[dpdk-dev] [PATCH 21.02 v2 1/2] net/virtio: fix missing backend features negotiation

[Xia, Chenbo]

Hi Maxime,

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin at redhat.com>
> Sent: Wednesday, November 25, 2020 11:21 PM
> To: dev at dpdk.org; Xia, Chenbo <chenbo.xia at intel.com>; amorenoz at redhat.com;
> jasowang at redhat.com; david.marchand at redhat.com
> Cc: Maxime Coquelin <maxime.coquelin at redhat.com>; stable at dpdk.org
> Subject: [PATCH 21.02 v2 1/2] net/virtio: fix missing backend features
> negotiation
> 
> This patch adds missing backend features negotiation for
> in Vhost-vDPA. Without it, IOTLB messages v2 could be sent
> by Virtio-user PMD while not supported by the backend.
> 
> Fixes: 6b901437056e ("net/virtio: introduce vhost-vDPA backend")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
> ---
>  drivers/net/virtio/virtio_user/vhost.h           |  4 ++++
>  drivers/net/virtio/virtio_user/vhost_vdpa.c      | 14 ++++++++++++++
>  drivers/net/virtio/virtio_user/virtio_user_dev.c | 14 ++++++++++----
>  3 files changed, 28 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_user/vhost.h
> b/drivers/net/virtio/virtio_user/vhost.h
> index 210a3704e7..c1dcc50b58 100644
> --- a/drivers/net/virtio/virtio_user/vhost.h
> +++ b/drivers/net/virtio/virtio_user/vhost.h
> @@ -86,6 +86,10 @@ enum vhost_user_request {
>  	VHOST_USER_MAX
>  };
> 
> +#ifndef VHOST_BACKEND_F_IOTLB_MSG_V2
> +#define VHOST_BACKEND_F_IOTLB_MSG_V2 1
> +#endif
> +
>  extern const char * const vhost_msg_strings[VHOST_USER_MAX];
> 
>  struct vhost_memory_region {
> diff --git a/drivers/net/virtio/virtio_user/vhost_vdpa.c
> b/drivers/net/virtio/virtio_user/vhost_vdpa.c
> index c7b9349fc8..b6c81d6f17 100644
> --- a/drivers/net/virtio/virtio_user/vhost_vdpa.c
> +++ b/drivers/net/virtio/virtio_user/vhost_vdpa.c
> @@ -35,6 +35,8 @@
>  #define VHOST_VDPA_SET_STATUS _IOW(VHOST_VIRTIO, 0x72, __u8)
>  #define VHOST_VDPA_SET_VRING_ENABLE	_IOW(VHOST_VIRTIO, 0x75, \
>  					     struct vhost_vring_state)
> +#define VHOST_SET_BACKEND_FEATURES _IOW(VHOST_VIRTIO, 0x25, __u64)
> +#define VHOST_GET_BACKEND_FEATURES _IOR(VHOST_VIRTIO, 0x26, __u64)
> 
>  static uint64_t vhost_req_user_to_vdpa[] = {
>  	[VHOST_USER_SET_OWNER] = VHOST_SET_OWNER,
> @@ -51,6 +53,8 @@ static uint64_t vhost_req_user_to_vdpa[] = {
>  	[VHOST_USER_SET_STATUS] = VHOST_VDPA_SET_STATUS,
>  	[VHOST_USER_GET_STATUS] = VHOST_VDPA_GET_STATUS,
>  	[VHOST_USER_SET_VRING_ENABLE] = VHOST_VDPA_SET_VRING_ENABLE,
> +	[VHOST_USER_GET_PROTOCOL_FEATURES] = VHOST_GET_BACKEND_FEATURES,
> +	[VHOST_USER_SET_PROTOCOL_FEATURES] = VHOST_SET_BACKEND_FEATURES,
>  };
> 
>  /* no alignment requirement */
> @@ -86,6 +90,11 @@ vhost_vdpa_dma_map(struct virtio_user_dev *dev, void *addr,
>  {
>  	struct vhost_msg msg = {};
> 
> +	if (!(dev->protocol_features & (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2)))
> {
> +		PMD_DRV_LOG(ERR, "IOTLB_MSG_V2 not supported by the backend.");
> +		return -1;
> +	}
> +
>  	msg.type = VHOST_IOTLB_MSG_V2;
>  	msg.iotlb.type = VHOST_IOTLB_UPDATE;
>  	msg.iotlb.iova = iova;
> @@ -108,6 +117,11 @@ vhost_vdpa_dma_unmap(struct virtio_user_dev *dev,
> __rte_unused void *addr,
>  {
>  	struct vhost_msg msg = {};
> 
> +	if (!(dev->protocol_features & (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2)))
> {
> +		PMD_DRV_LOG(ERR, "IOTLB_MSG_V2 not supported by the backend.");
> +		return -1;
> +	}
> +
>  	msg.type = VHOST_IOTLB_MSG_V2;
>  	msg.iotlb.type = VHOST_IOTLB_INVALIDATE;
>  	msg.iotlb.iova = iova;
> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> index 053f0267ca..96bc6b232d 100644
> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> @@ -439,11 +439,13 @@ virtio_user_dev_setup(struct virtio_user_dev *dev)
>  	 1ULL << VIRTIO_F_RING_PACKED		|	\
>  	 1ULL << VHOST_USER_F_PROTOCOL_FEATURES)
> 
> -#define VIRTIO_USER_SUPPORTED_PROTOCOL_FEATURES		\
> +#define VHOST_USER_SUPPORTED_PROTOCOL_FEATURES		\
>  	(1ULL << VHOST_USER_PROTOCOL_F_MQ |		\
>  	 1ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK |	\
>  	 1ULL << VHOST_USER_PROTOCOL_F_STATUS)
> 
> +#define VHOST_VDPA_SUPPORTED_PROTOCOL_FEATURES		\
> +	(1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2)
>  int
>  virtio_user_dev_init(struct virtio_user_dev *dev, char *path, int queues,
>  		     int cq, int queue_size, const char *mac, char **ifname,
> @@ -462,9 +464,13 @@ virtio_user_dev_init(struct virtio_user_dev *dev, char
> *path, int queues,
>  	dev->mac_specified = 0;
>  	dev->frontend_features = 0;
>  	dev->unsupported_features = ~VIRTIO_USER_SUPPORTED_FEATURES;
> -	dev->protocol_features = VIRTIO_USER_SUPPORTED_PROTOCOL_FEATURES;
>  	dev->backend_type = backend_type;
> 
> +	if (dev->backend_type == VIRTIO_USER_BACKEND_VHOST_USER)
> +		dev->protocol_features = VHOST_USER_SUPPORTED_PROTOCOL_FEATURES;
> +	else if (dev->backend_type == VIRTIO_USER_BACKEND_VHOST_VDPA)
> +		dev->protocol_features = VHOST_VDPA_SUPPORTED_PROTOCOL_FEATURES;
> +
>  	parse_mac(dev, mac);
> 
>  	if (*ifname) {
> @@ -497,8 +503,8 @@ virtio_user_dev_init(struct virtio_user_dev *dev, char
> *path, int queues,
>  		}
> 
> 
> -		if (dev->device_features &
> -				(1ULL << VHOST_USER_F_PROTOCOL_FEATURES)) {
> +		if ((dev->device_features & (1ULL <<
> VHOST_USER_F_PROTOCOL_FEATURES) ||
> +				dev->backend_type == VIRTIO_USER_BACKEND_VHOST_VDPA))

Do you mean:

if ((dev->device_features & (1ULL << VHOST_USER_F_PROTOCOL_FEATURES)) ||
				(dev->backend_type == VIRTIO_USER_BACKEND_VHOST_VDPA)) {

here?

Besides, I think it's better to update here as vhost-vdpa also uses protocol_features.
(http://code.dpdk.org/dpdk/v20.08/source/drivers/net/virtio/virtio_user/virtio_user_dev.h#L44)

Thanks!
Chenbo

> {
>  			if (dev->ops->send_request(dev,
>  					VHOST_USER_GET_PROTOCOL_FEATURES,
>  					&protocol_features))
> --
> 2.26.2