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 X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB56AC433E1 for ; Fri, 24 Jul 2020 15:56:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 899B62064B for ; Fri, 24 Jul 2020 15:56:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=deltatee.com header.i=@deltatee.com header.b="AdBphzVb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726719AbgGXP4z (ORCPT ); Fri, 24 Jul 2020 11:56:55 -0400 Received: from ale.deltatee.com ([204.191.154.188]:57556 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726381AbgGXP4y (ORCPT ); Fri, 24 Jul 2020 11:56:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=deltatee.com; s=20200525; h=Subject:Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Sender: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=gzDjJxP9G6lKPkDmU/12OxkP6YbdMfMKBEA31jhMTgI=; b=AdBphzVboE8kYWs2/6XvZ2V2UZ wlWyWzVkuSx+ERgBGrUCcdoVM9TfNB3Sw0dZnGl3o3bCX4JbOnZ1C64zG/+JrxG9fOp9W5Zl9Eyji zwQRdjKs8Au9B0ps8YbHEUhtKmYzFHz47KdKU63JInLIgZAVz2mZJ28oJ5jdDuxvCwvwJP0C7iUR3 CI1wSC96IxbypIEr1pLc0h6xgzLZ8EuwwAJhv4tIUmV7VoPdv2bztHeW4MlW2et/zpiF8gegIc+Yo Wa2dCUKTKd6fa2ld4ivneWflQxFW9wp5wOqoG1Og3dW1q5X9kQHAGNB3RRFyUp2/kLq+xALf4s5Tt ZvwGB+sA==; Received: from s01060023bee90a7d.cg.shawcable.net ([24.64.145.4] helo=[192.168.0.10]) by ale.deltatee.com with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1jz03u-0005Br-F1; Fri, 24 Jul 2020 09:56:43 -0600 To: Bjorn Helgaas Cc: Alex Deucher , LKML , Linux PCI , Bjorn Helgaas , =?UTF-8?Q?Christian_K=c3=b6nig?= , Huang Rui , Andrew Maier , "H. Peter Anvin" , Jonathan Cameron References: <20200724150641.GA1518875@bjorn-Precision-5520> From: Logan Gunthorpe Message-ID: <59b68da4-cd3c-bf65-6654-02d4feaede27@deltatee.com> Date: Fri, 24 Jul 2020 09:56:39 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200724150641.GA1518875@bjorn-Precision-5520> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 24.64.145.4 X-SA-Exim-Rcpt-To: jonathan.cameron@huawei.com, hpa@zytor.com, andrew.maier@eideticom.com, ray.huang@amd.com, christian.koenig@amd.com, bhelgaas@google.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, alexdeucher@gmail.com, helgaas@kernel.org X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH] PCI/P2PDMA: Add AMD Zen 2 root complex to the list of allowed bridges X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [+cc Jonathan] On 2020-07-24 9:06 a.m., Bjorn Helgaas wrote: > On Thu, Jul 23, 2020 at 02:10:52PM -0600, Logan Gunthorpe wrote: >> On 2020-07-23 1:57 p.m., Bjorn Helgaas wrote: >>> On Thu, Jul 23, 2020 at 02:01:17PM -0400, Alex Deucher wrote: >>>> On Thu, Jul 23, 2020 at 1:43 PM Logan Gunthorpe wrote: >>>>> >>>>> The AMD Zen 2 root complex (Starship/Matisse) was tested for P2PDMA >>>>> transactions between root ports and found to work. Therefore add it >>>>> to the list. >>>>> >>>>> Signed-off-by: Logan Gunthorpe >>>>> Cc: Bjorn Helgaas >>>>> Cc: Christian König >>>>> Cc: Huang Rui >>>>> Cc: Alex Deucher >>>> >>>> Starting with Zen, all AMD platforms support P2P for reads and writes. >>> >>> What's the plan for getting out of the cycle of "update this list for >>> every new chip"? Any new _DSMs planned, for instance? >> >> Well there was an effort to add capabilities in the PCI spec to describe >> this but, as far as I know, they never got anywhere, and hardware still >> doesn't self describe with this. > > Any idea what happened? Is there hope for the future? I'm really not > happy about signing up for open-ended device-specific patches like > this. It's certainly not in the plug and play spirit that has made > PCI successful. I know, preaching to the choir here. Agreed, though I'm not really hooked into the PCI SIG. The last email I got about this was an RFC from Jonathan Cameron in late 2018. I've CC'd him here, maybe he'll have a bit more insight. Logan