This reverts commit aff8fd18.

Both virtio-net and virtio-crypto do not balance
virtio_queue_set_notification() enable and disable calls.  This makes
the notifications_disabled counter unreliable and Doug Goldstein
reported the following assertion failure:

  #3  0x00007ffff44d1c62 in __GI___assert_fail (
      assertion=assertion@entry=0x555555ae8e8a "vq->notification_disabled > 0",
      file=file@entry=0x555555ae89c0 "/home/doug/work/qemu/hw/virtio/virtio.c",
      line=line@entry=215,
      function=function@entry=0x555555ae9630 <__PRETTY_FUNCTION__.43707>
      "virtio_queue_set_notification") at assert.c:101
  #4  0x00005555557f25d6 in virtio_queue_set_notification (vq=0x55555666aa90,
      enable=enable@entry=1) at /home/doug/work/qemu/hw/virtio/virtio.c:215
  #5  0x00005555557dc311 in virtio_net_has_buffers (q=<optimized out>,
      q=<optimized out>, bufsize=102)
      at /home/doug/work/qemu/hw/net/virtio-net.c:1008
  #6  virtio_net_receive (nc=<optimized out>, buf=0x555557386b88 "", size=102)
      at /home/doug/work/qemu/hw/net/virtio-net.c:1148
  #7  0x00005555559cad33 in nc_sendv_compat (flags=<optimized out>, iovcnt=1,
      iov=0x7fffead746d0, nc=0x55555788b340) at net/net.c:705
  #8  qemu_deliver_packet_iov (sender=<optimized out>, flags=<optimized out>,
      iov=0x7fffead746d0, iovcnt=1, opaque=0x55555788b340) at net/net.c:732
  #9  0x00005555559cd929 in qemu_net_queue_deliver (size=<optimized out>,
      data=<optimized out>, flags=<optimized out>, sender=<optimized out>,
      queue=0x55555788b550) at net/queue.c:164
  #10 qemu_net_queue_flush (queue=0x55555788b550) at net/queue.c:261

This patch is safe to revert since it's just an optimization for
virtqueue polling.  The next patch will improve the situation again
without resorting to nesting.
Reported-by: NDoug Goldstein <cardoe@cardoe.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Tested-by: NRichard Henderson <rth@twiddle.net>
Tested-by: NLaszlo Ersek <lersek@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

virtio-net-pci does not enable ioeventfd for historical reasons (and
nobody ever checked whether it should be revisited).  Note that other
backends do enable ioeventfd for virtio-net.

However, it has a major effect on performance.  On Windows, throughput is
_multiplied_ by 2 or 3 on TCP_STREAM (on small packets it is "only" a 30%
improvement) and a little less so on TCP_MAERTS albeit still very much
statistically significant.  Latency also has a single digit improvement.

This is not visible when using vhost, which forces ioeventfd=on, but it
is substantial without vhost.  In addition, also on Windows and with the
RHEL 7.3 kernel, APICv seems to slow down virtio-net performance a bit,
but the penalty with this patch goes from -25% to -7%.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

QAPI patches for 2017-01-16

# gpg: Signature made Mon 16 Jan 2017 09:26:49 GMT
# gpg:                using RSA key 0x3870B400EB918653
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>"
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>"
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867  4E5F 3870 B400 EB91 8653

* remotes/armbru/tags/pull-qapi-2017-01-16: (180 commits)
  build-sys: add qapi doc generation targets
  build-sys: add txt documentation rules
  build-sys: use a generic TEXI2MAN rule
  build-sys: remove dvi doc generation
  build-sys: use --no-split for info
  docs: add qemu logo to pdf
  qapi: add qapi2texi script
  qmp-events: move 'MIGRATION_PASS' doc to schema
  qmp-events: move 'DUMP_COMPLETED' doc to schema
  qmp-events: move 'MEM_UNPLUG_ERROR' doc to schema
  qmp-events: move 'VSERPORT_CHANGE' doc to schema
  qmp-events: move 'QUORUM_REPORT_BAD' doc to schema
  qmp-events: move 'QUORUM_FAILURE' doc to schema
  qmp-events: move 'GUEST_PANICKED' doc to schema
  qmp-events: move 'BALLOON_CHANGE' doc to schema
  qmp-events: move 'ACPI_DEVICE_OST' doc to schema
  qmp-events: move 'MIGRATION' doc to schema
  qmp-events: move 'SPICE_MIGRATE_COMPLETED' doc to schema
  qmp-events: move 'SPICE_DISCONNECTED' doc to schema
  qmp-events: move 'SPICE_INITIALIZED' doc to schema
  ...
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

# gpg: Signature made Mon 16 Jan 2017 13:38:52 GMT
# gpg:                using RSA key 0x9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha/tags/block-pull-request:
  async: optimize aio_bh_poll
  aio: document locking
  aio-win32: remove walking_handlers, protecting AioHandler list with list_lock
  aio-posix: remove walking_handlers, protecting AioHandler list with list_lock
  aio: tweak walking in dispatch phase
  aio-posix: split aio_dispatch_handlers out of aio_dispatch
  qemu-thread: optimize QemuLockCnt with futexes on Linux
  aio: make ctx->list_lock a QemuLockCnt, subsuming ctx->walking_bh
  qemu-thread: introduce QemuLockCnt
  aio: rename bh_lock to list_lock
  block: get rid of bdrv_io_unplugged_begin/end
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Merge remote-tracking branch 'remotes/stsquad/tags/pull-tcg-common-tlb-reset-20170113-r1' into staging

This is the same as the v3 posted except a re-base and a few extra signoffs

# gpg: Signature made Fri 13 Jan 2017 14:26:46 GMT
# gpg:                using RSA key 0xFBD0DB095A9E2A44
# gpg: Good signature from "Alex Bennée (Master Work Key) <alex.bennee@linaro.org>"
# Primary key fingerprint: 6685 AE99 E751 67BC AFC8  DF35 FBD0 DB09 5A9E 2A44

* remotes/stsquad/tags/pull-tcg-common-tlb-reset-20170113-r1:
  cputlb: drop flush_global flag from tlb_flush
  cpu_common_reset: wrap TCG specific code in tcg_enabled()
  qom/cpu: move tlb_flush to cpu_common_reset
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Avoid entering the slow path of qemu_lockcnt_dec_and_lock if
no bottom half has to be deleted.
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Message-id: 20170112180800.21085-11-pbonzini@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Message-id: 20170112180800.21085-10-pbonzini@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Message-id: 20170112180800.21085-9-pbonzini@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170112180800.21085-8-pbonzini@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Preparing for the following patch, use QLIST_FOREACH_SAFE and
modify the placement of walking_handlers increment/decrement.
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Message-id: 20170112180800.21085-7-pbonzini@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

This simplifies the handling of dispatch_fds.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170112180800.21085-6-pbonzini@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

This is complex, but I think it is reasonably documented in the source.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170112180800.21085-5-pbonzini@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

This will make it possible to walk the list of bottom halves without
holding the AioContext lock---and in turn to call bottom half
handlers without holding the lock.
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Message-id: 20170112180800.21085-4-pbonzini@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

A QemuLockCnt comprises a counter and a mutex, with primitives
to increment and decrement the counter, and to take and release the
mutex.  It can be used to do lock-free visits to a data structure
whenever mutexes would be too heavy-weight and the critical section
is too long for RCU.

This could be implemented simply by protecting the counter with the
mutex, but QemuLockCnt is harder to misuse and more efficient.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170112180800.21085-3-pbonzini@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

This will be used for AioHandlers too.  There is going to be little
or no contention, so it is better to reuse the same lock.
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Message-id: 20170112180800.21085-2-pbonzini@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

bdrv_io_plug and bdrv_io_unplug are only called (via their
BlockBackend equivalents) after starting asynchronous I/O.
bdrv_drain is not going to be called while they are running,
because---even if a coroutine runs for some reason---it will
only drain in the next iteration of the event loop through
bdrv_co_yield_to_drain.

So this mechanism is unnecessary, get rid of it.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-id: 20161129113334.605-1-pbonzini@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

# gpg: Signature made Sat 14 Jan 2017 09:06:31 GMT
# gpg:                using RSA key 0xF30C38BD3F2FBE3C
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>"
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>"
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>"
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier/tags/m68k-for-2.9-pull-request:
  target-m68k: increment/decrement with SP
  target-m68k: CAS doesn't need aligned access
  target-m68k: manage pre-dec et post-inc in CAS
  target-m68k: fix gen_flush_flags()
  target-m68k: fix bit operation with immediate value
  m68k: Remove PCI and USB from config file
  target-m68k: Implement bfffo
  target-m68k: Implement bitfield ops for memory
  target-m68k: Implement bitfield ops for registers
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Fixes and more queued patches

# gpg: Signature made Fri 13 Jan 2017 20:00:53 GMT
# gpg:                using RSA key 0xAD1270CC4DD0279B
# gpg: Good signature from "Richard Henderson <rth7680@gmail.com>"
# gpg:                 aka "Richard Henderson <rth@redhat.com>"
# gpg:                 aka "Richard Henderson <rth@twiddle.net>"
# Primary key fingerprint: 9CB1 8DDA F8E8 49AD 2AFC  16A4 AD12 70CC 4DD0 279B

* remotes/rth/tags/pull-tcg-20170113:
  tcg/aarch64: Fix tcg_out_movi
  tcg/aarch64: Fix addsub2 for 0+C
  target/arm: Fix ubfx et al for aarch64
  tcg/s390: Fix merge error with facilities
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Generate and install the man, txt and html versions of QAPI
documentation (generate and install qemu-doc.txt too).

Add it also to optional pdf/info targets.
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20170113144135.5150-22-marcandre.lureau@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Build plain text documentation, and install it.
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20170113144135.5150-21-marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

The recipe for making a man page from .texi is duplicated several
times over.  Capture it in suitable pattern rules instead.
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20170113144135.5150-20-marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

There is no clear reason to have rules to generate dvi format
documentation, pdf is generally better supported nowadays.
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20170113144135.5150-19-marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Splitting the info files doesn't bring much benefits these days.
This fixes also untracked generated info files from git ignore.

Let's use MAKEINFOFLAGS for common flags, --number-sections is already
the default anyway, so adding it doesn't change the info output.
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20170113144135.5150-18-marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Add a logo to texi2pdf output. Other formats (info/html) are left as
future improvements.

The PDF (needed by texi2pdf for vectorized images) was generated from
pc-bios/qemu_logo.svg like this:

inkscape --export-pdf=docs/qemu_logo.pdf pc-bios/qemu_logo.svg
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20170113144135.5150-17-marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

As the name suggests, the qapi2texi script converts JSON QAPI
description into a texi file suitable for different target
formats (info/man/txt/pdf/html...).

It parses the following kind of blocks:

Free-form:

  ##
  # = Section
  # == Subsection
  #
  # Some text foo with *emphasis*
  # 1. with a list
  # 2. like that
  #
  # And some code:
  # | $ echo foo
  # | -> do this
  # | <- get that
  #
  ##

Symbol description:

  ##
  # @symbol:
  #
  # Symbol body ditto ergo sum. Foo bar
  # baz ding.
  #
  # @param1: the frob to frobnicate
  # @param2: #optional how hard to frobnicate
  #
  # Returns: the frobnicated frob.
  #          If frob isn't frobnicatable, GenericError.
  #
  # Since: version
  # Notes: notes, comments can have
  #        - itemized list
  #        - like this
  #
  # Example:
  #
  # -> { "execute": "quit" }
  # <- { "return": {} }
  #
  ##

That's roughly following the following EBNF grammar:

api_comment = "##\n" comment "##\n"
comment = freeform_comment | symbol_comment
freeform_comment = { "# " text "\n" | "#\n" }
symbol_comment = "# @" name ":\n" { member | tag_section | freeform_comment }
member = "# @" name ':' [ text ] "\n" freeform_comment
tag_section = "# " ( "Returns:", "Since:", "Note:", "Notes:", "Example:", "Examples:" ) [ text ]  "\n" freeform_comment
text = free text with markup

Note that the grammar is ambiguous: a line "# @foo:\n" can be parsed
both as freeform_comment and as symbol_comment.  The actual parser
recognizes symbol_comment.

See docs/qapi-code-gen.txt for more details.

Deficiencies and limitations:
- the generated QMP documentation includes internal types
- union type support is lacking
- type information is lacking in generated documentation
- doc comment error message positions are imprecise, they point
  to the beginning of the comment.
- a few minor issues, all marked TODO/FIXME in the code
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20170113144135.5150-16-marcandre.lureau@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
[test-qapi.py tweaked to avoid trailing empty lines in .out]
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>