Re: [Xen-users] strange xm dmesg output

[Mark Williamson <mark.williamson@xxxxxxxxxxxx>]

Hi there,


On Thursday 21 August 2008, Marco Strullato wrote:
> Hi, today I noticed this error: have you ever seen that?
> My xen is the original 3.2 on centos 5 64 bit built from source
>
> [root@hyp12 ~]# xm dmesg
> 7 messages suppressed.
> (XEN) mm.c:645:d3 Non-privileged (3) attempt to map I/O space 000eada8
> (XEN) printk: 439 messages suppressed.
> (XEN) mm.c:645:d3 Non-privileged (3) attempt to map I/O space 000eada8
> (XEN) printk: 4399 messages suppressed.

This is not abnormal, I've seen it plenty of times.

It happens when a guest OS tries to map some memory-mapped IO areas that it 
doesn't have access to.  It typically means that *something* in the guest 
doesn't realise it's running on Xen and so is trying to do something silly 
like repeatedly attempting to access an MMIO region that isn't available...

This only happens for PV domains since HVM domains get some fake MMIO space to 
keep them happy.

What's the guest running?  It should be possible in principle to figure out 
(e.g. through some detective work on your part) what is causing the messages 
and then just disable that.

It's harmless if the guest is running OK anyhow (which it should).  If it's 
not bothering you (as long as it's not polluting your logs too much or 
pushing out useful information).

Cheers,
Mark

> (XEN) mm.c:645:d3 Non-privileged (3) attempt to map I/O space 000d97ca
> (XEN) printk: 131 messages suppressed.
> (XEN) mm.c:645:d3 Non-privileged (3) attempt to map I/O space 000eada8
> (XEN) printk: 4431 messages suppressed.
> (XEN) mm.c:645:d3 Non-privileged (3) attempt to map I/O space 000eada8
> (XEN) printk: 109 messages suppressed.
> (XEN) mm.c:645:d3 Non-privileged (3) attempt to map I/O space 000d97ca
> (XEN) printk: 4553 messages suppressed.
> (XEN) mm.c:645:d3 Non-privileged (3) attempt to map I/O space 000ccb48
> (XEN) printk: 1589 messages suppressed.
> (XEN) mm.c:645:d3 Non-privileged (3) attempt to map I/O space 000efc5a
> (XEN) printk: 4417 messages suppressed.
> (XEN) mm.c:645:d3 Non-privileged (3) attempt to map I/O space 000d97ca
> (XEN) printk: 1619 messages suppressed.
> (XEN) mm.c:645:d3 Non-privileged (3) attempt to map I/O space 000f9c98
> (XEN) printk: 4567 messages suppressed.
> (XEN) mm.c:645:d3 Non-privileged (3) attempt to map I/O space 000f9c98
>
>
> Regards,
>
> Marco Strullato
>
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> http://lists.xensource.com/xen-users



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