From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 97F4D384245; Tue, 10 Mar 2026 10:58:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773140336; cv=none; b=n4prLJnYwi4vLYRFhqOE0d6ryAemfAgSiLLYfB5ZXGQE6GcdUl4VpE2SdpIPq2ci27qvOUxdk226gIJBQXlIw++D6KWjIjWuedZ5SdmH3LH6PI/XjNzPN0SZQLn+/4D5qkNnCjPqoEZum9vX/BUj9CGV/Xb7OsLN8b4BtognAew= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773140336; c=relaxed/simple; bh=P3TywGqRAkhOoXBhCiCMOV9gwuUSxS2oeLYbxPkHnjA=; h=Mime-Version:Content-Type:Date:Message-Id:Cc:To:From:Subject: References:In-Reply-To; b=PLbKLdCA8dIac4bADABcoFa+zDJk4roQ6xjk5mRmuSnDCLVlCgHw+rKUrZWTX4UTNzSzeQA1vQFxCEEt9FeLEIojYn+SLF2UV+96SCDVYSLUEmlMwrIcFSUEiZnSZSF4s78lDOMPnbJ5RsKV55q8nuAL6n/HRw/k9BLVfUCvFKI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MpX9Pz0r; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="MpX9Pz0r" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 92DB4C19423; Tue, 10 Mar 2026 10:58:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773140336; bh=P3TywGqRAkhOoXBhCiCMOV9gwuUSxS2oeLYbxPkHnjA=; h=Date:Cc:To:From:Subject:References:In-Reply-To:From; b=MpX9Pz0rS3A+qDX6WlvyVrbiRpvWJ2KvhZUkWiofdPZlKDyhG8UGmlG4iPzeew84u 1YmVLm7gawNFKUUKq33UpP9vjIeih85cOxercEgGB+eYM2BcaQZTnYDyzWcTFvLSGM Wktl15nF2sSj54MbXVSAVoVNgvkA+5yW40YR785WEbWu/fbTJtbqXclkYp1q71xM3I knuaVyS9OSLWoftLEyn61NngFXUBF1L+zx/DF81AgKe+saojsica+dp7AP+xEePFGh 2V7Y/JgWLzPZfCN0Tky5B0Ok6GGzIn1LBnsgi8ppJH56FKAO06aNngkJvSwG/LjByn YXMtsOajf2+uw== Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Tue, 10 Mar 2026 11:58:53 +0100 Message-Id: Cc: , , , , , To: "Gary Guo" From: "Danilo Krummrich" Subject: Re: [PATCH] gpu: nova-core: gsp: fix UB in DmaGspMem pointer accessors References: <20260309225408.27714-1-dakr@kernel.org> In-Reply-To: On Tue Mar 10, 2026 at 3:01 AM CET, Gary Guo wrote: >> +// TODO: Revert to private once `IoView` projections replace the `gsp_m= em` module. >> +pub(in crate::gsp) struct Msgq { > > These could all be `(in super)`? Yes, or just pub(super). However, that's not the case for the functions in = the gsp_mem module, they could be pub(in super::super) though. But I think I pr= efer pub(in crate::gsp) for those. >> + pub(in crate::gsp) fn gsp_write_ptr(qs: &CoherentAllocation= ) -> u32 { >> + // PANIC: A `dma::CoherentAllocation` always contains at least = one element. >> + || -> Result { Ok(dma_read!(qs, [0]?.gspq.tx.0.writePtr) %= MSGQ_NUM_PAGES) }().unwrap() > > I wonder if I should add a panicking variant of index projection for this= case. > Perhaps of syntax `[index]!`. > > We could also make the existing `[index]` becoming a panicking one instea= d of > `build_error!` one. It is more consistent with Rust index operator that w= ay. I thought the same, as something like this `[n]?.ptes[i]` looks a bit odd. However, I think we ideally want both variants (I like your `[i]!` proposal above), since generally users should have the choice (as they also have wit= h a slice through get()). For instance, the index could come from userspace. Su= re, you can always validate the index in advance, but having a fallible variant= is a bit nicer.