[PATCH V3 0/6] Conditionally read fields in dev cfg space

[Zhu Lingshan <lingshan.zhu@intel.com>]

This series intends to read the fields in virtio-net device
configuration space conditionally on the feature bits,
this means:

MTU exists if VIRTIO_NET_F_MTU is set
MAC exists if VIRTIO_NET_F_NET is set
MQ exists if VIRTIO_NET_F_MQ or VIRTIO_NET_F_RSS is set.

This series report device features to userspace and invokes
vdpa_config_ops.get_config() rather than
vdpa_get_config_unlocked() to read the device config spcae,
so no races in vdpa_set_features_unlocked()

Thanks!

Changes form V2:
remove unnacessary checking for vdev->config->get_status (Jason)

Changes from V1:
1)Better comments for VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES,
only in the header file(Jason)
2)Split original 3/4 into separate patches(Jason)
3)Check FEATURES_OK for reporting driver features
in vdpa_dev_config_fill (Jason)
4) Add iproute2 example for reporting device features

Zhu Lingshan (6):
  vDPA: allow userspace to query features of a vDPA device
  vDPA: only report driver features if FEATURES_OK is set
  vDPA: check VIRTIO_NET_F_RSS for max_virtqueue_paris's presence
  vDPA: check virtio device features to detect MQ
  vDPA: fix spars cast warning in vdpa_dev_net_mq_config_fill
  vDPA: conditionally read MTU and MAC in dev cfg space

 drivers/vdpa/vdpa.c       | 68 ++++++++++++++++++++++++++++++---------
 include/uapi/linux/vdpa.h |  4 +++
 2 files changed, 56 insertions(+), 16 deletions(-)

-- 
2.31.1