nixos/libvirt: avoid dependency on two qemu packages

Currently libvirt requires two qemu derivations: qemu and qemu_kvm which is just a truncated version of qemu (defined as qemu.override { hostCpuOnly = true; }).

This patch exposes an option virtualisation.libvirtd.qemuPackage which allows to choose which package to use:

 * pkgs.qemu_kvm if all your guests have the same CPU as host, or
 * pkgs.qemu which allows to emulate alien architectures (for example ARMV7L on X86_64), or
 * a custom derivation

virtualisation.libvirtd.enableKVM option is vague and could be deprecate in favor of virtualisation.libvirtd.qemuPackage, anyway it does allow to enable/disable kvm.
This commit is contained in:
volth 2017-12-06 04:33:45 +00:00 committed by Orivej Desh
parent fd91e1441f
commit a52aa6aafb
2 changed files with 16 additions and 9 deletions

View File

@ -41,7 +41,16 @@ in {
type = types.bool;
default = true;
description = ''
This option enables support for QEMU/KVM in libvirtd.
This option disables support for non-KVM guests in libvirtd (e.g. aarch64 on x86).
KVM is available even if this setting is false.
'';
};
virtualisation.libvirtd.qemuPackage = mkOption {
type = types.package;
default = if cfg.enableKVM then pkgs.qemu_kvm else pkgs.qemu;
description = ''
Qemu package to use with libvirt
'';
};
@ -102,7 +111,7 @@ in {
config = mkIf cfg.enable {
environment.systemPackages = with pkgs; [ libvirt netcat-openbsd qemu_kvm ];
environment.systemPackages = with pkgs; [ libvirt netcat-openbsd cfg.qemuPackage ];
boot.kernelModules = [ "tun" ];
@ -154,9 +163,9 @@ in {
# stable (not GC'able as in /nix/store) paths for using in <emulator> section of xml configs
mkdir -p /run/libvirt/nix-emulators
ln -s --force ${pkgs.libvirt}/libexec/libvirt_lxc /run/libvirt/nix-emulators/
${optionalString pkgs.stdenv.isAarch64 "ln -s --force ${pkgs.qemu}/bin/qemu-system-aarch64 /run/libvirt/nix-emulators/"}
${optionalString cfg.enableKVM "ln -s --force ${pkgs.qemu_kvm}/bin/qemu-kvm /run/libvirt/nix-emulators/"}
for emulator in ${pkgs.libvirt}/libexec/libvirt_lxc ${cfg.qemuPackage}/bin/qemu-kvm ${cfg.qemuPackage}/bin/qemu-system-*; do
ln -s --force "$emulator" /run/libvirt/nix-emulators/
done
${optionalString cfg.qemuOvmf ''
mkdir -p /run/libvirt/nix-ovmf

View File

@ -4,7 +4,7 @@
, iproute, iptables, readline, lvm2, utillinux, systemd, libpciaccess, gettext
, libtasn1, ebtables, libgcrypt, yajl, pmutils, libcap_ng, libapparmor
, dnsmasq, libnl, libpcap, libxslt, xhtml1, numad, numactl, perlPackages
, curl, libiconv, gmp, xen, zfs, parted, qemu
, curl, libiconv, gmp, xen, zfs, parted
}:
with stdenv.lib;
@ -41,8 +41,6 @@ stdenv.mkDerivation rec {
# the path to qemu-kvm will be stored in VM's .xml and .save files
# do not use "''${qemu_kvm}/bin/qemu-kvm" to avoid bound VMs to particular qemu derivations
substituteInPlace src/qemu/qemu_capabilities.c \
--replace '"/usr/libexec/qemu-kvm"' '"/run/libvirt/nix-emulators/${if stdenv.isAarch64 then "qemu-system-aarch64" else "qemu-kvm"}"'
substituteInPlace src/lxc/lxc_conf.c \
--replace 'lxc_path,' '"/run/libvirt/nix-emulators/libvirt_lxc",'
'' + ''
@ -91,7 +89,7 @@ stdenv.mkDerivation rec {
substituteInPlace $out/lib/systemd/system/libvirtd.service --replace /bin/kill ${coreutils}/bin/kill
rm $out/lib/systemd/system/{virtlockd,virtlogd}.*
wrapProgram $out/sbin/libvirtd \
--prefix PATH : ${makeBinPath [ iptables iproute pmutils numad numactl qemu ]}
--prefix PATH : /run/libvirt/nix-emulators:${makeBinPath [ iptables iproute pmutils numad numactl ]}
'';
enableParallelBuilding = true;