Hi Chenbo,
On 4/19/21 8:24 AM, Xia, Chenbo wrote:
> Hi Maxime,
>
>> -----Original Message-----
>> From: Maxime Coquelin <maxime.coque...@redhat.com>
>> Sent: Friday, March 19, 2021 6:35 AM
>> To: dev@dpdk.org; Xia, Chenbo <chenbo....@intel.com>; amore...@redhat.com;
>> david.march...@redhat.com
>> Cc: Maxime Coquelin <maxime.coque...@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.coque...@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
