[RFC PATCH v3 0/8] vhost lock annotations

[David Marchand]

vhost internals involves multiple locks to protect data access by
multiple threads.

This series is a try at using clang thread safety checks [1] to catch
issues during compilation: EAL spinlock and rwlock are annotated and
vhost code is instrumented so that clang can statically check
correctness.

This is still a work in progress (some documentation and a release note
update are missing).

Those annotations are quite heavy to maintain because the full path of
code must be annotated, but I think it is worth using.


1: https://clang.llvm.org/docs/ThreadSafetyAnalysis.html

Depends-on: patch-108840 ("vhost: fix missing virtqueue lock protection")

-- 
David Marchand

Changes since RFC v2:
- fixed trylock annotations for rwlock,
- annotated _tm flavors of spinlock and rwlock,
- removed Maxime vhost fix from series (since Mimecast does not like
  me sending Maxime patch...), added a dependency on original fix
  as a hint for reviewers,
- renamed attributes,

Changes since RFC v1:
- Cc'd people who have pending patches for vhost,
- moved annotations to EAL and removed wrappers in vhost,
- as a result of moving to EAL, this series will be tested against
  the main repo, so patch 1 has been kept as part of the series
  even if already applied to next-virtio,
- refined/split patches and annotated all spinlocks in vhost,

David Marchand (8):
  eal: annotate spinlock and rwlock
  vhost: annotate virtqueue access lock
  vhost: fix async access
  vhost: annotate async accesses
  vhost: annotate need reply handling
  vhost: annotate vDPA device list accesses
  vhost: annotate IOTLB locks
  vhost: enable lock check

 drivers/meson.build                    |  5 ++
 lib/eal/arm/include/rte_rwlock.h       |  4 ++
 lib/eal/arm/include/rte_spinlock.h     |  6 ++
 lib/eal/include/generic/rte_rwlock.h   | 27 +++++++--
 lib/eal/include/generic/rte_spinlock.h | 40 +++++++++----
 lib/eal/include/meson.build            |  1 +
 lib/eal/include/rte_lock_annotations.h | 67 +++++++++++++++++++++
 lib/eal/ppc/include/rte_rwlock.h       |  4 ++
 lib/eal/ppc/include/rte_spinlock.h     |  9 +++
 lib/eal/x86/include/rte_rwlock.h       |  4 ++
 lib/eal/x86/include/rte_spinlock.h     |  9 +++
 lib/meson.build                        |  5 ++
 lib/vhost/iotlb.h                      |  8 +++
 lib/vhost/meson.build                  |  2 +
 lib/vhost/vdpa.c                       | 18 +++---
 lib/vhost/vhost.c                      | 50 ++++++++--------
 lib/vhost/vhost.h                      | 26 ++++++---
 lib/vhost/vhost_crypto.c               |  7 +++
 lib/vhost/vhost_user.c                 |  6 ++
 lib/vhost/virtio_net.c                 | 80 ++++++++++++++++++++------
 20 files changed, 306 insertions(+), 72 deletions(-)
 create mode 100644 lib/eal/include/rte_lock_annotations.h

-- 
2.23.0