The ISA has a 128/64-bit division instruction.

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

The ISA has a 128/64-bit division instruction.

Tested-by: Emilio G. Cota <cota@braap.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

The __udiv_qrnnd primitive that we nicked from gmp requires its
inputs to be normalized.  We were not doing that.  Because the
inputs are nearly normalized already, finishing that is trivial.

Replace div128to64 with a "proper" udiv_qrnnd, so that this
remains a reusable primitive.

Fixes: cf07323d
Fixes: https://bugs.launchpad.net/qemu/+bug/1793119


Tested-by: Emilio G. Cota <cota@braap.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Our minimum required compiler for compiling QEMU is GCC 4.1 these days,
so we can drop the support for compilers which do not provide the
__builtin_clz*() functions yet. Since the countLeadingZeros32/64 are
then identical to the clz32/64 functions, and we do not have to sync
the softloat 2 codebase with upstream anymore (softloat 3 is a complete
rewrite) we can simply replace the functions with our QEMU versions.

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1538118095-7003-1-git-send-email-thuth@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

By leveraging berkeley's softfloat and testfloat.

With this we get decent coverage of softfloat.c:

$ ./fp-test -r even:	67.22% coverage
$ ./fp-test -r all:	73.11% coverage

Note that we do not yet test parts of softfloat.c that aren't
in the original softfloat library, namely:

- denormal inputs
- *_to_int16/uint16 conversions
- scalbn for fixed point
- muladd variants
- min/max
- exp2
- log2
- float*_compare (except float16_compare)

Signed-off-by: Emilio G. Cota <cota@braap.org>
[rth: Add the new modules to git_submodules.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

These are BSD-licensed so we can add them as submodules.

Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

It has not had users since f83311e4 ("target-m68k: use floatx80
internally", 2017-06-21).

Note that no other bit-width has floatX_trunc_to_int.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Various s390x updates:
- fix several struct definitions so that sparc hosts do not trip over
  unaligned accesses
- fence enabling huge pages for pre-3.1 machines
- sysbus init -> realize conversion
- fixes and improvements in tcg (instruction flags and AFP registers)

# gpg: Signature made Thu 04 Oct 2018 16:22:20 BST
# gpg:                using RSA key DECF6B93C6F02FAF
# gpg: Good signature from "Cornelia Huck <conny@cornelia-huck.de>"
# gpg:                 aka "Cornelia Huck <huckc@linux.vnet.ibm.com>"
# gpg:                 aka "Cornelia Huck <cornelia.huck@de.ibm.com>"
# gpg:                 aka "Cornelia Huck <cohuck@kernel.org>"
# gpg:                 aka "Cornelia Huck <cohuck@redhat.com>"
# Primary key fingerprint: C3D0 D66D C362 4FF6 A8C0  18CE DECF 6B93 C6F0 2FAF

* remotes/cohuck/tags/s390x-20181004:
  hw/s390x/s390-pci-bus: Convert sysbus init function to realize function
  s390x/tcg: refactor specification checking
  s390x/tcg: fix FP register pair checks
  s390x/tcg: handle privileged instructions via flags
  s390x/tcg: check for AFP-register, BFP and DFP data exceptions
  s390x/tcg: add instruction flags for floating point instructions
  s390x/tcg: support flags for instructions
  s390x/tcg: store in the TB flags if AFP is enabled
  s390x/tcg: factor out and fix DATA exception injection
  s390x: move tcg_s390_program_interrupt() into TCG code and mark it noreturn
  target/s390x: exception on non-aligned LPSW(E)
  s390x: Fence huge pages prior to 3.1
  hw/s390x/ioinst: Fix alignment problem in struct SubchDev
  hw/s390x/css: Remove QEMU_PACKED from struct SenseId
  hw/s390x/ipl: Fix alignment problems of S390IPLState members

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

nbd patches for 2018-10-03

Fix bugs in NBD_CMD_CACHE, drop support for oldstyle NBD server,
minor build and doc fixes

- Denis V. Lunev: nbd: fix NBD_CMD_CACHE negitiation... [retitled]
- Vladimir Sementsov-Ogievskiy: 0/2 server: drop old-style negotiation
- Eric Blake: qemu-nbd: Document --tls-creds
- Vladimir Sementsov-Ogievskiy: nbd/server: fix NBD_CMD_CACHE
- Peter Maydell: nbd: Don't take address of fields in packed structs

# gpg: Signature made Thu 04 Oct 2018 15:19:32 BST
# gpg:                using RSA key A7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>"
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>"
# gpg:                 aka "[jpeg image of size 6874]"
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-nbd-2018-10-03-v2:
  nbd: fix NBD_FLAG_SEND_CACHE value
  nbd/server: drop old-style negotiation
  qemu-nbd: drop old-style negotiation
  qemu-nbd: Document --tls-creds
  nbd/server: fix NBD_CMD_CACHE
  nbd: Don't take address of fields in packed structs

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Python queue, 2018-10-03

* Remove fixed serial device errors from device-crash-test
* Remove unnecessary Python 2.6 compatibility code

# gpg: Signature made Thu 04 Oct 2018 03:17:34 BST
# gpg:                using RSA key 2807936F984DC5A6
# gpg: Good signature from "Eduardo Habkost <ehabkost@redhat.com>"
# Primary key fingerprint: 5A32 2FD5 ABC4 D3DB ACCF  D1AA 2807 936F 984D C5A6

* remotes/ehabkost/tags/python-next-pull-request:
  scripts/device-crash-test: Remove entries for serial devices
  Revert "tests: migration/guestperf Python 2.6 argparse compatibility"
  Revert "docker.py: Python 2.6 argparse compatibility"
  device-crash-test: No need for sys.path hack

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Commit bc37b06a added NBD_CMD_CACHE support, but used the wrong value
for NBD_FLAG_SEND_CACHE flag for negotiation. That commit picked bit 8,
which had already been assigned by the NBD specification to mean
NBD_FLAG_CAN_MULTI_CONN, and which was already implemented in the
Linux kernel as a part of stable userspace-kernel API since 4.10:

"bit 8, NBD_FLAG_CAN_MULTI_CONN: Indicates that the server operates
entirely without cache, or that the cache it uses is shared among all
connections to the given device. In particular, if this flag is
present, then the effects of NBD_CMD_FLUSH and NBD_CMD_FLAG_FUA
MUST be visible across all connections when the server sends its reply
to that command to the client. In the absense of this flag, clients
SHOULD NOT multiplex their commands over more than one connection to
the export.
...
bit 10, NBD_FLAG_SEND_CACHE: documents that the server understands
NBD_CMD_CACHE; however, note that server implementations exist
which support the command without advertising this bit, and
conversely that this bit does not guarantee that the command will
succeed or have an impact."

Consequences:
- a client trying to use NBD_CMD_CACHE per the NBD spec will not
see the feature as available from a qemu 3.0 server (not fatal,
clients already have to be prepared for caching to not exist)
- a client accidentally coded to the qemu 3.0 bit value instead
of following the spec may interpret NBD_CMD_CACHE as being available
when it is not (probably not fatal, the spec says the server should
gracefully fail unknown commands, and that clients of NBD_CMD_CACHE
should be prepared for failure even when the feature is advertised);
such clients are unlikely (perhaps only in unreleased Virtuozzo code),
and will disappear over time
- a client prepared to use multiple connections based on
NBD_FLAG_CAN_MULTI_CONN may cause data corruption when it assumes
that caching is consistent when in reality qemu 3.0 did not have
a consistent cache. Partially mitigated by using read-only
connections (where nothing needs to be flushed, so caching is
indeed consistent) or when using qemu-nbd with the default -e 1
(at most one client at a time); visible only when using -e 2 or
more for a writable export.

Thus the commit fixes negotiation flag in QEMU according to the
specification.

Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
CC: Valery Vdovin <valery.vdovin@acronis.com>
CC: Eric Blake <eblake@redhat.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: qemu-stable@nongnu.org
Message-Id: <20181004100313.4253-1-den@openvz.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: enhance commit message, add defines for unimplemented flags]
Signed-off-by: Eric Blake <eblake@redhat.com>

The SysBusDeviceClass->init() interface is considered as a legacy interface
and there are currently some efforts going on to get rid of it. Thus let's
convert the init function in the s390x code to realize() instead.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1538466491-2073-1-git-send-email-thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

We can fit this nicely into less LOC, without harming readability.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180927130303.12236-10-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

Valid register pairs are 0/2, 1/3, 4/6, 5/7, 8/10, 9/11, 12/14, 13/15.

R1/R2 always selects the lower number, so the current checks are not
correct as e.g. 2/4 could be selected as a pair.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180927130303.12236-9-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

Let's check this also at a central place.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180927130303.12236-8-david@redhat.com>
Acked-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

With the annotated functions, we can now easily check this at a central
place.

DXC 1 is to be injected if an AFP register is used (for a HFP AND FPS
instruction) when AFP is disabled.
DXC 2 is to be injected if a BFP instruction is used when AFP is
disabled.
DXC 3 is to be injected if a DFP instruction is used when AFP is
disabled.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180927130303.12236-7-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

These flags allow us to later on detect if a DATA program interrupt
is to be injected, and which DXC (1,2,3) is to be used.

Interestingly, some support FP instructions are considered as HFP
instructions (I assume simply because they were available very early).

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180927130303.12236-6-david@redhat.com>
Acked-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

Storing flags for instructions allows us to efficiently verify certain
properties at a central point. Examples might later be handling if
AFP is disabled in CR0, we are not in problem state, or if vector
instructions are disabled in CR0.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180927130303.12236-5-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

We exit the TB when changing the control registers, so just like PSW
bits, this should always be consistent for a TB.

Using the PSW bit semantic makes things a lot easier compared to
manually defining the spare, shifted bits.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180927130303.12236-4-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

The DXC is to be stored in the low core, and only in the FPC in case AFP
is enabled in CR0. Stub is not required in current code, but this way
we never run into problems.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180927130303.12236-3-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

Move it into TCG-only code and provide a stub. Turn it into noreturn.

As Richard noted, we currently don't log the psw.addr before restoring
the state, fix that by moving (duplicating) the qemu_log_mask in the
tcg/kvm handlers.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180927130303.12236-2-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

Both LPSW and LPSWE should raise a specification exception when their
operand is not doubleword aligned.

Signed-off-by: Pavel Zbitskiy <pavel.zbitskiy@gmail.com>
Message-Id: <20180902003322.3428-3-pavel.zbitskiy@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

As the kernel has no way of disallowing the start of a huge page
backed VM, we can migrate a running huge backed VM to a host that has
no huge page KVM support.

Let's glue huge page support support to the 3.1 machine, so we do not
migrate to a destination host that doesn't have QEMU huge page support
and can stop migration if KVM doesn't indicate support.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Message-Id: <20180928093435.198573-1-frankja@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

struct SubchDev embeds several other structures which are marked with
QEMU_PACKED. This causes the compiler to not care for proper alignment
of these structures. When we later pass around pointers to the unaligned
struct members during migration, this causes problems on host architectures
like Sparc that can not do unaligned memory access.

Most of the structs in ioinst.h are naturally aligned, so we can fix
most of the problem by removing the QEMU_PACKED statements (and use
QEMU_BUILD_BUG_MSG() statements instead to make sure that there is no
padding). However, for the struct SCHIB, we have to keep the QEMU_PACKED
since the compiler adds some padding here otherwise. Move this struct
to the beginning of struct SubchDev instead to fix the alignment problem
here, too.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1538036615-32542-4-git-send-email-thuth@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

The uint16_t member cu_type of struct SenseId is not naturally aligned,
and since the struct is marked with QEMU_PACKED, this can lead to
unaligned memory accesses - which does not work on architectures like
Sparc. Thus remove the QEMU_PACKED here and rather copy the struct
byte by byte when we do copy_sense_id_to_guest().

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1538036615-32542-3-git-send-email-thuth@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

The IplParameterBlock and QemuIplParameters structures are declared with
QEMU_PACKED, so the compiler assumes that the structures do not need to
be aligned in memory. Since the are listed after a "bool" within the
S390IPLState, the IplParameterBlock and QemuIplParameters are also indeed
mis-aligned in memory. This causes problems on Sparc during migration, since
we use VMSTATE_UINT16 in vmstate_iplb to access the devno member for example,
and the corresponding migration functions (like qemu_get_be16s) then try to
access a 16-bit value from a misaligned memory address.
The easiest solution to fix this problem is to move the packed structures
to the beginning of the S390IPLState, right after the DeviceState of course
which has to stay first for QOM reasons. But since DeviceState is a non-packed
struct, we can be sure that it will be padded to the correct alignment at the
end. If not, the QEMU_BUILD_BUG_MSG in this patch will tell us.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1538036615-32542-2-git-send-email-thuth@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

The problem with the various serial devices has been fixed a while
ago in commit 47c4f85a ("hw/char/serial:
Allow disconnected chardevs") already, so we can remove these entries
from the "ignore" list in the device-crash-test script now.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1538403190-27146-1-git-send-email-thuth@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

This reverts commit 0ea47d0f.

scripts/argparse.py was removed from the tree, so we don't
need this hack anymore.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20180618225131.13113-4-ehabkost@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

This reverts commit c2d31896.

scripts/argparse.py was removed from the tree, so we don't need
this hack anymore.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20180618225131.13113-3-ehabkost@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

The device-crash-test script is already inside the 'scripts'
directory, there's no need to add the directory manually to
sys.path.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20180618225131.13113-2-ehabkost@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

After the previous commit, nbd_client_new's first parameter is always
NULL. Let's drop it with all corresponding old-style negotiation code
path which is unreachable now.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20181003170228.95973-3-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: re-wrap short line]
Signed-off-by: Eric Blake <eblake@redhat.com>

Use new-style negotiation always, with default "" (empty) export name
if it is not specified with '-x' option.

qemu as client can manage either style since 2.6.0, commit 69b49502

For comparison:

nbd 3.10 dropped oldstyle long ago (Mar 2015):
https://github.com/NetworkBlockDevice/nbd/commit/36940193

nbdkit 1.3 switched its default to newstyle (Jan 2018):
https://github.com/libguestfs/nbdkit/commit/b2a8aecc
https://github.com/libguestfs/nbdkit/commit/8158e773



Furthermore, if a client that only speaks oldstyle still needs to
communicate to qemu, nbdkit remains available to perform the
translation between the two protocols.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20181003170228.95973-2-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: enhance commit message]
Signed-off-by: Eric Blake <eblake@redhat.com>

Commit 145614a1 introduced --tls-creds and documented it in
qemu-nbd.texi, but forgot to document it in 'qemu-nbd --help'.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20181003180426.602765-1-eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

We should not go to structured-read branch on CACHE command, fix that.

Bug introduced in bc37b06a "nbd/server: introduce NBD_CMD_CACHE"
with the whole feature and affects 3.0.0 release.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
CC: qemu-stable@nongnu.org
Message-Id: <20181003144738.70670-1-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: commit message typo fix]
Signed-off-by: Eric Blake <eblake@redhat.com>

Taking the address of a field in a packed struct is a bad idea, because
it might not be actually aligned enough for that pointer type (and
thus cause a crash on dereference on some host architectures). Newer
versions of clang warn about this. Avoid the bug by not using the
"modify in place" byte swapping functions.

This patch was produced with the following spatch script:
@@
expression E;
@@
-be16_to_cpus(&E);
+E = be16_to_cpu(E);
@@
expression E;
@@
-be32_to_cpus(&E);
+E = be32_to_cpu(E);
@@
expression E;
@@
-be64_to_cpus(&E);
+E = be64_to_cpu(E);
@@
expression E;
@@
-cpu_to_be16s(&E);
+E = cpu_to_be16(E);
@@
expression E;
@@
-cpu_to_be32s(&E);
+E = cpu_to_be32(E);
@@
expression E;
@@
-cpu_to_be64s(&E);
+E = cpu_to_be64(E);

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20180927164200.15097-1-peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: rebase, and squash in missed changes]
Signed-off-by: Eric Blake <eblake@redhat.com>

chardev patches

# gpg: Signature made Wed 03 Oct 2018 11:57:34 BST
# gpg:                using RSA key DAE8E10975969CE5
# gpg: Good signature from "Marc-André Lureau <marcandre.lureau@redhat.com>"
# gpg:                 aka "Marc-André Lureau <marcandre.lureau@gmail.com>"
# Primary key fingerprint: 87A9 BD93 3F87 C606 D276  F62D DAE8 E109 7596 9CE5

* remotes/elmarco/tags/chardev-pull-request:
  chardev: use a child source for qio input source
  chardev: mark the calls that allow an implicit mux monitor
  char.h: fix gtk-doc comment style
  chardev: unref if underlying chardev has no parent
  chardev: remove qemu_chr_fe_read_all() counter
  chardev: avoid crash if no associated address

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

GLib child source were added with version 2.28. We can use them now
that we bumped our requirement to 2.40.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

This is mostly for readability of the code. Let's make it clear which
callers can create an implicit monitor when the chardev is muxed.

This will also enforce a safer behaviour, as we don't really support
creating monitor anywhere/anytime at the moment. Add an assert() to
make sure the programmer explicitely wanted that behaviour.

There are documented cases, such as: -serial/-parallel/-virtioconsole
and to less extent -debugcon.

Less obvious and questionable ones are -gdb, SLIRP -guestfwd and Xen
console. Add a FIXME note for those, but keep the support for now.

Other qemu_chr_new() callers either have a fixed parameter/filename
string or do not need it, such as -qtest:

* qtest.c: qtest_init()
  Afaik, only used by tests/libqtest.c, without mux. I don't think we
  support it outside of qemu testing: drop support for implicit mux
  monitor (qemu_chr_new() call: no implicit mux now).

* hw/
  All with literal @filename argument that doesn't enable mux monitor.

* tests/
  All with @filename argument that doesn't enable mux monitor.

On a related note, the list of monitor creation places:

- the chardev creators listed above: all from command line (except
  perhaps Xen console?)

- -gdb & hmp gdbserver will create a "GDB monitor command" chardev
  that is wired to an HMP monitor.

- -mon command line option

From this short study, I would like to think that a monitor may only
be created in the main thread today, though I remain skeptical :)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>

Fix up conformance to GTK-Doc function comment style, as documented in
https://developer.gnome.org/gtk-doc-manual/stable/documenting_symbols.html.en



Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>

It's possible to write code creating a chardev backend that is not
registered. When it is not user-created, it makes sense to keep it
hidden. Let the associated frontend destroy it also in this case.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>