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

[Adrian Moreno <amorenoz@redhat.com>]

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?


> 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