kstat namespace collision warnings

[esproul]

Seen by an OmniOS user on an X4150 (pre-EPT Intel CPU):

Configuring devices.
WARNING: kstat_create('unix', 0, 'kvm_pte_chain'): namespace collision
WARNING: kstat_create('unix', 0, 'kvm_rmap_desc'): namespace collision
WARNING: kstat_create('unix', 0, 'kvm_mmu_page_header'): namespace collision
WARNING: kvm: insufficient hardware support (lacking EPT)

Presumably there's some code path that we only take when EPT support is absent that results in this condition. The user reports that these warnings only appear on the first boot after applying a kernel update, and not on subsequent boots.

This is on OmniOS r151006, which ships illumos-kvm at SHA 2bbad6a788

[rmustacc]

Presumably this has happened because the module was loaded and then unloaded and then loaded again which would cause us to try and create those again. We're probably missing a clean up path there. I'll take a look.

[kwatsen]

I just hit this again (see http://lists.omniti.com/pipermail/omnios-discuss/2013-September/001346.html) but this time on omnios r151012. First upgrade since I did this a year ago. As of now, I've tried both current r151006 (the long-term stable branch) as well as 151012. For both, the only way I can get add_drv kvm to succeed is immediately after a fresh OS install, rem_drv kvm, and the copy over precompiled illumos_kvm binaries, and add_drv kvm. I don't dare reboot - every time I do, I'm now longer able to load the kvm driver due to an error similar to the above error. See my link above for my exact error...

FWIW, I'm on an AMD system and am compiling https://github.com/arekinath/illumos-kvm/tree/master. Worked fine for over a year (haven't rebooted in that long) - reboots are deadly for me...