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Mon, 20 May 2024 20:01:54 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20240520172554.182094-1-dakr@redhat.com> <20240520172554.182094-11-dakr@redhat.com> In-Reply-To: From: Wedson Almeida Filho Date: Tue, 21 May 2024 00:01:45 -0300 Message-ID: Subject: Re: [RFC PATCH 10/11] rust: add basic abstractions for iomem operations To: Dave Airlie Cc: Miguel Ojeda , Danilo Krummrich , gregkh@linuxfoundation.org, rafael@kernel.org, bhelgaas@google.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, a.hindborg@samsung.com, aliceryhl@google.com, fujita.tomonori@gmail.com, lina@asahilina.net, pstanner@redhat.com, ajanulgu@redhat.com, lyude@redhat.com, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org Content-Type: text/plain; charset="UTF-8" On Mon, 20 May 2024 at 23:07, Dave Airlie wrote: > > > > > Wedson wrote a similar abstraction in the past > > (`rust/kernel/io_mem.rs` in the old `rust` branch), with a > > compile-time `SIZE` -- it is probably worth taking a look. > > > > Just on this point, we can't know in advance what size the IO BARs are > at compile time. > > The old method just isn't useful for real devices with runtime IO BAR sizes. The compile-time `SIZE` in my implementation is a minimum size. Attempts to read/write with constants within that size (offset + size) were checked at compile time, that is, they would have zero additional runtime cost when compared to C. Reads/writes beyond the minimum would have to be checked at runtime.