Re: [dpdk-stable] [dpdk-dev v2 1/2] vhost: add backend type in driver start

["Zhang, Roy Fan" <roy.fan.zhang@intel.com>]

Hi Maxime,

I think you are right :-)

Regards,
Fan

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Tuesday, October 6, 2020 8:54 AM
> To: Zhang, Roy Fan <roy.fan.zhang@intel.com>; dev@dpdk.org
> Cc: Xia, Chenbo <chenbo.xia@intel.com>; Liu, Changpeng
> <changpeng.liu@intel.com>; Yigit, Ferruh <ferruh.yigit@intel.com>;
> stable@dpdk.org
> Subject: Re: [dpdk-dev v2 1/2] vhost: add backend type in driver start
> 
> Hi Fan,
> 
> On 10/2/20 5:36 PM, Fan Zhang wrote:
> > This patch adds an internal driver start function with a newly
> > added backend type identifier as parameter. With this way
> > different built-in driver types (net, crypto) can be identified.
> >
> > Signed-off-by: Fan Zhang <roy.fan.zhang@intel.com>
> > ---
> >  lib/librte_vhost/socket.c     | 39 ++++++++++++++++++++++++++++-------
> >  lib/librte_vhost/vhost_user.h |  8 +++++++
> >  2 files changed, 39 insertions(+), 8 deletions(-)
> >
> > diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c
> > index 0169d3648..a53e536ac 100644
> > --- a/lib/librte_vhost/socket.c
> > +++ b/lib/librte_vhost/socket.c
> > @@ -38,7 +38,7 @@ struct vhost_user_socket {
> >  	bool is_server;
> >  	bool reconnect;
> >  	bool iommu_support;
> > -	bool use_builtin_virtio_net;
> > +	enum virtio_backend_type backend_type;
> >  	bool extbuf;
> >  	bool linearbuf;
> >  	bool async_copy;
> > @@ -224,7 +224,9 @@ vhost_user_add_connection(int fd, struct
> vhost_user_socket *vsocket)
> >  	size = strnlen(vsocket->path, PATH_MAX);
> >  	vhost_set_ifname(vid, vsocket->path, size);
> >
> > -	vhost_set_builtin_virtio_net(vid, vsocket->use_builtin_virtio_net);
> > +	vhost_set_builtin_virtio_net(vid,
> > +			vsocket->backend_type ==
> VIRTIO_DEV_BUILTIN_NET ?
> > +					true : false);
> >
> >  	vhost_attach_vdpa_device(vid, vsocket->vdpa_dev);
> >
> > @@ -632,7 +634,7 @@ rte_vhost_driver_disable_features(const char
> *path, uint64_t features)
> >  	pthread_mutex_lock(&vhost_user.mutex);
> >  	vsocket = find_vhost_user_socket(path);
> >
> > -	/* Note that use_builtin_virtio_net is not affected by this function
> > +	/* Note that backend type is not affected by this function
> >  	 * since callers may want to selectively disable features of the
> >  	 * built-in vhost net device backend.
> >  	 */
> > @@ -681,7 +683,8 @@ rte_vhost_driver_set_features(const char *path,
> uint64_t features)
> >  		/* Anyone setting feature bits is implementing their own
> vhost
> >  		 * device backend.
> >  		 */
> > -		vsocket->use_builtin_virtio_net = false;
> > +		if (vsocket->backend_type == VIRTIO_DEV_BUILTIN_NET)
> > +			vsocket->backend_type = VIRTIO_DEV_UNKNOWN;
> >  	}
> >  	pthread_mutex_unlock(&vhost_user.mutex);
> >
> > @@ -899,7 +902,7 @@ rte_vhost_driver_register(const char *path,
> uint64_t flags)
> >  	 * rte_vhost_driver_set_features(), which will overwrite following
> >  	 * two values.
> >  	 */
> > -	vsocket->use_builtin_virtio_net = true;
> > +	vsocket->backend_type = VIRTIO_DEV_BUILTIN_NET;
> >  	vsocket->supported_features =
> VIRTIO_NET_SUPPORTED_FEATURES;
> >  	vsocket->features           = VIRTIO_NET_SUPPORTED_FEATURES;
> >  	vsocket->protocol_features  = VHOST_USER_PROTOCOL_FEATURES;
> > @@ -1117,10 +1120,17 @@ vhost_driver_callback_get(const char *path)
> >  }
> >
> >  int
> > -rte_vhost_driver_start(const char *path)
> > +vhost_driver_start(const char *path, enum virtio_backend_type
> backend_type)
> >  {
> >  	struct vhost_user_socket *vsocket;
> >  	static pthread_t fdset_tid;
> > +	int ret;
> > +
> > +	if (backend_type <= VIRTIO_DEV_UNKNOWN ||
> > +			backend_type > VIRTIO_DEV_BUILTIN_CRYPTO) {
> > +		VHOST_LOG_CONFIG(ERR, "Wrong backend type\n");
> > +		return -1;
> > +	}
> >
> >  	pthread_mutex_lock(&vhost_user.mutex);
> >  	vsocket = find_vhost_user_socket(path);
> > @@ -1153,7 +1163,20 @@ rte_vhost_driver_start(const char *path)
> >  	}
> >
> >  	if (vsocket->is_server)
> > -		return vhost_user_start_server(vsocket);
> > +		ret = vhost_user_start_server(vsocket);
> >  	else
> > -		return vhost_user_start_client(vsocket);
> > +		ret = vhost_user_start_client(vsocket);
> > +
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	vsocket->backend_type = backend_type;
> > +
> > +	return 0;
> 
> Looking at it again, I think patch 1 is not necessary.
> Patch 2 should be enough and would be easier to backport.
> 
> What do you think?
> 
> Regards,
> Maxime
> 
> > +}
> > +
> > +int
> > +rte_vhost_driver_start(const char *path)
> > +{
> > +	return vhost_driver_start(path, VIRTIO_DEV_BUILTIN_NET);
> >  }
> > diff --git a/lib/librte_vhost/vhost_user.h b/lib/librte_vhost/vhost_user.h
> > index 16fe03f88..9f526e676 100644
> > --- a/lib/librte_vhost/vhost_user.h
> > +++ b/lib/librte_vhost/vhost_user.h
> > @@ -158,6 +158,12 @@ typedef struct VhostUserMsg {
> >  /* The version of the protocol we support */
> >  #define VHOST_USER_VERSION    0x1
> >
> > +/* virtio backend types */
> > +enum virtio_backend_type {
> > +	VIRTIO_DEV_UNKNOWN = 0, /* Likely external */
> > +	VIRTIO_DEV_BUILTIN_NET, /* Virtio-net device */
> > +	VIRTIO_DEV_BUILTIN_CRYPTO, /* Virtio-crypto device */
> > +};
> >
> >  /* vhost_user.c */
> >  int vhost_user_msg_handler(int vid, int fd);
> > @@ -167,5 +173,7 @@ int vhost_user_iotlb_miss(struct virtio_net *dev,
> uint64_t iova, uint8_t perm);
> >  int read_fd_message(int sockfd, char *buf, int buflen, int *fds, int
> max_fds,
> >  		int *fd_num);
> >  int send_fd_message(int sockfd, char *buf, int buflen, int *fds, int
> fd_num);
> > +int vhost_driver_start(const char *path,
> > +		enum virtio_backend_type backend_type);
> >
> >  #endif
> >