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=-11.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 AAEBFC433DF for ; Tue, 11 Aug 2020 02:53:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88E91206DA for ; Tue, 11 Aug 2020 02:53:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="BRjS9o/6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728168AbgHKCx1 (ORCPT ); Mon, 10 Aug 2020 22:53:27 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:23500 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726994AbgHKCx1 (ORCPT ); Mon, 10 Aug 2020 22:53:27 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1597114405; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=0Uybr7bUWG76B7NZzZpYoruROjuEoNEFed1mvtj7ELc=; b=BRjS9o/6wgVlyw0Fqpid5rLMrR/LIdlSXKBGyFWdjrUpUcC8O6CL0wHgyBxANTBZ+A0l9+ LBIz7UJAZd05kP0gi5TZoglMZjEqCAorTk6NkO8nrJT/BLbcKtpc2F4Kk37I6NHeGK3HrR vrXJ3dL8uV0PAOxhnPP4boT+wWYWUxQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-429-YzemLnq8NfGmYei6ueFNDw-1; Mon, 10 Aug 2020 22:53:21 -0400 X-MC-Unique: YzemLnq8NfGmYei6ueFNDw-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5979E1005504; Tue, 11 Aug 2020 02:53:19 +0000 (UTC) Received: from [10.72.13.186] (ovpn-13-186.pek2.redhat.com [10.72.13.186]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9D4AD61983; Tue, 11 Aug 2020 02:53:11 +0000 (UTC) Subject: Re: [PATCH 1/4] vdpa: introduce config op to get valid iova range To: "Michael S. Tsirkin" , Eli Cohen Cc: virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, rob.miller@broadcom.com, lingshan.zhu@intel.com, eperezma@redhat.com, lulu@redhat.com, shahafs@mellanox.com, hanand@xilinx.com, mhabets@solarflare.com, gdawar@xilinx.com, saugatm@xilinx.com, vmireyno@marvell.com, zhangweining@ruijie.com.cn References: <20200617032947.6371-1-jasowang@redhat.com> <20200617032947.6371-2-jasowang@redhat.com> <20200805085035-mutt-send-email-mst@kernel.org> <20200806120354.GA171218@mtl-vdi-166.wap.labs.mlnx> <20200806082727-mutt-send-email-mst@kernel.org> <20200806124354.GA172661@mtl-vdi-166.wap.labs.mlnx> <20200810080410-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: <2d1e6278-e57e-c340-399e-40ff102c74a3@redhat.com> Date: Tue, 11 Aug 2020 10:53:09 +0800 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: <20200810080410-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/8/10 下午8:05, Michael S. Tsirkin wrote: > On Thu, Aug 06, 2020 at 03:43:54PM +0300, Eli Cohen wrote: >> On Thu, Aug 06, 2020 at 08:29:22AM -0400, Michael S. Tsirkin wrote: >>> On Thu, Aug 06, 2020 at 03:03:55PM +0300, Eli Cohen wrote: >>>> On Wed, Aug 05, 2020 at 08:51:56AM -0400, Michael S. Tsirkin wrote: >>>>> On Wed, Jun 17, 2020 at 11:29:44AM +0800, Jason Wang wrote: >>>>>> This patch introduce a config op to get valid iova range from the vDPA >>>>>> device. >>>>>> >>>>>> Signed-off-by: Jason Wang >>>>>> --- >>>>>> include/linux/vdpa.h | 14 ++++++++++++++ >>>>>> 1 file changed, 14 insertions(+) >>>>>> >>>>>> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h >>>>>> index 239db794357c..b7633ed2500c 100644 >>>>>> --- a/include/linux/vdpa.h >>>>>> +++ b/include/linux/vdpa.h >>>>>> @@ -41,6 +41,16 @@ struct vdpa_device { >>>>>> unsigned int index; >>>>>> }; >>>>>> >>>>>> +/** >>>>>> + * vDPA IOVA range - the IOVA range support by the device >>>>>> + * @start: start of the IOVA range >>>>>> + * @end: end of the IOVA range >>>>>> + */ >>>>>> +struct vdpa_iova_range { >>>>>> + u64 start; >>>>>> + u64 end; >>>>>> +}; >>>>>> + >>>>> >>>>> This is ambiguous. Is end in the range or just behind it? >>>>> How about first/last? >>>> It is customary in the kernel to use start-end where end corresponds to >>>> the byte following the last in the range. See struct vm_area_struct >>>> vm_start and vm_end fields >>> Exactly my point: >>> >>> include/linux/mm_types.h: unsigned long vm_end; /* The first byte after our end address >>> >>> in this case Jason wants it to be the last byte, not one behind. >>> >>> >> Maybe start, size? Not ambiguous, and you don't need to do annoying >> calculations like size = last - start + 1 > Size has a bunch of issues: can overlap, can not cover the entire 64 bit > range. The requisite checks are arguably easier to get wrong than > getting the size if you need it. Yes, so do you still prefer first/last or just begin/end which is consistent with iommu_domain_geometry? Thanks >