diff --git a/nbdkit.spec b/nbdkit.spec
index ee2d1e0..52b9c2a 100644
--- a/nbdkit.spec
+++ b/nbdkit.spec
@@ -16,6 +16,11 @@
 %global have_python3 1
 %endif
 
+# Disable libvirt on riscv64 for now.
+%ifnarch riscv64
+%global have_libvirt 1
+%endif
+
 # If we should verify tarball signature with GPGv2.
 %global verify_tarball_signature 1
 
@@ -27,7 +32,7 @@
 
 Name:           nbdkit
 Version:        1.5.6
-Release:        1%{?dist}
+Release:        2%{?dist}
 Summary:        NBD server
 
 License:        BSD
@@ -61,7 +66,9 @@ BuildRequires:  libselinux-devel
 %if 0%{?have_libguestfs}
 BuildRequires:  libguestfs-devel
 %endif
+%if 0%{?have_libvirt}
 BuildRequires:  libvirt-devel
+%endif
 BuildRequires:  xz-devel
 BuildRequires:  zlib-devel
 BuildRequires:  libcurl-devel
@@ -279,6 +286,7 @@ Obsoletes:      %{name}-plugin-gzip <= %{version}-%{release}
 This package is a gzip file serving plugin for %{name}.
 
 
+%if 0%{?have_libvirt}
 %package libvirt-plugin
 Summary:        Libvirt plugin for %{name}
 License:        BSD
@@ -294,6 +302,7 @@ Obsoletes:      %{name}-plugin-libvirt <= %{version}-%{release}
 This package is a libvirt plugin for %{name}.  It lets you access
 libvirt guest disks readonly.  It is implemented using the libvirt
 virDomainBlockPeek API.
+%endif
 
 
 %package lua-plugin
@@ -610,13 +619,36 @@ copy="$(mktemp -d)"
 cp -a . "$copy"
 mv "$copy" python3
 
-%configure --disable-static --with-tls-priority=@NBDKIT,SYSTEM
+%configure \
+    --disable-static \
+%if 0%{?have_libguestfs}
+    --with-libguestfs \
+%else
+    --without-libguestfs \
+%endif
+%if 0%{?have_libvirt}
+    --with-libvirt \
+%else
+    --without-libvirt \
+%endif
+    --with-tls-priority=@NBDKIT,SYSTEM
 make %{?_smp_mflags}
 
 %if 0%{?have_python3}
 pushd python3
 export PYTHON=%{_bindir}/python3
-%configure --disable-static --disable-lua --disable-perl --disable-ocaml --disable-ruby --disable-tcl
+%configure \
+    --disable-static \
+    --disable-lua \
+    --disable-perl \
+    --disable-ocaml \
+    --disable-ruby \
+    --disable-tcl \
+    --without-curl \
+    --without-ext2 \
+    --without-libvirt \
+    --without-liblzma \
+    --without-zlib
 # Verify that it picked the correct version of Python
 # to avoid RHBZ#1404631 happening again silently.
 grep '^PYTHON_VERSION = 3' Makefile
@@ -774,11 +806,13 @@ popd
 %{_mandir}/man1/nbdkit-gzip-plugin.1*
 
 
+%if 0%{?have_libvirt}
 %files libvirt-plugin
 %doc README
 %license LICENSE
 %{_libdir}/%{name}/plugins/nbdkit-libvirt-plugin.so
 %{_mandir}/man1/nbdkit-libvirt-plugin.1*
+%endif
 
 
 %files lua-plugin
@@ -915,6 +949,10 @@ popd
 
 
 %changelog
+* Sat Aug 18 2018 Richard W.M. Jones <rjones@redhat.com> - 1.5.6-2
+- Disable libvirt on riscv64.
+- Other simplifications to %%configure line.
+
 * Thu Aug 16 2018 Richard W.M. Jones <rjones@redhat.com> - 1.5.6-1
 - New upstream version 1.5.6.