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 D1338CD98CC for ; Wed, 10 Jun 2026 18:40:02 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id F20DC10EB67; Wed, 10 Jun 2026 18:40:01 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="AXQg2sOU"; 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 CC10510EB67 for ; Wed, 10 Jun 2026 18:40:00 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 7149643B70; Wed, 10 Jun 2026 18:40:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5BD661F00893; Wed, 10 Jun 2026 18:39:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781116800; bh=2O7wrREt4oiDQ0b6njA5QsbmFiFGcobC6ew3dRXWqcA=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=AXQg2sOUQCvZAEJpOUDjFxgGFGvNfk8Y+NFsIF1/5oh/Jf0NM00X8fx1vrkj5uHRU OlivCH41ngLCnSfN3Chi7Nbnl211nqRmBag5EgqKauDJGnoTKxPiAeXPg3Im9QJr7C G/Mq1DzVMYclnYZohJe3cwSTZr098ztfrRB47bVZbuSTaTrtVEE98yEqSH9XqmKUs9 3yot7t6yapyBUqRxmz6sKh59pKB+J1q5svMihAX9BkJwa/BC5TRn3xH7sUWMMWKBlM mSJOMDo83XjooT0ElGcgMVQVMiOomdtvmuTfggBaGn8mtlW19fIc56coy6MYgdanRT AW/Wmn8mfjmvA== Date: Wed, 10 Jun 2026 21:39:54 +0300 From: Leon Romanovsky To: Matt Evans Cc: Alex Williamson , Jason Gunthorpe , Alex Mastro , Christian =?iso-8859-1?Q?K=F6nig?= , Bjorn Helgaas , Logan Gunthorpe , Mahmoud Adam , David Matlack , =?iso-8859-1?Q?Bj=F6rn_T=F6pel?= , Sumit Semwal , Kevin Tian , Ankit Agrawal , Pranjal Shrivastava , Alistair Popple , Vivek Kasireddy , linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, kvm@vger.kernel.org, linux-pci@vger.kernel.org Subject: Re: [PATCH v3 1/9] PCI/P2PDMA: Add CONFIG_PCI_P2PDMA_CORE Message-ID: <20260610183954.GK327369@unreal> References: <20260610154327.37758-1-matt@ozlabs.org> <20260610154327.37758-2-matt@ozlabs.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260610154327.37758-2-matt@ozlabs.org> 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 Wed, Jun 10, 2026 at 04:43:15PM +0100, Matt Evans wrote: > The P2PDMA code currently provides two features under the same > CONFIG_PCI_P2PDMA option: > > 1. Locate providers via pcim_p2pdma_provider() > 2. Manage actual P2P DMA > > Some drivers (such as vfio-pci) depend on 1, without having a hard > dependency on 2. > > A future commit expands the use of DMABUF in vfio-pci for non-P2P > scenarios, relying on pcim_p2pdma_provider() always being present. If > that depended on CONFIG_PCI_P2PDMA, it would make vfio-pci only > available if CONFIG_ZONE_DEVICE is present (e.g. 64-bit systems), even > when P2P is not needed. > > To resolve this, introduce CONFIG_PCI_P2PDMA_CORE and refactor the > basic provider functionality into a new p2pdma_core.c file. This is > available even if the CONFIG_PCI_P2PDMA feature is disabled (or > unavailable due to !CONFIG_ZONE_DEVICE). Then, drivers can enable any > additional P2P features with the original CONFIG_PCI_P2PDMA (available > when CONFIG_ZONE_DEVICE is set). > > Signed-off-by: Matt Evans > --- > MAINTAINERS | 2 +- > drivers/pci/Kconfig | 10 ++-- > drivers/pci/Makefile | 1 + > drivers/pci/p2pdma.c | 109 ++-------------------------------- > drivers/pci/p2pdma.h | 29 +++++++++ > drivers/pci/p2pdma_core.c | 118 +++++++++++++++++++++++++++++++++++++ > include/linux/pci-p2pdma.h | 24 ++++---- > include/linux/pci.h | 2 +- > 8 files changed, 174 insertions(+), 121 deletions(-) > create mode 100644 drivers/pci/p2pdma.h > create mode 100644 drivers/pci/p2pdma_core.c Thanks, Reviewed-by: Leon Romanovsky