diff options
author | Alex Bennée <alex.bennee@linaro.org> | 2022-11-30 11:24:38 +0000 |
---|---|---|
committer | Michael S. Tsirkin <mst@redhat.com> | 2022-12-01 02:30:13 -0500 |
commit | 71e076a07dc195129fe25d90d4b276be3b2f12d8 (patch) | |
tree | ede68f35ad6fd8c5a9e785c01dbca02a76a92a98 /hw/virtio | |
parent | 060f4a944072ecf37cece0f16a0609babfb679b8 (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.c | 11 | ||||
-rw-r--r-- | hw/virtio/vhost-user.c | 71 |
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, |