[fedora-virt] how can i verify that HW extensions are being used?

Robert P. J. Day rpjday at crashcourse.ca
Thu Apr 16 11:48:52 UTC 2009

  apparently, i made one lame-brained move yesterday that almost
certainly caused my VM to run thigh-suckingly slowly.  following the
linux KVM FAQ, i wanted to configure KVM so i could run it as a
non-root user.  to that end, i

  * created a "kvm" group,
  * added my user account to the kvm group, and
  * added the rules file /etc/udev/rules.d/60-kvm.rules:

    KERNEL=="kvm", GROUP="kvm"

  i re-initialized udev with:

  # udevadm control --reload-rules   (right?)

unloaded my kvm modules (kvm and kvm_amd), reloaded them and, sure
enough, my new /dev/kvm device file had a group affiliation of kvm.
excellent, i thought, and away i went ... with still painfully slow
performance, until i realized that i was still in my original desktop
session which *wasn't* considered part of the kvm group.  so a quick
logout, log back in and things were much better.

  *that's* the sort of thing i'm trying to document as i write all of
this up -- those slight oversights which no one bothers to mention
that eventually bite you in the butt.  in any event, back to my
original question -- what could i have checked that would have told
me, no, you are *not* taking advantage of the AMD-V HW virt
extensions?  after all, my modules were loaded, /dev/kvm existed, it
clearly had the right group, but (and correct me if i'm wrong) i was
obviously not getting the benefit of HVM because my desktop session
wasn't considered part of the "kvm" group.



p.s.  my plan is, starting from scratch, to document every step in
installing f11 x86_64 under f11 x86_64, and end up with a recipe that
just plain *works*.  has this been done already?  URL?

Robert P. J. Day                               Waterloo, Ontario, CANADA

        Linux Consulting, Training and Annoying Kernel Pedantry.

Web page:                                          http://crashcourse.ca
Linked In:                             http://www.linkedin.com/in/rpjday
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