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

Robert P. J. Day rpjday at crashcourse.ca
Thu Apr 16 19:08:13 UTC 2009

On Thu, 16 Apr 2009, Mark McLoughlin wrote:

> On Thu, 2009-04-16 at 14:00 -0400, Robert P. J. Day wrote:
> >
> > http://www.linux-kvm.org/page/FAQ#How_can_I_check_that_I.27m_not_falling_back_to_qemu_with_no_hardware_acceleration.3F
> >
> > In that case, you can check that:
> >
> >     * the modules are correctly loaded lsmod|grep kvm
> >     * you don't have a "KVM: disabled by BIOS" line in the output of dmesg
> >     * /dev/kvm exists and you have the correct rights to use it
> >
> > that last point seems fairly adamant that your account *needs*
> > access to /dev/kvm so, if that's true, i *shouldn't* have had HW
> > support until i did all of the above.  i don't see how you could
> > shortcut any of the above.
> That information is only relevant if you're installing kvm yourself
> and running e.g. qemu-kvm. As I said, on Fedora we want it to "just
> work".
> virt-manager connects to the system libvirtd and it is that which
> spawns qemu-kvm, so it is spawned it as root currently. So, you
> don't need to modify the permissions on /dev/kvm.

  ok, i take it all back.  i created a totally generic user account,
"guest", didn't do anything special to it, logged in as guest, fired
up VMM and it seems to be as fast as my original account.  i'm
baffled.  all i can guess is that, somehow, i failed to activate HW
virt extensions before, when it was sooooooooo slow.

  here's the relevant snippet from the guest log file:

[Thu, 16 Apr 2009 14:55:27 virt-manager 15168] DEBUG (create:1438)
Creating a VM f11g
  Type: kvm,hvm
  UUID: 733e41a4-fd1a-d640-2f9b-ce5883fcc00a
  Install Source: /dev/sr0
  OS: linux:fedora11
  Kernel args: None
  Memory: 2048
  Max Memory: 2048
  # VCPUs: 2
  Filesize: 20.0

VM "f11g", "g" meaning guest so it's clearly working, and clearly
seeing hvm extensions.

  sorry for all the noise, i guess it really just works without
dicking around with udev and so on.

  argh.  i need a beer.

Robert P. J. Day                               Waterloo, Ontario, CANADA

        Linux Consulting, Training and Annoying Kernel Pedantry.

Web page:                                          http://crashcourse.ca
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