From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:35616) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TTYGh-000334-KN for qemu-devel@nongnu.org; Wed, 31 Oct 2012 09:23:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TTYGZ-0001mF-Pj for qemu-devel@nongnu.org; Wed, 31 Oct 2012 09:23:39 -0400 Received: from thoth.sbs.de ([192.35.17.2]:34500) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TTYGZ-0001lg-FH for qemu-devel@nongnu.org; Wed, 31 Oct 2012 09:23:31 -0400 Message-ID: <50912643.7010302@siemens.com> Date: Wed, 31 Oct 2012 14:23:15 +0100 From: Jan Kiszka MIME-Version: 1.0 References: <5073083C.1060201@siemens.com> <5077CC51.4080200@siemens.com> In-Reply-To: <5077CC51.4080200@siemens.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2] chardev: Use timer instead of bottom-half to postpone open event List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel , Anthony Liguori Cc: Peter Maydell , Aurelien Jarno , Paolo Bonzini On 2012-10-12 09:52, Jan Kiszka wrote: > As the block layer may decide to flush bottom-halfs while the machine is > still initializing (e.g. to read geometry data from the disk), our > postponed open event may be processed before the last frontend > registered with a muxed chardev. > > Until the semantics of BHs have been clarified, use an expired timer to > achieve the same effect (suggested by Paolo Bonzini). This requires to > perform the alarm timer initialization earlier as otherwise timer > subsystem can be used before being ready. > > Signed-off-by: Jan Kiszka > --- > > Changes in v2: > - Move init_alarm_timer call to fix e.g. -monitor stdio Ping? Jan > > qemu-char.c | 13 +++++++------ > qemu-char.h | 2 +- > vl.c | 10 +++++----- > 3 files changed, 13 insertions(+), 12 deletions(-) > > diff --git a/qemu-char.c b/qemu-char.c > index b082bae..d8eed21 100644 > --- a/qemu-char.c > +++ b/qemu-char.c > @@ -123,19 +123,20 @@ void qemu_chr_be_event(CharDriverState *s, int event) > s->chr_event(s->handler_opaque, event); > } > > -static void qemu_chr_generic_open_bh(void *opaque) > +static void qemu_chr_fire_open_event(void *opaque) > { > CharDriverState *s = opaque; > qemu_chr_be_event(s, CHR_EVENT_OPENED); > - qemu_bh_delete(s->bh); > - s->bh = NULL; > + qemu_free_timer(s->open_timer); > + s->open_timer = NULL; > } > > void qemu_chr_generic_open(CharDriverState *s) > { > - if (s->bh == NULL) { > - s->bh = qemu_bh_new(qemu_chr_generic_open_bh, s); > - qemu_bh_schedule(s->bh); > + if (s->open_timer == NULL) { > + s->open_timer = qemu_new_timer_ms(vm_clock, > + qemu_chr_fire_open_event, s); > + qemu_mod_timer(s->open_timer, qemu_get_clock_ms(vm_clock) - 1); > } > } > > diff --git a/qemu-char.h b/qemu-char.h > index 486644b..297dd98 100644 > --- a/qemu-char.h > +++ b/qemu-char.h > @@ -69,7 +69,7 @@ struct CharDriverState { > void (*chr_guest_open)(struct CharDriverState *chr); > void (*chr_guest_close)(struct CharDriverState *chr); > void *opaque; > - QEMUBH *bh; > + QEMUTimer *open_timer; > char *label; > char *filename; > int opened; > diff --git a/vl.c b/vl.c > index 5b357a3..586773c 100644 > --- a/vl.c > +++ b/vl.c > @@ -3439,6 +3439,11 @@ int main(int argc, char **argv, char **envp) > add_device_config(DEV_VIRTCON, "vc:80Cx24C"); > } > > + if (init_timer_alarm() < 0) { > + fprintf(stderr, "could not initialize alarm timer\n"); > + exit(1); > + } > + > socket_init(); > > if (qemu_opts_foreach(qemu_find_opts("chardev"), chardev_init_func, NULL, 1) != 0) > @@ -3506,11 +3511,6 @@ int main(int argc, char **argv, char **envp) > > os_set_line_buffering(); > > - if (init_timer_alarm() < 0) { > - fprintf(stderr, "could not initialize alarm timer\n"); > - exit(1); > - } > - > #ifdef CONFIG_SPICE > /* spice needs the timers to be initialized by this point */ > qemu_spice_init(); > -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux