Issue

• guestmount command fails on a vmware guest with following error .

qemu-kvm: /builddir/build/BUILD/qemu-2.6.0/target-i386/kvm.c:1736: kvm_put_msrs: Assertion `ret == n' failed.

• virt-customize command fails on a vmware guest with following error .

$ virt-customize -x --verbose -a overcloud-full.qcow2 --root-password password:password
......
libguestfs: trace: launch = -1 (error)
virt-customize: error: libguestfs error: could not create appliance through
libvirt.

Try running qemu directly without libvirt using this environment variable:
export LIBGUESTFS_BACKEND=direct

Original error from libvirt: internal error: process exited while
connecting to monitor: qemu-kvm:
/builddir/build/BUILD/qemu-2.6.0/target-i386/kvm.c:1736: kvm_put_msrs:
Assertion `ret == n' failed. [code=1 int1=-1]
libguestfs: trace: close
libguestfs: closing guestfs handle 0x274e2b0 (state 0)
libguestfs: command: run: rm
libguestfs: command: run: \ -rf /tmp/libguestfsrIaElp

• Nested virtualized guest on RHEL-KVM running on ESX Host failes with "kvm_put_msrs: Assertion `ret == n' failed" error.