From a18bc12081bcebf2d78883d1c6981c454149bb39 Mon Sep 17 00:00:00 2001

From: Laszlo Ersek <lersek@redhat.com>

Date: Thu, 23 Dec 2021 11:37:01 +0100

Subject: [PATCH] launch-libvirt: add virtio-net via the standard <interface>

 element

Starting with version 3.8.0, libvirt allows us to specify the network

address and network mask (as prefix) for SLIRP directly via the

<interface> element in the domain XML:

<https://libvirt.org/formatdomain.html#userspace-slirp-stack>. This means

we don't need the <qemu:commandline> hack for virtio-net on such versions.

Restrict the hack in construct_libvirt_xml_qemu_cmdline() to

libvirt<3.8.0, and generate the proper <interface> element in

construct_libvirt_xml_devices() on libvirt>=3.8.0.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2034160

Suggested-by: Richard W.M. Jones <rjones@redhat.com>

Signed-off-by: Laszlo Ersek <lersek@redhat.com>

Message-Id: <20211223103701.12702-4-lersek@redhat.com>

Reviewed-by: Richard W.M. Jones <rjones@redhat.com>

Tested-by: Richard W.M. Jones <rjones@redhat.com>

(cherry picked from commit 5858c2cf6c24b3776e3867eafd9d86a1f4912d9c)

---

 lib/guestfs-internal.h |  3 ++-

 lib/launch-libvirt.c   | 27 +++++++++++++++++++++++++--

 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/lib/guestfs-internal.h b/lib/guestfs-internal.h

index e24d570f5..4a19e5c6b 100644

--- a/lib/guestfs-internal.h

+++ b/lib/guestfs-internal.h

@@ -173,7 +173,8 @@ cleanup_mutex_unlock (pthread_mutex_t **ptr)

 #endif

 /* Place the virtio-net controller in slot 0x1e on the root bus, on normal

- * hardware with PCI. Refer to RHBZ#2034160.

+ * hardware with PCI. Necessary only before libvirt 3.8.0. Refer to

+ * RHBZ#2034160.

  */

 #ifdef HAVE_LIBVIRT_BACKEND

 #if defined(__arm__) || defined(__s390x__)

diff --git a/lib/launch-libvirt.c b/lib/launch-libvirt.c

index 266d88824..cc714c02e 100644

--- a/lib/launch-libvirt.c

+++ b/lib/launch-libvirt.c

@@ -1413,6 +1413,28 @@ construct_libvirt_xml_devices (guestfs_h *g,

       } end_element ();

     } end_element ();

+    /* Virtio-net NIC with SLIRP (= userspace) back-end, if networking is

+     * enabled. Starting with libvirt 3.8.0, we can specify the network address

+     * and prefix for SLIRP in the domain XML. Therefore, we can add the NIC

+     * via the standard <interface> element rather than <qemu:commandline>, and

+     * so libvirt can manage the PCI address of the virtio-net NIC like the PCI

+     * addresses of all other devices. Refer to RHBZ#2034160.

+     */

+    if (g->enable_network &&

+        guestfs_int_version_ge (&params->data->libvirt_version, 3, 8, 0)) {

+      start_element ("interface") {

+        attribute ("type", "user");

+        start_element ("model") {

+          attribute ("type", "virtio");

+        } end_element ();

+        start_element ("ip") {

+          attribute ("family", "ipv4");

+          attribute ("address", NETWORK_ADDRESS);

+          attribute ("prefix", NETWORK_PREFIX);

+        } end_element ();

+      } end_element ();

+    }

+

     /* Libvirt adds some devices by default.  Indicate to libvirt

      * that we don't want them.

      */

@@ -1835,9 +1857,10 @@ construct_libvirt_xml_qemu_cmdline (guestfs_h *g,

     } end_element ();

     /* Workaround because libvirt user networking cannot specify "net="

-     * parameter.

+     * parameter. Necessary only before libvirt 3.8.0; refer to RHBZ#2034160.

      */

-    if (g->enable_network) {

+    if (g->enable_network &&

+        !guestfs_int_version_ge (&params->data->libvirt_version, 3, 8, 0)) {

       start_element ("qemu:arg") {

         attribute ("value", "-netdev");

       } end_element ();

-- 

2.31.1