Re: [dpdk-dev] [PATCH 3/5] net/virtio: add VIRTIO_SET_STATUS support to Virtio-user

[Adrian Moreno <amorenoz@redhat.com>]

On 7/16/20 5:15 AM, Xia, Chenbo wrote:
> Hi Adrian,
> 
>> -----Original Message-----
>> From: Adrian Moreno <amorenoz@redhat.com>
>> Sent: Thursday, July 16, 2020 1:18 AM
>> To: dev@dpdk.org
>> Cc: maxime.coquelin@redhat.com; Wang, Zhihong <zhihong.wang@intel.com>;
>> amorenoz@redhat.com; Xia, Chenbo <chenbo.xia@intel.com>
>> Subject: [PATCH 3/5] net/virtio: add VIRTIO_SET_STATUS support to Virtio-user
>>
>> From: Maxime Coquelin <maxime.coquelin@redhat.com>
>>
>> This patch adds support for VHOST_USER_SET_STATUS request. It is used to
>> make the backend aware of Virtio devices status update.
>>
>> It is useful for the backend to know when the Virtio driver is done with the Virtio
>> device configuration.
>>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>> Signed-off-by: Adrian Moreno <amorenoz@redhat.com>
>> ---
>>  drivers/net/virtio/virtio_user/vhost.h        |  6 +++++
>>  drivers/net/virtio/virtio_user/vhost_user.c   | 10 ++++++++
>>  .../net/virtio/virtio_user/virtio_user_dev.c  | 23 ++++++++++++++++++-
>>   .../net/virtio/virtio_user/virtio_user_dev.h  |  1 +
>>  drivers/net/virtio/virtio_user_ethdev.c       |  1 +
>>  5 files changed, 40 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/virtio/virtio_user/vhost.h
>> b/drivers/net/virtio/virtio_user/vhost.h
>> index 260e1c308..8f49ef457 100644
>> --- a/drivers/net/virtio/virtio_user/vhost.h
>> +++ b/drivers/net/virtio/virtio_user/vhost.h
>> @@ -57,6 +57,10 @@ struct vhost_vring_addr {  #define
>> VHOST_USER_PROTOCOL_F_REPLY_ACK 3  #endif
>>
>> +#ifndef VHOST_USER_PROTOCOL_F_STATUS
>> +#define VHOST_USER_PROTOCOL_F_STATUS 16 #endif
>> +
>>  enum vhost_user_request {
>>  	VHOST_USER_NONE = 0,
>>  	VHOST_USER_GET_FEATURES = 1,
>> @@ -77,6 +81,8 @@ enum vhost_user_request {
>>  	VHOST_USER_SET_PROTOCOL_FEATURES = 16,
>>  	VHOST_USER_GET_QUEUE_NUM = 17,
>>  	VHOST_USER_SET_VRING_ENABLE = 18,
>> +	VHOST_USER_SET_STATUS = 39,
>> +	VHOST_USER_GET_STATUS = 40,
>>  	VHOST_USER_MAX
>>  };
>>
>> diff --git a/drivers/net/virtio/virtio_user/vhost_user.c
>> b/drivers/net/virtio/virtio_user/vhost_user.c
>> index 631d0e353..2332e01d1 100644
>> --- a/drivers/net/virtio/virtio_user/vhost_user.c
>> +++ b/drivers/net/virtio/virtio_user/vhost_user.c
>> @@ -244,6 +244,8 @@ const char * const vhost_msg_strings[] = {
>>  	[VHOST_USER_SET_VRING_ENABLE] = "VHOST_SET_VRING_ENABLE",
>>  	[VHOST_USER_GET_PROTOCOL_FEATURES] =
>> "VHOST_USER_GET_PROTOCOL_FEATURES",
>>  	[VHOST_USER_SET_PROTOCOL_FEATURES] =
>> "VHOST_USER_SET_PROTOCOL_FEATURES",
>> +	[VHOST_USER_SET_STATUS] = "VHOST_SET_STATUS",
>> +	[VHOST_USER_GET_STATUS] = "VHOST_GET_STATUS",
>>  };
>>
>>  static int
>> @@ -280,6 +282,14 @@ vhost_user_sock(struct virtio_user_dev *dev,
>>  		need_reply = 1;
>>  		break;
>>
>> +	case VHOST_USER_SET_STATUS:
>> +		if (!(dev->protocol_features &
>> +				(1ULL <<
>> VHOST_USER_PROTOCOL_F_STATUS)))
>> +			return 0;
>> +
>> +		if (has_reply_ack)
>> +			msg.flags |= VHOST_USER_NEED_REPLY_MASK;
>> +		/* Fallthrough */
> 
> There's a coding style issue here:
> WARNING:PREFER_FALLTHROUGH: Prefer 'fallthrough;' over fallthrough comment.
> Could you fix this?
> 
"fallthrough" is not defined. I think this macro is defined in the linux kernel
(where checkpatches.pl comes from?). We could define the same macro that would
depend in compiler support for __falthrough__ attribute.

In any case, this is not the only case:

$ find -name *.c | xargs grep -i "/\* fallthrough \*/" | wc -l
62

So maybe this warning is new?
Should I change all of them together in another patch?

>>  	case VHOST_USER_SET_FEATURES:
>>  	case VHOST_USER_SET_PROTOCOL_FEATURES:
>>  	case VHOST_USER_SET_LOG_BASE:
>> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c
>> b/drivers/net/virtio/virtio_user/virtio_user_dev.c
>> index 0a6991bcc..2c400a448 100644
>> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
>> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
>> @@ -424,7 +424,8 @@ virtio_user_dev_setup(struct virtio_user_dev *dev)
>>
>>  #define VIRTIO_USER_SUPPORTED_PROTOCOL_FEATURES		\
>>  	(1ULL << VHOST_USER_PROTOCOL_F_MQ |		\
>> -	 1ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK)
>> +	 1ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK |	\
>> +	 1ULL << VHOST_USER_PROTOCOL_F_STATUS)
>>
>>  int
>>  virtio_user_dev_init(struct virtio_user_dev *dev, char *path, int queues, @@ -
>> 783,3 +784,23 @@ virtio_user_handle_cq(struct virtio_user_dev *dev, uint16_t
>> queue_idx)
>>  		__atomic_add_fetch(&vring->used->idx, 1,
>> __ATOMIC_RELAXED);
>>  	}
>>  }
>> +
>> +int
>> +virtio_user_send_status_update(struct virtio_user_dev *dev, uint8_t
>> +status) {
>> +	int ret;
>> +	uint64_t arg = status;
>> +
>> +	/* Vhost-user only for now */
>> +	if (!is_vhost_user_by_type(dev->path))
>> +		return 0;
>> +
>> +	if (!(dev->protocol_features & (1ULL <<
>> VHOST_USER_PROTOCOL_F_STATUS)))
>> +		return 0;
>> +
>> +	ret = dev->ops->send_request(dev, VHOST_USER_SET_STATUS, &arg);
>> +	if (ret)
>> +		return -1;
> 
> Do you think we should add a log here to show if SET_STAUTS failed?
> 
Good idea! Will do in the next version. Thanks

> Thanks!
> Chenbo
> 
>> +
>> +	return 0;
>> +}
>> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.h
>> b/drivers/net/virtio/virtio_user/virtio_user_dev.h
>> index 10b274d19..a76d7cfaf 100644
>> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.h
>> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.h
>> @@ -74,4 +74,5 @@ void virtio_user_handle_cq(struct virtio_user_dev *dev,
>> uint16_t queue_idx);  void virtio_user_handle_cq_packed(struct virtio_user_dev
>> *dev,
>>  				  uint16_t queue_idx);
>>  uint8_t virtio_user_handle_mq(struct virtio_user_dev *dev, uint16_t q_pairs);
>> +int virtio_user_send_status_update(struct virtio_user_dev *dev, uint8_t
>> +status);
>>  #endif
>> diff --git a/drivers/net/virtio/virtio_user_ethdev.c
>> b/drivers/net/virtio/virtio_user_ethdev.c
>> index 5b06d8e89..e52f11341 100644
>> --- a/drivers/net/virtio/virtio_user_ethdev.c
>> +++ b/drivers/net/virtio/virtio_user_ethdev.c
>> @@ -273,6 +273,7 @@ virtio_user_set_status(struct virtio_hw *hw, uint8_t
>> status)
>>  	else if (status == VIRTIO_CONFIG_STATUS_RESET)
>>  		virtio_user_reset(hw);
>>  	dev->status = status;
>> +	virtio_user_send_status_update(dev, status);
>>  }
>>
>>  static uint8_t
>> --
>> 2.26.2
> 

-- 
Adrián Moreno