On 11/27/24 20:34, Laine Stump wrote:
For the full history behind this patch, look at the following:
https://issues.redhat.com/browse/RHEL-7036 commit v10.7.0-101-ga37bd2a15b commit v10.8.0-rc2-8-gbcd5ae4e73
Summary: original problem was unexpected failure of update-device when the user hadn't changed anything other than online status of the guest NIC (which should always be allowed).
The first commit "fixed" this by avoiding the allocation of a new ActualNetDef (i.e. creating a new networkport) for *all* network device updates (because that was inappropriately changing which ethernet physdev should be used for a macvtap connection, which by design can't be handled in an update-device).
But this commit caused a regression for update-device of bridge-based network devices (because some the updates of certain attributes *do* require the ActualNetDef be re-allocated), so...
The 2nd commit narrowed the list of network types that get the "don't allocate new ActualNetDef" treatment (so that only interfaces connected to a network that uses a pool of ethernet VFs *being used in passthrough mode* qualify).
But then it was pointed out that this re-broke simple updates of devices that used a direct/macvtap network in "bridge" mode (because it's possible to list multiple physdevs to use for bridge mode, in which case the network driver attempts to "load balance" (and so a new allocation might have a different ethernet physdev which, again, can't be supported in a device-update).
So this (single line of code) patch *widens* the list of network types that don't allocate a new ActualNetDef to also include the other direct (macvtap) modes, e.g. bridge, private, etc.
Signed-off-by: Laine Stump <laine@redhat.com> ---
There is a more comprehensive fix that also, e.g., makes updating the bandwidth or vlan info of a direct interface work correctly, but that is much more invasive (and also isn't done yet). This patch fixes the case of updating a direct interface's online status (for example) without breaking anything else.
src/qemu/qemu_hotplug.c | 38 +++++++++++++++++++++----------------- 1 file changed, 21 insertions(+), 17 deletions(-)
Reviewed-by: Michal Privoznik <mprivozn@redhat.com> Sorry for letting this miss the release. Michal