Some distributions create the defaut KVM (libvirtd) storage pool for images when they install KVM, others do this upon the creation of the first KVM guest. Creating the default pool from scratch is pretty straightforward. Here's how to do it with virsh.

First verify there is no existing default pool:

$ virsh pool-list --all
 Name      State    Autostart
-----------------------------

Assuming you want the physical path of the new pool to be /data1/libvirt/images, create that directory (sudo mkdir -p /data1/libvirt/images) and run the following commands:

$ virsh pool-define-as default dir --target "/data1/libvirt/images"
$ virsh pool-define-as default dir --target "/data1/libvirt/images"
$ virsh pool-build default
$ virsh pool-start default
$ virsh pool-autostart default

Check the configuration with virsh-info:

$ virsh pool-info default
Name:           default
UUID:           8b806f67-87b4-403b-ae64-c652c0764641
State:          running
Persistent:     yes
Autostart:      yes
Capacity:       915.82 GiB
Allocation:     1.15 GiB
Available:      914.66 GiB

And then with pool-dumpxml:

$ virsh pool-dumpxml default
<pool type='dir'>
  <name>default</name>
  <uuid>8b806f67-87b4-403b-ae64-c652c0764641</uuid>
  <capacity unit='bytes'>983349346304</capacity>
  <allocation unit='bytes'>1238208512</allocation>
  <available unit='bytes'>982111137792</available>
  <source>
  </source>
  <target>
    <path>/d1/libvirt/images</path>
    <permissions>
      <mode>0755</mode>
      <owner>0</owner>
      <group>0</group>
    </permissions>
  </target>
</pool>