Commit graph

89 commits

Author SHA1 Message Date
Emilio G. Cota 9ce38c20b9
tcg: access cpu->icount_decr.u16.high with atomics
Consistently access u16.high with atomics to avoid
undefined behaviour in MTTCG.

Note that icount_decr.u16.low is only used in icount mode,
so regular accesses to it are OK.

Backports part of commit fff42f183ea4c3967405d4c1dce6d97dae4d64c8 from
qemu
2018-10-23 14:36:46 -04:00
Marc-André Lureau df8790284f
qom/object: register 'type' property as class property
Let's save a few byte in each object instance.

Backports commit 7439a036d58f0def85751d6d4d3232461a35ebee from qemu
2018-10-08 14:14:45 -04:00
Marc-André Lureau 710467e034
qom/object: add some interface asserts
An interface can't have any instance size or callback, or itself
implement other interfaces (this is unsupported).

Backports commit 422ca1432f7b44f2a9f3ad94a65d36927da021fa from qemu
2018-10-04 04:30:42 -04:00
Marc-André Lureau ab4528c1e4
qobject: Replace qobject_incref/QINCREF qobject_decref/QDECREF
Now that we can safely call QOBJECT() on QObject * as well as its
subtypes, we can have macros qobject_ref() / qobject_unref() that work
everywhere instead of having to use QINCREF() / QDECREF() for QObject
and qobject_incref() / qobject_decref() for its subtypes.

The replacement is mechanical, except I broke a long line, and added a
cast in monitor_qmp_cleanup_req_queue_locked(). Unlike
qobject_decref(), qobject_unref() doesn't accept void *.

Note that the new macros evaluate their argument exactly once, thus no
need to shout them.

Backports commit cb3e7f08aeaab0ab13e629ce8496dca150a449ba from qemu
2018-05-04 10:16:07 -04:00
Lioncash 2dc6364de9
object: Add assert to ensure uc is not null 2018-03-21 12:47:44 -04:00
Bharata B Rao 309b85548f
cpu: Convert cpu_index into a bitmap
Currently CPUState::cpu_index is monotonically increasing and a newly
created CPU always gets the next higher index. The next available
index is calculated by counting the existing number of CPUs. This is
fine as long as we only add CPUs, but there are architectures which
are starting to support CPU removal, too. For an architecture like PowerPC
which derives its CPU identifier (device tree ID) from cpu_index, the
existing logic of generating cpu_index values causes problems.

With the currently proposed method of handling vCPU removal by parking
the vCPU fd in QEMU
(Ref: http://lists.gnu.org/archive/html/qemu-devel/2015-02/msg02604.html),
generating cpu_index this way will not work for PowerPC.

This patch changes the way cpu_index is handed out by maintaining
a bit map of the CPUs that tracks both addition and removal of CPUs.

The CPU bitmap allocation logic is part of cpu_exec_init(), which is
called by instance_init routines of various CPU targets. Newly added
cpu_exec_exit() API handles the deallocation part and this routine is
called from generic CPU instance_finalize.

Note: This new CPU enumeration is for !CONFIG_USER_ONLY only.
CONFIG_USER_ONLY continues to have the old enumeration logic.

Backports commit b7bca7333411bd19c449147e8202ae6b0e4a8e09 from qemu
2018-03-21 08:06:07 -04:00
Igor Mammedov 415b11ee49
cpu: drop unnecessary NULL check and cpu_common_class_by_name()
both do nothing as for the first all callers
parse_cpu_model() and qmp_query_cpu_model_()
should provide non NULL value, so just abort if it's not so.

While at it drop cpu_common_class_by_name() which is not need
any more as every target has CPUClass::class_by_name callback
by now, though abort in case a new arch will forget to define one.

Backports commit 99193d8f2ef594648ad67cc3d007b0e4fb2f8cf8 from qemu
2018-03-20 14:23:52 -04:00
Igor Mammedov f8eeacb280
Use cpu_create(type) instead of cpu_init(cpu_model)
With all targets defining CPU_RESOLVING_TYPE, refactor
cpu_parse_cpu_model(type, cpu_model) to parse_cpu_model(cpu_model)
so that callers won't have to know internal resolving cpu
type. Place it in exec.c so it could be called from both
target independed vl.c and *-user/main.c.

That allows us to stop abusing cpu type from
MachineClass::default_cpu_type
as resolver class in vl.c which were confusing part of
cpu_parse_cpu_model().

Also with new parse_cpu_model(), the last users of cpu_init()
in null-machine.c and bsd/linux-user targets could be switched
to cpu_create() API and cpu_init() API will be removed by
follow up patch.

With no longer users left remove MachineState::cpu_model field,
new code should use MachineState::cpu_type instead and
leave cpu_model parsing to generic code in vl.c.

Backports commit 2278b93941d42c30e2950d4b8dff4943d064e7de from qemu
2018-03-20 14:20:30 -04:00
Igor Mammedov 555eeb4120
qom: cpus: split cpu_generic_init() on feature parsing and cpu creation parts
it would allow to reuse feature parsing part in various machines
that have CPU features instead of re-implementing the same feature
parsing each time.

Backports commit 3c72234c98004a01d79a24f78b07053cfebd0f22 from qemu
2018-03-20 13:09:04 -04:00
Igor Mammedov cdc86cee50
qom: cpu: fix parsed feature string length
since commit ( 9262685 cpu: Factor out cpu_generic_init() )
features parsed by it were truncated only to the 1st feature
after CPU name due to fact that

   featurestr = strtok(NULL, ",");
   cc->parse_features(cpu, featurestr, &err);

would extract exactly one feature and parse_features() callback
would parse it and only it leaving the rest of features ignored.

Reuse approach from x86 custom impl. i.e. replace strtok() token
parsing with g_strsplit(), which would split feature string in
2 parts name and features list and pass the later to
parse_features() callback.

Backports commit 3e2cf187eb3954fc406f81247a3fa598437ce1de from qemu
2018-03-20 13:05:10 -04:00
Igor Mammedov 8344a5a63c
pc: Parse CPU features only once
Considering that features are converted to global properties and
global properties are automatically applied to every new instance
of created CPU (at object_new() time), there is no point in
parsing cpu_model string every time a CPU created. So move
parsing outside CPU creation loop and do it only once.

Parsing also should be done before any CPU is created so that
features would affect the first CPU a well.

Backports commit 6aff24c6a61c6fec31e555c7748ba6085b7b2c06 from qemu
2018-03-20 12:27:44 -04:00
Igor Mammedov 87db6e033b
cpu: Use CPUClass->parse_features() as convertor to global properties
Currently CPUClass->parse_features() is used to parse -cpu
features string and set properties on created CPU instances.

But considering that features specified by -cpu apply to every
created CPU instance, it doesn't make sense to parse the same
features string for every CPU created. It also makes every target
that cares about parsing features string explicitly call
CPUClass->parse_features() parser, which gets in a way if we
consider using generic device_add for CPU hotplug as device_add
has not a clue about CPU specific hooks.

Turns out we can use global properties mechanism to set
properties on every created CPU instance for a given type. That
way it's possible to convert CPU features into a set of global
properties for CPU type specified by -cpu cpu_model and common
Device.device_post_init() will apply them to CPU of given type
automatically regardless whether it's manually created CPU or CPU
created with help of device_add.

Backports commits 62a48a2a5798425997152dea3fc48708f9116c04 and
f313369fdb78f849ecbbd8e5d88f01ddf38786c8 from qemu
2018-03-20 12:00:27 -04:00
Lioncash 14653b00db
qobject: let object_property_get_str() use new API 2018-03-20 11:25:30 -04:00
Max Reitz 275b2ac328
qapi: Replace qobject_to_X(o) by qobject_to(X, o)
This patch was generated using the following Coccinelle script:

@@
expression Obj;
@@
(
- qobject_to_qnum(Obj)
+ qobject_to(QNum, Obj)
|
- qobject_to_qstring(Obj)
+ qobject_to(QString, Obj)
|
- qobject_to_qdict(Obj)
+ qobject_to(QDict, Obj)
|
- qobject_to_qlist(Obj)
+ qobject_to(QList, Obj)
|
- qobject_to_qbool(Obj)
+ qobject_to(QBool, Obj)
)

and a bit of manual fix-up for overly long lines and three places in
tests/check-qjson.c that Coccinelle did not find.

Backports commit 7dc847ebba953db90853d15f140c20eef74d4fb2 from qemu
2018-03-20 10:55:57 -04:00
Paolo Bonzini 37117a74ed
qom: introduce object_class_get_list_sorted
Unify half a dozen copies of very similar code (the only difference being
whether comparisons were case-sensitive) and use it also in Tricore,
which did not do any sorting of CPU model names.

Backports commit 47c66009ab793241e8210b3018c77a9ce9506aa8 from qemu
2018-03-17 19:16:25 -04:00
Eduardo Habkost 46e1c5482b
machine: Set MachineClass::name automatically
Now all TYPE_MACHINE subclasses use MACHINE_TYPE_NAME to generate the
class name. So instead of requiring each subclass to set
MachineClass::name manually, we can now set it automatically at the
TYPE_MACHINE class_base_init() function.

Backports commit 98cec76a7076c4a38e16f1a9de170a7942b3be54 from qemu
2018-03-11 14:38:58 -04:00
Markus Armbruster 3277400723
qapi: Move qapi-schema.json to qapi/, rename generated files
Move qapi-schema.json to qapi/, so it's next to its modules, and all
files get generated to qapi/, not just the ones generated for modules.

Consistently name the generated files qapi-MODULE.EXT:
qmp-commands.[ch] become qapi-commands.[ch], qapi-event.[ch] become
qapi-events.[ch], and qmp-introspect.[ch] become qapi-introspect.[ch].
This gets rid of the temporary hacks in scripts/qapi/commands.py,
scripts/qapi/events.py, and scripts/qapi/common.py.

Backports commit eb815e248f50cde9ab86eddd57eca5019b71ca78 from qemu
2018-03-09 11:35:11 -05:00
Markus Armbruster 5500a5e912
Include less of the generated modular QAPI headers
In my "build everything" tree, a change to the types in
qapi-schema.json triggers a recompile of about 4800 out of 5100
objects.

The previous commit split up qmp-commands.h, qmp-event.h, qmp-visit.h,
qapi-types.h. Each of these headers still includes all its shards.
Reduce compile time by including just the shards we actually need.

To illustrate the benefits: adding a type to qapi/migration.json now
recompiles some 2300 instead of 4800 objects. The next commit will
improve it further.

Backports commit 9af2398977a78d37bf184d6ff6bd04c72bfbf006 from qemu
2018-03-09 10:06:19 -05:00
Markus Armbruster 801dbfce3d
Include qapi/qmp/qobject.h exactly where needed
Backports commit 5ee9d2fe9e1e15d6e4a112220da3ad8a3512819b from qemu
2018-03-08 08:48:27 -05:00
Igor Mammedov c97583fc42
qom: introduce type_register_static_array()
it will help to remove code duplication of registration
static types in places that have open coded loop to
perform batch type registering.

Backports commit aa04c9d20704fa5b9ab239d5111adbcce5f49808 from qemu
2018-03-05 03:49:50 -05:00
Philippe Mathieu-Daudé 0cb01a52bd
qom/cpu: move cpu_model null check to cpu_class_by_name()
and clean every implementation.

Backports commit 8301ea444abb49f7b7fb939b09c1e23b22977f30 from qemu
2018-03-05 02:02:29 -05:00
Peter Xu 0741c3880a
qom: provide root container for internal objs
We have object_get_objects_root() to keep user created objects, however
no place for objects that will be used internally. Create such a
container for internal objects.

Backports commit 7c47c4ead75d0b733ee8f2f51fd1de0644cc1308 from qemu
2018-03-05 01:16:50 -05:00
Peter Maydell 2070ef1c37
boards.h: Define new flag ignore_memory_transaction_failures
Define a new MachineClass field ignore_memory_transaction_failures.
If this is flag is true then the CPU will ignore memory transaction
failures which should cause the CPU to take an exception due to an
access to an unassigned physical address; the transaction will
instead return zero (for a read) or be ignored (for a write). This
should be set only by legacy board models which rely on the old
RAZ/WI behaviour for handling devices that QEMU does not yet model.
New board models should instead use "unimplemented-device" for all
memory ranges where the guest will attempt to probe for a device that
QEMU doesn't implement and a stub device is required.

We need this for ARM boards, where we're about to implement support for
generating external aborts on memory transaction failures. Too many
of our legacy board models rely on the RAZ/WI behaviour and we
would break currently working guests when their "probe for device"
code provoked an external abort rather than a RAZ.

Backports commit ed860129acd3fcd0b1e47884e810212aaca4d21b from qemu
2018-03-04 21:27:15 -05:00
Eduardo Habkost 382022929e
cpu: cpu_by_arch_id() helper
The helper can be used for CPU object lookup using the CPU's
arch-specific ID (the one returned by CPUClass::get_arch_id()).

Backports commit 5ce46cb34eecec0bc94a4b1394763f9a1bbe20c3 from qemu
2018-03-04 12:16:39 -05:00
Michael S. Tsirkin fd472c53c6
Revert "cpu: add APIs to allocate/free CPU environment"
This reverts commit e2a7f28693aea7e194ec1435697ec4feb24f8a6f.

This was not supposed to go upstream yet. Reverting.

Backports commit cde0a63ad721dbb538419a00f9405587680be436 from qemu
2018-03-04 01:42:49 -05:00
Joseph Myers e5b84c6d59
target/i386: set rip_offset for some SSE4.1 instructions
When emulating various SSE4.1 instructions such as pinsrd, the address
of a memory operand is computed without allowing for the 8-bit
immediate operand located after the memory operand, meaning that the
memory operand uses the wrong address in the case where it is
rip-relative. This patch adds the required rip_offset setting for
those instructions, so fixing some GCC test failures (13 in the gcc
testsuite in my GCC 6-based testing) when testing with a default CPU
setting enabling those instructions.

Backports commit ab6ab3e9972a49a359f59895a88bed311472ca97 from qemu
2018-03-04 01:41:43 -05:00
Michael S. Tsirkin 71bf994214
cpu: add APIs to allocate/free CPU environment
These will be implemented and then used by follow-up patches.

Backports commit e2a7f28693aea7e194ec1435697ec4feb24f8a6f from qemu
2018-03-04 01:39:09 -05:00
Eduardo Habkost 570c064065
qom: Fix ambiguous path detection when ambiguous=NULL
object_resolve_path*() ambiguous path detection breaks when
ambiguous==NULL and the object tree have 3 objects of the same type and
only 2 of them are under the same parent. e.g.:

/container/obj1 (TYPE_FOO)
/container/obj2 (TYPE_FOO)
/obj2 (TYPE_FOO)

With the above tree, object_resolve_path_type("", TYPE_FOO, NULL) will
incorrectly return /obj2, because the search inside "/container" will
return NULL, and the match at "/obj2" won't be detected as ambiguous.

Fix that by always calling object_resolve_partial_path() with a non-NULL
ambiguous parameter.

Backports commit ebcc479eee740937e70a94a468effcf2126a572b from qemu
2018-03-03 22:49:21 -05:00
Igor Mammedov fe4152c6a5
qom: enforce readonly nature of link's check callback
link's check callback is supposed to verify/permit setting it,
however currently nothing restricts it from misusing it
and modifying target object from within.
Make sure that readonly semantics are checked by compiler
to prevent callback's misuse.

Backports commit 8f5d58ef2c92d7b82d9a6eeefd7c8854a183ba4a from qemu
2018-03-03 22:17:20 -05:00
Lioncash 0f4ebf07d8
qom/cpu: Silence an unused variable warning 2018-03-03 21:37:04 -05:00
Thomas Huth cf5d583ef0
cpu: Introduce a wrapper for tlb_flush() that can be used in common code
Commit 1f5c00cfdb8114c ("qom/cpu: move tlb_flush to cpu_common_reset")
moved the call to tlb_flush() from the target-specific reset handlers
into the common code qom/cpu.c file, and protected the call with
"#ifdef CONFIG_SOFTMMU" to avoid that it is called for linux-user
only targets. But since qom/cpu.c is common code, CONFIG_SOFTMMU is
*never* defined here, so the tlb_flush() was simply never executed
anymore. Fix it by introducing a wrapper for tlb_flush() in a file
that is re-compiled for each target, i.e. in translate-all.c.

Backports commit 2cd53943115be5118b5b2d4b80ee0a39c94c4f73 from qemu
2018-03-03 21:24:55 -05:00
Emilio G. Cota f66e74d65b
tcg: consistently access cpu->tb_jmp_cache atomically
Some code paths can lead to atomic accesses racing with memset()
on cpu->tb_jmp_cache, which can result in torn reads/writes
and is undefined behaviour in C11.

These torn accesses are unlikely to show up as bugs, but from code
inspection they seem possible. For example, tb_phys_invalidate does:
/* remove the TB from the hash list */
h = tb_jmp_cache_hash_func(tb->pc);
CPU_FOREACH(cpu) {
if (atomic_read(&cpu->tb_jmp_cache[h]) == tb) {
atomic_set(&cpu->tb_jmp_cache[h], NULL);
}
}
Here atomic_set might race with a concurrent memset (such as the
ones scheduled via "unsafe" async work, e.g. tlb_flush_page) and
therefore we might end up with a torn pointer (or who knows what,
because we are under undefined behaviour).

This patch converts parallel accesses to cpu->tb_jmp_cache to use
atomic primitives, thereby bringing these accesses back to defined
behaviour. The price to pay is to potentially execute more instructions
when clearing cpu->tb_jmp_cache, but given how infrequently they happen
and the small size of the cache, the performance impact I have measured
is within noise range when booting debian-arm.

Note that under "safe async" work (e.g. do_tb_flush) we could use memset
because no other vcpus are running. However I'm keeping these accesses
atomic as well to keep things simple and to avoid confusing analysis
tools such as ThreadSanitizer.

Backports commit f3ced3c59287dabc253f83f0c70aa4934470c15e from qemu
2018-03-03 21:12:36 -05:00
Marc-André Lureau ca25248ecd
object: add uint property setter/getter
Backports commit 3152779cd63ba41331ef41659406f65b03e7911a from qemu
2018-03-03 18:43:17 -05:00
Marc-André Lureau dd77730d49
qapi: merge QInt and QFloat in QNum
We would like to use a same QObject type to represent numbers, whether
they are int, uint, or floats. Getters will allow some compatibility
between the various types if the number fits other representations.

Add a few more tests while at it.

Backports commit 01b2ffcedd94ad7b42bc870e4c6936c87ad03429 from qemu
2018-03-03 18:16:28 -05:00
Marc-André Lureau c4e0911f95
object: fix potential leak in getters
If the property is not of the requested type, the getters will leak a
QObject.

Backports commit 560f19f162529d691619ac69ed032321c7f5f1fb from qemu
2018-03-03 17:22:32 -05:00
Markus Armbruster e0ee098c4a
qapi: Drop unused non-strict qobject input visitor
The split between tests/test-qobject-input-visitor.c and
tests/test-qobject-input-strict.c now makes less sense than ever. The
next commit will take care of that.

Backports commit 048abb7b20c9f822ad9d4b730bade73b3311a47a from qemu
2018-03-02 12:14:52 -05:00
Markus Armbruster 3e8b0c66a3
qom: Make object_property_set_qobject()'s input visitor strict
Commit 240f64b made all qobject input visitors created outside tests
strict, except for the one in object_property_set_qobject(). That one
was left behind only because Eric couldn't spare the time to figure
out whether making it strict would break anything, with a TODO
comment. Time to resolve it.

Strict makes a difference only for otherwise successful visits of QAPI
structs or unions. Let's examine what the callers of
object_property_set_qobject() visit:

* object_property_set_str(), object_property_set_bool(),
object_property_set_int() visit a QString, QBool, QInt,
respectively. Strictness can't matter.

* qmp_qom_set visits its @value argument. Comes straight from QMP and
can be anything ('any' in the QAPI schema). Strictness matters when
the property's set() method visits a struct or union QAPI type.

No such methods exist, thus switching to strict can't break
anything.

If we acquire such methods in the future, we'll *want* the visitor
to be strict, so that unexpected members get rejected as they should
be.

Switch to strict.

Backports commit 05601ed2de60df0e344d6b783a6bc0c1ff2b5d1f from qemu
2018-03-02 12:10:50 -05:00
Julian Brown cc217b0c90
arm: Correctly handle watchpoints for BE32 CPUs
In BE32 mode, sub-word size watchpoints can fail to trigger because the
address of the access is adjusted in the opcode helpers before being
compared with the watchpoint registers. This patch reverses the address
adjustment before performing the comparison with the help of a new CPUClass
hook.

This version of the patch augments and tidies up comments a little.

Backports commit 40612000599e52e792d23c998377a0fa429c4036 from qemu
2018-03-02 00:24:33 -05:00
Alex Bennée e3e57ca08e
cputlb: drop flush_global flag from tlb_flush
We have never has the concept of global TLB entries which would avoid
the flush so we never actually use this flag. Drop it and make clear
that tlb_flush is the sledge-hammer it has always been.

Backports commit  d10eb08f5d8389c814b554d01aa2882ac58221bf from qemu
2018-03-01 19:36:04 -05:00
Alex Bennée 7e2cc86ad2
cpu_common_reset: wrap TCG specific code in tcg_enabled()
Both the cpu->tb_jmp_cache and SoftMMU TLB structures are only used
when running TCG code so we might as well skip them for anything else.

Backports commit ba7d3d1858c257e39b47f7f12fa2016ffd960b11 from qemu
2018-03-01 19:29:57 -05:00
Alex Bennée 780ed8722e
qom/cpu: move tlb_flush to cpu_common_reset
It is a common thing amongst the various cpu reset functions want to
flush the SoftMMU's TLB entries. This is done either by calling
tlb_flush directly or by way of a general memset of the CPU
structure (sometimes both).

This moves the tlb_flush call to the common reset function and
additionally ensures it is only done for the CONFIG_SOFTMMU case and
when tcg is enabled.

In some target cases we add an empty end_of_reset_fields structure to the
target vCPU structure so have a clear end point for any memset which
is resetting value in the structure before CPU_COMMON (where the TLB
structures are).

While this is a nice clean-up in general it is also a precursor for
changes coming to cputlb for MTTCG where the clearing of entries
can't be done arbitrarily across vCPUs. Currently the cpu_reset
function is usually called from the context of another vCPU as the
architectural power up sequence is run. By using the cputlb API
functions we can ensure the right behaviour in the future.

Backports commit 1f5c00cfdb8114c1e3a13426588ceb64f82c9ddb from qemu
2018-03-01 19:21:07 -05:00
Daniel P. Berrange 83a5bf2d25
qapi: rename QmpOutputVisitor to QObjectOutputVisitor
The QmpOutputVisitor has no direct dependency on QMP. It is
valid to use it anywhere that one wants a QObject. Rename it
to better reflect its functionality as a generic QAPI
to QObject converter.

The commit before previous renamed the files, this one renames C
identifiers.

Backports commit 7d5e199ade76c53ec316ab6779800581bb47c50a from qemu
2018-02-27 08:05:33 -05:00
Daniel P. Berrange 2949a90977
qapi: rename QmpInputVisitor to QObjectInputVisitor
The QmpInputVisitor has no direct dependency on QMP. It is
valid to use it anywhere that one has a QObject. Rename it
to better reflect its functionality as a generic QObject
to QAPI converter.

The previous commit renamed the files, this one renames C identifiers.

Backports commit 09e68369a88d7de0f988972bf28eec1b80cc47f9 from qemu
2018-02-26 15:54:15 -05:00
Daniel P. Berrange 228f122248
qapi: rename *qmp-*-visitor* to *qobject-*-visitor*
The QMP visitors have no direct dependency on QMP. It is
valid to use them anywhere that one has a QObject. Rename them
to better reflect their functionality as a generic QObject
to QAPI converter.

This is the first of three parts: rename the files. The next two
parts will rename C identifiers. The split is necessary to make git
rename detection work.

Backports commit b3db211f3c80bb996a704d665fe275619f728bd4 from qemu
2018-02-26 15:42:37 -05:00
Alex Bennée d4cb954102
cpu: atomically modify cpu->exit_request
ThreadSanitizer picks up potential races although we already use
barriers to ensure things are in the correct order when processing exit
requests. For true C11 defined behaviour across threads we need to use
relaxed atomic_set/atomic_read semantics to reassure tsan.

Backports commit 027d9a7d2911e993cdcbd21c7c35d1dd058f05bb from qemu
2018-02-26 05:11:18 -05:00
Alex Bennée e1cf9ca84a
qom/cpu: atomically clear the tb_jmp_cache
The ThreadSanitizer rightly complains that something initialised with a
normal access is later updated and read atomically.

Backports commit ce7cf6a973f4b614162b9518954d441fa5e32fc6 from qemu
2018-02-26 05:09:05 -05:00
Alex Bennée 12d7e946a1
qom/object: update class cache atomically
The idiom CPU_GET_CLASS(cpu) is fairly extensively used in various
threads and trips of ThreadSanitizer due to the fact it updates
obj->class->object_cast_cache behind the scenes. As this is just a
fast-path cache there is no need to lock updates.

However to ensure defined C11 behaviour across threads we need to use
the plain atomic_read/set primitives and keep the sanitizer happy.

Backports commit b6b3ccfda015dcd5ab50f70c189ee5cc6c622e91 from qemu
2018-02-26 05:06:40 -05:00
Eric Blake 85af4b2030
qapi: Add new visit_complete() function
Making each output visitor provide its own output collection
function was the only remaining reason for exposing visitor
sub-types to the rest of the code base. Add a polymorphic
visit_complete() function which is a no-op for input visitors,
and which populates an opaque pointer for output visitors. For
maximum type-safety, also add a parameter to the output visitor
constructors with a type-correct version of the output pointer,
and assert that the two uses match.

This approach was considered superior to either passing the
output parameter only during construction (action at a distance
during visit_free() feels awkward) or only during visit_complete()
(defeating type safety makes it easier to use incorrectly).

Most callers were function-local, and therefore a mechanical
conversion; the testsuite was a bit trickier, but the previous
cleanup patch minimized the churn here.

The visit_complete() function may be called at most once; doing
so lets us use transfer semantics rather than duplication or
ref-count semantics to get the just-built output back to the
caller, even though it means our behavior is not idempotent.

Generated code is simplified as follows for events:

|@@ -26,7 +26,7 @@ void qapi_event_send_acpi_device_ost(ACP
| QDict *qmp;
| Error *err = NULL;
| QMPEventFuncEmit emit;
|- QmpOutputVisitor *qov;
|+ QObject *obj;
| Visitor *v;
| q_obj_ACPI_DEVICE_OST_arg param = {
| info
|@@ -39,8 +39,7 @@ void qapi_event_send_acpi_device_ost(ACP
|
| qmp = qmp_event_build_dict("ACPI_DEVICE_OST");
|
|- qov = qmp_output_visitor_new();
|- v = qmp_output_get_visitor(qov);
|+ v = qmp_output_visitor_new(&obj);
|
| visit_start_struct(v, "ACPI_DEVICE_OST", NULL, 0, &err);
| if (err) {
|@@ -55,7 +54,8 @@ void qapi_event_send_acpi_device_ost(ACP
| goto out;
| }
|
|- qdict_put_obj(qmp, "data", qmp_output_get_qobject(qov));
|+ visit_complete(v, &obj);
|+ qdict_put_obj(qmp, "data", obj);
| emit(QAPI_EVENT_ACPI_DEVICE_OST, qmp, &err);

and for commands:

| {
| Error *err = NULL;
|- QmpOutputVisitor *qov = qmp_output_visitor_new();
| Visitor *v;
|
|- v = qmp_output_get_visitor(qov);
|+ v = qmp_output_visitor_new(ret_out);
| visit_type_AddfdInfo(v, "unused", &ret_in, &err);
|- if (err) {
|- goto out;
|+ if (!err) {
|+ visit_complete(v, ret_out);
| }
|- *ret_out = qmp_output_get_qobject(qov);
|-
|-out:
| error_propagate(errp, err);

Backports commit 3b098d56979d2f7fd707c5be85555d114353a28d from qemu
2018-02-25 01:20:03 -05:00
Eric Blake ec53301cda
qmp-output-visitor: Favor new visit_free() function
Now that we have a polymorphic visit_free(), we no longer need
qmp_output_visitor_cleanup(); however, we still need to
expose the subtype for qmp_output_get_qobject().

Backports commit 1830f22a6777cedaccd67a08f675d30f7a85ebfd from qemu
2018-02-25 01:12:27 -05:00
Eric Blake f008d93ac0
qmp-input-visitor: Favor new visit_free() function
Now that we have a polymorphic visit_free(), we no longer need
qmp_input_visitor_cleanup(); which in turn means we no longer
need to return a subtype from qmp_input_visitor_new() nor a
public upcast function.

Generated code changes to qmp-marshal.c look like:

|@@ -52,11 +52,10 @@ void qmp_marshal_add_fd(QDict *args, QOb
| {
| Error *err = NULL;
| AddfdInfo *retval;
|- QmpInputVisitor *qiv = qmp_input_visitor_new(QOBJECT(args), true);
| Visitor *v;
| q_obj_add_fd_arg arg = {0};
|
|- v = qmp_input_get_visitor(qiv);
|+ v = qmp_input_visitor_new(QOBJECT(args), true);
| visit_start_struct(v, NULL, NULL, 0, &err);
| if (err) {
| goto out;

Backports commit b70ce1018a251c0c33498d9c927a07cade655a5e from qemu
2018-02-25 01:10:53 -05:00