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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 3/3] [linux-2.6.18-xen.hg] delay xenbus init if xenbus master is a separate domain
This patch modifies xenbus to lazily initialize. This is necessary when
xenstored is running in a seperate minios domain, since it can't connect as a
slave just yet.
Ian Campbell has looked at an earlier version of this patch, and seems
to generally approve.
Here's an explanation of the states:
It starts out in XENBUS_XSD_UNCOMMITTED.
As the master xenbus (the one local to xenstored), it will receive an
mmap from xenstore, putting it in XENBUS_XSD_LOCAL_INIT. This enables
the wake_waiting IRQ, which will put it in XENBUS_XSD_LOCAL_READY.
Alternatively, as a slave xenbus, it will receive an ioctl from the
xenstore domain builder, putting it in XENBUS_XSD_FOREIGN_INIT. This
enables the wake_waiting IRQ, which will put it in
XENBUS_XSD_FOREIGN_READY.
DomU's are immediately initialized to XENBUS_XSD_FOREIGN_READY.
TODO: The types in the IOCTL might not be correct.
Signed-off-by: Diego Ongaro <diego.ongaro@xxxxxxxxxx>
Signed-off-by: Alex Zeffertt <alex.zeffertt@xxxxxxxxxxxxx>
---
diff -r e68a58170585 drivers/xen/core/xen_sysfs.c
--- a/drivers/xen/core/xen_sysfs.c Mon Mar 16 17:02:03 2009 +0000
+++ b/drivers/xen/core/xen_sysfs.c Thu Mar 19 10:46:26 2009 +0000
@@ -16,6 +16,7 @@
#include <xen/hypervisor_sysfs.h>
#include <xen/xenbus.h>
#include <xen/interface/kexec.h>
+#include "../xenbus/xenbus_comms.h"
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mike D. Day <ncmike@xxxxxxxxxx>");
@@ -105,9 +106,8 @@
{
char *vm, *val;
int ret;
- extern int xenstored_ready;
- if (!xenstored_ready)
+ if (!is_xenstored_ready())
return -EBUSY;
vm = xenbus_read(XBT_NIL, "vm", "", NULL);
diff -r e68a58170585 drivers/xen/xenbus/xenbus_comms.c
--- a/drivers/xen/xenbus/xenbus_comms.c Mon Mar 16 17:02:03 2009 +0000
+++ b/drivers/xen/xenbus/xenbus_comms.c Thu Mar 19 10:46:26 2009 +0000
@@ -50,18 +50,39 @@
static int xenbus_irq;
extern void xenbus_probe(void *);
-extern int xenstored_ready;
static DECLARE_WORK(probe_work, xenbus_probe, NULL);
static DECLARE_WAIT_QUEUE_HEAD(xb_waitq);
static irqreturn_t wake_waiting(int irq, void *unused, struct pt_regs *regs)
{
- if (unlikely(xenstored_ready == 0)) {
- xenstored_ready = 1;
- schedule_work(&probe_work);
+ int old, new;
+
+ old = atomic_read(&xenbus_xsd_state);
+ switch (old) {
+ case XENBUS_XSD_UNCOMMITTED:
+ BUG();
+ return IRQ_HANDLED;
+
+ case XENBUS_XSD_FOREIGN_INIT:
+ new = XENBUS_XSD_FOREIGN_READY;
+ break;
+
+ case XENBUS_XSD_LOCAL_INIT:
+ new = XENBUS_XSD_LOCAL_READY;
+ break;
+
+ case XENBUS_XSD_FOREIGN_READY:
+ case XENBUS_XSD_LOCAL_READY:
+ default:
+ goto wake;
}
+ old = atomic_cmpxchg(&xenbus_xsd_state, old, new);
+ if (old != new)
+ schedule_work(&probe_work);
+
+wake:
wake_up(&xb_waitq);
return IRQ_HANDLED;
}
diff -r e68a58170585 drivers/xen/xenbus/xenbus_comms.h
--- a/drivers/xen/xenbus/xenbus_comms.h Mon Mar 16 17:02:03 2009 +0000
+++ b/drivers/xen/xenbus/xenbus_comms.h Thu Mar 19 10:46:26 2009 +0000
@@ -43,4 +43,20 @@
extern struct xenstore_domain_interface *xen_store_interface;
extern int xen_store_evtchn;
+/* For xenbus internal use. */
+enum {
+ XENBUS_XSD_UNCOMMITTED = 0,
+ XENBUS_XSD_FOREIGN_INIT,
+ XENBUS_XSD_FOREIGN_READY,
+ XENBUS_XSD_LOCAL_INIT,
+ XENBUS_XSD_LOCAL_READY,
+};
+extern atomic_t xenbus_xsd_state;
+
+static inline int is_xenstored_ready(void)
+{
+ int s = atomic_read(&xenbus_xsd_state);
+ return s == XENBUS_XSD_FOREIGN_READY || s == XENBUS_XSD_LOCAL_READY;
+}
+
#endif /* _XENBUS_COMMS_H */
diff -r e68a58170585 drivers/xen/xenbus/xenbus_dev.c
--- a/drivers/xen/xenbus/xenbus_dev.c Mon Mar 16 17:02:03 2009 +0000
+++ b/drivers/xen/xenbus/xenbus_dev.c Thu Mar 19 10:46:26 2009 +0000
@@ -53,6 +53,8 @@
#include <xen/platform-compat.h>
#endif
+#include <xen/public/xenbus.h>
+
struct xenbus_dev_transaction {
struct list_head list;
struct xenbus_transaction handle;
@@ -95,6 +97,9 @@
struct xenbus_dev_data *u = filp->private_data;
struct read_buffer *rb;
int i, ret;
+
+ if (!is_xenstored_ready())
+ return -ENODEV;
mutex_lock(&u->reply_mutex);
while (list_empty(&u->read_buffers)) {
@@ -205,6 +210,9 @@
char *path, *token;
struct watch_adapter *watch, *tmp_watch;
int err, rc = len;
+
+ if (!is_xenstored_ready())
+ return -ENODEV;
if ((len + u->len) > sizeof(u->u.buffer)) {
rc = -EINVAL;
@@ -391,10 +399,63 @@
{
struct xenbus_dev_data *u = file->private_data;
+ if (!is_xenstored_ready())
+ return -ENODEV;
+
poll_wait(file, &u->read_waitq, wait);
if (!list_empty(&u->read_buffers))
return POLLIN | POLLRDNORM;
return 0;
+}
+
+static long xenbus_dev_ioctl(struct file *file,
+ unsigned int cmd, unsigned long data)
+{
+ extern int xenbus_conn(domid_t remote_dom, int *grant_ref,
+ evtchn_port_t *local_port);
+ void __user *udata = (void __user *) data;
+ int ret = -ENOTTY;
+
+ if (!is_initial_xendomain())
+ return -ENODEV;
+
+
+ switch (cmd) {
+ case IOCTL_XENBUS_ALLOC: {
+ xenbus_alloc_t xa;
+ int old;
+
+ old = atomic_cmpxchg(&xenbus_xsd_state,
+ XENBUS_XSD_UNCOMMITTED,
+ XENBUS_XSD_FOREIGN_INIT);
+ if (old != XENBUS_XSD_UNCOMMITTED)
+ return -EBUSY;
+
+ if (copy_from_user(&xa, udata, sizeof(xa))) {
+ ret = -EFAULT;
+ atomic_set(&xenbus_xsd_state, XENBUS_XSD_UNCOMMITTED);
+ break;
+ }
+
+ ret = xenbus_conn(xa.dom, &xa.grant_ref, &xa.port);
+ if (ret != 0) {
+ atomic_set(&xenbus_xsd_state, XENBUS_XSD_UNCOMMITTED);
+ break;
+ }
+
+ if (copy_to_user(udata, &xa, sizeof(xa))) {
+ ret = -EFAULT;
+ atomic_set(&xenbus_xsd_state, XENBUS_XSD_UNCOMMITTED);
+ break;
+ }
+ }
+ break;
+
+ default:
+ break;
+ }
+
+ return ret;
}
static const struct file_operations xenbus_dev_file_ops = {
@@ -403,6 +464,7 @@
.open = xenbus_dev_open,
.release = xenbus_dev_release,
.poll = xenbus_dev_poll,
+ .unlocked_ioctl = xenbus_dev_ioctl
};
int xenbus_dev_init(void)
diff -r e68a58170585 drivers/xen/xenbus/xenbus_probe.c
--- a/drivers/xen/xenbus/xenbus_probe.c Mon Mar 16 17:02:03 2009 +0000
+++ b/drivers/xen/xenbus/xenbus_probe.c Thu Mar 19 10:46:26 2009 +0000
@@ -44,6 +44,7 @@
#include <linux/notifier.h>
#include <linux/mutex.h>
#include <linux/module.h>
+#include <xen/gnttab.h>
#include <asm/io.h>
#include <asm/page.h>
@@ -347,7 +348,12 @@
DPRINTK("%s", dev->nodename);
+/* Commented out since xenstored stubdom is now minios based not linux based
+#define XENSTORE_DOMAIN_SHARES_THIS_KERNEL
+*/
+#ifndef XENSTORE_DOMAIN_SHARES_THIS_KERNEL
if (is_initial_xendomain())
+#endif
return;
get_device(&dev->dev);
@@ -820,14 +826,13 @@
EXPORT_SYMBOL_GPL(xenbus_suspend_cancel);
/* A flag to determine if xenstored is 'ready' (i.e. has started) */
-int xenstored_ready = 0;
-
+atomic_t xenbus_xsd_state = ATOMIC_INIT(XENBUS_XSD_UNCOMMITTED);
int register_xenstore_notifier(struct notifier_block *nb)
{
int ret = 0;
- if (xenstored_ready > 0)
+ if (is_xenstored_ready())
ret = nb->notifier_call(nb, 0, NULL);
else
blocking_notifier_chain_register(&xenstore_chain, nb);
@@ -845,7 +850,7 @@
void xenbus_probe(void *unused)
{
- BUG_ON((xenstored_ready <= 0));
+ BUG_ON(!is_xenstored_ready());
/* Enumerate devices in xenstore and watch for changes. */
xenbus_probe_devices(&xenbus_frontend);
@@ -865,6 +870,28 @@
static int xsd_kva_mmap(struct file *file, struct vm_area_struct *vma)
{
size_t size = vma->vm_end - vma->vm_start;
+ int old;
+ int rc;
+
+ old = atomic_cmpxchg(&xenbus_xsd_state,
+ XENBUS_XSD_UNCOMMITTED,
+ XENBUS_XSD_LOCAL_INIT);
+ switch (old) {
+ case XENBUS_XSD_UNCOMMITTED:
+ rc = xb_init_comms();
+ if (rc != 0)
+ return rc;
+ break;
+
+ case XENBUS_XSD_FOREIGN_INIT:
+ case XENBUS_XSD_FOREIGN_READY:
+ return -EBUSY;
+
+ case XENBUS_XSD_LOCAL_INIT:
+ case XENBUS_XSD_LOCAL_READY:
+ default:
+ break;
+ }
if ((size > PAGE_SIZE) || (vma->vm_pgoff != 0))
return -EINVAL;
@@ -896,6 +923,62 @@
return len;
}
#endif
+
+static int xb_free_port(evtchn_port_t port)
+{
+ struct evtchn_close close;
+ close.port = port;
+ return HYPERVISOR_event_channel_op(EVTCHNOP_close, &close);
+}
+
+int xenbus_conn(domid_t remote_dom, unsigned long *grant_ref, evtchn_port_t
*local_port)
+{
+ struct evtchn_alloc_unbound alloc_unbound;
+ int rc, rc2;
+
+ BUG_ON(atomic_read(&xenbus_xsd_state) != XENBUS_XSD_FOREIGN_INIT);
+ BUG_ON(!is_initial_xendomain());
+
+#if defined(CONFIG_PROC_FS) && defined(CONFIG_XEN_PRIVILEGED_GUEST)
+ remove_xen_proc_entry("xsd_kva");
+ remove_xen_proc_entry("xsd_port");
+#endif
+
+ rc = xb_free_port(xen_store_evtchn);
+ if (rc != 0)
+ goto fail0;
+
+ alloc_unbound.dom = DOMID_SELF;
+ alloc_unbound.remote_dom = remote_dom;
+ rc = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
+ &alloc_unbound);
+ if (rc != 0)
+ goto fail0;
+ *local_port = xen_store_evtchn = alloc_unbound.port;
+
+ /* keep the old page (xen_store_mfn, xen_store_interface) */
+ rc = gnttab_grant_foreign_access(remote_dom, xen_store_mfn,
+ GTF_permit_access);
+ if (rc < 0)
+ goto fail1;
+ *grant_ref = rc;
+
+ rc = xb_init_comms();
+ if (rc != 0)
+ goto fail1;
+
+ return 0;
+
+fail1:
+ rc2 = xb_free_port(xen_store_evtchn);
+ if (rc2 != 0)
+ printk(KERN_WARNING
+ "XENBUS: Error freeing xenstore event channel: %d\n",
+ rc2);
+fail0:
+ xen_store_evtchn = -1;
+ return rc;
+}
static int xenbus_probe_init(void)
{
@@ -958,7 +1041,7 @@
#endif
xen_store_interface = mfn_to_virt(xen_store_mfn);
} else {
- xenstored_ready = 1;
+ atomic_set(&xenbus_xsd_state, XENBUS_XSD_FOREIGN_READY);
#ifdef CONFIG_XEN
xen_store_evtchn = xen_start_info->store_evtchn;
xen_store_mfn = xen_start_info->store_mfn;
@@ -969,8 +1052,11 @@
xen_store_interface = ioremap(xen_store_mfn << PAGE_SHIFT,
PAGE_SIZE);
#endif
+ /* Initialize the shared memory rings to talk to xenstored */
+ err = xb_init_comms();
+ if (err)
+ goto err;
}
-
xenbus_dev_init();
diff -r e68a58170585 drivers/xen/xenbus/xenbus_xs.c
--- a/drivers/xen/xenbus/xenbus_xs.c Mon Mar 16 17:02:03 2009 +0000
+++ b/drivers/xen/xenbus/xenbus_xs.c Thu Mar 19 10:46:26 2009 +0000
@@ -872,7 +872,6 @@
int xs_init(void)
{
- int err;
struct task_struct *task;
INIT_LIST_HEAD(&xs_state.reply_list);
@@ -883,11 +882,6 @@
mutex_init(&xs_state.response_mutex);
init_rwsem(&xs_state.transaction_mutex);
init_rwsem(&xs_state.watch_mutex);
-
- /* Initialize the shared memory rings to talk to xenstored */
- err = xb_init_comms();
- if (err)
- return err;
task = kthread_run(xenwatch_thread, NULL, "xenwatch");
if (IS_ERR(task))
diff -r e68a58170585 include/xen/public/xenbus.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/include/xen/public/xenbus.h Thu Mar 19 10:46:26 2009 +0000
@@ -0,0 +1,56 @@
+/******************************************************************************
+ * xenbus.h
+ *
+ * Interface to /proc/xen/xenbus.
+ *
+ * Copyright (c) 2008, Diego Ongaro <diego.ongaro@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef __LINUX_PUBLIC_XENBUS_H__
+#define __LINUX_PUBLIC_XENBUS_H__
+
+#include <linux/types.h>
+
+#ifndef __user
+#define __user
+#endif
+
+typedef struct xenbus_alloc {
+ domid_t dom;
+ __u32 port;
+ __u32 grant_ref;
+} xenbus_alloc_t;
+
+/*
+ * @cmd: IOCTL_XENBUS_ALLOC
+ * @arg: &xenbus_alloc_t
+ * Return: 0, or -1 for error
+ */
+#define IOCTL_XENBUS_ALLOC \
+ _IOC(_IOC_NONE, 'X', 0, sizeof(xenbus_alloc_t))
+
+#endif /* __LINUX_PUBLIC_XENBUS_H__ */
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