xen-3.1.0 and dom0 problems with /dev/ksyms

[Juraj Hercek <nbsd%hck.sk@localhost>]

Hello,

I've got trouble with netstat on dom0 booted by xen-3.1.0 hypervisor. 
Symptoms:

$ netstat -ni
Name  Mtu   Network       Address              Ipkts Ierrs    Opkts 
Oerrs Colls
netstat: kvm_read: Bad address

The same thing works fine with xen-3.0.3 hypervisor. I've done traces of 
the 'netstat -ni' when running both hypervisors, and it seems that dom0 
running on 3.1.0 has troubles accessing /dev/ksyms - instead it directly 
opens /netbsd and takes what's necessary from there:

1 netstat  CALL  open(0xbbbc8667,0,0)
1 netstat  NAMI  "/dev/ksyms"
1 netstat  RET   open -1 errno 6 Device not configured
1 netstat  CALL  open(0xbbbc86f1,0,0)
1 netstat  NAMI  "/netbsd"
1 netstat  RET   open 6

On the other hand, the 3.0.3 hypervisor worked fine:

1 netstat  CALL  open(0xbbbc8667,0,0)
1 netstat  NAMI  "/dev/ksyms"
1 netstat  RET   open 6

Since I boot using grub (and I have kernels on different partition), I 
didn't care about upgrading /netbsd on netbsd partition - the running 
kernel was different from /netbsd (which was a GENERIC one). This caused 
the "netsat kvm_read: Bad address", which can be cured by properly 
synchronizing /netbsd with really booted kernel.

Question, however, is, how to get /dev/ksyms working with xen 3.1.0 
hypervisor?

Maybe the unaccessible /dev/ksyms is related to this?:
$ sudo xm dmesg | tail -15
(XEN) Scrubbing Free RAM: .................done.
(XEN) Xen trace buffers: disabled
(XEN) Std. Loglevel: Errors and warnings
(XEN) Guest Loglevel: Nothing (Rate-limited: Errors and warnings)
(XEN) *** Serial input -> DOM0 (type 'CTRL-a' three times to switch 
input to Xen).
(XEN) mm.c:503:d0 Could not get page ref for pfn bff02
(XEN) mm.c:2324:d0 Could not get page for normal update
(XEN) mm.c:503:d0 Could not get page ref for pfn bff02
(XEN) mm.c:2324:d0 Could not get page for normal update
(XEN) mm.c:503:d0 Could not get page ref for pfn bff02
(XEN) mm.c:2324:d0 Could not get page for normal update
(XEN) mm.c:503:d0 Could not get page ref for pfn bff02
(XEN) mm.c:2324:d0 Could not get page for normal update
(XEN) mm.c:503:d0 Could not get page ref for pfn bff02
(XEN) mm.c:2324:d0 Could not get page for normal update

Any Idea how to get rid of those "Could not get page ..." things?


Regards,
Juraj