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 BA97CC88E53 for ; Tue, 15 Sep 2026 13:37:36 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 21E8D10E2EC; Tue, 15 Sep 2026 13:37:36 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="RvFjMZIS"; 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 5094F10E2EC for ; Tue, 15 Sep 2026 13:37:34 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 1007143CAF; Tue, 15 Sep 2026 13:37:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 439941F00893; Tue, 15 Sep 2026 13:37:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789479453; bh=BM51LqCTQKkxQjHuUWYfXlc+A3jyZ7CPDkL+FFiZnQU=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=RvFjMZISrAofoxatI3txRLvKezud9CwyRisHK6u/f7qV4yUT2+fhG50Licn4tOFTn aUpbIemAcM0nYY73vFMmlmR1G3bd+rt/EKqZZnRrCEtiulHGzVYlo1mfwJKw5wEt1L veYt//N/IyOSrGXAkw1MeTdTZ2AM54UXpTGiPVffI88yWhxPkdAceI85FeCNds2r4u sMz8bBUFz776GaC6PwE+AI/nJ0iZQZZSS6dOKyITBPk7GK5hUpSLwFzs/e94djAAI5 B1VOzp9xLYXS5P36Ut/yF0LzCU8F2BPhT15C5ehGRRkZgEiLj+ihYaoD/RGFGUzvdG Nl076XXX2qyeQ== Date: Tue, 15 Sep 2026 16:37:29 +0300 From: Leon Romanovsky To: Christian =?iso-8859-1?Q?K=F6nig?= Cc: Zhiping Zhang , kvm@vger.kernel.org, linux-rdma@vger.kernel.org, linux-pci@vger.kernel.org, dri-devel@lists.freedesktop.org, Bjorn Helgaas , Alex Williamson , Jason Gunthorpe Subject: Re: [PATCH v13 0/5] vfio/dma-buf: add TPH support for peer-to-peer access - ping Message-ID: <20260915133729.GO13683@unreal> References: <20260731211601.3033906-1-zhipingz@meta.com> <20260915113752.GK13683@unreal> <92950084-ddd1-4868-a81a-bfe214184122@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <92950084-ddd1-4868-a81a-bfe214184122@amd.com> 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, Sep 15, 2026 at 02:59:43PM +0200, Christian König wrote: > On 9/15/26 13:37, Leon Romanovsky wrote: > > On Fri, Sep 11, 2026 at 09:58:28AM +0200, Christian König wrote: > >> Hi Zhiping, > >> > >> sorry I'm completely underwater at the moment and don't have time to take another look at the full set. > >> > >> But IIRC you already fixed my documentation requirements and skimming over the patch once more I can't see anything wrong of hand. > >> > >> So feel free to add Acked-by: Christian König to patch "dma-buf: add optional get_pci_tph() callback" and push it upstream through the VFIO channels. > > > > Christian, > > > > I'm slightly confused here. In the other thread, you expressed concerns > > about having PCI details common to every device in the P2P world in the > > dma-buf code, but here you seem fine with adding a niche P2P feature. > > That one is only using u16 and u8 types and has no dependency on the PCI subsystem whatsoever. > > Giving those adjacent information sounds perfectly fine to me, we just can't have any hard dependency on PCI subsystem types or functions. > > DMA-buf itself is massively used with vendor specific P2P interconnects, PCI P2P is just a special case of that. You are looking at it from the DRM perspective. Outside the DRM world, PCI is THE interconnect, everything else is a special case :). Thanks > > Regards, > Christian. > > > > > Thanks,