[RFC PATCH 00/10] vdpa: get/set_config() rework

[Stefano Garzarella]

Following the discussion with Michael and Jason [1], I reworked a bit
get/set_config() in vdpa.

I changed vdpa_get_config() to check the boundaries and added vdpa_set_config().
When 'offset' or 'len' parameters exceed boundaries, we limit the reading to
the available configuration space in the device, and we return the amount of
bytes read/written.

In this way the user space can pass buffers bigger than config space.
I also returned the amount of bytes read and written to user space.

Patches also available here:
https://github.com/stefano-garzarella/linux/tree/vdpa-get-set-config-refactoring

Thanks for your comments,
Stefano

[1] https://lkml.org/lkml/2021/2/10/350

Stefano Garzarella (10):
  vdpa: add get_config_size callback in vdpa_config_ops
  vdpa: check vdpa_get_config() parameters and return bytes read
  vdpa: add vdpa_set_config() helper
  vdpa: remove param checks in the get/set_config callbacks
  vdpa: remove WARN_ON() in the get/set_config callbacks
  virtio_vdpa: use vdpa_set_config()
  vhost/vdpa: use vdpa_set_config()
  vhost/vdpa: allow user space to pass buffers bigger than config space
  vhost/vdpa: use get_config_size callback in
    vhost_vdpa_config_validate()
  vhost/vdpa: return configuration bytes read and written to user space

 include/linux/vdpa.h              | 22 ++++-------
 drivers/vdpa/ifcvf/ifcvf_base.c   |  3 +-
 drivers/vdpa/ifcvf/ifcvf_main.c   |  8 +++-
 drivers/vdpa/mlx5/net/mlx5_vnet.c |  9 ++++-
 drivers/vdpa/vdpa.c               | 51 ++++++++++++++++++++++++
 drivers/vdpa/vdpa_sim/vdpa_sim.c  | 15 +++++---
 drivers/vhost/vdpa.c              | 64 ++++++++++++++++---------------
 drivers/virtio/virtio_vdpa.c      |  3 +-
 8 files changed, 116 insertions(+), 59 deletions(-)

-- 
2.29.2