[PATCH for 5.10 v2 0/5] vdpa_sim: fix param validation in vdpasim_get_config()

[Stefano Garzarella]

v1: https://lore.kernel.org/stable/20210211162519.215418-1-sgarzare@xxxxxxxxxx/

v2:
- backport the upstream patch and related patches needed

Commit 65b709586e22 ("vdpa_sim: add get_config callback in
vdpasim_dev_attr") unintentionally solved an issue in vdpasim_get_config()
upstream while refactoring vdpa_sim.c to support multiple devices.

Before that patch, if 'offset + len' was equal to
sizeof(struct virtio_net_config), the entire buffer wasn't filled,
returning incorrect values to the caller.

Since 'vdpasim->config' type is 'struct virtio_net_config', we can
safely copy its content under this condition.

The minimum set of patches to backport the patch that fixes the issue, is the
following:

   423248d60d2b vdpa_sim: remove hard-coded virtq count
   6c6e28fe4579 vdpa_sim: add struct vdpasim_dev_attr for device attributes
   cf1a3b35382c vdpa_sim: store parsed MAC address in a buffer
   f37cbbc65178 vdpa_sim: make 'config' generic and usable for any device type
   65b709586e22 vdpa_sim: add get_config callback in vdpasim_dev_attr

The patches apply fairly cleanly. There are a few contextual differences
due to the lack of the other patches:

   $ git backport-diff -u master -r linux-5.10.y..HEAD
   Key:
   [----] : patches are identical
   [####] : number of functional differences between upstream/downstream patch
   [down] : patch is downstream-only
   The flags [FC] indicate (F)unctional and (C)ontextual differences, respectively

   001/5:[----] [--] 'vdpa_sim: remove hard-coded virtq count'
   002/5:[----] [-C] 'vdpa_sim: add struct vdpasim_dev_attr for device attributes'
   003/5:[----] [--] 'vdpa_sim: store parsed MAC address in a buffer'
   004/5:[----] [-C] 'vdpa_sim: make 'config' generic and usable for any device type'
   005/5:[----] [-C] 'vdpa_sim: add get_config callback in vdpasim_dev_attr'

Thanks,
Stefano

Max Gurtovoy (1):
  vdpa_sim: remove hard-coded virtq count

Stefano Garzarella (4):
  vdpa_sim: add struct vdpasim_dev_attr for device attributes
  vdpa_sim: store parsed MAC address in a buffer
  vdpa_sim: make 'config' generic and usable for any device type
  vdpa_sim: add get_config callback in vdpasim_dev_attr

 drivers/vdpa/vdpa_sim/vdpa_sim.c | 83 +++++++++++++++++++++++---------
 1 file changed, 60 insertions(+), 23 deletions(-)

-- 
2.29.2