There is no "nested" parameter for kvm on POWER. So I think we can just remove the file.

Adding cc: Eric Auger as the problem is the same for aarch64

Fix included in qemu-kvm-rhev-2.10.0-9.el7

Verified qemu-kvm-rhev-2.10.0-9.el7 on Power8,9, s390x and x86_84:

(1) Power:

# cat /etc/modprobe.d/kvm.conf 
#
# User changes in this file are preserved across upgrades.
#

Also checked s390x and x86_64:

(2) s390x:

# cat /etc/modprobe.d/kvm.conf 
# Setting "modprobe kvm nested=1" only enables Nested Virtualization until
# the next reboot or module reload. Uncomment the option below to enable
# the feature permanently.
#
# User changes in this file are preserved across upgrades.
#
#options kvm nested=1

(3) x86_64:
# cat /etc/modprobe.d/kvm.conf 
# Setting modprobe kvm_intel/kvm_amd nested = 1
# only enables Nested Virtualization until the next reboot or
# module reload. Uncomment the option applicable
# to your system below to enable the feature permanently.
#
# User changes in this file are preserved across upgrades.
#
# For Intel
#options kvm_intel nested=1
#
# For AMD
#options kvm_amd nested=1


Based on above, the issue is fixed.  Thanks!

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2018:1104