xenbus call too early?

xenbus call too early?

[Dan Magenheimer]

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I added a xenbus_printk call that causes boot to fail,
I suspect because I am calling it before xenbus is up
and working.  (Same code works fine if called later.)

Is there a function that does is_xenbus_ready()?
If not, what's the best way to do the equivalent?

Thanks,
Dan

===================================
If Xen could save time in a bottle / then clocks wouldn't virtually skew /
It would save every tick / for VMs that aren't quick /
and Xen then would send them anew
(with apologies to the late great Jim Croce)

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Re: xenbus call too early?

[Samuel Thibault]

Hello,

Dan Magenheimer, le Fri 02 May 2008 10:13:55 -0600, a écrit :
> I added a xenbus_printk call that causes boot to fail,
> I suspect because I am calling it before xenbus is up
> and working.
> 
> (Same code works fine if called later.)
> 
> Is there a function that does is_xenbus_ready()?
> If not, what's the best way to do the equivalent?

There apparently is a xenstored_ready variable.

Samuel

RE: xenbus call too early?

[Dan Magenheimer]

> Dan Magenheimer, le Fri 02 May 2008 10:13:55 -0600, a écrit :
> > I added a xenbus_printk call that causes boot to fail,
> > I suspect because I am calling it before xenbus is up
> > and working.
> >
> > (Same code works fine if called later.)
> >
> > Is there a function that does is_xenbus_ready()?
> > If not, what's the best way to do the equivalent?
> 
> There apparently is a xenstored_ready variable.

Thanks, but hmmm..., it doesn't look like this is accessed
anywhere, nor is it EXPORTed so it wouldn't be accessible
from a module.

>From more code reading, I'm guessing the right way to do
this is to key off of a xenstore_notifier call which
can set the local static equivalent of xenstored_ready.
True?

Thanks,
Dan

Re: xenbus call too early?

[Mark Williamson]

> > > I added a xenbus_printk call that causes boot to fail,
> > > I suspect because I am calling it before xenbus is up
> > > and working.
> > >
> > > (Same code works fine if called later.)
> > >
> > > Is there a function that does is_xenbus_ready()?
> > > If not, what's the best way to do the equivalent?
> >
> > There apparently is a xenstored_ready variable.
>
> Thanks, but hmmm..., it doesn't look like this is accessed
> anywhere, nor is it EXPORTed so it wouldn't be accessible
> from a module.
>
> >From more code reading, I'm guessing the right way to do
>
> this is to key off of a xenstore_notifier call which
> can set the local static equivalent of xenstored_ready.
> True?

Sounds sensible based on my rather vague memories of the code.

Cheers,
mark


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