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 14BF6FEFB6D for ; Fri, 27 Feb 2026 16:49:22 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9205710EBCC; Fri, 27 Feb 2026 16:49:22 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="BMGK66Il"; dkim-atps=neutral Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7C80710E125; Fri, 27 Feb 2026 16:49:21 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 269B9444D5; Fri, 27 Feb 2026 16:49:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D3011C116C6; Fri, 27 Feb 2026 16:49:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772210961; bh=jznU9LDSkQYILvcSIV46IxA3CrI9OTrcodpcP2KE/Rk=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=BMGK66IlpUYHanCwORkjV1r5gD4tZdmf3FdgQyvpYqd87OnPE/XYM3XTkW4Ksw/Y2 Y3jxv1rvP5tPMlEvJt5tjaSTDHFbZ6E0cmQiJ4sJ1nQ4Fa0ouKncl5VoVtiCuVxIzZ wWKIJt52O1sSUx08jbmlf8//snPIjiC+zltv0lkdOUs2BhGHuFA3bE4uAUcyVVBSxy qaQx337ysm56rZiMRyNkrrziyLzOmk1FheLkVIlnP9JOrOh9Vg2yq723loCPFce4ld PQ+fWhfMBe0FBUqcD3yCDZF4bHUCb4tFZLXFqqmmZy1DAO7HVlmZIQO39PRRlHaFGU +2b9qvGprKjDg== Date: Fri, 27 Feb 2026 10:49:19 -0600 From: Bjorn Helgaas To: Vivian Wang , Thomas Gleixner Cc: Mark Bloch , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , Alex Deucher , Christian =?utf-8?B?S8O2bmln?= , David Airlie , Simona Vetter , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Bjorn Helgaas , Jaroslav Kysela , Takashi Iwai , Brett Creeley , Han Gao , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, netdev@vger.kernel.org, linux-pci@vger.kernel.org, linux-sound@vger.kernel.org, linux-riscv@lists.infradead.org, sophgo@lists.linux.dev, Takashi Iwai , Maor Gottlieb Subject: Re: [PATCH v4 1/4] PCI/MSI: Conservatively generalize no_64bit_msi into msi_addr_mask Message-ID: <20260227164919.GA3897300@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" On Fri, Feb 27, 2026 at 01:25:03PM +0800, Vivian Wang wrote: > On 2/27/26 02:25, Mark Bloch wrote: > > On 29/01/2026 3:56, Vivian Wang wrote: > >> Some PCI devices have PCI_MSI_FLAGS_64BIT in the MSI capability, but > >> implement less than 64 address bits. This breaks on platforms where such > >> a device is assigned an MSI address higher than what's reachable. > >> > >> Currently, the no_64bit_msi bit is set for these devices, meaning that > >> only 32-bit MSI addresses are allowed for them. However, on some > >> platforms the MSI doorbell address is above the 32-bit limit but within > >> the addressable range of the device. > >> > >> As a first step to enabling MSI on those combinations of devices and > >> platforms, conservatively generalize the single-bit flag no_64bit_msi > >> into msi_addr_mask. (The name msi_addr_mask is chosen to avoid confusion > >> with msi_mask.) > >> > >> The translation is essentially: > >> > >> - no_64bit_msi = 1 -> msi_addr_mask = DMA_BIT_MASK(32) > >> - no_64bit_msi = 0 -> msi_addr_mask = DMA_BIT_MASK(64) > >> - if (no_64bit_msi) -> if (msi_addr_mask < DMA_BIT_MASK(64)) > >> > > Hey Vivian, > > > > We are seeing issues while reloading mlx5 on a PPC64 platform. > > Mea culpa. There's a fix on the list [1] since last Friday. I'm not sure > why it hasn't moved yet, but please take a look. > > [1]: https://lore.kernel.org/all/20260220070239.1693303-1-nilay@linux.ibm.com/ We needed testing on powerpc and sparc, which has now been done, thanks to Han Gao (SPARC Enterprise T5220), Nathaniel Roach (SPARC T5-2), and Venkat Rao Bagalkote (IBM Power System LPAR (pseries)). It would be ideal to have acks from the powerpc and sparc maintainers, so I just solicited those. Thomas merged 386ced19e9a3 ("PCI/MSI: Convert the boolean no_64bit_msi flag to a DMA address mask"), and could merge the fixes. Otherwise I can merge via PCI. Bjorn