vhost internals involves multiple locks to protect data access by multiple threads.
This series uses clang thread safety checks [1] to catch issues during compilation: EAL spinlock, seqlock and rwlock are annotated and vhost code is instrumented so that clang can statically check correctness. Those annotations are quite heavy to maintain because the full path of code must be annotated (as can be seen in the vhost datapath code), but I think it is worth using. This has been tested against the whole tree and some fixes are already flying on the mailing list (see [2] for a list). If this first series is merged, I will prepare a followup series for EAL and other libraries. 1: https://clang.llvm.org/docs/ThreadSafetyAnalysis.html 2: https://patchwork.dpdk.org/bundle/dmarchand/lock_fixes/?state=*&archive=both -- David Marchand Changes since RFC v3: - sorry Maxime, it has been too long since RFC v3 and the code evolved, so I dropped all your review tags, - rebased, - added documentation, - dropped/fixed annotations in arch-specific and EAL headers, - rewrote need reply handling so that we don't have to waive the check on the associated functions, - separated IOTLB lock unconditional acquire from the annotation patch, - rewrote runtime checks for "unsafe" functions using a panicking assert helper, 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 (9): eal: annotate spinlock, rwlock and seqlock vhost: simplify need reply handling vhost: terminate when access lock is not taken vhost: annotate virtqueue access lock vhost: annotate async accesses vhost: always take IOTLB lock vhost: annotate IOTLB lock vhost: annotate vDPA device list accesses vhost: enable lock check .../prog_guide/env_abstraction_layer.rst | 24 ++++ doc/guides/rel_notes/release_23_03.rst | 5 + drivers/meson.build | 5 + lib/eal/include/generic/rte_rwlock.h | 27 +++- lib/eal/include/generic/rte_spinlock.h | 31 +++-- lib/eal/include/meson.build | 1 + lib/eal/include/rte_lock_annotations.h | 73 ++++++++++ lib/eal/include/rte_seqlock.h | 6 + lib/eal/ppc/include/rte_spinlock.h | 3 + lib/eal/x86/include/rte_rwlock.h | 4 + lib/eal/x86/include/rte_spinlock.h | 9 ++ lib/meson.build | 5 + lib/vhost/iotlb.h | 4 + lib/vhost/meson.build | 2 + lib/vhost/vdpa.c | 20 +-- lib/vhost/vhost.c | 38 ++--- lib/vhost/vhost.h | 34 ++++- lib/vhost/vhost_crypto.c | 8 ++ lib/vhost/vhost_user.c | 131 ++++++++---------- lib/vhost/virtio_net.c | 109 +++++++++++---- 20 files changed, 389 insertions(+), 150 deletions(-) create mode 100644 lib/eal/include/rte_lock_annotations.h -- 2.39.0
