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

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

[Jens Freimann]

.dev_unplug_pending is set up by virtio-net code indepent of whether
failover=on 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>
---
 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 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>
---
 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

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

[Michael S. Tsirkin]

On Thu, Nov 14, 2019 at 03:16:11PM +0100, Jens Freimann wrote:
> 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 3/4] net/virtio: avoid passing NULL to qdev_set_parent_bus

[Jens Freimann]

Make sure no arguments for qdev_set_parent_bus are NULL.
This fixes CID 1407224.

Fixes: 9711cd0dfc3f ("net/virtio: add failover support")
Signed-off-by: Jens Freimann <jfreimann@redhat.com>
---
 hw/net/virtio-net.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index ac4d19109e..81650d4dc0 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -2809,8 +2809,16 @@ static bool failover_replug_primary(VirtIONet *n, Error **errp)
     if (n->primary_device_opts) {
         if (n->primary_dev) {
             n->primary_bus = n->primary_dev->parent_bus;
+            if (n->primary_bus) {
+                qdev_set_parent_bus(n->primary_dev, n->primary_bus);
+            } else  {
+                error_setg(errp, "virtio_net: couldn't set bus for primary");
+                goto out;
+            }
+        } else {
+            error_setg(errp, "virtio_net: couldn't find primary device");
+            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);
@@ -2819,10 +2827,8 @@ static bool failover_replug_primary(VirtIONet *n, Error **errp)
             hotplug_handler_pre_plug(hotplug_ctrl, n->primary_dev, errp);
             hotplug_handler_plug(hotplug_ctrl, n->primary_dev, errp);
         }
-        if (!n->primary_dev) {
-            error_setg(errp, "virtio_net: couldn't find primary device");
-        }
     }
+out:
     return *errp != NULL;
 }
 
-- 
2.21.0

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

[Michael S. Tsirkin]

On Thu, Nov 14, 2019 at 03:16:12PM +0100, Jens Freimann wrote:
> Make sure no arguments for qdev_set_parent_bus are NULL.
> This fixes CID 1407224.
> 
> Fixes: 9711cd0dfc3f ("net/virtio: add failover support")
> Signed-off-by: Jens Freimann <jfreimann@redhat.com>
> ---
>  hw/net/virtio-net.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index ac4d19109e..81650d4dc0 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -2809,8 +2809,16 @@ static bool failover_replug_primary(VirtIONet *n, Error **errp)
>      if (n->primary_device_opts) {
>          if (n->primary_dev) {
>              n->primary_bus = n->primary_dev->parent_bus;
> +            if (n->primary_bus) {
> +                qdev_set_parent_bus(n->primary_dev, n->primary_bus);
> +            } else  {
> +                error_setg(errp, "virtio_net: couldn't set bus for primary");
> +                goto out;
> +            }
> +        } else {
> +            error_setg(errp, "virtio_net: couldn't find primary device");
> +            goto out;
>          }


A bit less messy:

if (!n->primary_dev) {
            error_setg(errp, "virtio_net: couldn't find primary device");
            goto err;
}

n->primary_bus = n->primary_dev->parent_bus;
if (!n->primary_bus) {
      error_setg(errp, "virtio_net: couldn't find primary device");
          goto err;
}

qdev_set_parent_bus(n->primary_dev, n->primary_bus);

err:
	return false;

also is it valid for primary_device_opts to not be present at all?
Maybe we should check that too.



> -        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);
> @@ -2819,10 +2827,8 @@ static bool failover_replug_primary(VirtIONet *n, Error **errp)
>              hotplug_handler_pre_plug(hotplug_ctrl, n->primary_dev, errp);
>              hotplug_handler_plug(hotplug_ctrl, n->primary_dev, errp);
>          }
> -        if (!n->primary_dev) {
> -            error_setg(errp, "virtio_net: couldn't find primary device");
> -        }
>      }
> +out:
>      return *errp != NULL;
>  }

I'd handle errors separately from good path.
BTW I don't understand something here:
*errp != NULL is true on error, no?
Why are we returning success?
Confused.
Just return true would be cleaner imho.

>  
> -- 
> 2.21.0

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

[Jens Freimann]

On Wed, Nov 20, 2019 at 05:46:36AM -0500, Michael S. Tsirkin wrote:
>On Thu, Nov 14, 2019 at 03:16:12PM +0100, Jens Freimann wrote:
>> Make sure no arguments for qdev_set_parent_bus are NULL.
>> This fixes CID 1407224.
>>
>> Fixes: 9711cd0dfc3f ("net/virtio: add failover support")
>> Signed-off-by: Jens Freimann <jfreimann@redhat.com>
>> ---
>>  hw/net/virtio-net.c | 14 ++++++++++----
>>  1 file changed, 10 insertions(+), 4 deletions(-)
>>
>> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
>> index ac4d19109e..81650d4dc0 100644
>> --- a/hw/net/virtio-net.c
>> +++ b/hw/net/virtio-net.c
>> @@ -2809,8 +2809,16 @@ static bool failover_replug_primary(VirtIONet *n, Error **errp)
>>      if (n->primary_device_opts) {
>>          if (n->primary_dev) {
>>              n->primary_bus = n->primary_dev->parent_bus;
>> +            if (n->primary_bus) {
>> +                qdev_set_parent_bus(n->primary_dev, n->primary_bus);
>> +            } else  {
>> +                error_setg(errp, "virtio_net: couldn't set bus for primary");
>> +                goto out;
>> +            }
>> +        } else {
>> +            error_setg(errp, "virtio_net: couldn't find primary device");
>> +            goto out;
>>          }
>
>
>A bit less messy:
>
>if (!n->primary_dev) {
>            error_setg(errp, "virtio_net: couldn't find primary device");
>            goto err;
>}
>
>n->primary_bus = n->primary_dev->parent_bus;
>if (!n->primary_bus) {
>      error_setg(errp, "virtio_net: couldn't find primary device");
>          goto err;
>}
>
>qdev_set_parent_bus(n->primary_dev, n->primary_bus);
>
>err:
>	return false;
>
>also is it valid for primary_device_opts to not be present at all?
>Maybe we should check that too.
>
>
>
>> -        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);
>> @@ -2819,10 +2827,8 @@ static bool failover_replug_primary(VirtIONet *n, Error **errp)
>>              hotplug_handler_pre_plug(hotplug_ctrl, n->primary_dev, errp);
>>              hotplug_handler_plug(hotplug_ctrl, n->primary_dev, errp);
>>          }
>> -        if (!n->primary_dev) {
>> -            error_setg(errp, "virtio_net: couldn't find primary device");
>> -        }
>>      }
>> +out:
>>      return *errp != NULL;
>>  }
>
>I'd handle errors separately from good path.
>BTW I don't understand something here:
>*errp != NULL is true on error, no?
>Why are we returning success?
>Confused.
>Just return true would be cleaner imho.

I'll fix this and sent a new version as a single patch. As you said
this is not really a series, just individual patches. 

Thanks!

regards
Jens

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

[Michael S. Tsirkin]

On Wed, Nov 20, 2019 at 01:03:57PM +0100, Jens Freimann wrote:
> On Wed, Nov 20, 2019 at 05:46:36AM -0500, Michael S. Tsirkin wrote:
> > On Thu, Nov 14, 2019 at 03:16:12PM +0100, Jens Freimann wrote:
> > > Make sure no arguments for qdev_set_parent_bus are NULL.
> > > This fixes CID 1407224.
> > > 
> > > Fixes: 9711cd0dfc3f ("net/virtio: add failover support")
> > > Signed-off-by: Jens Freimann <jfreimann@redhat.com>
> > > ---
> > >  hw/net/virtio-net.c | 14 ++++++++++----
> > >  1 file changed, 10 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> > > index ac4d19109e..81650d4dc0 100644
> > > --- a/hw/net/virtio-net.c
> > > +++ b/hw/net/virtio-net.c
> > > @@ -2809,8 +2809,16 @@ static bool failover_replug_primary(VirtIONet *n, Error **errp)
> > >      if (n->primary_device_opts) {
> > >          if (n->primary_dev) {
> > >              n->primary_bus = n->primary_dev->parent_bus;
> > > +            if (n->primary_bus) {
> > > +                qdev_set_parent_bus(n->primary_dev, n->primary_bus);
> > > +            } else  {
> > > +                error_setg(errp, "virtio_net: couldn't set bus for primary");
> > > +                goto out;
> > > +            }
> > > +        } else {
> > > +            error_setg(errp, "virtio_net: couldn't find primary device");
> > > +            goto out;
> > >          }
> > 
> > 
> > A bit less messy:
> > 
> > if (!n->primary_dev) {
> >            error_setg(errp, "virtio_net: couldn't find primary device");
> >            goto err;
> > }
> > 
> > n->primary_bus = n->primary_dev->parent_bus;
> > if (!n->primary_bus) {
> >      error_setg(errp, "virtio_net: couldn't find primary device");
> >          goto err;
> > }
> > 
> > qdev_set_parent_bus(n->primary_dev, n->primary_bus);
> > 
> > err:
> > 	return false;
> > 
> > also is it valid for primary_device_opts to not be present at all?
> > Maybe we should check that too.
> > 
> > 
> > 
> > > -        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);
> > > @@ -2819,10 +2827,8 @@ static bool failover_replug_primary(VirtIONet *n, Error **errp)
> > >              hotplug_handler_pre_plug(hotplug_ctrl, n->primary_dev, errp);
> > >              hotplug_handler_plug(hotplug_ctrl, n->primary_dev, errp);
> > >          }
> > > -        if (!n->primary_dev) {
> > > -            error_setg(errp, "virtio_net: couldn't find primary device");
> > > -        }
> > >      }
> > > +out:
> > >      return *errp != NULL;
> > >  }
> > 
> > I'd handle errors separately from good path.
> > BTW I don't understand something here:
> > *errp != NULL is true on error, no?
> > Why are we returning success?
> > Confused.
> > Just return true would be cleaner imho.
> 
> I'll fix this and sent a new version as a single patch. As you said
> this is not really a series, just individual patches.
> 
> Thanks!
> 
> regards
> Jens

I'd just repost them all then. The series was also threaded weirdly
(e.g. there's no cover letter instead patches 2 and on link to patch 1).

-- 
MST

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

[Jens Freimann]

device_opts could be NULL. Make sure we don't pass it to
qemu_opts_to_dict. When we made sure it can't be NULL we can also remove
it from the if condition.
This fixes CID 1407222.

Fixes: 9711cd0dfc3f ("net/virtio: add failover support")
Signed-off-by: Jens Freimann <jfreimann@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 81650d4dc0..d53aa5796b 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -2878,9 +2878,12 @@ 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) {
@@ -2888,7 +2891,7 @@ 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 4/4] net/virtio: return error when device_opts arg is NULL

[Michael S. Tsirkin]

On Thu, Nov 14, 2019 at 03:16:13PM +0100, Jens Freimann wrote:
> device_opts could be NULL. Make sure we don't pass it to
> qemu_opts_to_dict. When we made sure it can't be NULL we can also remove
> it from the if condition.
> 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 81650d4dc0..d53aa5796b 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -2878,9 +2878,12 @@ 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) {
> @@ -2888,7 +2891,7 @@ 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 1/4] net/virtio: fix dev_unplug_pending

[Michael S. Tsirkin]

On Thu, Nov 14, 2019 at 03:16:10PM +0100, Jens Freimann wrote:
> .dev_unplug_pending is set up by virtio-net code indepent of whether
> failover=on 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>

This isn't really a series, is it?
Just a bunch of independent patches...

anyway:

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