From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9C5C5EB104B for ; Tue, 10 Mar 2026 10:58:59 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0B3CB10E24C; Tue, 10 Mar 2026 10:58:59 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="MpX9Pz0r"; dkim-atps=neutral Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1DF3310E24C; Tue, 10 Mar 2026 10:58:57 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 4A869600B0; Tue, 10 Mar 2026 10:58:56 +0000 (UTC) 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== 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: X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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.