vdpa: add vdpa simulator for block device

v3:
- added new patches
  - 'vringh: explain more about cleaning riov and wiov'
  - 'vdpa: add return value to get_config/set_config callbacks'
  - 'vhost/vdpa: remove vhost_vdpa_config_validate()'
- split Xie's patch 'vhost/vdpa: Remove the restriction that only supports
  virtio-net devices'
- updated Mellanox copyright to NVIDIA [Max]
- explained in the 'vdpa: add vdpa simulator for block device' commit
  message that inputs are validated in subsequent patches [Stefan]

v2: https://lore.kernel.org/lkml/20210128144127.113245-1-sgar...
v1: https://lore.kernel.org/lkml/93f207c0-61e6-3696-f218-e7d7...

This series is the second part of the v1 linked above. The first part with
refactoring of vdpa_sim has already been merged.

The patches are based on Max Gurtovoy's work and extend the block simulator to
have a ramdisk behaviour.

As mentioned in the v1 there was 2 issues and I fixed them in this series:
1. The identical mapping in the IOMMU used until now in vdpa_sim created issues
   when mapping different virtual pages with the same physical address.
   Fixed by patch "vdpa_sim: use iova module to allocate IOVA addresses"

2. There was a race accessing the IOMMU between the vdpasim_blk_work() and the
   device driver that map/unmap DMA regions. Fixed by patch "vringh: add
   'iotlb_lock' to synchronize iotlb accesses"

I used the Xie's patch coming from VDUSE series to allow vhost-vdpa to use
block devices. As Jason suggested I split it into two patches and I added
a return value to get_config()/set_config() callbacks.

The series also includes small fixes for vringh, vdpa, and vdpa_sim that I
discovered while implementing and testing the block simulator.

Thanks for your feedback,
Stefano

Max Gurtovoy (1):
  vdpa: add vdpa simulator for block device

Stefano Garzarella (11):
  vdpa_sim: use iova module to allocate IOVA addresses
  vringh: add 'iotlb_lock' to synchronize iotlb accesses
  vringh: reset kiov 'consumed' field in __vringh_iov()
  vringh: explain more about cleaning riov and wiov
  vringh: implement vringh_kiov_advance()
  vringh: add vringh_kiov_length() helper
  vdpa_sim: cleanup kiovs in vdpasim_free()
  vdpa: add return value to get_config/set_config callbacks
  vhost/vdpa: remove vhost_vdpa_config_validate()
  vdpa_sim_blk: implement ramdisk behaviour
  vdpa_sim_blk: handle VIRTIO_BLK_T_GET_ID

Xie Yongji (1):
  vhost/vdpa: Remove the restriction that only supports virtio-net
    devices

 drivers/vdpa/vdpa_sim/vdpa_sim.h     |   2 +
 include/linux/vdpa.h                 |  18 +-
 include/linux/vringh.h               |  19 +-
 drivers/vdpa/ifcvf/ifcvf_main.c      |  24 ++-
 drivers/vdpa/mlx5/net/mlx5_vnet.c    |  17 +-
 drivers/vdpa/vdpa_sim/vdpa_sim.c     | 134 ++++++++-----
 drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 288 +++++++++++++++++++++++++++
 drivers/vhost/vdpa.c                 |  47 ++---
 drivers/vhost/vringh.c               |  69 +++++--
 drivers/vdpa/Kconfig                 |   8 +
 drivers/vdpa/vdpa_sim/Makefile       |   1 +
 11 files changed, 504 insertions(+), 123 deletions(-)
 create mode 100644 drivers/vdpa/vdpa_sim/vdpa_sim_blk.c

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2.29.2