aboutsummaryrefslogtreecommitdiff
path: root/hw/virtio
diff options
context:
space:
mode:
authorAlex Bennée <alex.bennee@linaro.org>2022-11-30 11:24:38 +0000
committerMichael S. Tsirkin <mst@redhat.com>2022-12-01 02:30:13 -0500
commit71e076a07dc195129fe25d90d4b276be3b2f12d8 (patch)
treeede68f35ad6fd8c5a9e785c01dbca02a76a92a98 /hw/virtio
parent060f4a944072ecf37cece0f16a0609babfb679b8 (diff)
hw/virtio: generalise CHR_EVENT_CLOSED handling
..and use for both virtio-user-blk and virtio-user-gpio. This avoids the circular close by deferring shutdown due to disconnection until a later point. virtio-user-blk already had this mechanism in place so generalise it as a vhost-user helper function and use for both blk and gpio devices. While we are at it we also fix up vhost-user-gpio to re-establish the event handler after close down so we can reconnect later. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com> Message-Id: <20221130112439.2527228-5-alex.bennee@linaro.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw/virtio')
-rw-r--r--hw/virtio/vhost-user-gpio.c11
-rw-r--r--hw/virtio/vhost-user.c71
2 files changed, 81 insertions, 1 deletions
diff --git a/hw/virtio/vhost-user-gpio.c b/hw/virtio/vhost-user-gpio.c
index be9be08b4c..b7b82a1099 100644
--- a/hw/virtio/vhost-user-gpio.c
+++ b/hw/virtio/vhost-user-gpio.c
@@ -233,6 +233,8 @@ static int vu_gpio_connect(DeviceState *dev, Error **errp)
return 0;
}
+static void vu_gpio_event(void *opaque, QEMUChrEvent event);
+
static void vu_gpio_disconnect(DeviceState *dev)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
@@ -245,6 +247,11 @@ static void vu_gpio_disconnect(DeviceState *dev)
vu_gpio_stop(vdev);
vhost_dev_cleanup(&gpio->vhost_dev);
+
+ /* Re-instate the event handler for new connections */
+ qemu_chr_fe_set_handlers(&gpio->chardev,
+ NULL, NULL, vu_gpio_event,
+ NULL, dev, NULL, true);
}
static void vu_gpio_event(void *opaque, QEMUChrEvent event)
@@ -262,7 +269,9 @@ static void vu_gpio_event(void *opaque, QEMUChrEvent event)
}
break;
case CHR_EVENT_CLOSED:
- vu_gpio_disconnect(dev);
+ /* defer close until later to avoid circular close */
+ vhost_user_async_close(dev, &gpio->chardev, &gpio->vhost_dev,
+ vu_gpio_disconnect);
break;
case CHR_EVENT_BREAK:
case CHR_EVENT_MUX_IN:
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index abe23d4ebe..8f635844af 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -21,6 +21,7 @@
#include "qemu/error-report.h"
#include "qemu/main-loop.h"
#include "qemu/sockets.h"
+#include "sysemu/runstate.h"
#include "sysemu/cryptodev.h"
#include "migration/migration.h"
#include "migration/postcopy-ram.h"
@@ -2670,6 +2671,76 @@ void vhost_user_cleanup(VhostUserState *user)
user->chr = NULL;
}
+
+typedef struct {
+ vu_async_close_fn cb;
+ DeviceState *dev;
+ CharBackend *cd;
+ struct vhost_dev *vhost;
+} VhostAsyncCallback;
+
+static void vhost_user_async_close_bh(void *opaque)
+{
+ VhostAsyncCallback *data = opaque;
+ struct vhost_dev *vhost = data->vhost;
+
+ /*
+ * If the vhost_dev has been cleared in the meantime there is
+ * nothing left to do as some other path has completed the
+ * cleanup.
+ */
+ if (vhost->vdev) {
+ data->cb(data->dev);
+ }
+
+ g_free(data);
+}
+
+/*
+ * We only schedule the work if the machine is running. If suspended
+ * we want to keep all the in-flight data as is for migration
+ * purposes.
+ */
+void vhost_user_async_close(DeviceState *d,
+ CharBackend *chardev, struct vhost_dev *vhost,
+ vu_async_close_fn cb)
+{
+ if (!runstate_check(RUN_STATE_SHUTDOWN)) {
+ /*
+ * A close event may happen during a read/write, but vhost
+ * code assumes the vhost_dev remains setup, so delay the
+ * stop & clear.
+ */
+ AioContext *ctx = qemu_get_current_aio_context();
+ VhostAsyncCallback *data = g_new0(VhostAsyncCallback, 1);
+
+ /* Save data for the callback */
+ data->cb = cb;
+ data->dev = d;
+ data->cd = chardev;
+ data->vhost = vhost;
+
+ /* Disable any further notifications on the chardev */
+ qemu_chr_fe_set_handlers(chardev,
+ NULL, NULL, NULL, NULL, NULL, NULL,
+ false);
+
+ aio_bh_schedule_oneshot(ctx, vhost_user_async_close_bh, data);
+
+ /*
+ * Move vhost device to the stopped state. The vhost-user device
+ * will be clean up and disconnected in BH. This can be useful in
+ * the vhost migration code. If disconnect was caught there is an
+ * option for the general vhost code to get the dev state without
+ * knowing its type (in this case vhost-user).
+ *
+ * Note if the vhost device is fully cleared by the time we
+ * execute the bottom half we won't continue with the cleanup.
+ */
+ vhost->started = false;
+ }
+}
+
static int vhost_user_dev_start(struct vhost_dev *dev, bool started)
{
if (!virtio_has_feature(dev->protocol_features,