From: Aaron M. Brown <aaronmbr@linux.ibm.com>
Date: Fri, 19 Sep 2025 19:26:19 +0000 (-0400)
Subject: domain_addr.c: Fix virtio console port autoassign on virtio-serial bus
X-Git-Tag: v11.10.0-rc1~42
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2083efe0302348e98292a11798cbca8841eea35f;p=thirdparty%2Flibvirt.git

domain_addr.c: Fix virtio console port autoassign on virtio-serial bus

This change fixes an issue with virtio console port assignment on virtio-serial buses.
Currently, when trying to autoassign a virtio console device, the device cannot be
assigned to a port greater than 0 on virtio-serial buses.
You will receive the following error:

`virtio-serial-bus: A port already exists at id 0`

Therefore, the data needs to be passed back into info when allowZero is true.
We should also preserve the controller data when allowZero is true, and
propagate allowZero into virDomainVirtioSerialAddrNextFromController
to get an appropriate startPort.

Fixes: 16db8d2e ("Add functions to track virtio-serial addresses")
Signed-off-by: Aaron M. Brown <aaronmbr@linux.ibm.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
---

diff --git a/src/conf/domain_addr.c b/src/conf/domain_addr.c
index 6aa5ac1b9f..87c5973fab 100644
--- a/src/conf/domain_addr.c
+++ b/src/conf/domain_addr.c
@@ -1717,12 +1717,17 @@ virDomainVirtioSerialAddrNext(virDomainDef *def,
 
 static int
 virDomainVirtioSerialAddrNextFromController(virDomainVirtioSerialAddrSet *addrs,
-                                            virDomainDeviceVirtioSerialAddress *addr)
+                                            virDomainDeviceVirtioSerialAddress *addr,
+                                            bool allowZero)
 {
+    ssize_t startPort = 0;
     ssize_t port;
     ssize_t i;
     virBitmap *map;
 
+    if (allowZero)
+        startPort = -1;
+
     i = virDomainVirtioSerialAddrFindController(addrs, addr->controller);
     if (i < 0) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
@@ -1732,7 +1737,7 @@ virDomainVirtioSerialAddrNextFromController(virDomainVirtioSerialAddrSet *addrs,
     }
 
     map = addrs->controllers[i]->ports;
-    if ((port = virBitmapNextClearBit(map, 0)) <= 0) {
+    if ((port = virBitmapNextClearBit(map, startPort)) < 0) {
         virReportError(VIR_ERR_XML_ERROR,
                        _("Unable to find a free port on virtio-serial controller %1$u"),
                        addr->controller);
@@ -1755,13 +1760,33 @@ virDomainVirtioSerialAddrAssign(virDomainDef *def,
 {
     virDomainDeviceInfo nfo = { 0 };
     virDomainDeviceInfo *ptr = allowZero ? &nfo : info;
+    virBitmap *map;
+    ssize_t i;
 
     ptr->type = VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_SERIAL;
+    ptr->addr.vioserial.controller = info->addr.vioserial.controller;
 
     if (portOnly) {
         if (virDomainVirtioSerialAddrNextFromController(addrs,
-                                                        &ptr->addr.vioserial) < 0)
+                                                        &ptr->addr.vioserial,
+                                                        allowZero) < 0)
             return -1;
+
+        if (ptr == &nfo) {
+            /* pass the vioserial data back into info as info is used
+             * later for port assignment */
+            info->addr.vioserial = ptr->addr.vioserial;
+
+            /* if the next available port from the controller is zero,
+             * let's reserve it in the map and return */
+            if (ptr->addr.vioserial.port == 0) {
+                i = virDomainVirtioSerialAddrFindController(addrs, ptr->addr.vioserial.controller);
+                map = addrs->controllers[i]->ports;
+                ignore_value(virBitmapSetBit(map, 0));
+                return 0;
+            }
+        }
+
     } else {
         if (virDomainVirtioSerialAddrNext(def, addrs, &ptr->addr.vioserial,
                                           allowZero) < 0)
diff --git a/tests/qemuxmlconfdata/console-virtio-serial-autoassign-address.x86_64-latest.args b/tests/qemuxmlconfdata/console-virtio-serial-autoassign-address.x86_64-latest.args
index 4fbd1e1a5e..8070b3e2af 100644
--- a/tests/qemuxmlconfdata/console-virtio-serial-autoassign-address.x86_64-latest.args
+++ b/tests/qemuxmlconfdata/console-virtio-serial-autoassign-address.x86_64-latest.args
@@ -33,9 +33,9 @@ XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-QEMUGuest1/.config \
 -chardev pty,id=charconsole1 \
 -device '{"driver":"virtconsole","bus":"virtio-serial0.0","nr":0,"chardev":"charconsole1","id":"console1"}' \
 -chardev pty,id=charconsole2 \
--device '{"driver":"virtconsole","bus":"virtio-serial0.0","nr":0,"chardev":"charconsole2","id":"console2"}' \
+-device '{"driver":"virtconsole","bus":"virtio-serial0.0","nr":1,"chardev":"charconsole2","id":"console2"}' \
 -chardev pty,id=charconsole3 \
--device '{"driver":"virtconsole","bus":"virtio-serial0.0","nr":0,"chardev":"charconsole3","id":"console3"}' \
+-device '{"driver":"virtconsole","bus":"virtio-serial0.0","nr":2,"chardev":"charconsole3","id":"console3"}' \
 -audiodev '{"id":"audio1","driver":"none"}' \
 -device '{"driver":"virtio-balloon-pci","id":"balloon0","bus":"pci.0","addr":"0x3"}' \
 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny \
diff --git a/tests/qemuxmlconfdata/console-virtio-serial-autoassign-address.x86_64-latest.xml b/tests/qemuxmlconfdata/console-virtio-serial-autoassign-address.x86_64-latest.xml
index 9939584a9a..971443457a 100644
--- a/tests/qemuxmlconfdata/console-virtio-serial-autoassign-address.x86_64-latest.xml
+++ b/tests/qemuxmlconfdata/console-virtio-serial-autoassign-address.x86_64-latest.xml
@@ -38,11 +38,11 @@
     </console>
     <console type='pty'>
       <target type='virtio' port='2'/>
-      <address type='virtio-serial' controller='0' bus='0' port='0'/>
+      <address type='virtio-serial' controller='0' bus='0' port='1'/>
     </console>
     <console type='pty'>
       <target type='virtio' port='3'/>
-      <address type='virtio-serial' controller='0' bus='0' port='0'/>
+      <address type='virtio-serial' controller='0' bus='0' port='2'/>
     </console>
     <input type='mouse' bus='ps2'/>
     <input type='keyboard' bus='ps2'/>