[Qemu-devel] [PATCH 20/21] spice-core: allow an interface to be in AIO context

["Marc-André Lureau" <marcandre.lureau@gmail.com>]

The Spice block driver must be able complete operations within a AIO
context only.

Spice is currently only running within the main loop, and doesn't allow
the block driver to complete operations, such as flush during migration.

This patch allows a Spice interface to be associated with a different
context. Currently, the interface user_data is simply used to
differentiate main loop from AIO, but could later be used to associate
an interface with a particular thread.

Signed-off-by: Marc-André Lureau <marcandre.lureau@gmail.com>
---
 include/ui/qemu-spice.h |  2 +-
 qemu-char.c             |  2 +-
 spice-qemu-char.c       |  9 +++----
 ui/spice-core.c         | 62 +++++++++++++++++++++++++++++++++++++++++++------
 4 files changed, 62 insertions(+), 13 deletions(-)

diff --git a/include/ui/qemu-spice.h b/include/ui/qemu-spice.h
index a93b4b2..d5ba702 100644
--- a/include/ui/qemu-spice.h
+++ b/include/ui/qemu-spice.h
@@ -48,7 +48,7 @@ int qemu_spice_migrate_info(const char *hostname, int port, int tls_port,
 void do_info_spice_print(Monitor *mon, const QObject *data);
 void do_info_spice(Monitor *mon, QObject **ret_data);
 
-CharDriverState *qemu_chr_open_spice_vmc(const char *type);
+CharDriverState *qemu_chr_open_spice_vmc(const char *type, bool aio);
 #if SPICE_SERVER_VERSION >= 0x000c02
 CharDriverState *qemu_chr_open_spice_port(const char *name);
 void qemu_spice_register_ports(void);
diff --git a/qemu-char.c b/qemu-char.c
index 418dc69..bfac7bf 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -3747,7 +3747,7 @@ ChardevReturn *qmp_chardev_add(const char *id, ChardevBackend *backend,
 #endif
 #ifdef CONFIG_SPICE
     case CHARDEV_BACKEND_KIND_SPICEVMC:
-        chr = qemu_chr_open_spice_vmc(backend->spicevmc->type);
+        chr = qemu_chr_open_spice_vmc(backend->spicevmc->type, false);
         break;
     case CHARDEV_BACKEND_KIND_SPICEPORT:
         chr = qemu_chr_open_spice_port(backend->spiceport->fqdn);
diff --git a/spice-qemu-char.c b/spice-qemu-char.c
index 16439c5..421f7de 100644
--- a/spice-qemu-char.c
+++ b/spice-qemu-char.c
@@ -248,7 +248,7 @@ static void print_allowed_subtypes(void)
     fprintf(stderr, "\n");
 }
 
-static CharDriverState *chr_open(const char *subtype)
+static CharDriverState *chr_open(const char *subtype, bool aio)
 {
     CharDriverState *chr;
     SpiceCharDriver *s;
@@ -257,6 +257,7 @@ static CharDriverState *chr_open(const char *subtype)
     s = g_malloc0(sizeof(SpiceCharDriver));
     s->chr = chr;
     s->active = false;
+    s->sin.base.user_data = (void*)aio;
     s->sin.subtype = g_strdup(subtype);
     chr->opaque = s;
     chr->chr_write = spice_chr_write;
@@ -271,7 +272,7 @@ static CharDriverState *chr_open(const char *subtype)
     return chr;
 }
 
-CharDriverState *qemu_chr_open_spice_vmc(const char *type)
+CharDriverState *qemu_chr_open_spice_vmc(const char *type, bool aio)
 {
     const char **psubtype = spice_server_char_device_recognized_subtypes();
 
@@ -291,7 +292,7 @@ CharDriverState *qemu_chr_open_spice_vmc(const char *type)
         return NULL;
     }
 
-    return chr_open(type);
+    return chr_open(type, aio);
 }
 
 #if SPICE_SERVER_VERSION >= 0x000c02
@@ -305,7 +306,7 @@ CharDriverState *qemu_chr_open_spice_port(const char *name)
         return NULL;
     }
 
-    chr = chr_open("port");
+    chr = chr_open("port", false);
     s = chr->opaque;
     s->sin.portname = g_strdup(name);
 
diff --git a/ui/spice-core.c b/ui/spice-core.c
index e4d533d..0f69630 100644
--- a/ui/spice-core.c
+++ b/ui/spice-core.c
@@ -53,34 +53,64 @@ static QemuThread me;
 
 struct SpiceTimer {
     QEMUTimer *timer;
+    QEMUBH *bh;
     QTAILQ_ENTRY(SpiceTimer) next;
 };
 static QTAILQ_HEAD(, SpiceTimer) timers = QTAILQ_HEAD_INITIALIZER(timers);
 
+#if SPICE_INTERFACE_CORE_MAJOR >= 2
+static SpiceTimer *timer_add(SpiceTimerFunc func, void *opaque, SpiceBaseInstance *sin)
+#else
 static SpiceTimer *timer_add(SpiceTimerFunc func, void *opaque)
+#endif
 {
     SpiceTimer *timer;
 
     timer = g_malloc0(sizeof(*timer));
-    timer->timer = timer_new_ms(QEMU_CLOCK_REALTIME, func, opaque);
+
+#if SPICE_INTERFACE_CORE_MAJOR >= 2
+    bool aio = sin ? !!sin->user_data : false;
+    if (aio) {
+        fprintf(stderr, "AIO doesn't have timers yet, using BH\n");
+        timer->bh = qemu_bh_new(func, opaque);
+    } else
+#endif
+    {
+        timer->timer = timer_new_ms(QEMU_CLOCK_REALTIME, func, opaque);
+    }
+
     QTAILQ_INSERT_TAIL(&timers, timer, next);
+
     return timer;
 }
 
 static void timer_start(SpiceTimer *timer, uint32_t ms)
 {
-    timer_mod(timer->timer, qemu_clock_get_ms(QEMU_CLOCK_REALTIME) + ms);
+    if (timer->bh) {
+        qemu_bh_schedule_idle(timer->bh); /* at least every 10ms, see async.c */
+    } else {
+        timer_mod(timer->timer, qemu_clock_get_ms(QEMU_CLOCK_REALTIME) + ms);
+    }
 }
 
 static void timer_cancel(SpiceTimer *timer)
 {
-    timer_del(timer->timer);
+    if (timer->bh) {
+        qemu_bh_cancel(timer->bh);
+    } else {
+        timer_del(timer->timer);
+    }
 }
 
 static void timer_remove(SpiceTimer *timer)
 {
-    timer_del(timer->timer);
-    timer_free(timer->timer);
+    if (timer->bh) {
+        qemu_bh_delete(timer->bh);
+    } else {
+        timer_del(timer->timer);
+        timer_free(timer->timer);
+    }
+
     QTAILQ_REMOVE(&timers, timer, next);
     g_free(timer);
 }
@@ -89,6 +119,7 @@ struct SpiceWatch {
     int fd;
     int event_mask;
     SpiceWatchFunc func;
+    bool aio;
     void *opaque;
     QTAILQ_ENTRY(SpiceWatch) next;
 };
@@ -118,10 +149,19 @@ static void watch_update_mask(SpiceWatch *watch, int event_mask)
     if (watch->event_mask & SPICE_WATCH_EVENT_WRITE) {
         on_write = watch_write;
     }
-    qemu_set_fd_handler(watch->fd, on_read, on_write, watch);
+
+    if (watch->aio) {
+        qemu_aio_set_fd_handler(watch->fd, on_read, on_write, watch);
+    } else {
+        qemu_set_fd_handler(watch->fd, on_read, on_write, watch);
+    }
 }
 
+#if SPICE_INTERFACE_CORE_MAJOR >= 2
+static SpiceWatch *watch_add(int fd, int event_mask, SpiceWatchFunc func, void *opaque, SpiceBaseInstance *sin)
+#else
 static SpiceWatch *watch_add(int fd, int event_mask, SpiceWatchFunc func, void *opaque)
+#endif
 {
     SpiceWatch *watch;
 
@@ -129,6 +169,10 @@ static SpiceWatch *watch_add(int fd, int event_mask, SpiceWatchFunc func, void *
     watch->fd     = fd;
     watch->func   = func;
     watch->opaque = opaque;
+#if SPICE_INTERFACE_CORE_MAJOR >= 2
+    watch->aio    = sin ? !!sin->user_data : false;
+#endif
+
     QTAILQ_INSERT_TAIL(&watches, watch, next);
 
     watch_update_mask(watch, event_mask);
@@ -137,7 +181,11 @@ static SpiceWatch *watch_add(int fd, int event_mask, SpiceWatchFunc func, void *
 
 static void watch_remove(SpiceWatch *watch)
 {
-    qemu_set_fd_handler(watch->fd, NULL, NULL, NULL);
+    if (watch->aio) {
+        qemu_aio_set_fd_handler(watch->fd, NULL, NULL, NULL);
+    } else {
+        qemu_set_fd_handler(watch->fd, NULL, NULL, NULL);
+    }
     QTAILQ_REMOVE(&watches, watch, next);
     g_free(watch);
 }
-- 
1.8.3.1