On 4/7/26 11:19 AM, Peter Krempa via Devel wrote:
On Mon, Apr 06, 2026 at 23:15:32 -0400, Laine Stump via Devel wrote:
From: Laine Stump <[email protected]>
When support for vhostuser devices was added, it was just
blanket-prevented from making any changes to a live device with
update-device. This is problematic because the link state of a network
device is modified with update-device. Most all of the parameters of a
vhostuser network device are individually checked within
qemuDomainChangeNet() anyway, so we don't need to just do a BRS (Big
Red Switch) forbidding of any change. We do need to check for
modifications to the socket parameters (path, type, reconnect) though,
since those are vhostuser-specific (we're not already checking for
them elsewhere) and they can't be changed on a live interface.
Resolves https://redhat.atlassian.net/browse/RHEL-152533
Resolves: https://bugs.passt.top/show_bug.cgi?id=198
Signed-off-by: Laine Stump <[email protected]>
---
src/qemu/qemu_hotplug.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 7ab28bed6d..e33ef5e1e9 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -4129,6 +4129,24 @@ qemuDomainChangeNet(virQEMUDriver *driver,
break;
case VIR_DOMAIN_NET_TYPE_VHOSTUSER:
+ /* the path the to vhostuser socket and its parameters
+ * can't be changed. In the case of a PASST backend using
+ * vhostuser, all of those parameters are internally
+ * generated anyway, so the user wouldn't be able to
+ * specify them in the updated XML.
+ */
While the comment explains it, the condition is a bit unpleasant to
read.
I'd suggest doing:
if (newdev->backend.type == VIR_DOMAIN_NET_BACKEND_PASST)
break;
Sure, I can do that.
first with the comment stating that the passt stuff is autogenerated and
then follow up ...
+ if (newdev->backend.type != VIR_DOMAIN_NET_BACKEND_PASST &&
... with the rest of this as another condition:
+ (STRNEQ_NULLABLE(olddev->data.vhostuser->data.nix.path,
newdev->data.vhostuser->data.nix.path) ||
+ olddev->data.vhostuser->data.nix.listen !=
newdev->data.vhostuser->data.nix.listen ||
+ olddev->data.vhostuser->data.nix.reconnect.enabled !=
newdev->data.vhostuser->data.nix.reconnect.enabled ||
+ olddev->data.vhostuser->data.nix.reconnect.timeout !=
newdev->data.vhostuser->data.nix.reconnect.timeout)) {
+ virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
+ _("unable to change socket config on '%1$s' network
type"),
+ virDomainNetTypeToString(newdev->type));
+ goto cleanup;
+ }
+ break;
+
case VIR_DOMAIN_NET_TYPE_HOSTDEV:
case VIR_DOMAIN_NET_TYPE_VDPA:
case VIR_DOMAIN_NET_TYPE_NULL:
Reviewed-by: Peter Krempa <[email protected]>
