Running PV kernel on XenServer kills all VMs

[Stephen Borrill <netbsd%precedence.co.uk@localhost>]

I've finally worked out how to get NetBSD i386 and amd64 mostly running in 
full PV mode rather than HVM within Citrix XenServer. I say mostly running 
because the downside is that booting the VM kills networking for all other 
VMs and even stops them being able to shutdown cleanly leading to a forced 
reboot of the XenServer.

dmesg on the dom0 shows:

__ratelimit: 1431411 callbacks suppressed
xen_net: Memory squeeze in netback driver.
xen_net: Memory squeeze in netback driver.
xen_net: Memory squeeze in netback driver.

Google suggests that raising (or hardwiring) dom0_mem may help, but other 
guests don't appear to need this and it's already set to 752M.

Details on switching to PV from HVM can be found at:

http://www.precedence.co.uk/wiki/Support-KB-NetBSD/XenServer

XenServer is free from:
http://www.citrix.com/English/ps2/products/feature.asp?contentID=2300356

--
Stephen