diff options
author | Stefan Hajnoczi <stefanha@redhat.com> | 2025-02-10 10:23:03 -0500 |
---|---|---|
committer | Stefan Hajnoczi <stefanha@redhat.com> | 2025-02-10 10:23:03 -0500 |
commit | 9c72ba3af2587d2e2870ea0f92aa20de336a86f2 (patch) | |
tree | 8c48a7ae252af795fb6b60c61070ec76e0a02199 | |
parent | 852712695749c0ad23cca1d9983f225b14371933 (diff) | |
parent | 476d6e4c9c4965734d6f47ee299ac9f84440a9b3 (diff) | |
download | qemu-9c72ba3af2587d2e2870ea0f92aa20de336a86f2.zip qemu-9c72ba3af2587d2e2870ea0f92aa20de336a86f2.tar.gz qemu-9c72ba3af2587d2e2870ea0f92aa20de336a86f2.tar.bz2 |
Merge tag 'for-upstream' of https://gitlab.com/bonzini/qemu into staging
* tcg/optimize: optimize TSTNE using smask and zmask
* target/i386: fix exceptions for 0 * Inf + QNaN
* rust: cleanups to the configuration and the warnings
* rust: add developer docs
# -----BEGIN PGP SIGNATURE-----
#
# iQFIBAABCAAyFiEE8TM4V0tmI4mGbHaCv/vSX3jHroMFAmep0nsUHHBib256aW5p
# QHJlZGhhdC5jb20ACgkQv/vSX3jHroN0aggAo8mKY4c7LGLF+5xGM1W/ZLxaBrMN
# 4/LGMV3UJJq+OIEb+e7ThtfyHzcAsYXdO2SIMJ6ffW58ukmwM1SycA8WUjG3JMya
# m05dVnI//D/G7iqYgyNlsiTbqazdr3P/Ha0ty10l9K9dL3SjB3Nm3xLD4XnD3tzM
# U+0yXrn1ngMZ3Y1knTuWwjoH7JT5QftwGCVZ5aeq0KlSAvWb8M8jupYFunLBcZ0z
# LkFSWXbxhw9HRkI+Lp6c2IjIBDEd7267tEfnXf+d29ykVnrdyIWgyYw08/Un72i+
# C5hNEUMiwcD7preTYX5YqDcxSASG1zWNFzEWGhTphMWf1O60f2PIXMWX5g==
# =0KKa
# -----END PGP SIGNATURE-----
# gpg: Signature made Mon 10 Feb 2025 05:18:35 EST
# gpg: using RSA key F13338574B662389866C7682BFFBD25F78C7AE83
# gpg: issuer "pbonzini@redhat.com"
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>" [full]
# gpg: aka "Paolo Bonzini <pbonzini@redhat.com>" [full]
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4 E2F7 7E15 100C CD36 69B1
# Subkey fingerprint: F133 3857 4B66 2389 866C 7682 BFFB D25F 78C7 AE83
* tag 'for-upstream' of https://gitlab.com/bonzini/qemu:
rust: restrict missing_const_for_fn to qemu_api crate
rust: pl011: use default set of lints
tcg/optimize: optimize TSTNE using smask and zmask
tests/tcg/x86_64/fma: Test some x86 fused-multiply-add cases
target/i386: Do not raise Invalid for 0 * Inf + QNaN
rust: add clippy configuration file
rust: add docs
rust: include rust_version in Cargo.toml
rust: remove unnecessary Cargo.toml metadata
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-rw-r--r-- | docs/devel/index-process.rst | 1 | ||||
-rw-r--r-- | docs/devel/rust.rst | 430 | ||||
-rw-r--r-- | fpu/softfloat-parts.c.inc | 5 | ||||
-rw-r--r-- | include/fpu/softfloat-types.h | 16 | ||||
-rw-r--r-- | rust/Cargo.toml | 1 | ||||
-rw-r--r-- | rust/clippy.toml | 2 | ||||
-rw-r--r-- | rust/hw/char/pl011/Cargo.toml | 4 | ||||
-rw-r--r-- | rust/hw/char/pl011/README.md | 31 | ||||
-rw-r--r-- | rust/hw/char/pl011/src/device_class.rs | 1 | ||||
-rw-r--r-- | rust/hw/char/pl011/src/lib.rs | 23 | ||||
-rw-r--r-- | rust/qemu-api-macros/Cargo.toml | 4 | ||||
-rw-r--r-- | rust/qemu-api-macros/README.md | 1 | ||||
-rw-r--r-- | rust/qemu-api/Cargo.toml | 1 | ||||
-rw-r--r-- | rust/qemu-api/src/lib.rs | 1 | ||||
-rw-r--r-- | target/i386/tcg/fpu_helper.c | 5 | ||||
-rw-r--r-- | tcg/optimize.c | 13 | ||||
-rw-r--r-- | tests/tcg/x86_64/Makefile.target | 1 | ||||
-rw-r--r-- | tests/tcg/x86_64/fma.c | 109 |
18 files changed, 581 insertions, 68 deletions
diff --git a/docs/devel/index-process.rst b/docs/devel/index-process.rst index 362f97e..cb7c664 100644 --- a/docs/devel/index-process.rst +++ b/docs/devel/index-process.rst @@ -17,3 +17,4 @@ Notes about how to interact with the community and how and where to submit patch stable-process submitting-a-pull-request secure-coding-practices + rust diff --git a/docs/devel/rust.rst b/docs/devel/rust.rst new file mode 100644 index 0000000..390aae4 --- /dev/null +++ b/docs/devel/rust.rst @@ -0,0 +1,430 @@ +.. |msrv| replace:: 1.63.0 + +Rust in QEMU +============ + +Rust in QEMU is a project to enable using the Rust programming language +to add new functionality to QEMU. + +Right now, the focus is on making it possible to write devices that inherit +from ``SysBusDevice`` in `*safe*`__ Rust. Later, it may become possible +to write other kinds of devices (e.g. PCI devices that can do DMA), +complete boards, or backends (e.g. block device formats). + +__ https://doc.rust-lang.org/nomicon/meet-safe-and-unsafe.html + +Building the Rust in QEMU code +------------------------------ + +The Rust in QEMU code is included in the emulators via Meson. Meson +invokes rustc directly, building static libraries that are then linked +together with the C code. This is completely automatic when you run +``make`` or ``ninja``. + +However, QEMU's build system also tries to be easy to use for people who +are accustomed to the more "normal" Cargo-based development workflow. +In particular: + +* the set of warnings and lints that are used to build QEMU always + comes from the ``rust/Cargo.toml`` workspace file + +* it is also possible to use ``cargo`` for common Rust-specific coding + tasks, in particular to invoke ``clippy``, ``rustfmt`` and ``rustdoc``. + +To this end, QEMU includes a ``build.rs`` build script that picks up +generated sources from QEMU's build directory and puts it in Cargo's +output directory (typically ``rust/target/``). A vanilla invocation +of Cargo will complain that it cannot find the generated sources, +which can be fixed in different ways: + +* by using special shorthand targets in the QEMU build directory:: + + make clippy + make rustfmt + make rustdoc + +* by invoking ``cargo`` through the Meson `development environment`__ + feature:: + + pyvenv/bin/meson devenv -w ../rust cargo clippy --tests + pyvenv/bin/meson devenv -w ../rust cargo fmt + + If you are going to use ``cargo`` repeatedly, ``pyvenv/bin/meson devenv`` + will enter a shell where commands like ``cargo clippy`` just work. + +__ https://mesonbuild.com/Commands.html#devenv + +* by pointing the ``MESON_BUILD_ROOT`` to the top of your QEMU build + tree. This third method is useful if you are using ``rust-analyzer``; + you can set the environment variable through the + ``rust-analyzer.cargo.extraEnv`` setting. + +As shown above, you can use the ``--tests`` option as usual to operate on test +code. Note however that you cannot *build* or run tests via ``cargo``, because +they need support C code from QEMU that Cargo does not know about. Tests can +be run via ``meson test`` or ``make``:: + + make check-rust + +Building Rust code with ``--enable-modules`` is not supported yet. + +Supported tools +''''''''''''''' + +QEMU supports rustc version 1.63.0 and newer. Notably, the following features +are missing: + +* ``core::ffi`` (1.64.0). Use ``std::os::raw`` and ``std::ffi`` instead. + +* ``cast_mut()``/``cast_const()`` (1.65.0). Use ``as`` instead. + +* "let ... else" (1.65.0). Use ``if let`` instead. This is currently patched + in QEMU's vendored copy of the bilge crate. + +* Generic Associated Types (1.65.0) + +* ``CStr::from_bytes_with_nul()`` as a ``const`` function (1.72.0). + +* "Return position ``impl Trait`` in Traits" (1.75.0, blocker for including + the pinned-init create). + +* ``MaybeUninit::zeroed()`` as a ``const`` function (1.75.0). QEMU's + ``Zeroable`` trait can be implemented without ``MaybeUninit::zeroed()``, + so this would be just a cleanup. + +* ``c"" literals`` (stable in 1.77.0). QEMU provides a ``c_str!()`` macro + to define ``CStr`` constants easily + +* ``offset_of!`` (stable in 1.77.0). QEMU uses ``offset_of!()`` heavily; it + provides a replacement in the ``qemu_api`` crate, but it does not support + lifetime parameters and therefore ``&'a Something`` fields in the struct + may have to be replaced by ``NonNull<Something>``. *Nested* ``offset_of!`` + was only stabilized in Rust 1.82.0, but it is not used. + +* inline const expression (stable in 1.79.0), currently worked around with + associated constants in the ``FnCall`` trait. + +* associated constants have to be explicitly marked ``'static`` (`changed in + 1.81.0`__) + +* ``&raw`` (stable in 1.82.0). Use ``addr_of!`` and ``addr_of_mut!`` instead, + though hopefully the need for raw pointers will go down over time. + +* ``new_uninit`` (stable in 1.82.0). This is used internally by the ``pinned_init`` + crate, which is planned for inclusion in QEMU, but it can be easily patched + out. + +* referencing statics in constants (stable in 1.83.0). For now use a const + function; this is an important limitation for QEMU's migration stream + architecture (VMState). Right now, VMState lacks type safety because + it is hard to place the ``VMStateField`` definitions in traits. + +* associated const equality would be nice to have for some users of + ``callbacks::FnCall``, but is still experimental. ``ASSERT_IS_SOME`` + replaces it. + +__ https://github.com/rust-lang/rust/pull/125258 + +It is expected that QEMU will advance its minimum supported version of +rustc to 1.77.0 as soon as possible; as of January 2025, blockers +for that right now are Debian bookworm and 32-bit MIPS processors. +This unfortunately means that references to statics in constants will +remain an issue. + +QEMU also supports version 0.60.x of bindgen, which is missing option +``--generate-cstr``. This option requires version 0.66.x and will +be adopted as soon as supporting these older versions is not necessary +anymore. + +Writing Rust code in QEMU +------------------------- + +Right now QEMU includes three crates: + +* ``qemu_api`` for bindings to C code and useful functionality + +* ``qemu_api_macros`` defines several procedural macros that are useful when + writing C code + +* ``pl011`` (under ``rust/hw/char/pl011``) is the sample device that is being + used to further develop ``qemu_api`` and ``qemu_api_macros``. It is a functional + replacement for the ``hw/char/pl011.c`` file. + +This section explains how to work with them. + +Status +'''''' + +Modules of ``qemu_api`` can be defined as: + +- *complete*: ready for use in new devices; if applicable, the API supports the + full functionality available in C + +- *stable*: ready for production use, the API is safe and should not undergo + major changes + +- *proof of concept*: the API is subject to change but allows working with safe + Rust + +- *initial*: the API is in its initial stages; it requires large amount of + unsafe code; it might have soundness or type-safety issues + +The status of the modules is as follows: + +================ ====================== +module status +================ ====================== +``assertions`` stable +``bitops`` complete +``callbacks`` complete +``cell`` stable +``c_str`` complete +``irq`` complete +``module`` complete +``offset_of`` stable +``qdev`` stable +``qom`` stable +``sysbus`` stable +``vmstate`` proof of concept +``zeroable`` stable +================ ====================== + +.. note:: + API stability is not a promise, if anything because the C APIs are not a stable + interface either. Also, ``unsafe`` interfaces may be replaced by safe interfaces + later. + +Common pitfalls +''''''''''''''' + +Rust has very strict rules with respect to how you get an exclusive (``&mut``) +reference; failure to respect those rules is a source of undefined behavior. +In particular, even if a value is loaded from a raw mutable pointer (``*mut``), +it *cannot* be casted to ``&mut`` unless the value was stored to the ``*mut`` +from a mutable reference. Furthermore, it is undefined behavior if any +shared reference was created between the store to the ``*mut`` and the load:: + + let mut p: u32 = 42; + let p_mut = &mut p; // 1 + let p_raw = p_mut as *mut u32; // 2 + + // p_raw keeps the mutable reference "alive" + + let p_shared = &p; // 3 + println!("access from &u32: {}", *p_shared); + + // Bring back the mutable reference, its lifetime overlaps + // with that of a shared reference. + let p_mut = unsafe { &mut *p_raw }; // 4 + println!("access from &mut 32: {}", *p_mut); + + println!("access from &u32: {}", *p_shared); // 5 + +These rules can be tested with `MIRI`__, for example. + +__ https://github.com/rust-lang/miri + +Almost all Rust code in QEMU will involve QOM objects, and pointers to these +objects are *shared*, for example because they are part of the QOM composition +tree. This creates exactly the above scenario: + +1. a QOM object is created + +2. a ``*mut`` is created, for example as the opaque value for a ``MemoryRegion`` + +3. the QOM object is placed in the composition tree + +4. a memory access dereferences the opaque value to a ``&mut`` + +5. but the shared reference is still present in the composition tree + +Because of this, QOM objects should almost always use ``&self`` instead +of ``&mut self``; access to internal fields must use *interior mutability* +to go from a shared reference to a ``&mut``. + +Whenever C code provides you with an opaque ``void *``, avoid converting it +to a Rust mutable reference, and use a shared reference instead. Rust code +will then have to use QEMU's ``BqlRefCell`` and ``BqlCell`` type, which +enforce that locking rules for the "Big QEMU Lock" are respected. These cell +types are also known to the ``vmstate`` crate, which is able to "look inside" +them when building an in-memory representation of a ``struct``s layout. +Note that the same is not true of a ``RefCell`` or ``Mutex``. + +In the future, similar cell types might also be provided for ``AioContext``-based +locking as well. + +Writing bindings to C code +'''''''''''''''''''''''''' + +Here are some things to keep in mind when working on the ``qemu_api`` crate. + +**Look at existing code** + Very often, similar idioms in C code correspond to similar tricks in + Rust bindings. If the C code uses ``offsetof``, look at qdev properties + or ``vmstate``. If the C code has a complex const struct, look at + ``MemoryRegion``. Reuse existing patterns for handling lifetimes; + for example use ``&T`` for QOM objects that do not need a reference + count (including those that can be embedded in other objects) and + ``Owned<T>`` for those that need it. + +**Use the type system** + Bindings often will need access information that is specific to a type + (either a builtin one or a user-defined one) in order to pass it to C + functions. Put them in a trait and access it through generic parameters. + The ``vmstate`` module has examples of how to retrieve type information + for the fields of a Rust ``struct``. + +**Prefer unsafe traits to unsafe functions** + Unsafe traits are much easier to prove correct than unsafe functions. + They are an excellent place to store metadata that can later be accessed + by generic functions. C code usually places metadata in global variables; + in Rust, they can be stored in traits and then turned into ``static`` + variables. Often, unsafe traits can be generated by procedural macros. + +**Document limitations due to old Rust versions** + If you need to settle for an inferior solution because of the currently + supported set of Rust versions, document it in the source and in this + file. This ensures that it can be fixed when the minimum supported + version is bumped. + +**Keep locking in mind**. + When marking a type ``Sync``, be careful of whether it needs the big + QEMU lock. Use ``BqlCell`` and ``BqlRefCell`` for interior data, + or assert ``bql_locked()``. + +**Don't be afraid of complexity, but document and isolate it** + It's okay to be tricky; device code is written more often than bindings + code and it's important that it is idiomatic. However, you should strive + to isolate any tricks in a place (for example a ``struct``, a trait + or a macro) where it can be documented and tested. If needed, include + toy versions of the code in the documentation. + +Writing procedural macros +''''''''''''''''''''''''' + +By conventions, procedural macros are split in two functions, one +returning ``Result<proc_macro2::TokenStream, MacroError>` with the body of +the procedural macro, and the second returning ``proc_macro::TokenStream`` +which is the actual procedural macro. The former's name is the same as +the latter with the ``_or_error`` suffix. The code for the latter is more +or less fixed; it follows the following template, which is fixed apart +from the type after ``as`` in the invocation of ``parse_macro_input!``:: + + #[proc_macro_derive(Object)] + pub fn derive_object(input: TokenStream) -> TokenStream { + let input = parse_macro_input!(input as DeriveInput); + let expanded = derive_object_or_error(input).unwrap_or_else(Into::into); + + TokenStream::from(expanded) + } + +The ``qemu_api_macros`` crate has utility functions to examine a +``DeriveInput`` and perform common checks (e.g. looking for a struct +with named fields). These functions return ``Result<..., MacroError>`` +and can be used easily in the procedural macro function:: + + fn derive_object_or_error(input: DeriveInput) -> + Result<proc_macro2::TokenStream, MacroError> + { + is_c_repr(&input, "#[derive(Object)]")?; + + let name = &input.ident; + let parent = &get_fields(&input, "#[derive(Object)]")?[0].ident; + ... + } + +Use procedural macros with care. They are mostly useful for two purposes: + +* Performing consistency checks; for example ``#[derive(Object)]`` checks + that the structure has ``#[repr[C])`` and that the type of the first field + is consistent with the ``ObjectType`` declaration. + +* Extracting information from Rust source code into traits, typically based + on types and attributes. For example, ``#[derive(TryInto)]`` builds an + implementation of ``TryFrom``, and it uses the ``#[repr(...)]`` attribute + as the ``TryFrom`` source and error types. + +Procedural macros can be hard to debug and test; if the code generation +exceeds a few lines of code, it may be worthwhile to delegate work to +"regular" declarative (``macro_rules!``) macros and write unit tests for +those instead. + + +Coding style +'''''''''''' + +Code should pass clippy and be formatted with rustfmt. + +Right now, only the nightly version of ``rustfmt`` is supported. This +might change in the future. While CI checks for correct formatting via +``cargo fmt --check``, maintainers can fix this for you when applying patches. + +It is expected that ``qemu_api`` provides full ``rustdoc`` documentation for +bindings that are in their final shape or close. + +Adding dependencies +------------------- + +Generally, the set of dependent crates is kept small. Think twice before +adding a new external crate, especially if it comes with a large set of +dependencies itself. Sometimes QEMU only needs a small subset of the +functionality; see for example QEMU's ``assertions`` or ``c_str`` modules. + +On top of this recommendation, adding external crates to QEMU is a +slightly complicated process, mostly due to the need to teach Meson how +to build them. While Meson has initial support for parsing ``Cargo.lock`` +files, it is still highly experimental and is therefore not used. + +Therefore, external crates must be added as subprojects for Meson to +learn how to build them, as well as to the relevant ``Cargo.toml`` files. +The versions specified in ``rust/Cargo.lock`` must be the same as the +subprojects; note that the ``rust/`` directory forms a Cargo `workspace`__, +and therefore there is a single lock file for the whole build. + +__ https://doc.rust-lang.org/cargo/reference/workspaces.html#virtual-workspace + +Choose a version of the crate that works with QEMU's minimum supported +Rust version (|msrv|). + +Second, a new ``wrap`` file must be added to teach Meson how to download the +crate. The wrap file must be named ``NAME-SEMVER-rs.wrap``, where ``NAME`` +is the name of the crate and ``SEMVER`` is the version up to and including the +first non-zero number. For example, a crate with version ``0.2.3`` will use +``0.2`` for its ``SEMVER``, while a crate with version ``1.0.84`` will use ``1``. + +Third, the Meson rules to build the crate must be added at +``subprojects/NAME-SEMVER-rs/meson.build``. Generally this includes: + +* ``subproject`` and ``dependency`` lines for all dependent crates + +* a ``static_library`` or ``rust.proc_macro`` line to perform the actual build + +* ``declare_dependency`` and a ``meson.override_dependency`` lines to expose + the result to QEMU and to other subprojects + +Remember to add ``native: true`` to ``dependency``, ``static_library`` and +``meson.override_dependency`` for dependencies of procedural macros. +If a crate is needed in both procedural macros and QEMU binaries, everything +apart from ``subproject`` must be duplicated to build both native and +non-native versions of the crate. + +It's important to specify the right compiler options. These include: + +* the language edition (which can be found in the ``Cargo.toml`` file) + +* the ``--cfg`` (which have to be "reverse engineered" from the ``build.rs`` + file of the crate). + +* usually, a ``--cap-lints allow`` argument to hide warnings from rustc + or clippy. + +After every change to the ``meson.build`` file you have to update the patched +version with ``meson subprojects update --reset ``NAME-SEMVER-rs``. This might +be automated in the future. + +Also, after every change to the ``meson.build`` file it is strongly suggested to +do a dummy change to the ``.wrap`` file (for example adding a comment like +``# version 2``), which will help Meson notice that the subproject is out of date. + +As a last step, add the new subproject to ``scripts/archive-source.sh``, +``scripts/make-release`` and ``subprojects/.gitignore``. diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc index fee05d0..73621f4 100644 --- a/fpu/softfloat-parts.c.inc +++ b/fpu/softfloat-parts.c.inc @@ -126,7 +126,8 @@ static FloatPartsN *partsN(pick_nan_muladd)(FloatPartsN *a, FloatPartsN *b, float_raise(float_flag_invalid | float_flag_invalid_snan, s); } - if (infzero) { + if (infzero && + !(s->float_infzeronan_rule & float_infzeronan_suppress_invalid)) { /* This is (0 * inf) + NaN or (inf * 0) + NaN */ float_raise(float_flag_invalid | float_flag_invalid_imz, s); } @@ -144,7 +145,7 @@ static FloatPartsN *partsN(pick_nan_muladd)(FloatPartsN *a, FloatPartsN *b, * Inf * 0 + NaN -- some implementations return the * default NaN here, and some return the input NaN. */ - switch (s->float_infzeronan_rule) { + switch (s->float_infzeronan_rule & ~float_infzeronan_suppress_invalid) { case float_infzeronan_dnan_never: break; case float_infzeronan_dnan_always: diff --git a/include/fpu/softfloat-types.h b/include/fpu/softfloat-types.h index 616c290..2e43d1d 100644 --- a/include/fpu/softfloat-types.h +++ b/include/fpu/softfloat-types.h @@ -280,11 +280,21 @@ typedef enum __attribute__((__packed__)) { /* No propagation rule specified */ float_infzeronan_none = 0, /* Result is never the default NaN (so always the input NaN) */ - float_infzeronan_dnan_never, + float_infzeronan_dnan_never = 1, /* Result is always the default NaN */ - float_infzeronan_dnan_always, + float_infzeronan_dnan_always = 2, /* Result is the default NaN if the input NaN is quiet */ - float_infzeronan_dnan_if_qnan, + float_infzeronan_dnan_if_qnan = 3, + /* + * Don't raise Invalid for 0 * Inf + NaN. Default is to raise. + * IEEE 754-2008 section 7.2 makes it implementation defined whether + * 0 * Inf + QNaN raises Invalid or not. Note that 0 * Inf + SNaN will + * raise the Invalid flag for the SNaN anyway. + * + * This is a flag which can be ORed in with any of the above + * DNaN behaviour options. + */ + float_infzeronan_suppress_invalid = (1 << 7), } FloatInfZeroNaNRule; /* diff --git a/rust/Cargo.toml b/rust/Cargo.toml index 5b6b6ca..5b0cb55 100644 --- a/rust/Cargo.toml +++ b/rust/Cargo.toml @@ -52,7 +52,6 @@ empty_structs_with_brackets = "deny" ignored_unit_patterns = "deny" implicit_clone = "deny" macro_use_imports = "deny" -missing_const_for_fn = "deny" missing_safety_doc = "deny" multiple_crate_versions = "deny" mut_mut = "deny" diff --git a/rust/clippy.toml b/rust/clippy.toml new file mode 100644 index 0000000..5d190f9 --- /dev/null +++ b/rust/clippy.toml @@ -0,0 +1,2 @@ +doc-valid-idents = ["PrimeCell", ".."] +msrv = "1.63.0" diff --git a/rust/hw/char/pl011/Cargo.toml b/rust/hw/char/pl011/Cargo.toml index 58f3e85..f2296ca 100644 --- a/rust/hw/char/pl011/Cargo.toml +++ b/rust/hw/char/pl011/Cargo.toml @@ -4,14 +4,12 @@ version = "0.1.0" edition = "2021" authors = ["Manos Pitsidianakis <manos.pitsidianakis@linaro.org>"] license = "GPL-2.0-or-later" -readme = "README.md" -homepage = "https://www.qemu.org" description = "pl011 device model for QEMU" -repository = "https://gitlab.com/epilys/rust-for-qemu" resolver = "2" publish = false keywords = [] categories = [] +rust-version = "1.63.0" [lib] crate-type = ["staticlib"] diff --git a/rust/hw/char/pl011/README.md b/rust/hw/char/pl011/README.md deleted file mode 100644 index cd7dea3..0000000 --- a/rust/hw/char/pl011/README.md +++ /dev/null @@ -1,31 +0,0 @@ -# PL011 QEMU Device Model - -This library implements a device model for the PrimeCell® UART (PL011) -device in QEMU. - -## Build static lib - -Host build target must be explicitly specified: - -```sh -cargo build --target x86_64-unknown-linux-gnu -``` - -Replace host target triplet if necessary. - -## Generate Rust documentation - -To generate docs for this crate, including private items: - -```sh -cargo doc --no-deps --document-private-items --target x86_64-unknown-linux-gnu -``` - -To include direct dependencies like `bilge` (bitmaps for register types): - -```sh -cargo tree --depth 1 -e normal --prefix none \ - | cut -d' ' -f1 \ - | xargs printf -- '-p %s\n' \ - | xargs cargo doc --no-deps --document-private-items --target x86_64-unknown-linux-gnu -``` diff --git a/rust/hw/char/pl011/src/device_class.rs b/rust/hw/char/pl011/src/device_class.rs index 8a157a6..dbef93f 100644 --- a/rust/hw/char/pl011/src/device_class.rs +++ b/rust/hw/char/pl011/src/device_class.rs @@ -12,7 +12,6 @@ use qemu_api::{ use crate::device::{PL011Registers, PL011State}; -#[allow(clippy::missing_const_for_fn)] extern "C" fn pl011_clock_needed(opaque: *mut c_void) -> bool { let state = NonNull::new(opaque).unwrap().cast::<PL011State>(); unsafe { state.as_ref().migrate_clock } diff --git a/rust/hw/char/pl011/src/lib.rs b/rust/hw/char/pl011/src/lib.rs index e2df458..3c72f12 100644 --- a/rust/hw/char/pl011/src/lib.rs +++ b/rust/hw/char/pl011/src/lib.rs @@ -1,29 +1,18 @@ // Copyright 2024, Linaro Limited // Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org> // SPDX-License-Identifier: GPL-2.0-or-later -// -// PL011 QEMU Device Model -// -// This library implements a device model for the PrimeCell® UART (PL011) -// device in QEMU. -// -#![doc = include_str!("../README.md")] + +//! PL011 QEMU Device Model +//! +//! This library implements a device model for the PrimeCell® UART (PL011) +//! device in QEMU. +//! //! # Library crate //! //! See [`PL011State`](crate::device::PL011State) for the device model type and //! the [`registers`] module for register types. -#![deny( - clippy::correctness, - clippy::suspicious, - clippy::complexity, - clippy::perf, - clippy::cargo, - clippy::nursery, - clippy::style -)] #![allow(clippy::upper_case_acronyms)] -#![allow(clippy::result_unit_err)] use qemu_api::c_str; diff --git a/rust/qemu-api-macros/Cargo.toml b/rust/qemu-api-macros/Cargo.toml index 5a27b52..89dee1c 100644 --- a/rust/qemu-api-macros/Cargo.toml +++ b/rust/qemu-api-macros/Cargo.toml @@ -4,14 +4,12 @@ version = "0.1.0" edition = "2021" authors = ["Manos Pitsidianakis <manos.pitsidianakis@linaro.org>"] license = "GPL-2.0-or-later" -readme = "README.md" -homepage = "https://www.qemu.org" description = "Rust bindings for QEMU - Utility macros" -repository = "https://gitlab.com/qemu-project/qemu/" resolver = "2" publish = false keywords = [] categories = [] +rust-version = "1.63.0" [lib] proc-macro = true diff --git a/rust/qemu-api-macros/README.md b/rust/qemu-api-macros/README.md deleted file mode 100644 index f60f54a..0000000 --- a/rust/qemu-api-macros/README.md +++ /dev/null @@ -1 +0,0 @@ -# `qemu-api-macros` - Utility macros for defining QEMU devices diff --git a/rust/qemu-api/Cargo.toml b/rust/qemu-api/Cargo.toml index 4aa22f3..a51dd14 100644 --- a/rust/qemu-api/Cargo.toml +++ b/rust/qemu-api/Cargo.toml @@ -12,6 +12,7 @@ resolver = "2" publish = false keywords = [] categories = [] +rust-version = "1.63.0" [dependencies] qemu_api_macros = { path = "../qemu-api-macros" } diff --git a/rust/qemu-api/src/lib.rs b/rust/qemu-api/src/lib.rs index 83c6a98..3cf9371 100644 --- a/rust/qemu-api/src/lib.rs +++ b/rust/qemu-api/src/lib.rs @@ -3,6 +3,7 @@ // SPDX-License-Identifier: GPL-2.0-or-later #![cfg_attr(not(MESON), doc = include_str!("../README.md"))] +#![deny(clippy::missing_const_for_fn)] #[rustfmt::skip] pub mod bindings; diff --git a/target/i386/tcg/fpu_helper.c b/target/i386/tcg/fpu_helper.c index 3d764bc..de6d0b2 100644 --- a/target/i386/tcg/fpu_helper.c +++ b/target/i386/tcg/fpu_helper.c @@ -178,8 +178,11 @@ void cpu_init_fp_statuses(CPUX86State *env) * "Fused-Multiply-ADD (FMA) Numeric Behavior" the NaN handling is * specified -- for 0 * inf + NaN the input NaN is selected, and if * there are multiple input NaNs they are selected in the order a, b, c. + * We also do not raise Invalid for the 0 * inf + (Q)NaN case. */ - set_float_infzeronan_rule(float_infzeronan_dnan_never, &env->sse_status); + set_float_infzeronan_rule(float_infzeronan_dnan_never | + float_infzeronan_suppress_invalid, + &env->sse_status); set_float_3nan_prop_rule(float_3nan_prop_abc, &env->sse_status); /* Default NaN: sign bit set, most significant frac bit set */ set_float_default_nan_pattern(0b11000000, &env->fp_status); diff --git a/tcg/optimize.c b/tcg/optimize.c index 8c6303e..bca11cc 100644 --- a/tcg/optimize.c +++ b/tcg/optimize.c @@ -766,6 +766,7 @@ static int do_constant_folding_cond1(OptContext *ctx, TCGOp *op, TCGArg dest, TCGArg *p1, TCGArg *p2, TCGArg *pcond) { TCGCond cond; + TempOptInfo *i1; bool swap; int r; @@ -783,19 +784,21 @@ static int do_constant_folding_cond1(OptContext *ctx, TCGOp *op, TCGArg dest, return -1; } + i1 = arg_info(*p1); + /* * TSTNE x,x -> NE x,0 - * TSTNE x,-1 -> NE x,0 + * TSTNE x,i -> NE x,0 if i includes all nonzero bits of x */ - if (args_are_copies(*p1, *p2) || arg_is_const_val(*p2, -1)) { + if (args_are_copies(*p1, *p2) || + (arg_is_const(*p2) && (i1->z_mask & ~arg_info(*p2)->val) == 0)) { *p2 = arg_new_constant(ctx, 0); *pcond = tcg_tst_eqne_cond(cond); return -1; } - /* TSTNE x,sign -> LT x,0 */ - if (arg_is_const_val(*p2, (ctx->type == TCG_TYPE_I32 - ? INT32_MIN : INT64_MIN))) { + /* TSTNE x,i -> LT x,0 if i only includes sign bit copies */ + if (arg_is_const(*p2) && (arg_info(*p2)->val & ~i1->s_mask) == 0) { *p2 = arg_new_constant(ctx, 0); *pcond = tcg_tst_ltge_cond(cond); return -1; diff --git a/tests/tcg/x86_64/Makefile.target b/tests/tcg/x86_64/Makefile.target index d6dff55..be20fc6 100644 --- a/tests/tcg/x86_64/Makefile.target +++ b/tests/tcg/x86_64/Makefile.target @@ -18,6 +18,7 @@ X86_64_TESTS += adox X86_64_TESTS += test-1648 X86_64_TESTS += test-2175 X86_64_TESTS += cross-modifying-code +X86_64_TESTS += fma TESTS=$(MULTIARCH_TESTS) $(X86_64_TESTS) test-x86_64 else TESTS=$(MULTIARCH_TESTS) diff --git a/tests/tcg/x86_64/fma.c b/tests/tcg/x86_64/fma.c new file mode 100644 index 0000000..09c622e --- /dev/null +++ b/tests/tcg/x86_64/fma.c @@ -0,0 +1,109 @@ +/* + * Test some fused multiply add corner cases. + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ +#include <stdio.h> +#include <stdint.h> +#include <stdbool.h> +#include <inttypes.h> + +#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) + +/* + * Perform one "n * m + a" operation using the vfmadd insn and return + * the result; on return *mxcsr_p is set to the bottom 6 bits of MXCSR + * (the Flag bits). If ftz is true then we set MXCSR.FTZ while doing + * the operation. + * We print the operation and its results to stdout. + */ +static uint64_t do_fmadd(uint64_t n, uint64_t m, uint64_t a, + bool ftz, uint32_t *mxcsr_p) +{ + uint64_t r; + uint32_t mxcsr = 0; + uint32_t ftz_bit = ftz ? (1 << 15) : 0; + uint32_t saved_mxcsr = 0; + + asm volatile("stmxcsr %[saved_mxcsr]\n" + "stmxcsr %[mxcsr]\n" + "andl $0xffff7fc0, %[mxcsr]\n" + "orl %[ftz_bit], %[mxcsr]\n" + "ldmxcsr %[mxcsr]\n" + "movq %[a], %%xmm0\n" + "movq %[m], %%xmm1\n" + "movq %[n], %%xmm2\n" + /* xmm0 = xmm0 + xmm2 * xmm1 */ + "vfmadd231sd %%xmm1, %%xmm2, %%xmm0\n" + "movq %%xmm0, %[r]\n" + "stmxcsr %[mxcsr]\n" + "ldmxcsr %[saved_mxcsr]\n" + : [r] "=r" (r), [mxcsr] "=m" (mxcsr), + [saved_mxcsr] "=m" (saved_mxcsr) + : [n] "r" (n), [m] "r" (m), [a] "r" (a), + [ftz_bit] "r" (ftz_bit) + : "xmm0", "xmm1", "xmm2"); + *mxcsr_p = mxcsr & 0x3f; + printf("vfmadd132sd 0x%" PRIx64 " 0x%" PRIx64 " 0x%" PRIx64 + " = 0x%" PRIx64 " MXCSR flags 0x%" PRIx32 "\n", + n, m, a, r, *mxcsr_p); + return r; +} + +typedef struct testdata { + /* Input n, m, a */ + uint64_t n; + uint64_t m; + uint64_t a; + bool ftz; + /* Expected result */ + uint64_t expected_r; + /* Expected low 6 bits of MXCSR (the Flag bits) */ + uint32_t expected_mxcsr; +} testdata; + +static testdata tests[] = { + { 0, 0x7ff0000000000000, 0x7ff000000000aaaa, false, /* 0 * Inf + SNaN */ + 0x7ff800000000aaaa, 1 }, /* Should be QNaN and does raise Invalid */ + { 0, 0x7ff0000000000000, 0x7ff800000000aaaa, false, /* 0 * Inf + QNaN */ + 0x7ff800000000aaaa, 0 }, /* Should be QNaN and does *not* raise Invalid */ + /* + * These inputs give a result which is tiny before rounding but which + * becomes non-tiny after rounding. x86 is a "detect tininess after + * rounding" architecture, so it should give a non-denormal result and + * not set the Underflow flag (only the Precision flag for an inexact + * result). + */ + { 0x3fdfffffffffffff, 0x001fffffffffffff, 0x801fffffffffffff, false, + 0x8010000000000000, 0x20 }, + /* + * Flushing of denormal outputs to zero should also happen after + * rounding, so setting FTZ should not affect the result or the flags. + * QEMU currently does not emulate this correctly because we do the + * flush-to-zero check before rounding, so we incorrectly produce a + * zero result and set Underflow as well as Precision. + */ +#ifdef ENABLE_FAILING_TESTS + { 0x3fdfffffffffffff, 0x001fffffffffffff, 0x801fffffffffffff, true, + 0x8010000000000000, 0x20 }, /* Enabling FTZ shouldn't change flags */ +#endif +}; + +int main(void) +{ + bool passed = true; + for (int i = 0; i < ARRAY_SIZE(tests); i++) { + uint32_t mxcsr; + uint64_t r = do_fmadd(tests[i].n, tests[i].m, tests[i].a, + tests[i].ftz, &mxcsr); + if (r != tests[i].expected_r) { + printf("expected result 0x%" PRIx64 "\n", tests[i].expected_r); + passed = false; + } + if (mxcsr != tests[i].expected_mxcsr) { + printf("expected MXCSR flags 0x%x\n", tests[i].expected_mxcsr); + passed = false; + } + } + return passed ? 0 : 1; +} |