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Message-Id: <20190220201609.28290-20-joao.m.martins@oracle.com>
Date: Wed, 20 Feb 2019 20:15:49 +0000
From: Joao Martins <joao.m.martins@...cle.com>
To: kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
xen-devel@...ts.xenproject.org
Cc: Ankur Arora <ankur.a.arora@...cle.com>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Joao Martins <joao.m.martins@...cle.com>,
Paolo Bonzini <pbonzini@...hat.com>,
Radim Krčmář <rkrcmar@...hat.com>,
Juergen Gross <jgross@...e.com>,
Stefano Stabellini <sstabellini@...nel.org>
Subject: [PATCH RFC 19/39] xen/xenbus: xenbus uninit support
This allows reinitialization of xenbus which is useful for
xen_shim_domain() support. Cleaning xenbus state means cancelling
pending watch events, and deleting all watches, closing xenstore event
channel and finally stopping xenbus/xenwatch kthreads alongside
unregistering /proc/xen.
Signed-off-by: Joao Martins <joao.m.martins@...cle.com>
---
drivers/xen/xenbus/xenbus.h | 2 ++
drivers/xen/xenbus/xenbus_client.c | 5 ++++
drivers/xen/xenbus/xenbus_probe.c | 51 +++++++++++++++++++++++++++++++++++---
drivers/xen/xenbus/xenbus_xs.c | 38 ++++++++++++++++++++++++++++
4 files changed, 93 insertions(+), 3 deletions(-)
diff --git a/drivers/xen/xenbus/xenbus.h b/drivers/xen/xenbus/xenbus.h
index 092981171df1..e0e586d81d48 100644
--- a/drivers/xen/xenbus/xenbus.h
+++ b/drivers/xen/xenbus/xenbus.h
@@ -96,6 +96,7 @@ extern wait_queue_head_t xb_waitq;
extern struct mutex xb_write_mutex;
int xs_init(void);
+void xs_deinit(void);
int xb_init_comms(void);
void xb_deinit_comms(void);
int xs_watch_msg(struct xs_watch_event *event);
@@ -129,6 +130,7 @@ int xenbus_read_otherend_details(struct xenbus_device *xendev,
char *id_node, char *path_node);
void xenbus_ring_ops_init(void);
+void xenbus_ring_ops_deinit(void);
int xenbus_dev_request_and_reply(struct xsd_sockmsg *msg, void *par);
void xenbus_dev_queue_reply(struct xb_req_data *req);
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index e17ca8156171..ada1c9aa6525 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -935,3 +935,8 @@ void __init xenbus_ring_ops_init(void)
#endif
ring_ops = &ring_ops_hvm;
}
+
+void xenbus_ring_ops_deinit(void)
+{
+ ring_ops = NULL;
+}
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index 5b471889d723..2e0ed46b05e7 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -741,6 +741,21 @@ static int __init xenstored_local_init(void)
return err;
}
+static void xenstored_local_deinit(void)
+{
+ struct evtchn_close close;
+ void *page = NULL;
+
+ page = gfn_to_virt(xen_store_gfn);
+ free_page((unsigned long)page);
+
+ close.port = xen_store_evtchn;
+
+ HYPERVISOR_event_channel_op(EVTCHNOP_close, &close);
+
+ xen_store_evtchn = 0;
+}
+
static int xenbus_resume_cb(struct notifier_block *nb,
unsigned long action, void *data)
{
@@ -765,7 +780,11 @@ static struct notifier_block xenbus_resume_nb = {
.notifier_call = xenbus_resume_cb,
};
-static int __init xenbus_init(void)
+#ifdef CONFIG_XEN_COMPAT_XENFS
+struct proc_dir_entry *xen_procfs;
+#endif
+
+int xenbus_init(void)
{
int err = 0;
uint64_t v = 0;
@@ -833,13 +852,39 @@ static int __init xenbus_init(void)
* Create xenfs mountpoint in /proc for compatibility with
* utilities that expect to find "xenbus" under "/proc/xen".
*/
- proc_create_mount_point("xen");
+ xen_procfs = proc_create_mount_point("xen");
#endif
out_error:
return err;
}
-
+EXPORT_SYMBOL_GPL(xenbus_init);
postcore_initcall(xenbus_init);
+void xenbus_deinit(void)
+{
+ if (!xen_domain())
+ return;
+
+#ifdef CONFIG_XEN_COMPAT_XENFS
+ proc_remove(xen_procfs);
+ xen_procfs = NULL;
+#endif
+
+ xs_deinit();
+ xenstored_ready = 0;
+
+ switch (xen_store_domain_type) {
+ case XS_LOCAL:
+ xenstored_local_deinit();
+ xen_store_interface = NULL;
+ break;
+ default:
+ pr_warn("Xenstore state unknown\n");
+ break;
+ }
+ xenbus_ring_ops_deinit();
+}
+EXPORT_SYMBOL_GPL(xenbus_deinit);
+
MODULE_LICENSE("GPL");
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index 49a3874ae6bb..bd6db3703972 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -866,6 +866,7 @@ static int xenwatch_thread(void *unused)
for (;;) {
wait_event_interruptible(watch_events_waitq,
+ kthread_should_stop() ||
!list_empty(&watch_events));
if (kthread_should_stop())
@@ -917,6 +918,8 @@ static struct notifier_block xs_reboot_nb = {
.notifier_call = xs_reboot_notify,
};
+static struct task_struct *xenwatch_task;
+
int xs_init(void)
{
int err;
@@ -932,9 +935,44 @@ int xs_init(void)
task = kthread_run(xenwatch_thread, NULL, "xenwatch");
if (IS_ERR(task))
return PTR_ERR(task);
+ xenwatch_task = task;
/* shutdown watches for kexec boot */
xs_reset_watches();
return 0;
}
+
+void cancel_watches(void)
+{
+ struct xs_watch_event *event, *tmp;
+
+ /* Cancel pending watch events. */
+ spin_lock(&watch_events_lock);
+ list_for_each_entry_safe(event, tmp, &watch_events, list) {
+ list_del(&event->list);
+ kfree(event);
+ }
+ spin_unlock(&watch_events_lock);
+}
+
+void delete_watches(void)
+{
+ struct xenbus_watch *watch, *tmp;
+
+ spin_lock(&watches_lock);
+ list_for_each_entry_safe(watch, tmp, &watches, list) {
+ list_del(&watch->list);
+ }
+ spin_unlock(&watches_lock);
+}
+
+void xs_deinit(void)
+{
+ kthread_stop(xenwatch_task);
+ xenwatch_task = NULL;
+ xb_deinit_comms();
+ unregister_reboot_notifier(&xs_reboot_nb);
+ cancel_watches();
+ delete_watches();
+}
--
2.11.0
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