summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorAmit Shah <amit.shah@redhat.com>2011-07-20 13:30:56 +0530
committerAmit Shah <amit.shah@redhat.com>2011-07-26 11:21:14 +0530
commit1a39b0fcff1c3cc77ad21930821b43be890ba400 (patch)
tree566190fd2aff6d6a31964f0f07ac7ccecbbb570d
parentvirtio-balloon: Separate status handling into separate function (diff)
downloadqemu-kvm-1a39b0fcff1c3cc77ad21930821b43be890ba400.tar.gz
qemu-kvm-1a39b0fcff1c3cc77ad21930821b43be890ba400.tar.bz2
qemu-kvm-1a39b0fcff1c3cc77ad21930821b43be890ba400.zip
balloon: Separate out stat and balloon handling
Passing on '0' as ballooning target to indicate retrieval of stats is bad API. It also makes 'balloon 0' in the monitor cause a segfault. Have two different functions handle the different functionality instead. Detailed explanation from Markus's review: 1. do_info_balloon() is an info_async() method. It receives a callback with argument, to be called exactly once (callback frees the argument). It passes the callback via qemu_balloon_status() and indirectly through qemu_balloon_event to virtio_balloon_to_target(). virtio_balloon_to_target() executes its balloon stats half. It stores the callback in the device state. If it can't send a stats request, it resets stats and calls the callback right away. Else, it sends a stats request. The device model runs the callback when it receives the answer. Works. 2. do_balloon() is a cmd_async() method. It receives a callback with argument, to be called when the command completes. do_balloon() calls it right before it succeeds. Odd, but should work. Nevertheless, it passes the callback on via qemu_ballon() and indirectly through qemu_balloon_event to virtio_balloon_to_target(). a. If the argument is non-zero, virtio_balloon_to_target() executes its balloon half, which doesn't use the callback in any way. Odd, but works. b. If the argument is zero, virtio_balloon_to_target() executes its balloon stats half, just like in 1. It either calls the callback right away, or arranges for it to be called later. Thus, the callback runs twice: use after free and double free. Test case: start with -S -device virtio-balloon, execute "balloon 0" in human monitor. Runs the callback first from virtio_balloon_to_target(), then again from do_balloon(). Reported-by: Mike Cao <bcao@redhat.com> Signed-off-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com>
-rw-r--r--balloon.c17
-rw-r--r--balloon.h8
-rw-r--r--hw/virtio-balloon.c7
3 files changed, 17 insertions, 15 deletions
diff --git a/balloon.c b/balloon.c
index d40be39b3..8be3812ee 100644
--- a/balloon.c
+++ b/balloon.c
@@ -32,30 +32,33 @@
static QEMUBalloonEvent *balloon_event_fn;
+static QEMUBalloonStatus *balloon_stat_fn;
static void *balloon_opaque;
-void qemu_add_balloon_handler(QEMUBalloonEvent *func, void *opaque)
+void qemu_add_balloon_handler(QEMUBalloonEvent *event_func,
+ QEMUBalloonStatus *stat_func, void *opaque)
{
- balloon_event_fn = func;
+ balloon_event_fn = event_func;
+ balloon_stat_fn = stat_func;
balloon_opaque = opaque;
}
-static int qemu_balloon(ram_addr_t target, MonitorCompletion cb, void *opaque)
+static int qemu_balloon(ram_addr_t target)
{
if (!balloon_event_fn) {
return 0;
}
trace_balloon_event(balloon_opaque, target);
- balloon_event_fn(balloon_opaque, target, cb, opaque);
+ balloon_event_fn(balloon_opaque, target);
return 1;
}
static int qemu_balloon_status(MonitorCompletion cb, void *opaque)
{
- if (!balloon_event_fn) {
+ if (!balloon_stat_fn) {
return 0;
}
- balloon_event_fn(balloon_opaque, 0, cb, opaque);
+ balloon_stat_fn(balloon_opaque, cb, opaque);
return 1;
}
@@ -135,7 +138,7 @@ int do_balloon(Monitor *mon, const QDict *params,
return -1;
}
- ret = qemu_balloon(qdict_get_int(params, "value"), cb, opaque);
+ ret = qemu_balloon(qdict_get_int(params, "value"));
if (ret == 0) {
qerror_report(QERR_DEVICE_NOT_ACTIVE, "balloon");
return -1;
diff --git a/balloon.h b/balloon.h
index 06a8a46b5..a6c31d587 100644
--- a/balloon.h
+++ b/balloon.h
@@ -16,10 +16,12 @@
#include "monitor.h"
-typedef void (QEMUBalloonEvent)(void *opaque, ram_addr_t target,
- MonitorCompletion cb, void *cb_data);
+typedef void (QEMUBalloonEvent)(void *opaque, ram_addr_t target);
+typedef void (QEMUBalloonStatus)(void *opaque, MonitorCompletion cb,
+ void *cb_data);
-void qemu_add_balloon_handler(QEMUBalloonEvent *func, void *opaque);
+void qemu_add_balloon_handler(QEMUBalloonEvent *event_func,
+ QEMUBalloonStatus *stat_func, void *opaque);
void monitor_print_balloon(Monitor *mon, const QObject *data);
int do_info_balloon(Monitor *mon, MonitorCompletion cb, void *opaque);
diff --git a/hw/virtio-balloon.c b/hw/virtio-balloon.c
index 2f371f2f6..40b43b060 100644
--- a/hw/virtio-balloon.c
+++ b/hw/virtio-balloon.c
@@ -227,8 +227,7 @@ static void virtio_balloon_stat(void *opaque, MonitorCompletion cb,
complete_stats_request(dev);
}
-static void virtio_balloon_to_target(void *opaque, ram_addr_t target,
- MonitorCompletion cb, void *cb_data)
+static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
{
VirtIOBalloon *dev = opaque;
@@ -238,8 +237,6 @@ static void virtio_balloon_to_target(void *opaque, ram_addr_t target,
if (target) {
dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
virtio_notify_config(&dev->vdev);
- } else {
- virtio_balloon_stat(opaque, cb, cb_data);
}
}
@@ -284,7 +281,7 @@ VirtIODevice *virtio_balloon_init(DeviceState *dev)
s->svq = virtio_add_queue(&s->vdev, 128, virtio_balloon_receive_stats);
reset_stats(s);
- qemu_add_balloon_handler(virtio_balloon_to_target, s);
+ qemu_add_balloon_handler(virtio_balloon_to_target, virtio_balloon_stat, s);
register_savevm(dev, "virtio-balloon", -1, 1,
virtio_balloon_save, virtio_balloon_load, s);