$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-incoming-8863-27823/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-incoming-8863-27823/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin e91de7180ad468b101f7d28cf6c7eb8c58eb4715:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         e91de7180ad468b101f7d28cf6c7eb8c58eb4715 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e91de71 8.3: cherry-pick "xenopsd: set xen-platform-pci-bar-uc key in xenstore"