[PATCH v2 0/4] net/virtio: fixes for failover

[PATCH v2 0/4] net/virtio: fixes for failover

[Jens Freimann]

This series fixes bugs found by coverity and one reported by David
Gilbert.

Jens Freimann (4):
  net/virtio: fix dev_unplug_pending
  net/virtio: return early when failover primary alread added
  net/virtio: avoid passing NULL to qdev_set_parent_bus
  net/virtio: return error when device_opts arg is NULL

 hw/net/virtio-net.c | 58 +++++++++++++++++++++++++++++----------------
 migration/savevm.c  |  3 ++-
 2 files changed, 40 insertions(+), 21 deletions(-)

-- 
2.21.0

[PATCH v2 1/4] net/virtio: fix dev_unplug_pending

[Jens Freimann]

.dev_unplug_pending is set up by virtio-net code indepent of failover
support was set for the device or not. This gives a wrong result when
we check for existing primary devices in migration code.

Fix this by actually calling dev_unplug_pending() instead of just
checking if the function pointer was set. When the feature was not
negotiated dev_unplug_pending() will always return false. This prevents
us from going into the wait-unplug state when there's no primary device
present.

Fixes: 9711cd0dfc3f ("net/virtio: add failover support")
Signed-off-by: Jens Freimann <jfreimann@redhat.com>
Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/net/virtio-net.c | 3 +++
 migration/savevm.c  | 3 ++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 97a5113f7e..946039c0dc 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -3124,6 +3124,9 @@ static bool primary_unplug_pending(void *opaque)
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VirtIONet *n = VIRTIO_NET(vdev);
 
+    if (!virtio_vdev_has_feature(vdev, VIRTIO_NET_F_STANDBY)) {
+        return false;
+    }
     return n->primary_dev ? n->primary_dev->pending_deleted_event : false;
 }
 
diff --git a/migration/savevm.c b/migration/savevm.c
index 966a9c3bdb..a71b930b91 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1119,7 +1119,8 @@ int qemu_savevm_nr_failover_devices(void)
     int n = 0;
 
     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
-        if (se->vmsd && se->vmsd->dev_unplug_pending) {
+        if (se->vmsd && se->vmsd->dev_unplug_pending &&
+            se->vmsd->dev_unplug_pending(se->opaque)) {
             n++;
         }
     }
-- 
2.21.0

[PATCH v2 2/4] net/virtio: return early when failover primary alread added

[Jens Freimann]

Bail out when primary device was already added before.
This avoids printing a wrong warning message during reboot.

Fixes: 9711cd0dfc3f ("net/virtio: add failover support")
Signed-off-by: Jens Freimann <jfreimann@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/net/virtio-net.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 946039c0dc..ac4d19109e 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -759,6 +759,10 @@ static void failover_add_primary(VirtIONet *n, Error **errp)
 {
     Error *err = NULL;
 
+    if (n->primary_dev) {
+        return;
+    }
+
     n->primary_device_opts = qemu_opts_find(qemu_find_opts("device"),
             n->primary_device_id);
     if (n->primary_device_opts) {
-- 
2.21.0

[PATCH v2 3/4] net/virtio: avoid passing NULL to qdev_set_parent_bus

[Jens Freimann]

Make sure we don't pass NULL to qdev_set_parent_bus(). Also simplify
code a bit and fix a typo.
This fixes CID 1407224.

Fixes: 9711cd0dfc3f ("net/virtio: add failover support")
Signed-off-by: Jens Freimann <jfreimann@redhat.com>
---
 hw/net/virtio-net.c | 42 +++++++++++++++++++++++++-----------------
 1 file changed, 25 insertions(+), 17 deletions(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index ac4d19109e..78f1e4e87c 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -2805,25 +2805,33 @@ static bool failover_replug_primary(VirtIONet *n, Error **errp)
         n->primary_device_opts = qemu_opts_from_qdict(
                 qemu_find_opts("device"),
                 n->primary_device_dict, errp);
-    }
-    if (n->primary_device_opts) {
-        if (n->primary_dev) {
-            n->primary_bus = n->primary_dev->parent_bus;
-        }
-        qdev_set_parent_bus(n->primary_dev, n->primary_bus);
-        n->primary_should_be_hidden = false;
-        qemu_opt_set_bool(n->primary_device_opts,
-                "partially_hotplugged", true, errp);
-        hotplug_ctrl = qdev_get_hotplug_handler(n->primary_dev);
-        if (hotplug_ctrl) {
-            hotplug_handler_pre_plug(hotplug_ctrl, n->primary_dev, errp);
-            hotplug_handler_plug(hotplug_ctrl, n->primary_dev, errp);
+        if (!n->primary_device_opts) {
+            error_setg(errp, "virtio_net: couldn't find primary device opts");
+            goto out;
         }
-        if (!n->primary_dev) {
+    }
+    if (!n->primary_dev) {
             error_setg(errp, "virtio_net: couldn't find primary device");
-        }
+            goto out;
     }
-    return *errp != NULL;
+
+    n->primary_bus = n->primary_dev->parent_bus;
+    if (!n->primary_bus) {
+        error_setg(errp, "virtio_net: couldn't find primary bus");
+        goto out;
+    }
+    qdev_set_parent_bus(n->primary_dev, n->primary_bus);
+    n->primary_should_be_hidden = false;
+    qemu_opt_set_bool(n->primary_device_opts,
+                      "partially_hotplugged", true, errp);
+    hotplug_ctrl = qdev_get_hotplug_handler(n->primary_dev);
+    if (hotplug_ctrl) {
+        hotplug_handler_pre_plug(hotplug_ctrl, n->primary_dev, errp);
+        hotplug_handler_plug(hotplug_ctrl, n->primary_dev, errp);
+    }
+
+out:
+    return *errp == NULL;
 }
 
 static void virtio_net_handle_migration_primary(VirtIONet *n,
@@ -2852,7 +2860,7 @@ static void virtio_net_handle_migration_primary(VirtIONet *n,
             warn_report("couldn't unplug primary device");
         }
     } else if (migration_has_failed(s)) {
-        /* We already unplugged the device let's plugged it back */
+        /* We already unplugged the device let's plug it back */
         if (!failover_replug_primary(n, &err)) {
             if (err) {
                 error_report_err(err);
-- 
2.21.0

[PATCH v2 4/4] net/virtio: return error when device_opts arg is NULL

[Jens Freimann]

This fixes CID 1407222.

Fixes: 9711cd0dfc3f ("net/virtio: add failover support")
Signed-off-by: Jens Freimann <jfreimann@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/net/virtio-net.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 78f1e4e87c..600c6e164f 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -2880,9 +2880,12 @@ static int virtio_net_primary_should_be_hidden(DeviceListener *listener,
             QemuOpts *device_opts)
 {
     VirtIONet *n = container_of(listener, VirtIONet, primary_listener);
-    bool match_found;
-    bool hide;
+    bool match_found = false;
+    bool hide = false;
 
+    if (!device_opts) {
+        return -1;
+    }
     n->primary_device_dict = qemu_opts_to_qdict(device_opts,
             n->primary_device_dict);
     if (n->primary_device_dict) {
@@ -2890,7 +2893,7 @@ static int virtio_net_primary_should_be_hidden(DeviceListener *listener,
         n->standby_id = g_strdup(qdict_get_try_str(n->primary_device_dict,
                     "failover_pair_id"));
     }
-    if (device_opts && g_strcmp0(n->standby_id, n->netclient_name) == 0) {
+    if (g_strcmp0(n->standby_id, n->netclient_name) == 0) {
         match_found = true;
     } else {
         match_found = false;
-- 
2.21.0

Re: [PATCH v2 3/4] net/virtio: avoid passing NULL to qdev_set_parent_bus

[Michael S. Tsirkin]

On Wed, Nov 20, 2019 at 03:38:58PM +0100, Jens Freimann wrote:
> Make sure we don't pass NULL to qdev_set_parent_bus(). Also simplify
> code a bit and fix a typo.
> This fixes CID 1407224.
> 
> Fixes: 9711cd0dfc3f ("net/virtio: add failover support")
> Signed-off-by: Jens Freimann <jfreimann@redhat.com>

patch itself is ok I think

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

but some questions on the commit log

> ---
>  hw/net/virtio-net.c | 42 +++++++++++++++++++++++++-----------------
>  1 file changed, 25 insertions(+), 17 deletions(-)
> 
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index ac4d19109e..78f1e4e87c 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -2805,25 +2805,33 @@ static bool failover_replug_primary(VirtIONet *n, Error **errp)
>          n->primary_device_opts = qemu_opts_from_qdict(
>                  qemu_find_opts("device"),
>                  n->primary_device_dict, errp);
> -    }
> -    if (n->primary_device_opts) {
> -        if (n->primary_dev) {
> -            n->primary_bus = n->primary_dev->parent_bus;
> -        }
> -        qdev_set_parent_bus(n->primary_dev, n->primary_bus);
> -        n->primary_should_be_hidden = false;
> -        qemu_opt_set_bool(n->primary_device_opts,
> -                "partially_hotplugged", true, errp);
> -        hotplug_ctrl = qdev_get_hotplug_handler(n->primary_dev);
> -        if (hotplug_ctrl) {
> -            hotplug_handler_pre_plug(hotplug_ctrl, n->primary_dev, errp);
> -            hotplug_handler_plug(hotplug_ctrl, n->primary_dev, errp);
> +        if (!n->primary_device_opts) {
> +            error_setg(errp, "virtio_net: couldn't find primary device opts");
> +            goto out;
>          }
> -        if (!n->primary_dev) {
> +    }
> +    if (!n->primary_dev) {
>              error_setg(errp, "virtio_net: couldn't find primary device");
> -        }
> +            goto out;
>      }
> -    return *errp != NULL;
> +
> +    n->primary_bus = n->primary_dev->parent_bus;
> +    if (!n->primary_bus) {
> +        error_setg(errp, "virtio_net: couldn't find primary bus");
> +        goto out;
> +    }
> +    qdev_set_parent_bus(n->primary_dev, n->primary_bus);
> +    n->primary_should_be_hidden = false;
> +    qemu_opt_set_bool(n->primary_device_opts,
> +                      "partially_hotplugged", true, errp);
> +    hotplug_ctrl = qdev_get_hotplug_handler(n->primary_dev);
> +    if (hotplug_ctrl) {
> +        hotplug_handler_pre_plug(hotplug_ctrl, n->primary_dev, errp);
> +        hotplug_handler_plug(hotplug_ctrl, n->primary_dev, errp);
> +    }
> +
> +out:
> +    return *errp == NULL;
>  }
>  
>  static void virtio_net_handle_migration_primary(VirtIONet *n,

So the logic actually was inverted here? Then ... how did this work?
and how was it tested?
Also, pls mention the change in the commit log.

> @@ -2852,7 +2860,7 @@ static void virtio_net_handle_migration_primary(VirtIONet *n,
>              warn_report("couldn't unplug primary device");
>          }
>      } else if (migration_has_failed(s)) {
> -        /* We already unplugged the device let's plugged it back */
> +        /* We already unplugged the device let's plug it back */
>          if (!failover_replug_primary(n, &err)) {
>              if (err) {
>                  error_report_err(err);
> -- 
> 2.21.0

Re: [PATCH v2 3/4] net/virtio: avoid passing NULL to qdev_set_parent_bus

[Jens Freimann]

On Wed, Nov 20, 2019 at 10:04:01AM -0500, Michael S. Tsirkin wrote:
>On Wed, Nov 20, 2019 at 03:38:58PM +0100, Jens Freimann wrote:
>> Make sure we don't pass NULL to qdev_set_parent_bus(). Also simplify
>> code a bit and fix a typo.
>> This fixes CID 1407224.
>>
>> Fixes: 9711cd0dfc3f ("net/virtio: add failover support")
>> Signed-off-by: Jens Freimann <jfreimann@redhat.com>
>
>patch itself is ok I think
>
>Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
>
>but some questions on the commit log
>
>> ---
>>  hw/net/virtio-net.c | 42 +++++++++++++++++++++++++-----------------
>>  1 file changed, 25 insertions(+), 17 deletions(-)
>>
>> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
>> index ac4d19109e..78f1e4e87c 100644
>> --- a/hw/net/virtio-net.c
>> +++ b/hw/net/virtio-net.c
>> @@ -2805,25 +2805,33 @@ static bool failover_replug_primary(VirtIONet *n, Error **errp)
>>          n->primary_device_opts = qemu_opts_from_qdict(
>>                  qemu_find_opts("device"),
>>                  n->primary_device_dict, errp);
>> -    }
>> -    if (n->primary_device_opts) {
>> -        if (n->primary_dev) {
>> -            n->primary_bus = n->primary_dev->parent_bus;
>> -        }
>> -        qdev_set_parent_bus(n->primary_dev, n->primary_bus);
>> -        n->primary_should_be_hidden = false;
>> -        qemu_opt_set_bool(n->primary_device_opts,
>> -                "partially_hotplugged", true, errp);
>> -        hotplug_ctrl = qdev_get_hotplug_handler(n->primary_dev);
>> -        if (hotplug_ctrl) {
>> -            hotplug_handler_pre_plug(hotplug_ctrl, n->primary_dev, errp);
>> -            hotplug_handler_plug(hotplug_ctrl, n->primary_dev, errp);
>> +        if (!n->primary_device_opts) {
>> +            error_setg(errp, "virtio_net: couldn't find primary device opts");
>> +            goto out;
>>          }
>> -        if (!n->primary_dev) {
>> +    }
>> +    if (!n->primary_dev) {
>>              error_setg(errp, "virtio_net: couldn't find primary device");
>> -        }
>> +            goto out;
>>      }
>> -    return *errp != NULL;
>> +
>> +    n->primary_bus = n->primary_dev->parent_bus;
>> +    if (!n->primary_bus) {
>> +        error_setg(errp, "virtio_net: couldn't find primary bus");
>> +        goto out;
>> +    }
>> +    qdev_set_parent_bus(n->primary_dev, n->primary_bus);
>> +    n->primary_should_be_hidden = false;
>> +    qemu_opt_set_bool(n->primary_device_opts,
>> +                      "partially_hotplugged", true, errp);
>> +    hotplug_ctrl = qdev_get_hotplug_handler(n->primary_dev);
>> +    if (hotplug_ctrl) {
>> +        hotplug_handler_pre_plug(hotplug_ctrl, n->primary_dev, errp);
>> +        hotplug_handler_plug(hotplug_ctrl, n->primary_dev, errp);
>> +    }
>> +
>> +out:
>> +    return *errp == NULL;
>>  }
>>
>>  static void virtio_net_handle_migration_primary(VirtIONet *n,
>
>So the logic actually was inverted here? Then ... how did this work?
>and how was it tested?

It did not work and I missed the error in my test output. I tested it
now manually by migrating and then cancelling. Device was added back
to source VM successfully.

Will sent new version with better patch description.

Thanks!

regards
Jens