Re: [fedora-virt] 3.13 - Nested KVM (vmx) totally broken?

[Ian Pilcher]

On 03/04/2014 03:30 AM, Kashyap Chamarthy wrote:
 If you want to try, I made a Fedora Kernel scratch build (i.e. not
 official) with fix Paolo pointed to below and this works for me:
 
   http://koji.fedoraproject.org/koji/taskinfo?taskID=6577700

Works here.  Thanks!

-- 

Ian Pilcher arequip...@gmail.com
   Sent from the cloud -- where it's already tomorrow

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Nested VMX stability - module parameters?

[Ian Pilcher]

I am trying to use nested KVM (VMX) to set up Red Hat Enterprise
Virtualization (RHEV) on a single Fedora 17 host.  The host hardware is
an Intel DQ67SW board with a Core i7 2600 processor.

I have successfully set up the environment, but I have experienced at
least 2 host kernel panics.

https://bugzilla.kernel.org/show_bug.cgi?id=42980

I'm not 100% sure, but I believe that both panics have occurred when
there was a lot of network traffic between nested guests running on
separate virtualized hypervisors.  (See high-quality ASCII art.)

+--+
|  |
|  +--+   +--+ |
|  |  |   |  | |
|  |   +--+   |   |   +--+   | |
|  |   |  |   |   |   |  |   | |
|  |   |  Nested  |   |   |   |  Nested  |   | |
|  |   |  Guest   |   |   |   |  Guest   |   | |
|  |   |  |   |   |   |  |   | |
|  |   +--+   |   |   +--+   |   +--+  |
|  |  |   |  |   |  |  |
|  | Virtual  |   | Virtual  |   |   RHEV   |  |
|  |Hypervisor|   |Hypervisor|   | Manager  |  |
|  |(RHEL 6.3)|   |(RHEL 6.3)|   |(RHEL 6.3)|  |
|  |  |   |  |   |  |  |
|  +--+   +--+   +--+  |
|  |
|  Physical host (Fedora 17)   |
|  |
+--+

After the first panic, I did two things to try to make the environment
more stable.

* Disabled VT-d in BIOS

* Changed processor type of the virtual hypervisors (as defined on the
  host) to Conroe:

  cpu mode='custom' match='exact'
model fallback='allow'Conroe/model
vendorIntel/vendor
feature policy='require' name='vmx'/
  /cpu

Unfortunately, those changes did not prevent me from experiencing the
host kernel panic again.

I see that the kvm and kvm_intel modules have a number of parameters.
Are any of these likely to affect the stability of nested VMX?

Thanks!

-- 

Ian Pilcher arequip...@gmail.com
Sometimes there's nothing left to do but crash and burn...or die trying.


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