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 01A9E24E4C4; Tue, 2 Dec 2025 06:32:40 +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=1764657161; cv=none; b=bFOwQCEYLKkFI1soiVnL9EnkXCiX4DBPGXcegktwzR7lc7elAZ10aAIHvtA29i1mYYwjQqaudUOD+hr874VFUxjSxmk1+9+Dvk5FcMdLHhiJSjtPJ3lpAuu85+oKLW1Ux2EZPoEHKfB3gvLd5v1HCWuJnufrCsChSZnoqsQ4DiI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764657161; c=relaxed/simple; bh=TgEB8wVKZ5xbL1Enc85Hn5PeEqpdms/JqisfACwfnkk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=e4egqqbaXAr5BGXfG462aIhshXZwKhZtZbX0AsazZ/9v2zavUdHWgWLDnFyHepg4QfQ0xnwX3mQZNqjgPfskK/0+j56oXv4g9LqvUVukEun8ScRTK2zgvC2lRUU7WmbDBdk+vicC0j8qY70+1HzX+mSZBOUYEZ3Fzbz1a4Dy7I0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Z2G5IvJl; 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="Z2G5IvJl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AD00EC4CEF1; Tue, 2 Dec 2025 06:32:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764657160; bh=TgEB8wVKZ5xbL1Enc85Hn5PeEqpdms/JqisfACwfnkk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Z2G5IvJlG159Qtj2L1uCxdVh489iCJxiCAEBCgUbF2645xJTjuQtWbvjOJbQBMJbb pv1mrDCrAixL6k/XD8MOkbjs67npdwzqiXDAigqBj+s/DyXqux9lUsM3YHN/34YRQG VOHvCL6AcPSwyhqMhGlEl0nFqx45syiziWX9s/HWUr2/BP6JapD7PpSkwxN7T/6+s0 BStRwP3JQp7dUAqtAJRMBi7KCRnE1FZ7Lg6vYpioozogzxQ1tDv7SDCMoHsdmEyQbL JiePoQ6D1tBcJB3zws78jhNCTPdI5h5zt3D/LzNUAL2ZD/GseuiLuOWy8lcIhB5LDz c/xc2mEgwjZVQ== Date: Tue, 2 Dec 2025 07:32:31 +0100 From: Niklas Cassel To: Koichiro Den Cc: ntb@lists.linux.dev, linux-pci@vger.kernel.org, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, Frank.Li@nxp.com, mani@kernel.org, kwilczynski@kernel.org, kishon@kernel.org, bhelgaas@google.com, corbet@lwn.net, vkoul@kernel.org, jdmason@kudzu.us, dave.jiang@intel.com, allenbh@gmail.com, Basavaraj.Natikar@amd.com, Shyam-sundar.S-k@amd.com, kurt.schwemmer@microsemi.com, logang@deltatee.com, jingoohan1@gmail.com, lpieralisi@kernel.org, robh@kernel.org, jbrunet@baylibre.com, fancer.lancer@gmail.com, arnd@arndb.de, pstanner@redhat.com, elfring@users.sourceforge.net, Damien Le Moal Subject: Re: [RFC PATCH v2 19/27] PCI: dwc: ep: Cache MSI outbound iATU mapping Message-ID: References: <20251129160405.2568284-1-den@valinux.co.jp> <20251129160405.2568284-20-den@valinux.co.jp> Precedence: bulk X-Mailing-List: dmaengine@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251129160405.2568284-20-den@valinux.co.jp> On Sun, Nov 30, 2025 at 01:03:57AM +0900, Koichiro Den wrote: > dw_pcie_ep_raise_msi_irq() currently programs an outbound iATU window > for the MSI target address on every interrupt and tears it down again > via dw_pcie_ep_unmap_addr(). > > On systems that heavily use the AXI bridge interface (for example when > the integrated eDMA engine is active), this means the outbound iATU > registers are updated while traffic is in flight. The DesignWare > endpoint spec warns that updating iATU registers in this situation is > not supported, and the behavior is undefined. Please reference a specific section in the EP databook, and the specific EP databook version that you are using. This patch appears to address quite a serious issue, so I think that you should submit it as a standalone patch, and not as part of a series. (Especially not as part of an RFC which can take quite long before it is even submitted as a normal (non-RFC) series.) Kind regards, Niklas