In rST markup syntax, the inline markup (*italics*, **bold** and
``monospaced``) must be separated from the surrending text by
non-word characters, otherwise it is not interpreted as markup.
To force interpretation as markup in the middle of a word,
you need to use a backslash-escaped space (which will not
appear as a space in the output).

Fix a missing backslash-space in this file, which meant that the ``
after "select" was output literally and the monospacing was
incorrectly extended all the way to the end of the next monospaced
word.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20230411105424.3994585-1-peter.maydell@linaro.org

The documentation for smp_read_barrier_depends() does not mention the architectures
for which it is an optimization, for example ARM and PPC.  As a result, it is not
clear to the reader why one would use it.  Relegate Alpha to a footnote together
with other architectures where it is equivalent to smp_rmb().

Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Adjust the VFIO dirty page tracking documentation and add a section to
describe device dirty page tracking.

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/r/20230307125450.62409-16-joao.m.martins@oracle.com


Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

On ARM, seqcst loads and stores (which QEMU does not use) are compiled
respectively as LDAR and STLR instructions.  Even though LDAR is
also used for load-acquire operations, it also waits for all STLRs to
leave the store buffer.  Thus, LDAR and STLR alone are load-acquire
and store-release operations, but LDAR also provides store-against-load
ordering as long as the previous store is a STLR.

Compare this to ARMv7, where store-release is DMB+STR and load-acquire
is LDR+DMB, but an additional DMB is needed between store-seqcst and
load-seqcst (e.g. DMB+STR+DMB+LDR+DMB); or with x86, where MOV provides
load-acquire and store-release semantics and the two can be reordered.

Likewise, on ARM sequentially consistent read-modify-write operations only
need to use LDAXR and STLXR respectively for the load and the store, while
on x86 they need to use the stronger LOCK prefix.

In a strange twist of events, however, the _stronger_ semantics
of the ARM instructions can end up causing bugs on ARM, not on x86.
The problems occur when seqcst atomics are mixed with relaxed atomics.

QEMU's atomics try to bridge the Linux API (that most of the developers
are familiar with) and the C11 API, and the two have a substantial
difference:

- in Linux, strongly-ordered atomics such as atomic_add_return() affect
  the global ordering of _all_ memory operations, including for example
  READ_ONCE()/WRITE_ONCE()

- in C11, sequentially consistent atomics (except for seq-cst fences)
  only affect the ordering of sequentially consistent operations.
  In particular, since relaxed loads are done with LDR on ARM, they are
  not ordered against seqcst stores (which are done with STLR).

QEMU implements high-level synchronization primitives with the idea that
the primitives contain the necessary memory barriers, and the callers can
use relaxed atomics (qatomic_read/qatomic_set) or even regular accesses.
This is very much incompatible with the C11 view that seqcst accesses
are only ordered against other seqcst accesses, and requires using seqcst
fences as in the following example:

   qatomic_set(&y, 1);            qatomic_set(&x, 1);
   smp_mb();                      smp_mb();
   ... qatomic_read(&x) ...       ... qatomic_read(&y) ...

When a qatomic_*() read-modify write operation is used instead of one
or both stores, developers that are more familiar with the Linux API may
be tempted to omit the smp_mb(), which will work on x86 but not on ARM.

This nasty difference between Linux and C11 read-modify-write operations
has already caused issues in util/async.c and more are being found.
Provide something similar to Linux smp_mb__before/after_atomic(); this
has the double function of documenting clearly why there is a memory
barrier, and avoiding a double barrier on x86 and s390x systems.

The new macro can already be put to use in qatomic_mb_set().

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

Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Rewrite the sections which talked about 'local temporaries'.
Remove some assumptions which no longer hold.

Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

The 22.04 LTS release has been out for almost a year now so its time
to update all the remaining images to the current LTS. We can also
drop some hacks we need for older clang TSAN support.

We will keep the ubuntu2004 container around for those who wish to
test builds on the currently still supported baseline.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20230228190653.1602033-9-alex.bennee@linaro.org>

Python 3.6 is at end-of-life.  Update the libvirt-ci module to a
version that supports overrides for targets and package mappings;
this way, QEMU can use the newer versions provided by CentOS 8 (Python
3.8) and OpenSUSE 15.3 (Python 3.9).

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Shorten a bit the description of what libvirt-ci does, the name of the
data files is not relevant at that point.  However, the procedures to add
new build prerequisites are lacking some information, particularly with
respect to regenerating the output test files for lcitool's unit tests.
While at it, also update the paths in the libvirt-ci repository.

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

When qemu-keymap is not available on the host, and enable-xkbcommon
is specified, parallel make fails with:

  % make clean
  ...
  % make -j 32
  ...
  FAILED: pc-bios/keymaps/is
  ./qemu-keymap -f pc-bios/keymaps/is -l is
  /bin/sh: ./qemu-keymap: No such file or directory
  ... many similar messages ...

The code always runs find_program, rather than waiting to build
qemu-keymap, because it looks for CONFIG_XKBCOMMON in config_host
rather than config_host_data.  Making serially succeeds, by soft
linking files from pc-bios/keymaps, but that is not the desired
result for enable-xkbcommon.

Examining all occurrences of 'in config_host' for similar bugs shows one
instance in the docs, which is also fixed here.

Fixes: 4113f4cf ("meson: move xkbcommon to meson")

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1675708442-74966-1-git-send-email-steven.sistare@oracle.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

Documentation of enumeration value conditions lacks a 'may'.  Fix
that.

Clarify SchemaInfo documentation for struct and union types.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230213132009.918801-3-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

Commit 013b4efc "qapi: Add feature flags to remaining
definitions" (v5.0.0), commit 84ab0086 "qapi: Add feature flags to
struct members" (v5.0.0), and commit b6c18755 "qapi: Add feature
flags to enum members" (v6.2.0) neglected to update section
"Features".  Make up for that.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230213132009.918801-2-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>

Now that VFIO migration protocol v2 has been implemented and v1 protocol
has been removed, update the documentation according to v2 protocol.

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Link: https://lore.kernel.org/r/20230216143630.25610-12-avihaih@nvidia.com


Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

We split the function into to:

- state_pending_estimate: We estimate the remaining state size without
  stopping the machine.

- state pending_exact: We calculate the exact amount of remaining
  state.

The only "device" that implements different functions for _estimate()
and _exact() is ram.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

This affects both system and user mode emulation so we should probably
list it up front.

Acked-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230124180127.1881110-21-alex.bennee@linaro.org>

Add ability to dump /tmp/perf-<pid>.map and jit-<pid>.dump.
The first one allows the perf tool to map samples to each individual
translation block. The second one adds the ability to resolve symbol
names, line numbers and inspect JITed code.

Example of use:

    perf record qemu-x86_64 -perfmap ./a.out
    perf report

or

    perf record -k 1 qemu-x86_64 -jitdump ./a.out
    DEBUGINFOD_URLS= perf inject -j -i perf.data -o perf.data.jitted
    perf report -i perf.data.jitted

Co-developed-by: Vanderson M. do Rosario <vandersonmr2@gmail.com>
Co-developed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20230112152013.125680-4-iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Rules for headers were proposed a long time ago, and generally liked:

    Message-ID: <87h9g8j57d.fsf@blackfin.pond.sub.org>
    https://lists.nongnu.org/archive/html/qemu-devel/2016-03/msg03345.html



Wortk them into docs/devel/style.rst.

Suggested-by: Bernhard Beschow <shentey@gmail.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20221222120813.727830-5-armbru@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Bernhard Beschow <shentey@gmail.com>

Convert tcg/README to rst and move it to docs/devel as a new "TCG Intermediate
Representation" page. There are a few minor changes to improve the aesthetic
of the final output which are as follows:

  - Rename the title from "Tiny Code Generator - Fabrice Bellard" to "TCG
    Intermediate Representation"

  - Remove the section numbering

  - Add the missing parameters to the ssadd_vec operations in the "Host
    vector operations" section

  - Change the path to the Atomic Operations document to use a proper
    reference

  - Replace tcg/README in tcg.rst with a proper reference to the new document

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Message-Id: <20221130100434.64207-2-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Debug specific actions can be enabled in bios bits acpi tests by passing
BITS_DEBUG in the environment variable while running the test. Document that.

CC: qemu-trivial@nongnu.org
Signed-off-by: Ani Sinha <ani@anisinha.ca>
Message-Id: <20221203132346.34479-1-ani@anisinha.ca>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>

This new annotation starts just a function wrapper that creates
a new coroutine. It assumes the caller is not a coroutine.
It will be the default annotation to be used in the future.

This is much better as c_w_mixed, because it is clear if the caller
is a coroutine or not, and provides the advantage of automating
the code creation. In the future all c_w_mixed functions will be
substituted by co_wrapper.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Message-Id: <20221128142337.657646-11-eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

In preparation to the incoming new function specifiers,
rename g_c_w with a more meaningful name and document it.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Message-Id: <20221128142337.657646-10-eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

In QAPI, absent optional members are distinct from any present value.
We thus represent an optional schema member FOO as two C members: a
FOO with the member's type, and a bool has_FOO.  Likewise for function
arguments.

However, has_FOO is actually redundant for a pointer-valued FOO, which
can be null only when has_FOO is false, i.e. has_FOO == !!FOO.  Except
for arrays, where we a null FOO can also be a present empty array.

The redundant has_FOO are a nuisance to work with.  Improve the
generator to elide them.  Uses of has_FOO need to be replaced as
follows.

Tests of has_FOO become the equivalent comparison of FOO with null.
For brevity, this is commonly done by implicit conversion to bool.

Assignments to has_FOO get dropped.

Likewise for arguments to has_FOO parameters.

Beware: code may violate the invariant has_FOO == !!FOO before the
transformation, and get away with it.  The above transformation can
then break things.  Two cases:

* Absent: if code ignores FOO entirely when !has_FOO (except for
  freeing it if necessary), even non-null / uninitialized FOO works.
  Such code is known to exist.

* Present: if code ignores FOO entirely when has_FOO, even null FOO
  works.  Such code should not exist.

In both cases, replacing tests of has_FOO by FOO reverts their sense.
We have to fix the value of FOO then.

To facilitate review of the necessary updates to handwritten code, add
means to opt out of this change, and opt out for all QAPI schema
modules where the change requires updates to handwritten code.  The
next few commits will remove these opt-outs in reviewable chunks, then
drop the means to opt out.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20221104160712.3005652-5-armbru@redhat.com>

The next commit will change the code generated for some optional
members.  The example schema contains an optional member affected by
the change.  Add one that is not affected.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20221104160712.3005652-4-armbru@redhat.com>

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20221104160712.3005652-3-armbru@redhat.com>

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20221104160712.3005652-2-armbru@redhat.com>

It is important that contributors take the review process seriously
and we collaborate in a respectful way while avoiding personal
attacks. Try and make this clear in the language.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20221117172532.538149-8-alex.bennee@linaro.org>

The bullet points are quite long and contain process tips. Move those
bits of the bullet to the relevant sections and link to them. Use a
table for nicer formatting of the checklist.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20221117172532.538149-7-alex.bennee@linaro.org>

We welcome all sorts of patches.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20221117172532.538149-6-alex.bennee@linaro.org>

We don't currently have a clear place in the documentation to describe
the roles and responsibilities of a maintainer. Lets create one so we
can. I've moved a few small bits out of other files to try and keep
everything in one place.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20221117172532.538149-5-alex.bennee@linaro.org>

Most of the changes are trivial. The bits test timeout has now been increased
to 200 seconds in order to accommodate slower systems and fewer unnecessary
failures. Removed of the reference to non-existent README file in docs. Some
minor corrections in the doc file.

Signed-off-by: Ani Sinha <ani@anisinha.ca>
Message-Id: <20221117053644.516649-1-ani@anisinha.ca>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

Those typos are in files which are used to generate the QEMU manual.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Message-Id: <20221110190825.879620-1-sw@weilnetz.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Ani Sinha <ani@anisinha.ca>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
[thuth: update sentence in can.rst as suggested by Peter]
Signed-off-by: Thomas Huth <thuth@redhat.com>

Most of them were found and fixed using codespell.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20221030105944.311940-1-sw@weilnetz.de>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

A doc file is added under docs/devel that describes the purpose of the various
test files and gives guidance to developers on where and how to make changes.

Cc: Daniel P. Berrange" <berrange@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Maydell Peter <peter.maydell@linaro.org>
Cc: John Snow <jsnow@redhat.com>
Cc: Thomas Huth <thuth@redhat.com>
Cc: Alex Bennée <alex.bennee@linaro.org>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Michael Tsirkin <mst@redhat.com>
Signed-off-by: Ani Sinha <ani@anisinha.ca>
Message-Id: <20221021095108.104843-7-ani@anisinha.ca>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

No functional change intended.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20221025084952.2139888-11-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

The code for handling the reset level count in the Resettable code
has two issues:

The reset count is only decremented for the 1->0 case.  This means
that if there's ever a nested reset that takes the count to 2 then it
will never again be decremented.  Eventually the count will exceed
the '50' limit in resettable_phase_enter() and QEMU will trip over
the assertion failure.  The repro case in issue 1266 is an example of
this that happens now the SCSI subsystem uses three-phase reset.

Secondly, the count is decremented only after the exit phase handler
is called.  Moving the reset count decrement from "just after" to
"just before" calling the exit phase handler allows
resettable_is_in_reset() to return false during the handler
execution.

This simplifies reset handling in resettable devices.  Typically, a
function that updates the device state will just need to read the
current reset state and not anymore treat the "in a reset-exit
transition" as a special case.

Note that the semantics change to the *_is_in_reset() functions
will have no effect on the current codebase, because only two
devices (hw/char/cadence_uart.c and hw/misc/zynq_sclr.c) currently
call those functions, and in neither case do they do it from the
device's exit phase methed.

Fixes: 4a5fc890 ("scsi: Use device_cold_reset() and bus_cold_reset()")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1266


Signed-off-by: Damien Hedde <damien.hedde@greensocs.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reported-by: Michael Peter <michael.peter@hensoldt-cyber.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20221020142749.3357951-1-peter.maydell@linaro.org
Buglink: https://bugs.launchpad.net/qemu/+bug/1905297


Reported-by: Michael Peter <michael.peter@hensoldt-cyber.com>
[PMM: adjust the docs paragraph changed to get the name of the
 'enter' phase right and to clarify exactly when the count is
 adjusted; rewrite the commit message]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Although the test plugins are fairly basic they are still useful for
some things so we should document their existence.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220929114231.583801-41-alex.bennee@linaro.org>

The API documentation is quite dry and doesn't flow nicely with the
rest of the document. Move it to its own section at the bottom along
with a little leader text to remind people to update it.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220929114231.583801-39-alex.bennee@linaro.org>

We currently have the final binaries in the root of the build dir so
the build prefix is superfluous. Additionally add a shell prompt to be
more in line with the rest of the code.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220929114231.583801-38-alex.bennee@linaro.org>