Re: [Xen-devel] [PATCH pvops] Fix a bug that shutdown watcher is disabled on pvops

[Frank Pan <frankpzh@xxxxxxxxx>]

> Is the issue you are seeing perhaps due to this patch being missing from
> that tree?
>
> commit a947f0f8f7012a5e8689a9cff7209ec6964ec154
> Author: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> Date: Â Mon Oct 4 16:10:06 2010 +0100
>
> Â Âxen: do not set xenstored_ready before xenbus_probe on hvm

> Stefano's "2.6.38-rc6-pvhvm" branch also contains this which looks
> related:
>
> commit 702d4eb9b3de4398ab99cf0a4e799e552c7ab756
> Author: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> Date: Â Thu Dec 2 17:54:50 2010 +0000
>
> Â Âxen: no need to delay xen_setup_shutdown_event for hvm guests anymore

FP: Yes, both commits seem like a solution of the issue I met.

> If possible we should prefer to backport patches from newer kernels
> rather than diverge in the 2.6.32 branch.

FP: The former commit seems ok. The latter one is more like a cleanup.
Here is a patch can be applied on xen/next-2.6.32:

---
 linux-2.6-xen/drivers/xen/xenbus/xenbus_probe.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/linux-2.6-xen/drivers/xen/xenbus/xenbus_probe.c
b/linux-2.6-xen/drivers/xen/xenbus/xenbus_probe.c
index 3a83ba2..f368db9 100644
--- a/linux-2.6-xen/drivers/xen/xenbus/xenbus_probe.c
+++ b/linux-2.6-xen/drivers/xen/xenbus/xenbus_probe.c
@@ -646,7 +646,10 @@ int register_xenstore_notifier(struct notifier_block *nb)
 {
        int ret = 0;

-       blocking_notifier_chain_register(&xenstore_chain, nb);
+       if (xenstored_ready > 0)
+               ret = nb->notifier_call(nb, 0, NULL);
+       else
+               blocking_notifier_chain_register(&xenstore_chain, nb);

        return ret;
 }
@@ -660,7 +663,7 @@ EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);

 void xenbus_probe(struct work_struct *unused)
 {
-       BUG_ON((xenstored_ready <= 0));
+       xenstored_ready = 1;

        /* Notify others that xenstore is up */
        blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
@@ -722,7 +725,6 @@ static int __init xenbus_init(void)

                xen_store_interface = mfn_to_virt(xen_store_mfn);
        } else {
-               xenstored_ready = 1;
                if (xen_hvm_domain()) {
                        uint64_t v = 0;
                        err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
@@ -738,6 +740,7 @@ static int __init xenbus_init(void)
                        xen_store_evtchn = xen_start_info->store_evtchn;
                        xen_store_mfn = xen_start_info->store_mfn;
                        xen_store_interface = mfn_to_virt(xen_store_mfn);
+                       xenstored_ready = 1;
                }
        }

-- 
1.7.0.4


-- 
æéç, Frank Pan

Computer Science and Technology
Tsinghua University

Attachment: 0001-xen-do-not-set-xenstored_ready-before-xenbus_probe-o.patch
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