diff mbox

[dpdk-dev] vhost: add interface name to virtio-net struct

Message ID 1418914523-24530-1-git-send-email-ciara.loftus@intel.com (mailing list archive)
State Superseded, archived
Headers show

Commit Message

Loftus, Ciara Dec. 18, 2014, 2:55 p.m. UTC
From: Ciara Loftus <ciara.loftus@intel.com>

This patch fixes the issue whereby when using userspace vhost ports
in the context of vSwitching, the name provided to the hypervisor/QEMU
of the vhost tap device needs to be exposed in the library, in order
for the vSwitch to be able to direct packets to the correct device.
This patch introduces an 'ifname' member to the virtio-net structure
which is populated with the tap device name when QEMU is brought up
with a vhost device.

Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
Signed-off-by: Anthony Fee <anthonyx.fee@intel.com>
Acked-by: Huawei Xie <huawei.xie@intel.com>
---
 lib/librte_vhost/rte_virtio_net.h |    1 +
 lib/librte_vhost/virtio-net.c     |   41 ++++++++++++++++++++++++++++++++++++-
 2 files changed, 41 insertions(+), 1 deletions(-)

Comments

Thomas Monjalon Dec. 18, 2014, 3:33 p.m. UTC | #1
2014-12-18 14:55, ciara.loftus@intel.com:
> This patch fixes the issue whereby when using userspace vhost ports
> in the context of vSwitching, the name provided to the hypervisor/QEMU
> of the vhost tap device needs to be exposed in the library, in order
> for the vSwitch to be able to direct packets to the correct device.

Do you mean that vhost was not working at all?
Please precise the context and how it is critical.
More informations are needed to understand wether it should be merged in
release 1.8.0 or not.

> --- a/lib/librte_vhost/rte_virtio_net.h
> +++ b/lib/librte_vhost/rte_virtio_net.h
> @@ -96,6 +96,7 @@ struct virtio_net {
>  	uint64_t		features;	/**< Negotiated feature set. */
>  	uint64_t		device_fh;	/**< device identifier. */
>  	uint32_t		flags;		/**< Device flags. Only used to check if device is running on data core. */
> +	char			ifname[32];	/** Name of the tap device **/

Wrong comment style.
Stephen Hemminger Dec. 18, 2014, 4:20 p.m. UTC | #2
On Thu, 18 Dec 2014 14:55:23 +0000
ciara.loftus@intel.com wrote:

> diff --git a/lib/librte_vhost/rte_virtio_net.h b/lib/librte_vhost/rte_virtio_net.h
> index 00b1328..aebb4b5 100644
> --- a/lib/librte_vhost/rte_virtio_net.h
> +++ b/lib/librte_vhost/rte_virtio_net.h
> @@ -96,6 +96,7 @@ struct virtio_net {
>  	uint64_t		features;	/**< Negotiated feature set. */
>  	uint64_t		device_fh;	/**< device identifier. */
>  	uint32_t		flags;		/**< Device flags. Only used to check if device is running on data core. */
> +	char			ifname[32];	/** Name of the tap device **/

Linux and BSD the maximum network device name size is 16
Vincent Jardin Dec. 18, 2014, 4:26 p.m. UTC | #3
>> +	char			ifname[32];	/** Name of the tap device **/
>
> Linux and BSD the maximum network device name size is 16
>
In any case, please, use IF_NAMESIZE or IFNAMSIZ

see:
http://fxr.watson.org/fxr/ident?v=FREEBSD51;im=bigexcerpts;i=IF_NAMESIZE
Loftus, Ciara Dec. 18, 2014, 5:01 p.m. UTC | #4
Hi Thomas,

A basic vHost use case will work, for example a single Virtual Machine with a vHost port. However normal vSwitching use cases will require the use of multiple vHost ports and multiple VMs. With that in mind, it is essential that the vSwitch has some way of knowing which vHost port it is sending to and receiving packets from. This patch resolves this issue by exposing the tap device name of the vHost device. Without that information we cannot determine the particular vHost port to send/receive from, which in the context of switching, is a critical problem.

Thanks,
Ciara

-----Original Message-----
From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com] 
Sent: Thursday, December 18, 2014 3:33 PM
To: Loftus, Ciara
Cc: dev@dpdk.org; Anthony Fee
Subject: Re: [dpdk-dev] [PATCH] vhost: add interface name to virtio-net struct

2014-12-18 14:55, ciara.loftus@intel.com:
> This patch fixes the issue whereby when using userspace vhost ports in 
> the context of vSwitching, the name provided to the hypervisor/QEMU of 
> the vhost tap device needs to be exposed in the library, in order for 
> the vSwitch to be able to direct packets to the correct device.

Do you mean that vhost was not working at all?
Please precise the context and how it is critical.
More informations are needed to understand wether it should be merged in release 1.8.0 or not.

> --- a/lib/librte_vhost/rte_virtio_net.h
> +++ b/lib/librte_vhost/rte_virtio_net.h
> @@ -96,6 +96,7 @@ struct virtio_net {
>  	uint64_t		features;	/**< Negotiated feature set. */
>  	uint64_t		device_fh;	/**< device identifier. */
>  	uint32_t		flags;		/**< Device flags. Only used to check if device is running on data core. */
> +	char			ifname[32];	/** Name of the tap device **/

Wrong comment style.

--
Thomas
--------------------------------------------------------------
Intel Shannon Limited
Registered in Ireland
Registered Office: Collinstown Industrial Park, Leixlip, County Kildare
Registered Number: 308263
Business address: Dromore House, East Park, Shannon, Co. Clare

This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). Any review or distribution by others is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.
Konstantin Ananyev Dec. 18, 2014, 5:03 p.m. UTC | #5
> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of ciara.loftus@intel.com
> Sent: Thursday, December 18, 2014 2:55 PM
> To: dev@dpdk.org
> Cc: Anthony Fee
> Subject: [dpdk-dev] [PATCH] vhost: add interface name to virtio-net struct
> 
> From: Ciara Loftus <ciara.loftus@intel.com>
> 
> This patch fixes the issue whereby when using userspace vhost ports
> in the context of vSwitching, the name provided to the hypervisor/QEMU
> of the vhost tap device needs to be exposed in the library, in order
> for the vSwitch to be able to direct packets to the correct device.
> This patch introduces an 'ifname' member to the virtio-net structure
> which is populated with the tap device name when QEMU is brought up
> with a vhost device.
> 
> Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
> Signed-off-by: Anthony Fee <anthonyx.fee@intel.com>
> Acked-by: Huawei Xie <huawei.xie@intel.com>
> ---
>  lib/librte_vhost/rte_virtio_net.h |    1 +
>  lib/librte_vhost/virtio-net.c     |   41 ++++++++++++++++++++++++++++++++++++-
>  2 files changed, 41 insertions(+), 1 deletions(-)
> 
> diff --git a/lib/librte_vhost/rte_virtio_net.h b/lib/librte_vhost/rte_virtio_net.h
> index 00b1328..aebb4b5 100644
> --- a/lib/librte_vhost/rte_virtio_net.h
> +++ b/lib/librte_vhost/rte_virtio_net.h
> @@ -96,6 +96,7 @@ struct virtio_net {
>  	uint64_t		features;	/**< Negotiated feature set. */
>  	uint64_t		device_fh;	/**< device identifier. */
>  	uint32_t		flags;		/**< Device flags. Only used to check if device is running on data core. */
> +	char			ifname[32];	/** Name of the tap device **/
>  	void			*priv;		/**< private context */
>  } __rte_cache_aligned;
> 
> diff --git a/lib/librte_vhost/virtio-net.c b/lib/librte_vhost/virtio-net.c
> index 852b6d1..7f90ecf 100644
> --- a/lib/librte_vhost/virtio-net.c
> +++ b/lib/librte_vhost/virtio-net.c
> @@ -43,6 +43,10 @@
>  #include <sys/mman.h>
>  #include <unistd.h>
> 
> +#include <sys/socket.h>
> +#include <linux/if_tun.h>
> +#include <linux/if.h>
> +
>  #include <rte_ethdev.h>
>  #include <rte_log.h>
>  #include <rte_string_fns.h>
> @@ -1000,6 +1004,39 @@ set_vring_kick(struct vhost_device_ctx ctx, struct vhost_vring_file *file)
>  }
> 
>  /*
> + * Function to get the tap device name from the provided file descriptor and
> + * save it in the device structure.
> + */
> +static int
> +get_ifname(struct virtio_net *dev, int tap_fd, int pid)
> +{
> +	struct eventfd_copy fd_tap;
> +	struct ifreq ifr;
> +	uint32_t size;
> +
> +	fd_tap.source_fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
> +	fd_tap.target_fd = tap_fd;
> +	fd_tap.target_pid = pid;
> +
> +	if (eventfd_copy(dev, &fd_tap))
> +		return -1;
> +
> +	ioctl(fd_tap.source_fd, TUNGETIFF, &ifr);

Shouldn't we check that ioctl() returns with success here,
and if it fails, don't copy stuff over?

> +
> +	if (close(fd_tap.source_fd) < 0)
> +		RTE_LOG(ERR, VHOST_CONFIG,
> +			"(%"PRIu64") fd close failed\n",
> +			dev->device_fh);
> +
> +	size = strnlen(ifr.ifr_name, sizeof(ifr.ifr_name)) > sizeof(dev->ifname)?
> +			sizeof(dev->ifname): strnlen(ifr.ifr_name, sizeof(ifr.ifr_name));
> +

So if sizeof(ifr.ifr_name) > sizeof(dev->ifname) then we can endup with dev->ifname not being null-termianted?
Another nit: there is no need to call strnlen() twice.

Konstantin

> +	strncpy(dev->ifname, ifr.ifr_name, size);
> +
> +	return 0;
> +}
> +
> +/*
>   * Called from CUSE IOCTL: VHOST_NET_SET_BACKEND
>   * To complete device initialisation when the virtio driver is loaded,
>   * we are provided with a valid fd for a tap device (not used by us).
> @@ -1026,8 +1063,10 @@ set_backend(struct vhost_device_ctx ctx, struct vhost_vring_file *file)
>  	 */
>  	if (!(dev->flags & VIRTIO_DEV_RUNNING)) {
>  		if (((int)dev->virtqueue[VIRTIO_TXQ]->backend != VIRTIO_DEV_STOPPED) &&
> -			((int)dev->virtqueue[VIRTIO_RXQ]->backend != VIRTIO_DEV_STOPPED))
> +			((int)dev->virtqueue[VIRTIO_RXQ]->backend != VIRTIO_DEV_STOPPED)) {
> +			get_ifname(dev, file->fd, ctx.pid);
>  			return notify_ops->new_device(dev);
> +		}
>  	/* Otherwise we remove it. */
>  	} else
>  		if (file->fd == VIRTIO_DEV_STOPPED)
> --
> 1.7.4.1
Huawei Xie Dec. 18, 2014, 5:16 p.m. UTC | #6
> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Loftus, Ciara
> Sent: Thursday, December 18, 2014 10:02 AM
> To: Thomas Monjalon
> Cc: dev@dpdk.org; Anthony Fee
> Subject: Re: [dpdk-dev] [PATCH] vhost: add interface name to virtio-net struct
> 
> Hi Thomas,
> 
> A basic vHost use case will work, for example a single Virtual Machine with a
> vHost port. However normal vSwitching use cases will require the use of multiple
> vHost ports and multiple VMs. With that in mind, it is essential that the vSwitch
> has some way of knowing which vHost port it is sending to and receiving packets
> from. This patch resolves this issue by exposing the tap device name of the
> vHost device. Without that information we cannot determine the particular
> vHost port to send/receive from, which in the context of switching, is a critical
> problem.


For example, in qemu command line, we specify tap device "tap1" for virtio device in "VM1", and "tap2" for virtio device in "VM2".
vSwitch wants to expose the tap device name in the virtio_net device structure otherwise it doesn't know the virtio_device it gets
is for which VM.
The mac address isn't enough for vSwitch.
The problem is for vhost-user, we have no such kind of identity, unless we create socket for each virtio device, and use the socket
path string.

> 
> Thanks,
> Ciara
> 
> -----Original Message-----
> From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> Sent: Thursday, December 18, 2014 3:33 PM
> To: Loftus, Ciara
> Cc: dev@dpdk.org; Anthony Fee
> Subject: Re: [dpdk-dev] [PATCH] vhost: add interface name to virtio-net struct
> 
> 2014-12-18 14:55, ciara.loftus@intel.com:
> > This patch fixes the issue whereby when using userspace vhost ports in
> > the context of vSwitching, the name provided to the hypervisor/QEMU of
> > the vhost tap device needs to be exposed in the library, in order for
> > the vSwitch to be able to direct packets to the correct device.
> 
> Do you mean that vhost was not working at all?
> Please precise the context and how it is critical.
> More informations are needed to understand wether it should be merged in
> release 1.8.0 or not.
> 
> > --- a/lib/librte_vhost/rte_virtio_net.h
> > +++ b/lib/librte_vhost/rte_virtio_net.h
> > @@ -96,6 +96,7 @@ struct virtio_net {
> >  	uint64_t		features;	/**< Negotiated feature set.
> */
> >  	uint64_t		device_fh;	/**< device identifier. */
> >  	uint32_t		flags;		/**< Device flags. Only used to
> check if device is running on data core. */
> > +	char			ifname[32];	/** Name of the tap device
> **/
> 
> Wrong comment style.
> 
> --
> Thomas
Czesnowicz, Przemyslaw Dec. 18, 2014, 5:20 p.m. UTC | #7
> Hi Thomas,
> 
> A basic vHost use case will work, for example a single Virtual Machine with a
> vHost port. However normal vSwitching use cases will require the use of multiple
> vHost ports and multiple VMs. With that in mind, it is essential that the vSwitch
> has some way of knowing which vHost port it is sending to and receiving packets
> from. This patch resolves this issue by exposing the tap device name of the
> vHost device. Without that information we cannot determine the particular
> vHost port to send/receive from, which in the context of switching, is a critical
> problem.


Exactly.
The vSwitch uses tap name to associate the virtio device with ovs port.
Without this change the vhost library cannot be used in vSwitch.

Regards
Przemek

> 
> Thanks,
> Ciara
>
Loftus, Ciara Dec. 18, 2014, 6:11 p.m. UTC | #8
Hi Konstantin,

Thank you for the feedback. 

As regards the following:
"So if sizeof(ifr.ifr_name) > sizeof(dev->ifname) then we can endup with dev->ifname not being null-termianted?"
This should never be the case as now both dev->ifname and ifr.ifr_name are of size IFNAMSIZ in v2 of the patch.

Thanks,
Ciara

-----Original Message-----
From: Ananyev, Konstantin 
Sent: Thursday, December 18, 2014 5:03 PM
To: Loftus, Ciara; dev@dpdk.org
Cc: Anthony Fee
Subject: RE: [dpdk-dev] [PATCH] vhost: add interface name to virtio-net struct



> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of 
> ciara.loftus@intel.com
> Sent: Thursday, December 18, 2014 2:55 PM
> To: dev@dpdk.org
> Cc: Anthony Fee
> Subject: [dpdk-dev] [PATCH] vhost: add interface name to virtio-net 
> struct
> 
> From: Ciara Loftus <ciara.loftus@intel.com>
> 
> This patch fixes the issue whereby when using userspace vhost ports in 
> the context of vSwitching, the name provided to the hypervisor/QEMU of 
> the vhost tap device needs to be exposed in the library, in order for 
> the vSwitch to be able to direct packets to the correct device.
> This patch introduces an 'ifname' member to the virtio-net structure 
> which is populated with the tap device name when QEMU is brought up 
> with a vhost device.
> 
> Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
> Signed-off-by: Anthony Fee <anthonyx.fee@intel.com>
> Acked-by: Huawei Xie <huawei.xie@intel.com>
> ---
>  lib/librte_vhost/rte_virtio_net.h |    1 +
>  lib/librte_vhost/virtio-net.c     |   41 ++++++++++++++++++++++++++++++++++++-
>  2 files changed, 41 insertions(+), 1 deletions(-)
> 
> diff --git a/lib/librte_vhost/rte_virtio_net.h 
> b/lib/librte_vhost/rte_virtio_net.h
> index 00b1328..aebb4b5 100644
> --- a/lib/librte_vhost/rte_virtio_net.h
> +++ b/lib/librte_vhost/rte_virtio_net.h
> @@ -96,6 +96,7 @@ struct virtio_net {
>  	uint64_t		features;	/**< Negotiated feature set. */
>  	uint64_t		device_fh;	/**< device identifier. */
>  	uint32_t		flags;		/**< Device flags. Only used to check if device is running on data core. */
> +	char			ifname[32];	/** Name of the tap device **/
>  	void			*priv;		/**< private context */
>  } __rte_cache_aligned;
> 
> diff --git a/lib/librte_vhost/virtio-net.c 
> b/lib/librte_vhost/virtio-net.c index 852b6d1..7f90ecf 100644
> --- a/lib/librte_vhost/virtio-net.c
> +++ b/lib/librte_vhost/virtio-net.c
> @@ -43,6 +43,10 @@
>  #include <sys/mman.h>
>  #include <unistd.h>
> 
> +#include <sys/socket.h>
> +#include <linux/if_tun.h>
> +#include <linux/if.h>
> +
>  #include <rte_ethdev.h>
>  #include <rte_log.h>
>  #include <rte_string_fns.h>
> @@ -1000,6 +1004,39 @@ set_vring_kick(struct vhost_device_ctx ctx, 
> struct vhost_vring_file *file)  }
> 
>  /*
> + * Function to get the tap device name from the provided file 
> +descriptor and
> + * save it in the device structure.
> + */
> +static int
> +get_ifname(struct virtio_net *dev, int tap_fd, int pid) {
> +	struct eventfd_copy fd_tap;
> +	struct ifreq ifr;
> +	uint32_t size;
> +
> +	fd_tap.source_fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
> +	fd_tap.target_fd = tap_fd;
> +	fd_tap.target_pid = pid;
> +
> +	if (eventfd_copy(dev, &fd_tap))
> +		return -1;
> +
> +	ioctl(fd_tap.source_fd, TUNGETIFF, &ifr);

Shouldn't we check that ioctl() returns with success here, and if it fails, don't copy stuff over?

> +
> +	if (close(fd_tap.source_fd) < 0)
> +		RTE_LOG(ERR, VHOST_CONFIG,
> +			"(%"PRIu64") fd close failed\n",
> +			dev->device_fh);
> +
> +	size = strnlen(ifr.ifr_name, sizeof(ifr.ifr_name)) > sizeof(dev->ifname)?
> +			sizeof(dev->ifname): strnlen(ifr.ifr_name, sizeof(ifr.ifr_name));
> +

So if sizeof(ifr.ifr_name) > sizeof(dev->ifname) then we can endup with dev->ifname not being null-termianted?
Another nit: there is no need to call strnlen() twice.

Konstantin

> +	strncpy(dev->ifname, ifr.ifr_name, size);
> +
> +	return 0;
> +}
> +
> +/*
>   * Called from CUSE IOCTL: VHOST_NET_SET_BACKEND
>   * To complete device initialisation when the virtio driver is loaded,
>   * we are provided with a valid fd for a tap device (not used by us).
> @@ -1026,8 +1063,10 @@ set_backend(struct vhost_device_ctx ctx, struct vhost_vring_file *file)
>  	 */
>  	if (!(dev->flags & VIRTIO_DEV_RUNNING)) {
>  		if (((int)dev->virtqueue[VIRTIO_TXQ]->backend != VIRTIO_DEV_STOPPED) &&
> -			((int)dev->virtqueue[VIRTIO_RXQ]->backend != VIRTIO_DEV_STOPPED))
> +			((int)dev->virtqueue[VIRTIO_RXQ]->backend != VIRTIO_DEV_STOPPED)) {
> +			get_ifname(dev, file->fd, ctx.pid);
>  			return notify_ops->new_device(dev);
> +		}
>  	/* Otherwise we remove it. */
>  	} else
>  		if (file->fd == VIRTIO_DEV_STOPPED)
> --
> 1.7.4.1

--------------------------------------------------------------
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Registered in Ireland
Registered Office: Collinstown Industrial Park, Leixlip, County Kildare
Registered Number: 308263
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This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). Any review or distribution by others is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.
diff mbox

Patch

diff --git a/lib/librte_vhost/rte_virtio_net.h b/lib/librte_vhost/rte_virtio_net.h
index 00b1328..aebb4b5 100644
--- a/lib/librte_vhost/rte_virtio_net.h
+++ b/lib/librte_vhost/rte_virtio_net.h
@@ -96,6 +96,7 @@  struct virtio_net {
 	uint64_t		features;	/**< Negotiated feature set. */
 	uint64_t		device_fh;	/**< device identifier. */
 	uint32_t		flags;		/**< Device flags. Only used to check if device is running on data core. */
+	char			ifname[32];	/** Name of the tap device **/
 	void			*priv;		/**< private context */
 } __rte_cache_aligned;
 
diff --git a/lib/librte_vhost/virtio-net.c b/lib/librte_vhost/virtio-net.c
index 852b6d1..7f90ecf 100644
--- a/lib/librte_vhost/virtio-net.c
+++ b/lib/librte_vhost/virtio-net.c
@@ -43,6 +43,10 @@ 
 #include <sys/mman.h>
 #include <unistd.h>
 
+#include <sys/socket.h>
+#include <linux/if_tun.h>
+#include <linux/if.h>
+
 #include <rte_ethdev.h>
 #include <rte_log.h>
 #include <rte_string_fns.h>
@@ -1000,6 +1004,39 @@  set_vring_kick(struct vhost_device_ctx ctx, struct vhost_vring_file *file)
 }
 
 /*
+ * Function to get the tap device name from the provided file descriptor and
+ * save it in the device structure.
+ */
+static int
+get_ifname(struct virtio_net *dev, int tap_fd, int pid)
+{
+	struct eventfd_copy fd_tap;
+	struct ifreq ifr;
+	uint32_t size;
+
+	fd_tap.source_fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
+	fd_tap.target_fd = tap_fd;
+	fd_tap.target_pid = pid;
+
+	if (eventfd_copy(dev, &fd_tap))
+		return -1;
+
+	ioctl(fd_tap.source_fd, TUNGETIFF, &ifr);
+
+	if (close(fd_tap.source_fd) < 0)
+		RTE_LOG(ERR, VHOST_CONFIG,
+			"(%"PRIu64") fd close failed\n",
+			dev->device_fh);
+
+	size = strnlen(ifr.ifr_name, sizeof(ifr.ifr_name)) > sizeof(dev->ifname)?
+			sizeof(dev->ifname): strnlen(ifr.ifr_name, sizeof(ifr.ifr_name));
+
+	strncpy(dev->ifname, ifr.ifr_name, size);
+
+	return 0;
+}
+
+/*
  * Called from CUSE IOCTL: VHOST_NET_SET_BACKEND
  * To complete device initialisation when the virtio driver is loaded,
  * we are provided with a valid fd for a tap device (not used by us).
@@ -1026,8 +1063,10 @@  set_backend(struct vhost_device_ctx ctx, struct vhost_vring_file *file)
 	 */
 	if (!(dev->flags & VIRTIO_DEV_RUNNING)) {
 		if (((int)dev->virtqueue[VIRTIO_TXQ]->backend != VIRTIO_DEV_STOPPED) &&
-			((int)dev->virtqueue[VIRTIO_RXQ]->backend != VIRTIO_DEV_STOPPED))
+			((int)dev->virtqueue[VIRTIO_RXQ]->backend != VIRTIO_DEV_STOPPED)) {
+			get_ifname(dev, file->fd, ctx.pid);
 			return notify_ops->new_device(dev);
+		}
 	/* Otherwise we remove it. */
 	} else
 		if (file->fd == VIRTIO_DEV_STOPPED)