Re: [Qemu-devel] [PATCH 4/5] monitor: Port do_info_balloon() to QObject

[Markus Armbruster <armbru@redhat.com>]

Luiz Capitulino <lcapitulino@redhat.com> writes:

> do_info_balloon() returns 0 on success or -1 when the 'balloon'
> value could not be queried.
>
> The returned data is always a QString.
>
> This also introduces monitor_print_qobject(), which can be
> used as a standard way to print QObjects in the user protocol
> format.
>
> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
> ---
>  monitor.c |   41 +++++++++++++++++++++++++++++++++--------
>  1 files changed, 33 insertions(+), 8 deletions(-)
>
> diff --git a/monitor.c b/monitor.c
> index f9f3cbd..545833d 100644
> --- a/monitor.c
> +++ b/monitor.c
[...]
> @@ -1586,18 +1602,27 @@ static void do_balloon(Monitor *mon, const QDict *qdict)
>      qemu_balloon(target << 20);
>  }
>  
> -static void do_info_balloon(Monitor *mon)
> +static int do_info_balloon(Monitor *mon, QObject **ret_data)
>  {
> +    QString *qs;
>      ram_addr_t actual;
> +    int ret = -1;
>  
>      actual = qemu_balloon_status();
> -    if (kvm_enabled() && !kvm_has_sync_mmu())
> -        monitor_printf(mon, "Using KVM without synchronous MMU, "
> +    if (kvm_enabled() && !kvm_has_sync_mmu()) {
> +        qs = qstring_from_str("Using KVM without synchronous MMU, "
>                         "ballooning disabled\n");
> -    else if (actual == 0)
> -        monitor_printf(mon, "Ballooning not activated in VM\n");
> -    else
> -        monitor_printf(mon, "balloon: actual=%d\n", (int)(actual >> 20));
> +    } else if (actual == 0) {
> +        qs = qstring_from_str("Ballooning not activated in VM\n");
> +    } else {
> +        char buf[128];
> +        sprintf(buf, "balloon: actual=%d\n", (int)(actual >> 20));
> +        qs = qstring_from_str(buf);
> +        ret = 0;

If this pattern turns out to be common, let's create qstring_printf() to
print to a new qstring.

> +    }
> +
> +    *ret_data = QOBJECT(qs);
> +    return ret;
>  }
>  
>  static qemu_acl *find_acl(Monitor *mon, const char *name)
> @@ -1898,7 +1923,7 @@ static const mon_cmd_t info_cmds[] = {
>        "", "show user network stack connection states", },
>  #endif
>      { "migrate", "", do_info_migrate, NULL, "", "show migration status" },
> -    { "balloon", "", do_info_balloon, NULL,
> +    { "balloon", "", do_info_balloon, monitor_print_qobject,
>        "", "show balloon information" },
>      { "qtree", "", do_info_qtree, NULL,
>        "", "show device tree" },