Re: [dpdk-dev] [PATCH 6/9] vhost: add support for virtio status

["Xia, Chenbo" <chenbo.xia@intel.com>]

Hi Adrian,

> -----Original Message-----
> From: Adrian Moreno <amorenoz@redhat.com>
> Sent: Monday, June 22, 2020 6:18 PM
> To: Xia, Chenbo <chenbo.xia@intel.com>; Maxime Coquelin
> <maxime.coquelin@redhat.com>; Ye, Xiaolong <xiaolong.ye@intel.com>;
> shahafs@mellanox.com; matan@mellanox.com; Wang, Xiao W
> <xiao.w.wang@intel.com>; viacheslavo@mellanox.com; dev@dpdk.org
> Cc: jasowang@redhat.com; lulu@redhat.com
> Subject: Re: [dpdk-dev] [PATCH 6/9] vhost: add support for virtio status
> 
> Hi Chenbo
> 
> On 6/16/20 6:29 AM, Xia, Chenbo wrote:
> > Hi Maxime,
> >
> >> -----Original Message-----
> >> From: dev <dev-bounces@dpdk.org> On Behalf Of Maxime Coquelin
> >> Sent: Thursday, May 14, 2020 4:02 PM
> >> To: Ye, Xiaolong <xiaolong.ye@intel.com>; shahafs@mellanox.com;
> >> matan@mellanox.com; amorenoz@redhat.com; Wang, Xiao W
> >> <xiao.w.wang@intel.com>; viacheslavo@mellanox.com; dev@dpdk.org
> >> Cc: jasowang@redhat.com; lulu@redhat.com; Maxime Coquelin
> >> <maxime.coquelin@redhat.com>
> >> Subject: [dpdk-dev] [PATCH 6/9] vhost: add support for virtio status
> >>
> >> This patch adds support to the new Virtio device status Vhost-user
> >> protocol feature.
> >>
> >> Getting such information in the backend helps to know when the driver
> >> is done with the device configuration and so makes the initialization phase
> more robust.
> >>
> >> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> >> ---
> >>  lib/librte_vhost/rte_vhost.h  |  4 ++++
> >>  lib/librte_vhost/vhost.h      |  9 ++++++++
> >>  lib/librte_vhost/vhost_user.c | 40
> >> +++++++++++++++++++++++++++++++++++
> >>  lib/librte_vhost/vhost_user.h |  6 ++++--
> >>  4 files changed, 57 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/lib/librte_vhost/rte_vhost.h
> >> b/lib/librte_vhost/rte_vhost.h index
> >> 5c72fba797..b4b7aa1928 100644
> >> --- a/lib/librte_vhost/rte_vhost.h
> >> +++ b/lib/librte_vhost/rte_vhost.h
> >> @@ -85,6 +85,10 @@ extern "C" {
> >>  #define VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD 12  #endif
> >>
> >> +#ifndef VHOST_USER_PROTOCOL_F_STATUS #define
> >> +VHOST_USER_PROTOCOL_F_STATUS 15 #endif
> >> +
> >>  /** Indicate whether protocol features negotiation is supported. */
> >> #ifndef VHOST_USER_F_PROTOCOL_FEATURES
> >>  #define VHOST_USER_F_PROTOCOL_FEATURES	30
> >> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> >> index
> >> df98d15de6..9a9c0a98f5 100644
> >> --- a/lib/librte_vhost/vhost.h
> >> +++ b/lib/librte_vhost/vhost.h
> >> @@ -202,6 +202,14 @@ struct vhost_virtqueue {
> >>  	TAILQ_HEAD(, vhost_iotlb_entry) iotlb_pending_list;  }
> >> __rte_cache_aligned;
> >>
> >> +/* Virtio device status as per Virtio specification */
> >> +#define VIRTIO_DEVICE_STATUS_ACK		0x01
> >> +#define VIRTIO_DEVICE_STATUS_DRIVER		0x02
> >> +#define VIRTIO_DEVICE_STATUS_DRIVER_OK		0x04
> >> +#define VIRTIO_DEVICE_STATUS_FEATURES_OK	0x08
> >> +#define VIRTIO_DEVICE_STATUS_DEV_NEED_RESET	0x40
> >> +#define VIRTIO_DEVICE_STATUS_FAILED		0x80
> >> +
> >>  /* Old kernels have no such macros defined */  #ifndef
> >> VIRTIO_NET_F_GUEST_ANNOUNCE
> >>   #define VIRTIO_NET_F_GUEST_ANNOUNCE 21 @@ -364,6 +372,7 @@
> struct
> >> virtio_net {
> >>  	uint64_t		log_addr;
> >>  	struct rte_ether_addr	mac;
> >>  	uint16_t		mtu;
> >> +	uint8_t			status;
> >>
> >>  	struct vhost_device_ops const *notify_ops;
> >>
> >> diff --git a/lib/librte_vhost/vhost_user.c
> >> b/lib/librte_vhost/vhost_user.c index 4a847f368c..e5a44be58d 100644
> >> --- a/lib/librte_vhost/vhost_user.c
> >> +++ b/lib/librte_vhost/vhost_user.c
> >> @@ -87,6 +87,7 @@ static const char
> >> *vhost_message_str[VHOST_USER_MAX]
> >> = {
> >>  	[VHOST_USER_POSTCOPY_END]  = "VHOST_USER_POSTCOPY_END",
> >>  	[VHOST_USER_GET_INFLIGHT_FD] = "VHOST_USER_GET_INFLIGHT_FD",
> >>  	[VHOST_USER_SET_INFLIGHT_FD] = "VHOST_USER_SET_INFLIGHT_FD",
> >> +	[VHOST_USER_SET_STATUS] = "VHOST_USER_SET_STATUS",
> >>  };
> >>
> >>  static int send_vhost_reply(int sockfd, struct VhostUserMsg *msg);
> >> @@ -1328,6
> >> +1329,11 @@ virtio_is_ready(struct virtio_net *dev)
> >>  			return 0;
> >>  	}
> >>
> >> +	/* If supported, ensure the frontend is really done with config */
> >> +	if (dev->protocol_features & (1ULL <<
> >> VHOST_USER_PROTOCOL_F_STATUS))
> >> +		if (!(dev->status & VIRTIO_DEVICE_STATUS_DRIVER_OK))
> >> +			return 0;
> >> +
> >>  	dev->flags |= VIRTIO_DEV_READY;
> >>
> >>  	VHOST_LOG_CONFIG(INFO,
> >> @@ -2425,6 +2431,39 @@ vhost_user_postcopy_end(struct virtio_net
> >> **pdev, struct VhostUserMsg *msg,
> >>  	return RTE_VHOST_MSG_RESULT_REPLY;
> >>  }
> >>
> >> +static int
> >> +vhost_user_set_status(struct virtio_net **pdev, struct VhostUserMsg *msg,
> >> +			int main_fd __rte_unused)
> >> +{
> >> +	struct virtio_net *dev = *pdev;
> >> +
> >> +	/* As per Virtio specification, the device status is 8bits long */
> >> +	if (msg->payload.u64 > UINT8_MAX) {
> >> +		VHOST_LOG_CONFIG(ERR, "Invalid VHOST_USER_SET_STATUS
> >> payload 0x%" PRIx64 "\n",
> >> +				msg->payload.u64);
> >> +		return RTE_VHOST_MSG_RESULT_ERR;
> >> +	}
> >> +
> >> +	dev->status = msg->payload.u64;
> >> +
> >> +	VHOST_LOG_CONFIG(INFO, "New device status(0x%08x):\n"
> >> +			"\t-ACKNOWLEDGE: %u\n"
> >> +			"\t-DRIVER: %u\n"
> >> +			"\t-FEATURES_OK: %u\n"
> >> +			"\t-DRIVER_OK: %u\n"
> >> +			"\t-DEVICE_NEED_RESET: %u\n"
> >> +			"\t-FAILED: %u\n",
> >> +			dev->status,
> >> +			!!(dev->status & VIRTIO_DEVICE_STATUS_ACK),
> >> +			!!(dev->status & VIRTIO_DEVICE_STATUS_DRIVER),
> >> +			!!(dev->status &
> >> VIRTIO_DEVICE_STATUS_FEATURES_OK),
> >> +			!!(dev->status & VIRTIO_DEVICE_STATUS_DRIVER_OK),
> >> +			!!(dev->status &
> >> VIRTIO_DEVICE_STATUS_DEV_NEED_RESET),
> >> +			!!(dev->status & VIRTIO_DEVICE_STATUS_FAILED));
> >> +
> >> +	return RTE_VHOST_MSG_RESULT_OK;
> >
> > I see in your patch for virtio-user SET_STATUS support
> > (http://patchwork.dpdk.org/patch/70677/), the VHOST_USER_SET_STATUS
> > msg may request a reply, but this func does not handle this case. If
> > we don't handle here,  vhost_user_msg_handler will return
> RTE_VHOST_MSG_RESULT_ERR later. So should we handle the case here?
> >
> Why should the reply be handled in this function?
> After this function is called, vhost_user_msg_handler() should handle the replies
> in:
> 
> 	if (msg.flags & VHOST_USER_NEED_REPLY) {
> 		msg.payload.u64 = ret == RTE_VHOST_MSG_RESULT_ERR;
> 		msg.size = sizeof(msg.payload.u64);
> 		msg.fd_num = 0;
> 		send_vhost_reply(fd, &msg);
> 	} else if (ret == RTE_VHOST_MSG_RESULT_ERR) {
> 		VHOST_LOG_CONFIG(ERR,
> 			"vhost message handling failed.\n");
> 		return -1;
> 	}
> 
> Am I missing something?

You're correct, I missed this one :)

Thanks!
Chenbo

> 
> 
> > Thanks,
> > Chenbo
> >
> >> +}
> >> +
> >>  typedef int (*vhost_message_handler_t)(struct virtio_net **pdev,
> >>  					struct VhostUserMsg *msg,
> >>  					int main_fd);
> >> @@ -2457,6 +2496,7 @@ static vhost_message_handler_t
> >> vhost_message_handlers[VHOST_USER_MAX] = {
> >>  	[VHOST_USER_POSTCOPY_END] = vhost_user_postcopy_end,
> >>  	[VHOST_USER_GET_INFLIGHT_FD] = vhost_user_get_inflight_fd,
> >>  	[VHOST_USER_SET_INFLIGHT_FD] = vhost_user_set_inflight_fd,
> >> +	[VHOST_USER_SET_STATUS] = vhost_user_set_status,
> >>  };
> >>
> >>  /* return bytes# of read on success or negative val on failure. */
> >> diff --git a/lib/librte_vhost/vhost_user.h
> >> b/lib/librte_vhost/vhost_user.h index 1f65efa4a9..74fd361e3a 100644
> >> --- a/lib/librte_vhost/vhost_user.h
> >> +++ b/lib/librte_vhost/vhost_user.h
> >> @@ -23,7 +23,8 @@
> >>  					 (1ULL <<
> >> VHOST_USER_PROTOCOL_F_CRYPTO_SESSION) | \
> >>  					 (1ULL <<
> >> VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD) | \
> >>  					 (1ULL <<
> >> VHOST_USER_PROTOCOL_F_HOST_NOTIFIER) | \
> >> -					 (1ULL <<
> >> VHOST_USER_PROTOCOL_F_PAGEFAULT))
> >> +					 (1ULL <<
> >> VHOST_USER_PROTOCOL_F_PAGEFAULT) | \
> >> +					 (1ULL <<
> >> VHOST_USER_PROTOCOL_F_STATUS))
> >>
> >>  typedef enum VhostUserRequest {
> >>  	VHOST_USER_NONE = 0,
> >> @@ -56,7 +57,8 @@ typedef enum VhostUserRequest {
> >>  	VHOST_USER_POSTCOPY_END = 30,
> >>  	VHOST_USER_GET_INFLIGHT_FD = 31,
> >>  	VHOST_USER_SET_INFLIGHT_FD = 32,
> >> -	VHOST_USER_MAX = 33
> >> +	VHOST_USER_SET_STATUS = 36,
> >> +	VHOST_USER_MAX = 37
> >>  } VhostUserRequest;
> >>
> >>  typedef enum VhostUserSlaveRequest {
> >> --
> >> 2.25.4
> >
> 
> --
> Adrián Moreno