[PATCH v6 00/21] Add virtual device fuzzing support

[Oleinik, Alexander]

This series adds a framework for coverage-guided fuzzing of
virtual-devices. Fuzzing targets are based on qtest and can make use of
the libqos abstractions.

In this version, I added a virtio-scsi fuzzer. The actual fuzzing code
is very similar to the the virtio-net fuzzer. I experimented with using
a single fuzzer with device-specific initialization for each virtio
device, but it did not come out as cleanly as I hoped, since I could not
find an easy way to override the qos drivers for devices that have
more-complete qos support (such as virtio-net), so these changes have
not made it into v6.

V5/V6: (V5 did not have review tags)
 * added virtio-scsi fuzzer
 * add support for using fork-based fuzzers with multiple libfuzzer
   workers
 * misc fixes addressing V4 comments
 * cleanup in-process handlers/globals in libqtest.c
 * small fixes to fork-based fuzzing and support for multiple workers
 * changes to the virtio-net fuzzer to kick after each vq add

V4:
 * add/transfer license headers to new files
 * restructure the added QTestClientTransportOps struct
 * restructure the FuzzTarget struct and fuzzer skeleton
 * fork-based fuzzer now directly mmaps shm over the coverage bitmaps
 * fixes to i440 and virtio-net fuzz targets
 * undo the changes to qtest_memwrite
 * possible to build /fuzz and /all in the same build-dir
 * misc fixes to address V3 comments

V3:
 * rebased onto v4.1.0+
 * add the fuzzer as a new build-target type in the build-system
 * add indirection to qtest client/server communication functions
 * remove ramfile and snapshot-based fuzzing support
 * add i440fx fuzz-target as a reference for developers.
 * add linker-script to assist with fork-based fuzzer

V2:
 * split off changes to qos virtio-net and qtest server to other patches
 * move vl:main initialization into new func: qemu_init
 * moved useful functions from qos-test.c to a separate object
 * use struct of function pointers for add_fuzz_target(), instead of
   arguments
 * move ramfile to migration/qemu-file
 * rewrite fork-based fuzzer pending patch to libfuzzer
 * pass check-patch

Alexander Bulekov (21):
  softmmu: split off vl.c:main() into main.c
  libqos: Rename i2c_send and i2c_recv
  fuzz: Add FUZZ_TARGET module type
  qtest: add qtest_server_send abstraction
  libqtest: Add a layer of abstraciton to send/recv
  module: check module wasn't already initialized
  qtest: add in-process incoming command handler
  tests: provide test variables to other targets
  libqos: split qos-test and libqos makefile vars
  libqos: move useful qos-test funcs to qos_external
  libqtest: make bufwrite rely on the TransportOps
  libqtest: add in-process qtest.c tx/rx handlers
  fuzz: add configure flag --enable-fuzzing
  fuzz: Add target/fuzz makefile rules
  fuzz: add fuzzer skeleton
  fuzz: add support for fork-based fuzzing.
  fuzz: add support for qos-assisted fuzz targets
  fuzz: add i440fx fuzz targets
  fuzz: add virtio-net fuzz target
  fuzz: add virtio-scsi fuzz target
  fuzz: add documentation to docs/devel/

 Makefile                      |  16 ++-
 Makefile.objs                 |   4 +
 Makefile.target               |  18 ++-
 configure                     |  39 ++++++
 docs/devel/fuzzing.txt        | 119 +++++++++++++++++
 exec.c                        |  12 +-
 include/qemu/module.h         |   4 +-
 include/sysemu/qtest.h        |   4 +
 include/sysemu/sysemu.h       |   4 +
 main.c                        |  53 ++++++++
 qtest.c                       |  31 ++++-
 tests/Makefile.include        |  75 +++++------
 tests/fuzz/Makefile.include   |  12 ++
 tests/fuzz/fork_fuzz.c        |  55 ++++++++
 tests/fuzz/fork_fuzz.h        |  23 ++++
 tests/fuzz/fork_fuzz.ld       |  37 ++++++
 tests/fuzz/fuzz.c             | 179 ++++++++++++++++++++++++++
 tests/fuzz/fuzz.h             |  94 ++++++++++++++
 tests/fuzz/i440fx_fuzz.c      | 176 ++++++++++++++++++++++++++
 tests/fuzz/qos_fuzz.c         | 232 ++++++++++++++++++++++++++++++++++
 tests/fuzz/qos_fuzz.h         |  33 +++++
 tests/fuzz/virtio_net_fuzz.c  | 105 +++++++++++++++
 tests/fuzz/virtio_scsi_fuzz.c | 200 +++++++++++++++++++++++++++++
 tests/libqos/i2c.c            |  10 +-
 tests/libqos/i2c.h            |   4 +-
 tests/libqos/qos_external.c   | 168 ++++++++++++++++++++++++
 tests/libqos/qos_external.h   |  28 ++++
 tests/libqtest.c              | 108 ++++++++++++++--
 tests/libqtest.h              |   4 +
 tests/pca9552-test.c          |  10 +-
 tests/qos-test.c              | 140 +-------------------
 util/module.c                 |   7 +
 vl.c                          |  38 ++----
 33 files changed, 1813 insertions(+), 229 deletions(-)
 create mode 100644 docs/devel/fuzzing.txt
 create mode 100644 main.c
 create mode 100644 tests/fuzz/Makefile.include
 create mode 100644 tests/fuzz/fork_fuzz.c
 create mode 100644 tests/fuzz/fork_fuzz.h
 create mode 100644 tests/fuzz/fork_fuzz.ld
 create mode 100644 tests/fuzz/fuzz.c
 create mode 100644 tests/fuzz/fuzz.h
 create mode 100644 tests/fuzz/i440fx_fuzz.c
 create mode 100644 tests/fuzz/qos_fuzz.c
 create mode 100644 tests/fuzz/qos_fuzz.h
 create mode 100644 tests/fuzz/virtio_net_fuzz.c
 create mode 100644 tests/fuzz/virtio_scsi_fuzz.c
 create mode 100644 tests/libqos/qos_external.c
 create mode 100644 tests/libqos/qos_external.h

-- 
2.23.0