[dpdk-dev] [PATCH v4 3/5] vhost: add apis for datapath configuration

Wang, Zhihong zhihong.wang at intel.com
Mon Apr 2 04:01:59 CEST 2018



> -----Original Message-----
> From: Maxime Coquelin [mailto:maxime.coquelin at redhat.com]
> Sent: Saturday, March 31, 2018 3:04 PM
> To: Wang, Zhihong <zhihong.wang at intel.com>; dev at dpdk.org
> Cc: Tan, Jianfeng <jianfeng.tan at intel.com>; Bie, Tiwei
> <tiwei.bie at intel.com>; yliu at fridaylinux.org; Liang, Cunming
> <cunming.liang at intel.com>; Wang, Xiao W <xiao.w.wang at intel.com>; Daly,
> Dan <dan.daly at intel.com>
> Subject: Re: [PATCH v4 3/5] vhost: add apis for datapath configuration
> 
> 
> 
> On 03/10/2018 11:01 AM, Zhihong Wang wrote:
> > This patch adds APIs for datapath configuration.
> >
> > The did of the vhost-user socket can be set to identify the backend device,
> > in this case each vhost-user socket can have only 1 connection. The did is
> > set to -1 by default when the software datapath is used.
> >
> > Signed-off-by: Zhihong Wang <zhihong.wang at intel.com>
> > ---
> > Changes in v4:
> >
> >   1. Remove the "engine" concept in the lib.
> >
> >   lib/librte_vhost/rte_vhost.h           | 35
> +++++++++++++++++++++++++++++++++
> >   lib/librte_vhost/rte_vhost_version.map |  3 +++
> >   lib/librte_vhost/socket.c              | 36
> ++++++++++++++++++++++++++++++++++
> >   lib/librte_vhost/vhost.c               | 25 +++++++++++++++++++++++
> >   lib/librte_vhost/vhost.h               |  9 +++++++++
> >   5 files changed, 108 insertions(+)
> >
> > diff --git a/lib/librte_vhost/rte_vhost.h b/lib/librte_vhost/rte_vhost.h
> > index 671ea5053..d50f4c67d 100644
> > --- a/lib/librte_vhost/rte_vhost.h
> > +++ b/lib/librte_vhost/rte_vhost.h
> > @@ -200,6 +200,30 @@ int rte_vhost_driver_register(const char *path,
> uint64_t flags);
> >   int rte_vhost_driver_unregister(const char *path);
> >
> >   /**
> > + * Set the device id, enforce single connection per socket
> > + *
> > + * @param path
> > + *  The vhost-user socket file path
> > + * @param did
> > + *  Device id
> > + * @return
> > + *  0 on success, -1 on failure
> > + */
> > +int __rte_experimental
> > +rte_vhost_driver_set_vdpa_did(const char *path, int did);
> 
> IIUC, we call this to attach a VDPA device to a Vhost-user port?
> 
> What about having this named explicitly? Something like:
> 
> rte_vhost_driver_attach_vdpa_did(const char *path, int did)
> rte_vhost_driver_detach_vdpa_did(const char *path)
> 
> The later would set to did -1

Great. This does make things clearer.

> 
> This is not mandatory though
> 
> > +
> > +/**
> > + * Get the device id
> > + *
> > + * @param path
> > + *  The vhost-user socket file path
> > + * @return
> > + *  Device id, -1 on failure
> > + */
> > +int __rte_experimental
> > +rte_vhost_driver_get_vdpa_did(const char *path);
> > +
> > +/**
> >    * Set the feature bits the vhost-user driver supports.
> >    *
> >    * @param path
> > @@ -464,6 +488,17 @@ int rte_vhost_vring_call(int vid, uint16_t vring_idx);
> >    */
> >   uint32_t rte_vhost_rx_queue_count(int vid, uint16_t qid);
> >
> > +/**
> > + * Get vdpa device id for vhost device.
> > + *
> > + * @param vid
> > + *  vhost device ID
> > + * @return
> > + *  device id
> > + */
> > +int __rte_experimental
> > +rte_vhost_get_vdpa_did(int vid);
> > +
> >   #ifdef __cplusplus
> >   }
> >   #endif
> > diff --git a/lib/librte_vhost/rte_vhost_version.map
> b/lib/librte_vhost/rte_vhost_version.map
> > index 7bcffb490..6e2d5364a 100644
> > --- a/lib/librte_vhost/rte_vhost_version.map
> > +++ b/lib/librte_vhost/rte_vhost_version.map
> > @@ -64,4 +64,7 @@ EXPERIMENTAL {
> >   	rte_vdpa_register_device;
> >   	rte_vdpa_unregister_device;
> >   	rte_vdpa_find_device_id;
> > +	rte_vhost_driver_set_vdpa_did;
> > +	rte_vhost_driver_get_vdpa_did;
> > +	rte_vhost_get_vdpa_did;
> >   } DPDK_18.02;
> > diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c
> > index cfc31e179..3d58da94e 100644
> > --- a/lib/librte_vhost/socket.c
> > +++ b/lib/librte_vhost/socket.c
> > @@ -52,6 +52,13 @@ struct vhost_user_socket {
> >   	uint64_t supported_features;
> >   	uint64_t features;
> >
> > +	/*
> > +	 * Device id to identify a specific backend device.
> > +	 * It's set to -1 for the default software implementation.
> > +	 * If valid, one socket can have 1 connection only.
> > +	 */
> > +	int did;
> I would rename it to something like vdpa_did or even better,
> vdpa_dev_id. At least prefix it with vdpa not to confuse the user.

Good suggestion.

> 
> > +
> >   	struct vhost_device_ops const *notify_ops;
> >   };
> >
> > @@ -545,6 +552,35 @@ find_vhost_user_socket(const char *path)
> >   }
> >
> >   int
> > +rte_vhost_driver_set_vdpa_did(const char *path, int did)
> > +{
> > +	struct vhost_user_socket *vsocket;
> > +
> > +	pthread_mutex_lock(&vhost_user.mutex);
> > +	vsocket = find_vhost_user_socket(path);
> > +	if (vsocket)
> > +		vsocket->did = did;
> 
> I guess it is possible to know whether the did exists
> at that time. Maybe we could check this?

Ok.

> 
> > +	pthread_mutex_unlock(&vhost_user.mutex);
> > +
> > +	return vsocket ? 0 : -1;
> > +}
> > +
> > +int
> > +rte_vhost_driver_get_vdpa_did(const char *path)
> > +{
> > +	struct vhost_user_socket *vsocket;
> > +	int did = -1;
> > +
> > +	pthread_mutex_lock(&vhost_user.mutex);
> > +	vsocket = find_vhost_user_socket(path);
> > +	if (vsocket)
> > +		did = vsocket->did;
> > +	pthread_mutex_unlock(&vhost_user.mutex);
> > +
> > +	return did;
> > +}
> > +
> > +int
> >   rte_vhost_driver_disable_features(const char *path, uint64_t features)
> >   {
> >   	struct vhost_user_socket *vsocket;
> > diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
> > index f6f12a03b..1740cc1ab 100644
> > --- a/lib/librte_vhost/vhost.c
> > +++ b/lib/librte_vhost/vhost.c
> > @@ -283,6 +283,7 @@ vhost_new_device(void)
> >   	dev->vid = i;
> >   	dev->flags = VIRTIO_DEV_BUILTIN_VIRTIO_NET;
> >   	dev->slave_req_fd = -1;
> > +	dev->did = -1;
> >
> >   	return i;
> >   }
> > @@ -311,6 +312,20 @@ vhost_destroy_device(int vid)
> >   }
> >
> >   void
> > +vhost_set_vdpa_did(int vid, int did)
> > +{
> > +	struct virtio_net *dev = get_device(vid);
> > +
> > +	if (did < 0)
> > +		return;
> > +
> > +	if (dev == NULL)
> > +		return;
> > +
> > +	dev->did = did;
> > +}
> > +
> > +void
> >   vhost_set_ifname(int vid, const char *if_name, unsigned int if_len)
> >   {
> >   	struct virtio_net *dev;
> > @@ -614,3 +629,13 @@ rte_vhost_rx_queue_count(int vid, uint16_t qid)
> >
> >   	return *((volatile uint16_t *)&vq->avail->idx) - vq->last_avail_idx;
> >   }
> > +
> > +int rte_vhost_get_vdpa_did(int vid)
> > +{
> > +	struct virtio_net *dev = get_device(vid);
> > +
> > +	if (dev == NULL)
> > +		return -1;
> > +
> > +	return dev->did;
> > +}
> > diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> > index 2e28e4026..2970c1eab 100644
> > --- a/lib/librte_vhost/vhost.h
> > +++ b/lib/librte_vhost/vhost.h
> > @@ -19,6 +19,7 @@
> >   #include <rte_rwlock.h>
> >
> >   #include "rte_vhost.h"
> > +#include "rte_vdpa.h"
> >
> >   /* Used to indicate that the device is running on a data core */
> >   #define VIRTIO_DEV_RUNNING 1
> > @@ -239,6 +240,12 @@ struct virtio_net {
> >   	struct guest_page       *guest_pages;
> >
> >   	int			slave_req_fd;
> > +
> > +	/*
> > +	 * Device id to identify a specific backend device.
> > +	 * It's set to -1 for the default software implementation.
> > +	 */
> > +	int			did;
> 
> Same as for struct vhost_user_socket, it would be less confusing to
> prefix it with vdpa.

Ok.

Thanks
-Zhihong

> 
> >   } __rte_cache_aligned;
> >
> >
> > @@ -365,6 +372,8 @@ void free_vq(struct vhost_virtqueue *vq);
> >
> >   int alloc_vring_queue(struct virtio_net *dev, uint32_t vring_idx);
> >
> > +void vhost_set_vdpa_did(int vid, int did);
> > +
> >   void vhost_set_ifname(int, const char *if_name, unsigned int if_len);
> >   void vhost_enable_dequeue_zero_copy(int vid);
> >   void vhost_set_builtin_virtio_net(int vid, bool enable);
> >


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