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
