This patch changes the vcpu-hotplug handler from using control message
over to using xenstore for triggers. Dropping the control messages also
fixes the issue with not being able to use xm vcpu-hotplug on dom0.
This patch depends in Dan Smith's [1]fix.
1. http://lists.xensource.com/archives/html/xen-devel/2005-08/msg00262.html
--
Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
(512) 838-9253 T/L: 678-9253
ryanh@xxxxxxxxxx
diffstat output:
linux-2.6-xen-sparse/arch/xen/i386/kernel/smpboot.c | 195 ++++++++++++--------
tools/python/xen/xend/XendDomainInfo.py | 33 ++-
2 files changed, 148 insertions(+), 80 deletions(-)
Signed-off-by: Ryan Harper <ryanh@xxxxxxxxxx>
---
diff -r b63577ff53a3 linux-2.6-xen-sparse/arch/xen/i386/kernel/smpboot.c
--- a/linux-2.6-xen-sparse/arch/xen/i386/kernel/smpboot.c Fri Aug 5
14:57:43 2005
+++ b/linux-2.6-xen-sparse/arch/xen/i386/kernel/smpboot.c Fri Aug 5
13:03:31 2005
@@ -1324,14 +1324,132 @@
}
#ifdef CONFIG_HOTPLUG_CPU
-#include <asm-xen/ctrl_if.h>
-
+#include <asm-xen/xenbus.h>
/* hotplug down/up funtion pointer and target vcpu */
struct vcpu_hotplug_handler_t {
- void (*fn)(int vcpu);
+ void (*fn) (int vcpu);
u32 vcpu;
};
static struct vcpu_hotplug_handler_t vcpu_hotplug_handler;
+
+static int vcpu_hotplug_cpu_process(void *unused)
+{
+ struct vcpu_hotplug_handler_t *handler = &vcpu_hotplug_handler;
+
+ if (handler->fn) {
+ (*(handler->fn)) (handler->vcpu);
+ handler->fn = NULL;
+ }
+ return 0;
+}
+
+static void __vcpu_hotplug_handler(void *unused)
+{
+ int err;
+
+ err = kernel_thread(vcpu_hotplug_cpu_process,
+ NULL, CLONE_FS | CLONE_FILES);
+ if (err < 0)
+ printk(KERN_ALERT "Error creating hotplug_cpu process!\n");
+}
+
+static void handle_cpus_watch(struct xenbus_watch *, const char *);
+static struct notifier_block xsn_cpus;
+
+/* xenbus watch struct */
+static struct xenbus_watch cpus_watch = {
+ .node = "cpus",
+ .callback = handle_cpus_watch,
+};
+
+static int setup_cpus_watcher(struct notifier_block *notifier,
+ unsigned long event, void *data)
+{
+ int err = 0;
+
+ down(&xenbus_lock);
+ err = register_xenbus_watch(&cpus_watch);
+ up(&xenbus_lock);
+
+ if (err) {
+ printk("Failed to set cpus watcher\n");
+ }
+ return NOTIFY_DONE;
+}
+
+static void handle_cpus_watch(struct xenbus_watch *watch, const char *node)
+{
+ static DECLARE_WORK(vcpu_hotplug_work, __vcpu_hotplug_handler, NULL);
+ struct vcpu_hotplug_handler_t *handler = &vcpu_hotplug_handler;
+ ssize_t ret;
+ int err, cpu, state;
+ char dir[32];
+ char *cpustr;
+
+ /* get a pointer to start of cpus/cpu string */
+ if ((cpustr = strstr(node, "cpus/cpu")) != NULL) {
+
+ /* find which cpu state changed, note vcpu for handler */
+ sscanf(cpustr, "cpus/cpu%d", &cpu);
+ handler->vcpu = cpu;
+
+ /* calc the dir for xenbus read */
+ sprintf(dir, "cpus/cpu%d", cpu);
+
+ /* make sure watch that was triggered is changes to the online
key */
+ if ((strcmp(node + strlen(dir), "/online")) != 0)
+ return;
+
+ /* get the state value */
+ xenbus_transaction_start("cpus");
+ err = xenbus_scanf(dir, "online", "%d", &state);
+ xenbus_transaction_end(0);
+
+ if (err != 1) {
+ printk(KERN_ERR
+ "XENBUS: Unable to read cpu online state\n");
+ return;
+ }
+
+ /* if we detect a state change, take action */
+ switch (state) {
+ /* offline -> online */
+ case 1:
+ if (!cpu_isset(cpu, cpu_online_map)) {
+ handler->fn = (void *)&cpu_up;
+ ret = schedule_work(&vcpu_hotplug_work);
+ }
+ break;
+ /* online -> offline */
+ case 0:
+ if (cpu_isset(cpu, cpu_online_map)) {
+ handler->fn = (void *)&cpu_down;
+ ret = schedule_work(&vcpu_hotplug_work);
+ }
+ break;
+ default:
+ printk(KERN_ERR
+ "XENBUS: unknown state(%d) on node(%s)\n", state,
+ node);
+ }
+ }
+ return;
+}
+
+static int __init setup_vcpu_hotplug_event(void)
+{
+ xsn_cpus.notifier_call = setup_cpus_watcher;
+
+ if (xen_start_info.store_evtchn) {
+ setup_cpus_watcher(&xsn_cpus, 0, NULL);
+ } else {
+ register_xenstore_notifier(&xsn_cpus);
+ }
+
+ return 0;
+}
+
+subsys_initcall(setup_vcpu_hotplug_event);
/* must be called with the cpucontrol mutex held */
static int __devinit cpu_enable(unsigned int cpu)
@@ -1401,77 +1519,6 @@
printk(KERN_ERR "CPU %u didn't die...\n", cpu);
}
-static int vcpu_hotplug_cpu_process(void *unused)
-{
- struct vcpu_hotplug_handler_t *handler = &vcpu_hotplug_handler;
-
- if (handler->fn) {
- (*(handler->fn))(handler->vcpu);
- handler->fn = NULL;
- }
- return 0;
-}
-
-static void __vcpu_hotplug_handler(void *unused)
-{
- int err;
-
- err = kernel_thread(vcpu_hotplug_cpu_process,
- NULL, CLONE_FS | CLONE_FILES);
- if (err < 0)
- printk(KERN_ALERT "Error creating hotplug_cpu process!\n");
-
-}
-
-static void vcpu_hotplug_event_handler(ctrl_msg_t *msg, unsigned long id)
-{
- static DECLARE_WORK(vcpu_hotplug_work, __vcpu_hotplug_handler, NULL);
- vcpu_hotplug_t *req = (vcpu_hotplug_t *)&msg->msg[0];
- struct vcpu_hotplug_handler_t *handler = &vcpu_hotplug_handler;
- ssize_t ret;
-
- if (msg->length != sizeof(vcpu_hotplug_t))
- goto parse_error;
-
- /* grab target vcpu from msg */
- handler->vcpu = req->vcpu;
-
- /* determine which function to call based on msg subtype */
- switch (msg->subtype) {
- case CMSG_VCPU_HOTPLUG_OFF:
- handler->fn = (void *)&cpu_down;
- ret = schedule_work(&vcpu_hotplug_work);
- req->status = (u32) ret;
- break;
- case CMSG_VCPU_HOTPLUG_ON:
- handler->fn = (void *)&cpu_up;
- ret = schedule_work(&vcpu_hotplug_work);
- req->status = (u32) ret;
- break;
- default:
- goto parse_error;
- }
-
- ctrl_if_send_response(msg);
- return;
- parse_error:
- msg->length = 0;
- ctrl_if_send_response(msg);
-}
-
-static int __init setup_vcpu_hotplug_event(void)
-{
- struct vcpu_hotplug_handler_t *handler = &vcpu_hotplug_handler;
-
- handler->fn = NULL;
- ctrl_if_register_receiver(CMSG_VCPU_HOTPLUG,
- vcpu_hotplug_event_handler, 0);
-
- return 0;
-}
-
-__initcall(setup_vcpu_hotplug_event);
-
#else /* ... !CONFIG_HOTPLUG_CPU */
int __cpu_disable(void)
{
diff -r b63577ff53a3 tools/python/xen/xend/XendDomainInfo.py
--- a/tools/python/xen/xend/XendDomainInfo.py Fri Aug 5 14:57:43 2005
+++ b/tools/python/xen/xend/XendDomainInfo.py Fri Aug 5 13:03:31 2005
@@ -266,6 +266,7 @@
self.restart_count = 0
self.vcpus = 1
+ self.vcpusdb = {}
self.bootloader = None
def setDB(self, db):
@@ -547,6 +548,16 @@
except:
raise VmError('invalid vcpus value')
+ def exportVCPUSToDB(self, vcpus):
+ for v in range(0,vcpus):
+ path = "/cpus/cpu%d"%(v)
+ if not self.vcpusdb.has_key(path):
+ self.vcpusdb[path] = self.db.addChild(path)
+ db = self.vcpusdb[path]
+ log.debug("writing key online=1 to path %s in store"%(path))
+ db['online'] = "1"
+ db.saveDB(save=True)
+
def init_image(self):
"""Create boot image handler for the domain.
"""
@@ -565,6 +576,8 @@
self.db.introduceDomain(self.id,
self.store_mfn,
self.store_channel)
+ # get the configured value of vcpus and update store
+ self.exportVCPUSToDB(self.vcpus)
def delete(self):
"""Delete the vm's db.
@@ -929,14 +942,20 @@
def vcpu_hotplug(self, vcpu, state):
"""Disable or enable VCPU in domain.
"""
- log.error("Holly Shit! %d %d\n" % (vcpu, state))
- if self.channel:
+ db = ""
+ try:
+ db = self.vcpusdb['/cpus/cpu%d'%(vcpu)]
+ except:
+ log.error("Invalid VCPU")
+ return
+
+ if self.store_channel:
if int(state) == 0:
- msg = messages.packMsg('vcpu_hotplug_off_t', { 'vcpu' : vcpu} )
+ db['online'] = "0"
else:
- msg = messages.packMsg('vcpu_hotplug_on_t', { 'vcpu' : vcpu} )
-
- self.channel.writeRequest(msg)
+ db['online'] = "1"
+
+ db.saveDB(save=True)
def shutdown(self, reason):
reasonid = shutdown_codes.get(reason)
@@ -966,6 +985,8 @@
self.db.introduceDomain(self.id, self.store_mfn,
self.store_channel)
self.exportToDB(save=True, sync=True)
+ # get run-time value of vcpus and update store
+ self.exportVCPUSToDB(dom_get(self.id)['vcpus'])
def vm_field_ignore(vm, config, val, index):
"""Dummy config field handler used for fields with built-in handling.
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