libvirt/libvirt-qemu-make-passt-vhostuser-reconnect-behave-identically-to-passt-user.patch

From 74aeb210bdbeba3389eff4f07860217dd8bb068e Mon Sep 17 00:00:00 2001
Message-ID: <74aeb210bdbeba3389eff4f07860217dd8bb068e.1747908718.git.jdenemar@redhat.com>
From: Laine Stump <laine@redhat.com>
Date: Fri, 4 Apr 2025 19:44:52 -0400
Subject: [PATCH] qemu: make passt+vhostuser reconnect behave identically to
 passt+user

When "original passt" support was added, we decided that we always
wanted to reconnect (i.e. restart the passt process) if it was somehow
terminated. Generic vhost-user, on the other hand, only turns on
reconnect if specified by the user in the config. But there is no
reason to require the user to specify this if the other end of the
vhost-user socket is a passt process - we know what has happened and
what we want to do; no reason to do the *wrong* thing by default, and
force the user to make an arbitrary decision about what to add to the
config in order to make it do the *right* thing; instead we just
hardcode it to always do the right thing.

(NB: when the backend is passt, <interface type='vhostuser'> has
always ignored the reconnect setting in <source> when parsing and
formatting, just as it has always ignored the socket path (since that
also is not user configurable for the passt backend)

Resolves: https://issues.redhat.com/browse/RHEL-80169

Signed-off-by: Laine Stump <laine@redhat.com>
Tested-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
(cherry picked from commit 44abaa0128ac0fc8be9de4eebc15c03809bf5867)

Conflicts:

tests/qemuxmlconfdata/schema-reorder-domain-subelements.x86_64-latest.args:
  This file (created by upstream commit be5332c81d28) was modified
  upstream but doesin't exist downstream

https://issues.redhat.com/browse/RHEL-80169
Signed-off-by: Laine Stump <laine@redhat.com>
---
 src/qemu/qemu_passt.c                            | 16 +++++++++++++---
 .../net-vhostuser-passt.x86_64-latest.args       |  6 +++---
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/src/qemu/qemu_passt.c b/src/qemu/qemu_passt.c
index bc495eca1e..fcc34de384 100644
--- a/src/qemu/qemu_passt.c
+++ b/src/qemu/qemu_passt.c
@@ -36,7 +36,7 @@ VIR_LOG_INIT("qemu.passt");
 
 
 #define PASST "passt"
-
+#define QEMU_PASST_RECONNECT_TIMEOUT 5
 
 static char *
 qemuPasstCreatePidFilename(virDomainObj *vm,
@@ -106,11 +106,15 @@ qemuPasstAddNetProps(virDomainObj *vm,
 
     if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_NETDEV_STREAM_RECONNECT)) {
         if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_NETDEV_STREAM_RECONNECT_MILISECONDS)) {
-            if (virJSONValueObjectAdd(netprops, "u:reconnect-ms", 5000, NULL) < 0)
+            if (virJSONValueObjectAdd(netprops, "u:reconnect-ms",
+                                      QEMU_PASST_RECONNECT_TIMEOUT * 1000, NULL) < 0) {
                 return -1;
+            }
         } else {
-            if (virJSONValueObjectAdd(netprops, "u:reconnect", 5, NULL) < 0)
+            if (virJSONValueObjectAdd(netprops, "u:reconnect",
+                                      QEMU_PASST_RECONNECT_TIMEOUT, NULL) < 0) {
                 return -1;
+            }
         }
     }
 
@@ -182,6 +186,12 @@ qemuPasstPrepareVhostUser(virDomainObj *vm,
      */
     g_free(net->data.vhostuser->data.nix.path);
     net->data.vhostuser->data.nix.path = qemuPasstCreateSocketPath(vm, net);
+
+    /* reconnect is always enabled, with timeout always at 5 seconds, when
+     * using passt
+     */
+    net->data.vhostuser->data.nix.reconnect.enabled = VIR_TRISTATE_BOOL_YES;
+    net->data.vhostuser->data.nix.reconnect.timeout = QEMU_PASST_RECONNECT_TIMEOUT;
 }
 
 int
diff --git a/tests/qemuxmlconfdata/net-vhostuser-passt.x86_64-latest.args b/tests/qemuxmlconfdata/net-vhostuser-passt.x86_64-latest.args
index 7c030d7067..afbbe188cf 100644
--- a/tests/qemuxmlconfdata/net-vhostuser-passt.x86_64-latest.args
+++ b/tests/qemuxmlconfdata/net-vhostuser-passt.x86_64-latest.args
@@ -28,13 +28,13 @@ XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-QEMUGuest1/.config \
 -boot strict=on \
 -blockdev '{"driver":"host_device","filename":"/dev/HostVG/QEMUGuest1","node-name":"libvirt-1-storage","read-only":false}' \
 -device '{"driver":"ide-hd","bus":"ide.0","unit":0,"drive":"libvirt-1-storage","id":"ide0-0-0","bootindex":1}' \
--chardev socket,id=charnet0,path=/var/run/libvirt/qemu/passt/-1-QEMUGuest1-net0.socket \
+-chardev socket,id=charnet0,path=/var/run/libvirt/qemu/passt/-1-QEMUGuest1-net0.socket,reconnect-ms=5000 \
 -netdev '{"type":"vhost-user","chardev":"charnet0","id":"hostnet0"}' \
 -device '{"driver":"virtio-net-pci","netdev":"hostnet0","id":"net0","mac":"00:11:22:33:44:55","bus":"pci.0","addr":"0x2"}' \
--chardev socket,id=charnet1,path=/var/run/libvirt/qemu/passt/-1-QEMUGuest1-net1.socket \
+-chardev socket,id=charnet1,path=/var/run/libvirt/qemu/passt/-1-QEMUGuest1-net1.socket,reconnect-ms=5000 \
 -netdev '{"type":"vhost-user","chardev":"charnet1","id":"hostnet1"}' \
 -device '{"driver":"virtio-net-pci","netdev":"hostnet1","id":"net1","mac":"00:11:22:33:44:11","bus":"pci.0","addr":"0x3"}' \
--chardev socket,id=charnet2,path=/var/run/libvirt/qemu/passt/-1-QEMUGuest1-net2.socket \
+-chardev socket,id=charnet2,path=/var/run/libvirt/qemu/passt/-1-QEMUGuest1-net2.socket,reconnect-ms=5000 \
 -netdev '{"type":"vhost-user","chardev":"charnet2","id":"hostnet2"}' \
 -device '{"driver":"virtio-net-pci","netdev":"hostnet2","id":"net2","mac":"00:11:22:33:44:11","bus":"pci.0","addr":"0x4"}' \
 -audiodev '{"id":"audio1","driver":"none"}' \
-- 
2.49.0