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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 D3EDEC04EB9 for ; Thu, 6 Dec 2018 01:23:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A4AE520892 for ; Thu, 6 Dec 2018 01:23:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A4AE520892 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728331AbeLFBXG (ORCPT ); Wed, 5 Dec 2018 20:23:06 -0500 Received: from mga01.intel.com ([192.55.52.88]:1112 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727575AbeLFBXG (ORCPT ); Wed, 5 Dec 2018 20:23:06 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Dec 2018 17:23:05 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,320,1539673200"; d="scan'208";a="116393805" Received: from allen-box.sh.intel.com (HELO [10.239.161.122]) ([10.239.161.122]) by FMSMGA003.fm.intel.com with ESMTP; 05 Dec 2018 17:23:02 -0800 Cc: baolu.lu@linux.intel.com, "Liu, Yi L" , David Woodhouse , "Raj, Ashok" , "Kumar, Sanjay K" , "Pan, Jacob jun" , "Tian, Kevin" , "Sun, Yi Y" , "peterx@redhat.com" , Jean-Philippe Brucker , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" , Jacob Pan Subject: Re: [PATCH v5 04/12] iommu/vt-d: Add 256-bit invalidation descriptor support To: Joerg Roedel References: <20181128035449.10226-1-baolu.lu@linux.intel.com> <20181128035449.10226-5-baolu.lu@linux.intel.com> <20181203134856.lui4us4ejm4d5avz@8bytes.org> <3b0eadd2-b99f-98d6-594f-0419f0542789@linux.intel.com> <20181205155646.GD16835@8bytes.org> From: Lu Baolu Message-ID: Date: Thu, 6 Dec 2018 09:19:56 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181205155646.GD16835@8bytes.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Joerg, On 12/5/18 11:56 PM, Joerg Roedel wrote: > On Tue, Dec 04, 2018 at 02:13:31PM +0800, Lu Baolu wrote: >> The existing code uses GFP_ATOMIC, this patch only changes the size of >> the allocated desc_page. >> >> I don't think we really need GFP_ATOMIC here (and also for some other >> places). I will clean up them in a separated patch. > > Okay, thanks. > >>> In this patch, there is some code like the code below. It calculates >>> destination address of memcpy with qi->desc. If it's still struct qi_desc >>> pointer, the calculation result would be wrong. >>> >>> + memcpy(desc, qi->desc + (wait_index << shift), >>> + 1 << shift); >>> >>> The change of the calculation method is to support 128 bits invalidation >>> descriptors and 256 invalidation descriptors in this unified code logic. >>> >>> Also, the conversation between Baolu and me may help. >>> >>> https://lore.kernel.org/patchwork/patch/1006756/ >> >> Yes. We need to support different descriptor size. > > Okay, pointer arithmetic on void* isn't well defined in the C standard, > afaik. But it should work with GCC, so it's probably fine. > > Unrelated to this patch-set, the whole qi management code needs some > cleanups, it queues a sync after every command and has very tricky > locking. This patch-set further complicates matters there, so it is > probably time for a clean re-write of that part? Sure. I will start the cleanups(including the unnecessary ATOMIC page allocation) and submit them in a separated patch set after well tested. Best regards, Lu Baolu