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hw/virtio: generalise CHR_EVENT_CLOSED handling

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..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>
This commit is contained in:
Alex Bennée 2022-11-30 11:24:38 +00:00 • committed by Michael S. Tsirkin
parent 060f4a9440
commit 71e076a07d
4 changed files with 104 additions and 37 deletions
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71
hw/virtio/vhost-user.c
View file

@ -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,