From 8a8d77f47e838413c829ee6202eb1f64613d12e1 Mon Sep 17 00:00:00 2001

Message-Id: <8a8d77f47e838413c829ee6202eb1f64613d12e1@dist-git>

From: Laine Stump <laine@redhat.com>

Date: Tue, 21 Feb 2023 01:16:04 -0500

Subject: [PATCH] qemu: respond to NETDEV_STREAM_DISCONNECTED event

When a QEMU netdev is of type "stream", if the socket it uses for

connectivity to the host network gets closed, then QEMU will send a

NETDEV_STREAM_DISCONNECTED event. We know that any stream netdev we've

created is backed by a passt process, and if the socket was closed,

that means the passt process has disappeared.

When we receive this event, we can respond by starting a new passt

process with the same options (including socket path) we originally

used. If we have previously created the stream netdev device with a

"reconnect" option, then QEMU will automatically reconnect to this new

passt process. (If we hadn't used "reconnect", then QEMU will never

try to reconnect to the new passt process, so there's no point in

starting it.)

Note that NETDEV_STREAM_DISCONNECTED is an event sent for the netdev

(ie "host side") of the network device, and so it sends the

"netdev-id" to specify which device was disconnected. But libvirt's

virDomainNetDef (the object used to keep track of network devices) is

the internal representation of both the host-side "netdev", and the

guest side device, and virDomainNetDef doesn't directly keep track of

the netdev-id, only of the device's "alias" (which is the "id"

parameter of the *guest* side of the device). Fortunately, by convention

libvirt always names the host-side of devices as "host" + alias, so in

order to search for the affected NetDef, all we need to do is trim the

1st 4 characters from the netdev-id and look for the NetDef having

that resulting trimmed string as its alias. (Contrast this to

NIC_RX_FILTER_CHANGED, which is an event received for the guest side

of the device, and so directly contains the device alias.)

Resolves: https://bugzilla.redhat.com/2172098

Signed-off-by: Laine Stump <laine@redhat.com>

Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

(cherry picked from commit f62ce81b8a57d8033be4c661e071cbd12b83bf7b)

Signed-off-by: Laine Stump <laine@redhat.com>

---

 src/qemu/qemu_domain.c       |  1 +

 src/qemu/qemu_domain.h       |  1 +

 src/qemu/qemu_driver.c       | 76 ++++++++++++++++++++++++++++++++++++

 src/qemu/qemu_monitor.c      | 11 ++++++

 src/qemu/qemu_monitor.h      |  6 +++

 src/qemu/qemu_monitor_json.c | 16 ++++++++

 src/qemu/qemu_process.c      | 18 +++++++++

 7 files changed, 129 insertions(+)

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c

index 247134672b..26408b90a2 100644

--- a/src/qemu/qemu_domain.c

+++ b/src/qemu/qemu_domain.c

@@ -11165,6 +11165,7 @@ qemuProcessEventFree(struct qemuProcessEvent *event)

         break;

     case QEMU_PROCESS_EVENT_WATCHDOG:

     case QEMU_PROCESS_EVENT_DEVICE_DELETED:

+    case QEMU_PROCESS_EVENT_NETDEV_STREAM_DISCONNECTED:

     case QEMU_PROCESS_EVENT_NIC_RX_FILTER_CHANGED:

     case QEMU_PROCESS_EVENT_SERIAL_CHANGED:

     case QEMU_PROCESS_EVENT_MONITOR_EOF:

diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h

index eca5404cdc..fb9ab4c5ed 100644

--- a/src/qemu/qemu_domain.h

+++ b/src/qemu/qemu_domain.h

@@ -442,6 +442,7 @@ typedef enum {

     QEMU_PROCESS_EVENT_WATCHDOG = 0,

     QEMU_PROCESS_EVENT_GUESTPANIC,

     QEMU_PROCESS_EVENT_DEVICE_DELETED,

+    QEMU_PROCESS_EVENT_NETDEV_STREAM_DISCONNECTED,

     QEMU_PROCESS_EVENT_NIC_RX_FILTER_CHANGED,

     QEMU_PROCESS_EVENT_SERIAL_CHANGED,

     QEMU_PROCESS_EVENT_JOB_STATUS_CHANGE,

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c

index 0603af6a35..d00b91fe0b 100644

--- a/src/qemu/qemu_driver.c

+++ b/src/qemu/qemu_driver.c

@@ -40,6 +40,7 @@

 #include "qemu_hostdev.h"

 #include "qemu_hotplug.h"

 #include "qemu_monitor.h"

+#include "qemu_passt.h"

 #include "qemu_process.h"

 #include "qemu_migration.h"

 #include "qemu_migration_params.h"

@@ -3622,6 +3623,78 @@ processDeviceDeletedEvent(virQEMUDriver *driver,

 }

+static void

+processNetdevStreamDisconnectedEvent(virDomainObj *vm,

+                                     const char *netdevId)

+{

+    virDomainDeviceDef dev;

+    virDomainNetDef *def;

+    virQEMUCaps *qemuCaps = QEMU_DOMAIN_PRIVATE(vm)->qemuCaps;

+    const char *devAlias = STRSKIP(netdevId, "host");

+

+    /* The event sends us the "netdev-id", but we don't store the

+     * netdev-id in the NetDef and thus can't use it to find the

+     * correct NetDef. We *do* keep the device alias in the NetDef,

+     * and by convention the netdev-id is always "host" + devAlias, so

+     * we just need to remove "host" from the front of netdev-id to

+     * get the alias, which we can then use to find the proper NetDef.

+     */

+

+    if (!devAlias) {

+        VIR_WARN("Received NETDEV_STREAM_DISCONNECTED event for unrecognized netdev %s from domain %p %s",

+                  netdevId, vm, vm->def->name);

+        return;

+    }

+

+    VIR_DEBUG("Received NETDEV_STREAM_DISCONNECTED event for device %s from domain %p %s",

+              devAlias, vm, vm->def->name);

+

+    if (virDomainObjBeginJob(vm, VIR_JOB_QUERY) < 0)

+        return;

+

+    if (!virDomainObjIsActive(vm)) {

+        VIR_DEBUG("Domain is not running");

+        goto endjob;

+    }

+

+    if (virDomainDefFindDevice(vm->def, devAlias, &dev, true) < 0) {

+        VIR_WARN("NETDEV_STREAM_DISCONNECTED event received for non-existent device %s in domain %s",

+                 devAlias, vm->def->name);

+        goto endjob;

+    }

+    if (dev.type != VIR_DOMAIN_DEVICE_NET) {

+        VIR_WARN("NETDEV_STREAM_DISCONNECTED event received for non-network device %s in domain %s",

+                 devAlias, vm->def->name);

+        goto endjob;

+    }

+    def = dev.data.net;

+

+    if (def->backend.type != VIR_DOMAIN_NET_BACKEND_PASST) {

+        VIR_DEBUG("ignore NETDEV_STREAM_DISCONNECTED event for non-passt network device %s in domain %s",

+                  def->info.alias, vm->def->name);

+        goto endjob;

+    }

+

+    if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_NETDEV_STREAM_RECONNECT)) {

+        VIR_WARN("ignore NETDEV_STREAM_DISCONNECTED event for passt network device %s in domain %s - QEMU binary does not support reconnect",

+                  def->info.alias, vm->def->name);

+        goto endjob;

+    }

+

+    /* handle the event - restart the passt process with its original

+     * parameters

+     */

+    VIR_DEBUG("process NETDEV_STREAM_DISCONNECTED event for network device %s in domain %s",

+              def->info.alias, vm->def->name);

+

+    if (qemuPasstStart(vm, def) < 0)

+        goto endjob;

+

+ endjob:

+    virDomainObjEndJob(vm);

+}

+

+

 static void

 processNicRxFilterChangedEvent(virDomainObj *vm,

                                const char *devAlias)

@@ -3971,6 +4044,9 @@ static void qemuProcessEventHandler(void *data, void *opaque)

     case QEMU_PROCESS_EVENT_DEVICE_DELETED:

         processDeviceDeletedEvent(driver, vm, processEvent->data);

         break;

+    case QEMU_PROCESS_EVENT_NETDEV_STREAM_DISCONNECTED:

+        processNetdevStreamDisconnectedEvent(vm, processEvent->data);

+        break;

     case QEMU_PROCESS_EVENT_NIC_RX_FILTER_CHANGED:

         processNicRxFilterChangedEvent(vm, processEvent->data);

         break;

diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c

index 38f89167e0..1fa35f03cc 100644

--- a/src/qemu/qemu_monitor.c

+++ b/src/qemu/qemu_monitor.c

@@ -1265,6 +1265,17 @@ qemuMonitorEmitNicRxFilterChanged(qemuMonitor *mon,

 }

+void

+qemuMonitorEmitNetdevStreamDisconnected(qemuMonitor *mon,

+                                        const char *devAlias)

+{

+    VIR_DEBUG("mon=%p", mon);

+

+    QEMU_MONITOR_CALLBACK(mon, domainNetdevStreamDisconnected,

+                          mon->vm, devAlias);

+}

+

+

 void

 qemuMonitorEmitSerialChange(qemuMonitor *mon,

                             const char *devAlias,

diff --git a/src/qemu/qemu_monitor.h b/src/qemu/qemu_monitor.h

index 2d16214ba2..2fa06b99a3 100644

--- a/src/qemu/qemu_monitor.h

+++ b/src/qemu/qemu_monitor.h

@@ -250,6 +250,9 @@ typedef void (*qemuMonitorDomainDeviceUnplugErrCallback)(qemuMonitor *mon,

                                                          virDomainObj *vm,

                                                          const char *devPath,

                                                          const char *devAlias);

+typedef void (*qemuMonitorDomainNetdevStreamDisconnectedCallback)(qemuMonitor *mon,

+                                                                  virDomainObj *vm,

+                                                                  const char *devAlias);

 typedef void (*qemuMonitorDomainNicRxFilterChangedCallback)(qemuMonitor *mon,

                                                             virDomainObj *vm,

                                                             const char *devAlias);

@@ -397,6 +400,7 @@ struct _qemuMonitorCallbacks {

     qemuMonitorDomainMemoryFailureCallback domainMemoryFailure;

     qemuMonitorDomainMemoryDeviceSizeChange domainMemoryDeviceSizeChange;

     qemuMonitorDomainDeviceUnplugErrCallback domainDeviceUnplugError;

+    qemuMonitorDomainNetdevStreamDisconnectedCallback domainNetdevStreamDisconnected;

 };

 qemuMonitor *qemuMonitorOpen(virDomainObj *vm,

@@ -480,6 +484,8 @@ void qemuMonitorEmitDeviceDeleted(qemuMonitor *mon,

 void qemuMonitorEmitDeviceUnplugErr(qemuMonitor *mon,

                                     const char *devPath,

                                     const char *devAlias);

+void qemuMonitorEmitNetdevStreamDisconnected(qemuMonitor *mon,

+                                             const char *devAlias);

 void qemuMonitorEmitNicRxFilterChanged(qemuMonitor *mon,

                                        const char *devAlias);

 void qemuMonitorEmitSerialChange(qemuMonitor *mon,

diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c

index db99017555..4510d0d3c9 100644

--- a/src/qemu/qemu_monitor_json.c

+++ b/src/qemu/qemu_monitor_json.c

@@ -84,6 +84,7 @@ static void qemuMonitorJSONHandleRdmaGidStatusChanged(qemuMonitor *mon, virJSONV

 static void qemuMonitorJSONHandleMemoryFailure(qemuMonitor *mon, virJSONValue *data);

 static void qemuMonitorJSONHandleMemoryDeviceSizeChange(qemuMonitor *mon, virJSONValue *data);

 static void qemuMonitorJSONHandleDeviceUnplugErr(qemuMonitor *mon, virJSONValue *data);

+static void qemuMonitorJSONHandleNetdevStreamDisconnected(qemuMonitor *mon, virJSONValue *data);

 typedef struct {

     const char *type;

@@ -106,6 +107,7 @@ static qemuEventHandler eventHandlers[] = {

     { "MEMORY_FAILURE", qemuMonitorJSONHandleMemoryFailure, },

     { "MIGRATION", qemuMonitorJSONHandleMigrationStatus, },

     { "MIGRATION_PASS", qemuMonitorJSONHandleMigrationPass, },

+    { "NETDEV_STREAM_DISCONNECTED", qemuMonitorJSONHandleNetdevStreamDisconnected, },

     { "NIC_RX_FILTER_CHANGED", qemuMonitorJSONHandleNicRxFilterChanged, },

     { "PR_MANAGER_STATUS_CHANGED", qemuMonitorJSONHandlePRManagerStatusChanged, },

     { "RDMA_GID_STATUS_CHANGED", qemuMonitorJSONHandleRdmaGidStatusChanged, },

@@ -1021,6 +1023,20 @@ qemuMonitorJSONHandleDeviceUnplugErr(qemuMonitor *mon, virJSONValue *data)

 }

+static void

+qemuMonitorJSONHandleNetdevStreamDisconnected(qemuMonitor *mon, virJSONValue *data)

+{

+    const char *name;

+

+    if (!(name = virJSONValueObjectGetString(data, "netdev-id"))) {

+        VIR_WARN("missing device in NETDEV_STREAM_DISCONNECTED event");

+        return;

+    }

+

+    qemuMonitorEmitNetdevStreamDisconnected(mon, name);

+}

+

+

 static void

 qemuMonitorJSONHandleNicRxFilterChanged(qemuMonitor *mon, virJSONValue *data)

 {

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c

index 7ae859d68f..298904fe2e 100644

--- a/src/qemu/qemu_process.c

+++ b/src/qemu/qemu_process.c

@@ -1360,6 +1360,23 @@ qemuProcessHandleBlockThreshold(qemuMonitor *mon G_GNUC_UNUSED,

 }

+static void

+qemuProcessHandleNetdevStreamDisconnected(qemuMonitor *mon G_GNUC_UNUSED,

+                                          virDomainObj *vm,

+                                          const char *devAlias)

+{

+    virObjectLock(vm);

+

+    VIR_DEBUG("Device %s Netdev Stream Disconnected in domain %p %s",

+              devAlias, vm, vm->def->name);

+

+    qemuProcessEventSubmit(vm, QEMU_PROCESS_EVENT_NETDEV_STREAM_DISCONNECTED,

+                           0, 0, g_strdup(devAlias));

+

+    virObjectUnlock(vm);

+}

+

+

 static void

 qemuProcessHandleNicRxFilterChanged(qemuMonitor *mon G_GNUC_UNUSED,

                                     virDomainObj *vm,

@@ -1801,6 +1818,7 @@ static qemuMonitorCallbacks monitorCallbacks = {

     .domainMemoryFailure = qemuProcessHandleMemoryFailure,

     .domainMemoryDeviceSizeChange = qemuProcessHandleMemoryDeviceSizeChange,

     .domainDeviceUnplugError = qemuProcessHandleDeviceUnplugErr,

+    .domainNetdevStreamDisconnected = qemuProcessHandleNetdevStreamDisconnected,

 };

 static void

-- 

2.39.2