
>              readline_handle_byte(mon->rs, buf[i]);
>          }
> +        monitor_accept_input(&mon->common);
>      } else {
>          if (size == 0 || buf[size - 1] != 0) {
>              monitor_printf(&mon->common, "corrupted command\n");
> diff --git a/monitor/monitor-internal.h b/monitor/monitor-internal.h
> index 9c3a09cb01..af33c3c617 100644
> --- a/monitor/monitor-internal.h
> +++ b/monitor/monitor-internal.h
> @@ -170,6 +170,7 @@ int monitor_puts(Monitor *mon, const char *str);
>  void monitor_data_init(Monitor *mon, bool is_qmp, bool skip_flush,
>                         bool use_io_thread);
>  void monitor_data_destroy(Monitor *mon);
> +void monitor_accept_input(Monitor *mon);
>  int monitor_can_read(void *opaque);
>  void monitor_list_append(Monitor *mon);
>  void monitor_fdsets_cleanup(void);
> diff --git a/monitor/monitor.c b/monitor/monitor.c
> index 46a171bca6..8e3cf4ad98 100644
> --- a/monitor/monitor.c
> +++ b/monitor/monitor.c
> @@ -519,13 +519,28 @@ int monitor_suspend(Monitor *mon)
>      return 0;
>  }
>
> -static void monitor_accept_input(void *opaque)
> +static void monitor_accept_input_bh(void *opaque)
>  {
>      Monitor *mon = opaque;
>
>      qemu_chr_fe_accept_input(&mon->chr);
>  }
>
> +void monitor_accept_input(Monitor *mon)
> +{
> +    if (!qatomic_mb_read(&mon->suspend_cnt)) {
> +        AioContext *ctx;
> +
> +        if (mon->use_io_thread) {
> +            ctx = iothread_get_aio_context(mon_iothread);
> +        } else {
> +            ctx = qemu_get_aio_context();
> +        }
> +
> +        aio_bh_schedule_oneshot(ctx, monitor_accept_input_bh, mon);
> +    }
> +}
> +
>  void monitor_resume(Monitor *mon)
>  {
>      if (monitor_is_hmp_non_interactive(mon)) {
> @@ -547,7 +562,7 @@ void monitor_resume(Monitor *mon)
>              readline_show_prompt(hmp_mon->rs);
>          }
>
> -        aio_bh_schedule_oneshot(ctx, monitor_accept_input, mon);
> +        aio_bh_schedule_oneshot(ctx, monitor_accept_input_bh, mon);
>      }
>
>      trace_monitor_suspend(mon, -1);
> --
> 2.26.2
>
>
>

-- 
Marc-André Lureau

Re: [PATCH] monitor/hmp: schedule qemu_chr_fe_accept_input() after read

Posted by Volker Rümelin 2 years, 9 months ago

>     Since commit 584af1f1d9 (ui/gtk: add a keyboard fifo to the VTE
>     consoles) a GTK VTE console chardev backend relies on the
>     connected chardev frontend to call qemu_chr_fe_accept_input()
>     whenever it can receive new characters. The HMP monitor doesn't
>     do this. It only schedules a call to qemu_chr_fe_accept_input()
>     after it handled a HMP command in monitor_command_cb().
>
>     This is a problem if you paste a few characters into the GTK
>     monitor console. Even entering a UTF-8 multibyte character leads
>     to the same problem.
>
>     Schedule a call to qemu_chr_fe_accept_input() after handling the
>     received bytes to fix the HMP monitor.
>
>     Signed-off-by: Volker Rümelin <vr_qemu@t-online.de
>     <mailto:vr_qemu@t-online.de>>
>
>
> Wouldn't it work to make gd_vc_send_chars() write in a loop (until it 
> fails)?

Hi Marc-André,

yes that works. I found similar code in the udp_chr_flush_buffer() 
function in chardev/char-udp.c. I will send a new patch within the next 
few hours.

With best regards,
Volker

>
> If not, I think monitor/qmp.c should be adjusted too.
>
>     ---
>      monitor/hmp.c              |  1 +
>      monitor/monitor-internal.h |  1 +
>      monitor/monitor.c          | 19 +++++++++++++++++--
>      3 files changed, 19 insertions(+), 2 deletions(-)
>
>     diff --git a/monitor/hmp.c b/monitor/hmp.c
>     index d50c3124e1..470f56a71d 100644
>     --- a/monitor/hmp.c
>     +++ b/monitor/hmp.c
>     @@ -1349,6 +1349,7 @@ static void monitor_read(void *opaque, const
>     uint8_t *buf, int size)
>              for (i = 0; i < size; i++) {
>                  readline_handle_byte(mon->rs, buf[i]);
>              }
>     +        monitor_accept_input(&mon->common);
>          } else {
>              if (size == 0 || buf[size - 1] != 0) {
>                  monitor_printf(&mon->common, "corrupted command\n");
>     diff --git a/monitor/monitor-internal.h b/monitor/monitor-internal.h
>     index 9c3a09cb01..af33c3c617 100644
>     --- a/monitor/monitor-internal.h
>     +++ b/monitor/monitor-internal.h
>     @@ -170,6 +170,7 @@ int monitor_puts(Monitor *mon, const char *str);
>      void monitor_data_init(Monitor *mon, bool is_qmp, bool skip_flush,
>                             bool use_io_thread);
>      void monitor_data_destroy(Monitor *mon);
>     +void monitor_accept_input(Monitor *mon);
>      int monitor_can_read(void *opaque);
>      void monitor_list_append(Monitor *mon);
>      void monitor_fdsets_cleanup(void);
>     diff --git a/monitor/monitor.c b/monitor/monitor.c
>     index 46a171bca6..8e3cf4ad98 100644
>     --- a/monitor/monitor.c
>     +++ b/monitor/monitor.c
>     @@ -519,13 +519,28 @@ int monitor_suspend(Monitor *mon)
>          return 0;
>      }
>
>     -static void monitor_accept_input(void *opaque)
>     +static void monitor_accept_input_bh(void *opaque)
>      {
>          Monitor *mon = opaque;
>
>          qemu_chr_fe_accept_input(&mon->chr);
>      }
>
>     +void monitor_accept_input(Monitor *mon)
>     +{
>     +    if (!qatomic_mb_read(&mon->suspend_cnt)) {
>     +        AioContext *ctx;
>     +
>     +        if (mon->use_io_thread) {
>     +            ctx = iothread_get_aio_context(mon_iothread);
>     +        } else {
>     +            ctx = qemu_get_aio_context();
>     +        }
>     +
>     +        aio_bh_schedule_oneshot(ctx, monitor_accept_input_bh, mon);
>     +    }
>     +}
>     +
>      void monitor_resume(Monitor *mon)
>      {
>          if (monitor_is_hmp_non_interactive(mon)) {
>     @@ -547,7 +562,7 @@ void monitor_resume(Monitor *mon)
>                  readline_show_prompt(hmp_mon->rs);
>              }
>
>     -        aio_bh_schedule_oneshot(ctx, monitor_accept_input, mon);
>     +        aio_bh_schedule_oneshot(ctx, monitor_accept_input_bh, mon);
>          }
>
>          trace_monitor_suspend(mon, -1);
>     -- 
>     2.26.2
>
>
>
>
> -- 
> Marc-André Lureau