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 55DD843E48D; Fri, 27 Feb 2026 15:34:09 +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=1772206449; cv=none; b=t87q/KplAPNVyGUdhxL7ZUbcIVv3CHMbwJRYgJyHr1ordtTLHepJInkQGkLsBzDbEUYFlXsorD9ZvzIrBuEUUU2wDZ+T1JzX0gjS4+mU6dEopmYKMd+Fx81+BiOGiANbn6f8UI6L+LY0Uajuu4MhIKEcqIGkeBOkS1zZOWMskAw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772206449; c=relaxed/simple; bh=xA4eq1B4WHkeDiKdaYvOGPnwQRl6UE44kUbEbocjO44=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Y3kflO1s1PzUoggaSQVtFURdsncfwQSRP4UlKHVr8P57/mOYDz9AKyCcYqCkPXLA70lD1iSmBJtLeHns3xNYorluHKRflj6kA12eLvMNFt5FPmEEkP5+X3GRQvJytp2vVCWBVUBrLJ6f15A0/p9BnJLHIjp3LDft5aIywPwctfM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BMiFut1A; 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="BMiFut1A" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 304ACC116C6; Fri, 27 Feb 2026 15:34:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772206448; bh=xA4eq1B4WHkeDiKdaYvOGPnwQRl6UE44kUbEbocjO44=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=BMiFut1AAajy3447HZ0FGatLcDBQjA21nQ/vmhIP1fZ8/bW0gH6pUI3zBKGlKTbuM 5uNhYBTuVsGtIjVf8itVzx42ISHdXLvJkYEN9zbmWgcvVM4BIYHWqrKT5UgeptieSy j3yBRAcvRl3JYEhgkR6H2s6kVL9tz9stZKlluFCeJmv6ETXqBOFmV8vY7qB7aIvKJg F5S/RqTRGK4Nniyfe+anUtc0HvftdQZtrBvgT9Z3f0SOZovdLPW4GWKFFZSKw+HFHR XyfUO7GTYVqenFvDZiSXD5MBPTFKxi7JuDXxkGSIE1VnD42DyafIEXIrO4ZwgLWqs0 Q6AhV8s5bMwWg== Date: Fri, 27 Feb 2026 16:34:02 +0100 From: Niklas Cassel To: Koichiro Den Cc: jingoohan1@gmail.com, mani@kernel.org, lpieralisi@kernel.org, kwilczynski@kernel.org, robh@kernel.org, bhelgaas@google.com, kishon@kernel.org, jdmason@kudzu.us, dave.jiang@intel.com, allenbh@gmail.com, Frank.Li@nxp.com, shinichiro.kawasaki@wdc.com, christian.bruel@foss.st.com, mmaddireddy@nvidia.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, ntb@lists.linux.dev Subject: Re: [PATCH v9 7/7] PCI: endpoint: pci-ep-msi: Add embedded doorbell fallback Message-ID: References: <20260219081318.4156901-1-den@valinux.co.jp> <20260219081318.4156901-8-den@valinux.co.jp> Precedence: bulk X-Mailing-List: ntb@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Sat, Feb 21, 2026 at 02:42:35AM +0900, Koichiro Den wrote: > On second thought, I'm wondering whether it makes sense to handle the case where > the embedded doorbell target resides behind an IOMMU in this series. > > In v9, we simply expose the raw physical address without establishing an IOMMU > mapping. When the EPC parent device is attached to an IOMMU domain, a Host->EP > MMIO write through the BAR window may result in an IOMMU fault. > > Initially, I planned to submit IOMMU support separately as a follow-up series > once this series is accepted, to avoid making this series too large [1]. > > Niklas, any comments would be appreciated. These patches are for NTB/vNTB: > [1] Supporting such an IOMMU-backed case would likely require additional > patches for vNTB + ntb_transport to demonstrate usability, such as: > https://lore.kernel.org/all/20260118135440.1958279-12-den@valinux.co.jp/ > https://lore.kernel.org/all/20260118135440.1958279-16-den@valinux.co.jp/ > https://lore.kernel.org/all/20260118135440.1958279-19-den@valinux.co.jp/ If the diff you pasted above is all you need for pci-epf-test to pass the doorbell test case when running against a PCI endpoint with IOMMU enabled, then I suggest you just send a v10 with those changes included, without any additional dependencies. I understand that you would need additional dependencies for vNTB to be able to use eDMA doorbell on a PCI endpoint with IOMMU enabled. Perhaps, drop the vNTB changes from this series, focus only on pci-epf-test, get this series merged, and then submit an follow up series that adds eDMA doorbells with IOMMU support for vNTB? Kind regards, Niklas