On 12/8/25 1:02 PM, Roman Bogorodskiy wrote:
Michal Prívozník wrote:
On 11/26/25 18:03, Roman Bogorodskiy wrote:
SLIRP networking in bhyve doesn't support MAC and IP addresses
configuration, so update the validation code to check that these options
are not specified.
Signed-off-by: Roman Bogorodskiy <[email protected]>
---
src/bhyve/bhyve_domain.c | 17 +++++++++++++-
.../bhyvexml2argv-slirp-ip.xml | 22 +++++++++++++++++++
.../bhyvexml2argv-slirp-mac-addr.xml | 22 +++++++++++++++++++
tests/bhyvexml2argvtest.c | 2 ++
4 files changed, 62 insertions(+), 1 deletion(-)
create mode 100644 tests/bhyvexml2argvdata/bhyvexml2argv-slirp-ip.xml
create mode 100644 tests/bhyvexml2argvdata/bhyvexml2argv-slirp-mac-addr.xml
diff --git a/src/bhyve/bhyve_domain.c b/src/bhyve/bhyve_domain.c
index 4c9ed29333..5c1ed86df6 100644
--- a/src/bhyve/bhyve_domain.c
+++ b/src/bhyve/bhyve_domain.c
@@ -325,6 +325,22 @@ bhyveDomainDeviceDefValidate(const virDomainDeviceDef *dev,
break;
}
+ case VIR_DOMAIN_DEVICE_NET: {
+ virDomainNetDef *net = dev->data.net;
+
+ if (net->type == VIR_DOMAIN_NET_TYPE_USER) {
+ if (!net->mac_generated) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+ _("setting MAC address for SLIRP networking is not
supported"));
+ return -1;
This is a bit unfortunate as many of our public APIs (e.g.
virDomainDetachDevice()) try to match <interface/> using its MAC address
first. OTOH, they can find a match using other values specific to
individual device and we specifically document that device XML should be
passed full.
Thanks for taking time to point that out. I looked to check how hard
would that be to support that, but apparently, it's already there,
just not mentioned in the manual page [1].
I'll push the series with this chunk removed after one more round of
testing.
1: https://reviews.freebsd.org/D54133
(just now noticed this - I haven't been paying attention :-/)
Whether or not the user provides a MAC address, the config that's stored
on disk will contain one (either user-supplied or auto-generated), and
that MAC address won't be honored, which could be confusing to users.
When a MAC address isn't specified for <interface> we will always
generate one prior to saving the config, so that the same MAC setting
will persist across restarts of the guest; doing otherwise wreaks havoc
in the guest OS - any time the MAC address changes, it will think there
is a new network device and want to configure it (MS Windows does this
even if the MAC address of the default router changes). (Of course I'm
assuming that bhyve makes the guest NIC appear with a random MAC; does
it instead always use the same hard-coded MAC address? What if someone
puts two slirp-backed interfaces in the config?)
