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[Qemu-devel] [PATCH 24/26] qemu-char: don't issue CHR_EVENT_OPEN in a BH
From: |
Michael Roth |
Subject: |
[Qemu-devel] [PATCH 24/26] qemu-char: don't issue CHR_EVENT_OPEN in a BH |
Date: |
Wed, 12 Jun 2013 16:41:36 -0500 |
When CHR_EVENT_OPENED was initially added, it was CHR_EVENT_RESET,
and it was issued as a bottom-half:
86e94dea5b740dad65446c857f6959eae43e0ba6
Which we basically used to print out a greeting/prompt for the
monitor.
AFAICT the only reason this was ever done in a BH was because in
some cases we'd modify the chr_write handler for a new chardev
backend *after* the site where we issued the reset (see:
86e94d:qemu_chr_open_stdio())
At some point this event was renamed to CHR_EVENT_OPENED, and we've
maintained the use of this BH ever since.
However, due to 9f939df955a4152aad69a19a77e0898631bb2c18, we schedule
the BH via g_idle_add(), which is causing events to sometimes be
delivered after we've already begun processing data from backends,
leading to:
known bugs:
QMP:
session negotation resets with OPENED event, in some cases this
is causing new sessions to get sporadically reset
potential bugs:
hw/usb/redirect.c:
can_read handler checks for dev->parser != NULL, which may be
true if CLOSED BH has not been executed yet. In the past, OPENED
quiesced outstanding CLOSED events prior to us reading client
data. If it's delayed, our check may allow reads to occur even
though we haven't processed the OPENED event yet, and when we
do finally get the OPENED event, our state may get reset.
qtest.c:
can begin session before OPENED event is processed, leading to
a spurious reset of the system and irq_levels
gdbstub.c:
may start a gdb session prior to the machine being paused
To fix these, let's just drop the BH.
Since the initial reasoning for using it still applies to an extent,
work around that by deferring the delivery of CHR_EVENT_OPENED until
after the chardevs have been fully initialized, toward the end of
qmp_chardev_add() (or some cases, qemu_chr_new_from_opts()). This
defers delivery long enough that we can be assured a CharDriverState
is fully initialized before CHR_EVENT_OPENED is sent.
Also, rather than requiring each chardev to do an explicit open, do it
automatically, and allow the small few who don't desire such behavior to
suppress the OPENED-on-init behavior by setting a 'explicit_be_open'
flag.
We additionally add missing OPENED events for stdio backends on w32,
which were previously not being issued, causing us to not recieve the
banner and initial prompts for qmp/hmp.
Reported-by: Stefan Priebe <address@hidden>
Signed-off-by: Michael Roth <address@hidden>
Message-id: address@hidden
Cc: address@hidden
Signed-off-by: Michael Roth <address@hidden>
Signed-off-by: Anthony Liguori <address@hidden>
(cherry picked from commit bd5c51ee6c4f1c79cae5ad2516d711a27b4ea8ec)
Signed-off-by: Michael Roth <address@hidden>
---
backends/baum.c | 2 --
backends/msmouse.c | 1 +
include/sysemu/char.h | 2 +-
qemu-char.c | 38 +++++++++++++++++---------------------
spice-qemu-char.c | 1 +
ui/console.c | 4 ++++
ui/gtk.c | 2 ++
7 files changed, 26 insertions(+), 24 deletions(-)
diff --git a/backends/baum.c b/backends/baum.c
index 4cba79f..62aa784 100644
--- a/backends/baum.c
+++ b/backends/baum.c
@@ -611,8 +611,6 @@ CharDriverState *chr_baum_init(void)
qemu_set_fd_handler(baum->brlapi_fd, baum_chr_read, NULL, baum);
- qemu_chr_be_generic_open(chr);
-
return chr;
fail:
diff --git a/backends/msmouse.c b/backends/msmouse.c
index 0ac05a0..c0dbfcd 100644
--- a/backends/msmouse.c
+++ b/backends/msmouse.c
@@ -70,6 +70,7 @@ CharDriverState *qemu_chr_open_msmouse(void)
chr = g_malloc0(sizeof(CharDriverState));
chr->chr_write = msmouse_chr_write;
chr->chr_close = msmouse_chr_close;
+ chr->explicit_be_open = true;
qemu_add_mouse_event_handler(msmouse_event, chr, 0, "QEMU Microsoft
Mouse");
diff --git a/include/sysemu/char.h b/include/sysemu/char.h
index 5e42c90..066c216 100644
--- a/include/sysemu/char.h
+++ b/include/sysemu/char.h
@@ -70,12 +70,12 @@ struct CharDriverState {
void (*chr_set_echo)(struct CharDriverState *chr, bool echo);
void (*chr_set_fe_open)(struct CharDriverState *chr, int fe_open);
void *opaque;
- int idle_tag;
char *label;
char *filename;
int be_open;
int fe_open;
int explicit_fe_open;
+ int explicit_be_open;
int avail_connections;
QemuOpts *opts;
QTAILQ_ENTRY(CharDriverState) next;
diff --git a/qemu-char.c b/qemu-char.c
index 6b5bd6f..a81fc4c 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -110,19 +110,9 @@ void qemu_chr_be_event(CharDriverState *s, int event)
s->chr_event(s->handler_opaque, event);
}
-static gboolean qemu_chr_be_generic_open_bh(gpointer opaque)
-{
- CharDriverState *s = opaque;
- qemu_chr_be_event(s, CHR_EVENT_OPENED);
- s->idle_tag = 0;
- return FALSE;
-}
-
void qemu_chr_be_generic_open(CharDriverState *s)
{
- if (s->idle_tag == 0) {
- s->idle_tag = g_idle_add(qemu_chr_be_generic_open_bh, s);
- }
+ qemu_chr_be_event(s, CHR_EVENT_OPENED);
}
int qemu_chr_fe_write(CharDriverState *s, const uint8_t *buf, int len)
@@ -247,6 +237,7 @@ static CharDriverState *qemu_chr_open_null(void)
chr = g_malloc0(sizeof(CharDriverState));
chr->chr_write = null_chr_write;
+ chr->explicit_be_open = true;
return chr;
}
@@ -504,9 +495,6 @@ static CharDriverState *qemu_chr_open_mux(CharDriverState
*drv)
/* Frontend guest-open / -close notification is not support with muxes */
chr->chr_set_fe_open = NULL;
- /* Muxes are always open on creation */
- qemu_chr_be_generic_open(chr);
-
return chr;
}
@@ -883,8 +871,6 @@ static CharDriverState *qemu_chr_open_fd(int fd_in, int
fd_out)
chr->chr_update_read_handler = fd_chr_update_read_handler;
chr->chr_close = fd_chr_close;
- qemu_chr_be_generic_open(chr);
-
return chr;
}
@@ -1243,6 +1229,7 @@ static CharDriverState *qemu_chr_open_pty(const char *id,
chr->chr_update_read_handler = pty_chr_update_read_handler;
chr->chr_close = pty_chr_close;
chr->chr_add_watch = pty_chr_add_watch;
+ chr->explicit_be_open = true;
s->fd = io_channel_from_fd(master_fd);
s->timer_tag = 0;
@@ -1595,8 +1582,6 @@ static CharDriverState *qemu_chr_open_pp_fd(int fd)
chr->chr_close = pp_close;
chr->opaque = drv;
- qemu_chr_be_generic_open(chr);
-
return chr;
}
#endif /* __linux__ */
@@ -1650,6 +1635,7 @@ static CharDriverState *qemu_chr_open_pp_fd(int fd)
chr->opaque = (void *)(intptr_t)fd;
chr->chr_write = null_chr_write;
chr->chr_ioctl = pp_ioctl;
+ chr->explicit_be_open = true;
return chr;
}
#endif
@@ -1880,7 +1866,6 @@ static CharDriverState *qemu_chr_open_win_path(const char
*filename)
g_free(chr);
return NULL;
}
- qemu_chr_be_generic_open(chr);
return chr;
}
@@ -1980,7 +1965,6 @@ static CharDriverState *qemu_chr_open_pipe(ChardevHostdev
*opts)
g_free(chr);
return NULL;
}
- qemu_chr_be_generic_open(chr);
return chr;
}
@@ -1994,7 +1978,6 @@ static CharDriverState *qemu_chr_open_win_file(HANDLE
fd_out)
s->hcom = fd_out;
chr->opaque = s;
chr->chr_write = win_chr_write;
- qemu_chr_be_generic_open(chr);
return chr;
}
@@ -2329,6 +2312,8 @@ static CharDriverState *qemu_chr_open_udp_fd(int fd)
chr->chr_write = udp_chr_write;
chr->chr_update_read_handler = udp_chr_update_read_handler;
chr->chr_close = udp_chr_close;
+ /* be isn't opened until we get a connection */
+ chr->explicit_be_open = true;
return chr;
}
@@ -2731,6 +2716,8 @@ static CharDriverState *qemu_chr_open_socket_fd(int fd,
bool do_nodelay,
chr->get_msgfd = tcp_get_msgfd;
chr->chr_add_client = tcp_chr_add_client;
chr->chr_add_watch = tcp_chr_add_watch;
+ /* be isn't opened until we get a connection */
+ chr->explicit_be_open = true;
if (is_listen) {
s->listen_fd = fd;
@@ -3325,6 +3312,12 @@ CharDriverState *qemu_chr_new_from_opts(QemuOpts *opts,
if (!chr->filename)
chr->filename = g_strdup(qemu_opt_get(opts, "backend"));
chr->init = init;
+ /* if we didn't create the chardev via qmp_chardev_add, we
+ * need to send the OPENED event here
+ */
+ if (!chr->explicit_be_open) {
+ qemu_chr_be_event(chr, CHR_EVENT_OPENED);
+ }
QTAILQ_INSERT_TAIL(&chardevs, chr, next);
if (qemu_opt_get_bool(opts, "mux", 0)) {
@@ -3804,6 +3797,9 @@ ChardevReturn *qmp_chardev_add(const char *id,
ChardevBackend *backend,
if (!chr->filename) {
chr->filename = g_strdup(ChardevBackendKind_lookup[backend->kind]);
}
+ if (!chr->explicit_be_open) {
+ qemu_chr_be_event(chr, CHR_EVENT_OPENED);
+ }
QTAILQ_INSERT_TAIL(&chardevs, chr, next);
return ret;
} else {
diff --git a/spice-qemu-char.c b/spice-qemu-char.c
index f10970c..6d147a7 100644
--- a/spice-qemu-char.c
+++ b/spice-qemu-char.c
@@ -255,6 +255,7 @@ static CharDriverState *chr_open(const char *subtype)
chr->chr_add_watch = spice_chr_add_watch;
chr->chr_close = spice_chr_close;
chr->chr_set_fe_open = spice_chr_set_fe_open;
+ chr->explicit_be_open = true;
QLIST_INSERT_HEAD(&spice_chars, s, next);
diff --git a/ui/console.c b/ui/console.c
index b30853f..28bba6d 100644
--- a/ui/console.c
+++ b/ui/console.c
@@ -1788,6 +1788,10 @@ static CharDriverState *text_console_init(ChardevVC *vc)
s->chr = chr;
chr->opaque = s;
chr->chr_set_echo = text_console_set_echo;
+ /* console/chardev init sometimes completes elsewhere in a 2nd
+ * stage, so defer OPENED events until they are fully initialized
+ */
+ chr->explicit_be_open = true;
if (display_state) {
text_console_do_init(chr, display_state);
diff --git a/ui/gtk.c b/ui/gtk.c
index 52c3f95..82cf852 100644
--- a/ui/gtk.c
+++ b/ui/gtk.c
@@ -1117,6 +1117,8 @@ static CharDriverState *gd_vc_handler(ChardevVC *unused)
chr = g_malloc0(sizeof(*chr));
chr->chr_write = gd_vc_chr_write;
+ /* defer OPENED events until our vc is fully initialized */
+ chr->explicit_be_open = true;
vcs[nb_vcs++] = chr;
--
1.7.9.5
- [Qemu-devel] [PATCH 14/26] xen: start PCI hole at 0xe0000000 (same as pc_init1 and qemu-xen-traditional), (continued)
- [Qemu-devel] [PATCH 14/26] xen: start PCI hole at 0xe0000000 (same as pc_init1 and qemu-xen-traditional), Michael Roth, 2013/06/12
- [Qemu-devel] [PATCH 11/26] update seabios to release 1.7.2.2, Michael Roth, 2013/06/12
- [Qemu-devel] [PATCH 15/26] do not check pointers after dereferencing them, Michael Roth, 2013/06/12
- [Qemu-devel] [PATCH 16/26] qdev: fix get_fw_dev_path to support to add nothing to fw_dev_path, Michael Roth, 2013/06/12
- [Qemu-devel] [PATCH 17/26] host-libusb: Correct test for USB packet state, Michael Roth, 2013/06/12
- [Qemu-devel] [PATCH 18/26] Fix usage of USB_DEV_FLAG_IS_HOST flag., Michael Roth, 2013/06/12
- [Qemu-devel] [PATCH 19/26] vmxnet3: fix NICState cleanup, Michael Roth, 2013/06/12
- [Qemu-devel] [PATCH 20/26] ui/gtk.c: Fix *BSD build of Gtk+ UI, Michael Roth, 2013/06/12
- [Qemu-devel] [PATCH 21/26] s390x/css: Fix concurrent sense., Michael Roth, 2013/06/12
- [Qemu-devel] [PATCH 22/26] virtio-ccw: Fix unsetting of indicators., Michael Roth, 2013/06/12
- [Qemu-devel] [PATCH 24/26] qemu-char: don't issue CHR_EVENT_OPEN in a BH,
Michael Roth <=
- [Qemu-devel] [PATCH 25/26] target-i386: Fix aflag logic for CODE64 and the 0x67 prefix, Michael Roth, 2013/06/12
- [Qemu-devel] [PATCH 26/26] q35: set fw_name, Michael Roth, 2013/06/12
- [Qemu-devel] [PATCH 23/26] xilinx_axidma: Do not set DMA .notify to NULL after notify, Michael Roth, 2013/06/12
- Re: [Qemu-devel] Patch Round-up for stable 1.5.1, freeze on 2013-06-19, Stefan Hajnoczi, 2013/06/13
- Re: [Qemu-devel] Patch Round-up for stable 1.5.1, freeze on 2013-06-19, Paolo Bonzini, 2013/06/13
- Re: [Qemu-devel] Patch Round-up for stable 1.5.1, freeze on 2013-06-19, Frederic Konrad, 2013/06/13
- Re: [Qemu-devel] Patch Round-up for stable 1.5.1, freeze on 2013-06-19, Frederic Konrad, 2013/06/13