Ubuntu
qemu-kvm package

  1. Bug #1100843
  2. Comment #28

Comment 28 for bug 1100843

Revision history for this message
C Cormier (ccormier) wrote :

Update:

From our testing this bug affects KVM Hypervisors on Intel processors that have the EPT feature enabled with Kernels 3.0 and greater. A list of Intel EPT supported CPUs here (http://ark.intel.com/Products/VirtualizationTechnology).

When using a KVM Hypervisor Host with Linux kernel 3.0 or newer kernel with Intel EPT this bug shows itself. If the kvm_intel module is loaded with option "ept=N" guest performance is significantly decreased versus enabled, but it does maintain consistent performance pre and post restoration/migration.

Exceptions:
-A KVM Host with 2.6.32 or 2.6.39 Kernel with EPT enabled this bug is not triggered.
-A KVM Host without the EPT feature enabled Intel CPU this bug is not triggered.
-A KVM Host with Kernel 3.0+ and EPT kvm_intel module option disabled in this bug is not triggered

A KVM hypervisor with EPT enabled on Linux Kernel > 3.0 appears to be the key here.