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From: Maxime Coquelin <mcoqueli@redhat.com>
To: "Xia, Chenbo" <chenbo.xia@intel.com>,
	Maxime Coquelin <maxime.coquelin@redhat.com>,
	"dev@dpdk.org" <dev@dpdk.org>,
	"amorenoz@redhat.com" <amorenoz@redhat.com>,
	"david.marchand@redhat.com" <david.marchand@redhat.com>
Subject: Re: [dpdk-dev] [RFC 3/3] net/virtio: add MAC device config getter and setter
Date: Thu, 3 Jun 2021 16:28:52 +0200
Message-ID: <bde411ae-b7fe-2fda-ea29-15d1422b457d@redhat.com> (raw)
In-Reply-To: <MN2PR11MB406326494A23798886BA08E89C499@MN2PR11MB4063.namprd11.prod.outlook.com>

Hi Chenbo,

On 4/19/21 8:24 AM, Xia, Chenbo wrote:
> Hi Maxime,
> 
>> -----Original Message-----
>> From: Maxime Coquelin <maxime.coquelin@redhat.com>
>> Sent: Friday, March 19, 2021 6:35 AM
>> To: dev@dpdk.org; Xia, Chenbo <chenbo.xia@intel.com>; amorenoz@redhat.com;
>> david.marchand@redhat.com
>> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
>> Subject: [RFC 3/3] net/virtio: add MAC device config getter and setter
>>
>> This patch uses the new device config ops to get and set
>> the MAC address if supported.
>>
>> If a valid MAC address is passed as devarg of the
>> Virtio-user PMD, the driver will try to store it in the
>> device config space. Otherwise the one provided in
>> the device config space will be used, if available.
> 
> I agree with the MAC selection strategy you proposed.
> 
>>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>> ---
>>  .../net/virtio/virtio_user/virtio_user_dev.c  | 78 ++++++++++++++++---
>>  .../net/virtio/virtio_user/virtio_user_dev.h  |  2 +
>>  drivers/net/virtio/virtio_user_ethdev.c       |  7 +-
>>  3 files changed, 74 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c
>> b/drivers/net/virtio/virtio_user/virtio_user_dev.c
>> index 8757a23f6e..61517692b3 100644
>> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
>> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
>> @@ -259,20 +259,76 @@ int virtio_user_stop_device(struct virtio_user_dev *dev)
>>  	return -1;
>>  }
>>
>> -static inline void
>> -parse_mac(struct virtio_user_dev *dev, const char *mac)
>> +int
>> +virtio_user_dev_set_mac(struct virtio_user_dev *dev)
>>  {
>> -	struct rte_ether_addr tmp;
>> +	int ret = 0;
>>
>> -	if (!mac)
>> -		return;
>> +	if (!(dev->device_features & (1ULL << VIRTIO_NET_F_MAC)))
>> +		return -ENOTSUP;
>> +
>> +	if (!dev->ops->set_config)
>> +		return -ENOTSUP;
>> +
>> +	ret = dev->ops->set_config(dev, dev->mac_addr,
>> +			offsetof(struct virtio_net_config, mac),
>> +			RTE_ETHER_ADDR_LEN);
>> +	if (ret)
>> +		PMD_DRV_LOG(ERR, "(%s) Failed to set MAC address in device\n",
>> dev->path);
>> +
>> +	return ret;
>> +}
>> +
>> +int
>> +virtio_user_dev_get_mac(struct virtio_user_dev *dev)
>> +{
>> +	int ret = 0;
>> +
>> +	if (!(dev->device_features & (1ULL << VIRTIO_NET_F_MAC)))
>> +		return -ENOTSUP;
>> +
>> +	if (!dev->ops->get_config)
>> +		return -ENOTSUP;
>> +
>> +	ret = dev->ops->get_config(dev, dev->mac_addr,
>> +			offsetof(struct virtio_net_config, mac),
>> +			RTE_ETHER_ADDR_LEN);
>> +	if (ret)
>> +		PMD_DRV_LOG(ERR, "(%s) Failed to get MAC address from device\n",
>> dev->path);
>>
>> -	if (rte_ether_unformat_addr(mac, &tmp) == 0) {
>> -		memcpy(dev->mac_addr, &tmp, RTE_ETHER_ADDR_LEN);
>> +	return ret;
>> +}
>> +
>> +static void
>> +virtio_user_dev_init_mac(struct virtio_user_dev *dev, const char *mac)
>> +{
>> +	struct rte_ether_addr cmdline_mac;
>> +	int ret;
>> +
>> +	if (mac && rte_ether_unformat_addr(mac, &cmdline_mac) == 0) {
>> +		/*
>> +		 * MAC address was passed from command-line, try to store
>> +		 * it in the device if it supports it. Otherwise try to use
>> +		 * the device one.
>> +		 */
>> +		memcpy(dev->mac_addr, &cmdline_mac, RTE_ETHER_ADDR_LEN);
>>  		dev->mac_specified = 1;
> 
> How do we define mac_specified? If I understand correctly, it means the mac
> we see is from device (we set it or we just use device's). Then 'dev->mac_specified = 1'
> should be after get_mac succeeds.

You are correct, mac_specified=1 means either user or device specified
MAC address. If get_mac fails below then we use the user specified MAC
address, so mac_specified = 1 is still valid in this case.

> Note that during virtio_user_dev_init, we also use
> this val to set VIRTIO_NET_F_MAC. But here the val is set without making sure the
> feature exists.

I am not sure to get youre point, but it sets VIRTIO_NET_F_MAC in the
frontend features there, that does not mean the feature is negotiated in
the end.

>> +
>> +		/* Setting MAC may fail, continue to get the device one in this
>> case */
>> +		virtio_user_dev_set_mac(dev);
>> +		ret = virtio_user_dev_get_mac(dev);
>> +		if (ret == -ENOTSUP)
>> +			return;
>> +
>> +		if (memcmp(&cmdline_mac, dev->mac_addr, RTE_ETHER_ADDR_LEN))
>> +			PMD_DRV_LOG(INFO, "(%s) Device MAC update failed\n", dev-
>>> path);
> 
> Besides Adrian's comments, if we decide to return no error on this, it may also
> be good to add something like 'using random MAC' to tell users that the driver will
> use random mac. Adding here or in the function that generates mac is both ok.

If it fails here, it won't be using a random MAC, but the MAC provided
by the user. The log could be improved with something like:
"Device MAC update failed, using MAC xx:xx:xx:xx:xx"

What do you think?

> The patchset overall looks good to me. I'm looking forward to v1 😊
> 
> Thanks,
> Chenbo

Thanks,
Maxime


  reply	other threads:[~2021-06-03 14:29 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-18 22:35 [dpdk-dev] [RFC 0/3] net/virtio: add vdpa device config support Maxime Coquelin
2021-03-18 22:35 ` [dpdk-dev] [RFC 1/3] net/virtio: keep device and frontend features separated Maxime Coquelin
2021-03-18 22:35 ` [dpdk-dev] [RFC 2/3] net/virtio: add device config support to vDPA Maxime Coquelin
2021-03-18 22:35 ` [dpdk-dev] [RFC 3/3] net/virtio: add MAC device config getter and setter Maxime Coquelin
2021-04-16  9:27   ` Adrian Moreno
2021-04-19  6:24   ` Xia, Chenbo
2021-06-03 14:28     ` Maxime Coquelin [this message]
2021-06-08  5:29       ` Xia, Chenbo
2021-06-08  6:22         ` Maxime Coquelin
2021-04-16  7:28 ` [dpdk-dev] [RFC 0/3] net/virtio: add vdpa device config support Adrian Moreno
2021-04-16  8:10   ` Maxime Coquelin

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