gdbstub and testing fixes for 8.2

This is the current state for my maintainer queue for when the tree
re-opens. It includes the previous testing/next fixes as well as some
more cleanups to modernise the gdbstub tests and code. It also
includes Matheus' fixes for SIGINT.

The following patches need review:

  gdbstub: replace global gdb_has_xml with a function
  gdbstub: refactor get_feature_xml
  gdbstub: remove unused user_ctx field
  tests/tcg: clean-up gdb confirm/pagination settings
  tests: remove test-gdbstub.py
  tests/tcg: remove quoting for info output

linux-user: extend -dfilter to accept paths

I was getting lost on debugging output and I couldn't get the mapped
address of libnative to be stable. So to help I hacked up this
extension which may or may not be worth developing further.

Consider this a debugging RFC tool for now.

some testing and gdbstub fixes

This is mostly gdbstub focused but I cleaned up some bits while I was
in the testing makefiles. This is mostly to make the "check-tcg"
output as clean as possible without ugly line wraps. I tried to
eliminate the gdbstub info() output but sadly this is harder than
expected.

I've tweaked the gdbstub handling for Ctrl-c packets as suggested by
Matheus. While I was there I also noticed we were being a bit precious
about gdb sending preemptive ACKS so I fixed that as well.

I don't know if this is all late 8.1-rc material but its fairly simple
testing updates and the ccache stuff from Daniel should help as well.

maintainer updates: testing, fuzz, plugins, docs, gdbstub

 - clean up gitlab artefact handling
 - ensure gitlab publishes artefacts with coverage data
 - reduce testing scope for coverage job
 - mention CI pipeline in developer docs
 - add ability to add plugin args to check-tcg
 - fix some memory leaks and UB in tests
 - suppress xcb leaks from fuzzing output
 - add a test-fuzz to mirror the CI run
 - allow lci-refresh to be run in $SRC
 - update lcitool to latest version
 - add qemu-minimal package set with gcc-native
 - convert riscv64-cross to lcitool
 - update sbsa-ref tests
 - don't include arm_casq_ptw emulation unless TCG
 - convert plugins to use g_memdup2
 - ensure plugins instrument SVE helper mem access
 - improve documentation of QOM/QDEV
 - make gdbstub send stop responses when it should
 - report user-mode pid in gdbstub
 - add support for info proc mappings in gdbstub

maintainer omnibus: testing, fuzz, plugins, documentation, gdbstub (pre-PR)

As softfreeze is fast approaching I thought it would be work combining
my various trees into an omnibus series to ease the review and
merging.

The testing updates exposed a number of latent leaks that confused the
oss-fuzz jobs (hence the test-fuzz addition to help debug that). This
also includes some minor plugin updates and finally some documentation
updates that clean-up and expose the QOM and QDEV APIs which are so
core to emulating anything in QEMU.

I was intending to roll the PR from the last post but as there is
still un-reviewed stuff and some changes I'd missed from previous
reviews so I though it was worth one last posting. I'll roll on
Monday.

v2
  - applied a bunch of review tags
  - added missing doc suggestions from Paolo
  - tweaked the plugin fix for CI

v3
  - few more tags
  - checkpatch cleanups
  - rolled in gdbstub/next

v4
  - added #ifdef CONFIG_TCG to the arm_casq_ptw
  - fixed plugin memory instrumentation with new helper for mmu access
  - added Thomas' test_arm_bpim2u_gmac tweak
  - moved pkgs from riscv64-cross patch to earlier qemu-minimal patch

The following are still missing review:

 - gdbstub: lightly refactor connection to avoid snprintf
 - tests/docker: convert riscv64-cross to lcitool
 - tests/lcitool: introduce qemu-minimal
 - tests/lcitool: add an explicit gcc-native package (1 acks, 1 sobs, 0 tbs)
 - tests/lcitool: update to latest version (1 acks, 1 sobs, 0 tbs)
 - tests/qtests: clean-up and fix leak in generic_fuzz

maintainer omnibus: testing, fuzz, plugins, documentation, gdbstub (pre-PR)

As softfreeze is fast approaching I thought it would be work combining
my various trees into an omnibus series to ease the review and
merging.

The testing updates exposed a number of latent leaks that confused the
oss-fuzz jobs (hence the test-fuzz addition to help debug that). This
also includes some minor plugin updates and finally some documentation
updates that clean-up and expose the QOM and QDEV APIs which are so
core to emulating anything in QEMU.

v2
  - applied a bunch of review tags
  - added missing doc suggestions from Paolo
  - tweaked the plugin fix for CI

v3
  - few more tags
  - checkpatch cleanups
  - rolled in gdbstub/next

The following are still missing review:

 - gdbstub: lightly refactor connection to avoid snprintf
 - docs/devel: introduce some key concepts for QOM development
 - tests/docker: convert riscv64-cross to lcitool
 - tests/lcitool: introduce qemu-minimal
 - tests/lcitool: add an explicit gcc-native package (1 acks, 1 sobs, 0 tbs)
 - tests/lcitool: update to latest version (1 acks, 1 sobs, 0 tbs)
 - tests/qtests: clean-up and fix leak in generic_fuzz

maintainer omnibus: testing, fuzz, plugins, documentation

As softfreeze is fast approaching I thought it would be work combining
my various trees into an omnibus series to ease the review and
merging.

The testing updates exposed a number of latent leaks that confused the
oss-fuzz jobs (hence the test-fuzz addition to help debug that). This
also includes some minor plugin updates and finally some documentation
updates that clean-up and expose the QOM and QDEV APIs which are so
core to emulating anything in QEMU.

v2
  - applied a bunch of review tags
  - added missing doc suggestions from Paolo
  - tweaked the plugin fix for CI

The following patches need review:

 - qemu-keymap: properly check return from xkb_keymap_mod_get_index

maintainer omnibus: testing, fuzz, plugins, documentation

As softfreeze is fast approaching I thought it would be work combining
my various trees into an omnibus series to ease the review and
merging.

The testing updates exposed a number of latent leaks that confused the
oss-fuzz jobs (hence the test-fuzz addition to help debug that). This
also includes some minor plugin updates and finally some documentation
updates that clean-up and expose the QOM and QDEV APIs which are so
core to emulating anything in QEMU.

Please review.

docs/devel: improve API documentation for QOM

Hi,

At the recent QEMU maintainers summit we lamented the fact it was hard
to push forward with our modernising plans as legacy approaches still
get introduced into the code. A lot of knowledge about the "modern"
way of doing things is locked up in senior developers heads. Lets make
a push to improve the developer documentation and ensure best
practice is easy to find.

Some sort of parable about distribution of fishes and knowledge seems
appropriate here.

Fixes for Python venv changes

Testing updates:

  - fix up xtensa docker container base to current Debian
  - document breakpoint and watchpoint support
  - clean up the ansible scripts for Ubuntu 22.04
  - add a minimal device profile
  - drop https on mipsdistros URL
  - fix Kconfig bug for XLNX_VERSAL

Testing and documentation updates:

  - bump avocado to 101.0
  - use snapshots for tuxrun baseline tests
  - add sbda-ref test to avocado
  - avoid spurious re-configure in gitlab
  - better description of blockdev options
  - drop FreeBSD 12 from Cirrus CI
  - fix up the ast2[56]00 tests to be more stable
  - improve coverage of ppc64 tests in tuxrun baselines
  - limit plugin tests to just the generic multiarch binaries

docs: various (style, punctuation and typo fixes)

I accumulated some doc fixes that didn't make it into 8.0 and thought
I might as well see if there was anything worth adding to the coding
style while at it.

Let me know what you think.

Final test and misc fixes:

  - add basic coverage analysis script
  - gdbstub only build one of libgdb_user/softmmu
  - don't break BSD gdb by advertising AUXV feature
  - add MAINTAINERS section for policy docs
  - update hexagon toolchain
  - explicitly invoke iotests with python for BSDs benefit
  - use system python on NetBSD
  - add some tests for the new KVM Xen guest support

Final test and misc fixes:

  - add basic coverage analysis script
  - gdbstub only build one of libgdb_user/softmmu
  - don't break BSD gdb by advertising AUXV feature
  - add MAINTAINERS section for policy docs
  - add more verbiage to -blockdev/-drive usage in docs
  - update hexagon toolchain
  - explicitly invoke iotests with python for BSDs benefit
  - use system python on NetBSD
  - add some tests for the new KVM Xen guest support

more misc fixes for 8.0 (tests, gdbstub, meta, docs)

Testing of kaniko as an alternative builder ran into the weeds so that
patch has been dropped. It looks like the gitlab registry doesn't
support layer caching. However the build also seems to be very
unstable leading to a bunch of container build failures, e.g.:

  https://gitlab.com/stsquad/qemu/-/pipelines/823381159/failures

I've also dropped the avocado version bump. We do gain two new patches
- one minor gdbstub fix for BSD and including the Xen KVM test.

It would be nice to get some review of the documentation update from
the block maintainers but if no one objects I still intend to merge it
in lieu of anything better.

I'll roll the PR tomorrow morning.

Alex.

more misc fixes for 8.0 (tests, gdbstub, meta, docs)

Here are a few more random fixes across the tree. All should be good
for the current phase of freeze although I can drop stuff if it causes
problems.

I've included another run at using the kaniko build tool and will see
if it improves the caching of things as it runs through my CI loop.

Alex.

Misc fixes for 8.0 (testing, plugins, gitdm)

  - update Alpine image used for testing images
  - include libslirp in custom runner build env
  - update gitlab-runner recipe for CentOS
  - update docker calls for better caching behaviour
  - document some plugin callbacks
  - don't use tags to define drives for lkft baseline tests
  - fix missing clear of plugin_mem_cbs
  - fix iotests to report individual results
  - update the gitdm metadata for contributors
  - avoid printing comments before g_test_init()
  - probe for multiprocess support before running avocado test
  - refactor igb.py into netdev-ethtool.py avocado test
  - rebuild openbsd to have more space space for iotests

Misc fixes for 8.0 (testing, plugins, gitdm)

  - update Alpine image used for testing images
  - include libslirp in custom runner build env
  - update gitlab-runner recipe for CentOS
  - update docker calls for better caching behaviour
  - document some plugin callbacks
  - don't use tags to define drives for lkft baseline tests
  - fix missing clear of plugin_mem_cbs
  - fix iotests to report individual results
  - update the gitdm metadata for contributors
  - avoid printing comments before g_test_init()

Misc fixes for 8.0 (testing, plugins, gitdm)

  - update Alpine image used for testing images
  - include libslirp in custom runner build env
  - update gitlab-runner recipe for CentOS
  - update docker calls for better caching behaviour
  - document some plugin callbacks
  - don't use tags to define drives for lkft baseline tests
  - fix missing clear of plugin_mem_cbs
  - fix iotests to report individual results
  - update the gitdm metadata for contributors
  - temporally disable gdb registers for pauth
  - avoid printing comments before g_test_init()