The patch that added qemuInterfaceStartDevices() (upstream commit 82977058f5b1d143a355079900029e9cbfee2fe4) had an extra conditional to prevent calling it if the reason for starting the CPUs was VIR_DOMAIN_RUNNING_UNPAUSED or VIR_DOMAIN_RUNNING_SAVE_CANCELED. This was put in by the author as the result of a reviewer asking if it was necessary to ifup the interfaces in *all* occasions (because these were the two cases where the CPU would have already been started (and stopped) once, so the interface would already be ifup'ed). It turns out that, as long as there is no corresponding qemuInterfaceStopDevices() to ifdown the interfaces anytime the CPUs are stopped, neglecting to ifup when reason is RUNNING_UNPAUSED or RUNNING_SAVE_CANCELED doesn't cause any problems (because it just happens that the interface will have already been ifup'ed by a prior call when the CPU was previously started for some other reason). However, it also doesn't *help*, and there will soon be a qemuInterfaceStopDevices() function which *will* ifdown these interfaces when the guest CPUs are stopped, and once that is done, the interfaces will be left down in some cases when they should be up (for example, if a domain is paused and then unpaused). So, this patch is removing the condition in favor of always calling qemuInterfaeStartDevices() when the guest CPUs are started. This patch (and the aforementioned patch) resolve: https://bugzilla.redhat.com/show_bug.cgi?id=1081461 --- src/qemu/qemu_process.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index ab4df9b..0028283 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -3126,9 +3126,7 @@ qemuProcessStartCPUs(virQEMUDriverPtr driver, virDomainObjPtr vm, virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver); /* Bring up netdevs before starting CPUs */ - if (reason != VIR_DOMAIN_RUNNING_UNPAUSED && - reason != VIR_DOMAIN_RUNNING_SAVE_CANCELED && - qemuInterfaceStartDevices(vm->def) < 0) + if (qemuInterfaceStartDevices(vm->def) < 0) goto cleanup; VIR_DEBUG("Using lock state '%s'", NULLSTR(priv->lockState));

We now have a qemuInterfaceStartDevices() which does the final activation needed for the host-side tap/macvtap devices that are used for qemu network connections. It will soon make sense to have the converse qemuInterfaceStopDevices() which will undo whatever was done during qemuInterfaceStartDevices(). A function to "stop" a single device has also been added, and is called from the appropriate place in qemuDomainDetachNetDevice(), although this is currently unnecessary - the device is going to immediately be deleted anyway, so any extra "deactivation" will be for naught. The call is included for completeness, though, in anticipation that in the future there may be some required action that *isn't* nullified by deleting the device. This patch is a part of a more complete fix for: https://bugzilla.redhat.com/show_bug.cgi?id=1081461 --- src/qemu/qemu_hotplug.c | 8 ++++++ src/qemu/qemu_interface.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++ src/qemu/qemu_interface.h | 2 ++ src/qemu/qemu_process.c | 3 +++ 4 files changed, 79 insertions(+) diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c index 8c0642e..e56cffe 100644 --- a/src/qemu/qemu_hotplug.c +++ b/src/qemu/qemu_hotplug.c @@ -3513,6 +3513,14 @@ qemuDomainDetachNetDevice(virQEMUDriverPtr driver, VIR_WARN("cannot clear bandwidth setting for device : %s", detach->ifname); + /* deactivate the tap/macvtap device on the host (currently this + * isn't necessary, as everything done in + * qemuInterfaceStopDevice() is made meaningless when the device + * is deleted anyway, but in the future it may be important, and + * doesn't hurt anything for now) + */ + ignore_value(qemuInterfaceStopDevice(detach)); + qemuDomainMarkDeviceForRemoval(vm, &detach->info); qemuDomainObjEnterMonitor(driver, vm); diff --git a/src/qemu/qemu_interface.c b/src/qemu/qemu_interface.c index b0f0c5d..b9694c8 100644 --- a/src/qemu/qemu_interface.c +++ b/src/qemu/qemu_interface.c @@ -98,3 +98,69 @@ qemuInterfaceStartDevices(virDomainDefPtr def) } return 0; } + + +/** + * qemuInterfaceStopDevice: + * @net: net device to stop + * + * Based upon the type of device provided, perform the appropriate + * work to deactivate the device so that packets aren't forwarded to + * it from the rest of the network. + */ +int +qemuInterfaceStopDevice(virDomainNetDefPtr net) +{ + int ret = -1; + + switch (virDomainNetGetActualType(net)) { + case VIR_DOMAIN_NET_TYPE_BRIDGE: + case VIR_DOMAIN_NET_TYPE_NETWORK: + break; + + case VIR_DOMAIN_NET_TYPE_DIRECT: + /* macvtap interfaces need to be marked !IFF_UP (ie "down") to + * prevent any host-generated traffic sent from this interface + * from putting bad info into the arp caches of other machines + * on this network. + */ + if (virNetDevSetOnline(net->ifname, false) < 0) + goto cleanup; + break; + + case VIR_DOMAIN_NET_TYPE_USER: + case VIR_DOMAIN_NET_TYPE_ETHERNET: + case VIR_DOMAIN_NET_TYPE_VHOSTUSER: + case VIR_DOMAIN_NET_TYPE_SERVER: + case VIR_DOMAIN_NET_TYPE_CLIENT: + case VIR_DOMAIN_NET_TYPE_MCAST: + case VIR_DOMAIN_NET_TYPE_INTERNAL: + case VIR_DOMAIN_NET_TYPE_HOSTDEV: + case VIR_DOMAIN_NET_TYPE_LAST: + /* these types all require no action */ + break; + } + + ret = 0; + cleanup: + return ret; +} + +/** + * qemuInterfaceStopDevices: + * @def: domain definition + * + * Make all interfaces associated with this domain inaccessible from + * the rest of the network. + */ +int +qemuInterfaceStopDevices(virDomainDefPtr def) +{ + size_t i; + + for (i = 0; i < def->nnets; i++) { + if (qemuInterfaceStopDevice(def->nets[i]) < 0) + return -1; + } + return 0; +} diff --git a/src/qemu/qemu_interface.h b/src/qemu/qemu_interface.h index d040f52..b4c1efc 100644 --- a/src/qemu/qemu_interface.h +++ b/src/qemu/qemu_interface.h @@ -28,5 +28,7 @@ int qemuInterfaceStartDevice(virDomainNetDefPtr net); int qemuInterfaceStartDevices(virDomainDefPtr def); +int qemuInterfaceStopDevice(virDomainNetDefPtr net); +int qemuInterfaceStopDevices(virDomainDefPtr def); #endif /* __QEMU_INTERFACE_H__ */ diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index 0028283..a19e71a 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -3182,6 +3182,9 @@ int qemuProcessStopCPUs(virQEMUDriverPtr driver, if (ret < 0) goto cleanup; + /* de-activate netdevs after stopping CPUs */ + ignore_value(qemuInterfaceStopDevices(vm->def)); + if (priv->job.current) ignore_value(virTimeMillisNow(&priv->job.current->stopped));