On Thu, Dec 9, 2021 at 8:25 AM Si-Wei Liu [off-list ref] wrote:

On 12/8/2021 12:14 PM, Eli Cohen wrote:

quoted

Add netlink support to configure the max virtqueue pairs for a device.
At least one pair is required. The maximum is dictated by the device.

Example:

$ vdpa dev add name vdpa-a mgmtdev auxiliary/mlx5_core.sf.1 max_vqp 5

Not this patch, but I think there should be a mega attribute defined
ahead to specify the virtio class/type to create vdpa instance with.
Like the existing ones e.g. mac_addr and mtu, max_vqp is also vdpa net
specific attribute.

Probably, but this only works for the case when a single parent is
allowed to create different types of devices. It looks to me the
current model to have a per type parent.

Thanks

-Siwei

quoted

Signed-off-by: Eli Cohen <redacted>
---
v0 -> v1:
1. fix typo
2. move max_vq_pairs to net specific struct

  drivers/vdpa/vdpa.c  | 14 +++++++++++++-
  include/linux/vdpa.h |  1 +
  2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index c37d384c0f33..3bf016e03512 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c

@@ -480,7 +480,8 @@ vdpa_nl_cmd_mgmtdev_get_dumpit(struct sk_buff *msg, struct netlink_callback *cb)
  }

  #define VDPA_DEV_NET_ATTRS_MASK ((1 << VDPA_ATTR_DEV_NET_CFG_MACADDR) | \
-                              (1 << VDPA_ATTR_DEV_NET_CFG_MTU))
+                              (1 << VDPA_ATTR_DEV_NET_CFG_MTU) | \
+                              (1 << VDPA_ATTR_DEV_NET_CFG_MAX_VQP))

  static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *info)
  {

@@ -506,6 +507,17 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *i
                      nla_get_u16(nl_attrs[VDPA_ATTR_DEV_NET_CFG_MTU]);
              config.mask |= (1 << VDPA_ATTR_DEV_NET_CFG_MTU);
      }
+     if (nl_attrs[VDPA_ATTR_DEV_NET_CFG_MAX_VQP]) {
+             config.net.max_vq_pairs =
+                     nla_get_u16(nl_attrs[VDPA_ATTR_DEV_NET_CFG_MAX_VQP]);
+             if (!config.net.max_vq_pairs) {
+                     NL_SET_ERR_MSG_MOD(info->extack,
+                                        "At least one pair of VQs is required");
+                     err = -EINVAL;
+                     goto err;
+             }
+             config.mask |= BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MAX_VQP);
+     }

      /* Skip checking capability if user didn't prefer to configure any
       * device networking attributes. It is likely that user might have used

diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index db24317d61b6..b62032573780 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h

@@ -99,6 +99,7 @@ struct vdpa_dev_set_config {
      struct {
              u8 mac[ETH_ALEN];
              u16 mtu;
+             u16 max_vq_pairs;
      } net;
      u64 mask;
  };

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