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 3C79CC433E0 for ; Thu, 6 Aug 2020 03:27:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 139552245C for ; Thu, 6 Aug 2020 03:27:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="bcQw6mra" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730525AbgHFD1h (ORCPT ); Wed, 5 Aug 2020 23:27:37 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:25628 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730500AbgHFD1f (ORCPT ); Wed, 5 Aug 2020 23:27:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1596684454; 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=Yj1ihXQO2M1TsL9VeUKDmXbzc/ApdSgHZZHy2dOrKJk=; b=bcQw6mraHDsF+rsx9l6d783z9bp7TUCV220sotl2PexpvrFbKLjMCBTf2aqZLhAOblvFLc phgvIuZ7S4t2vRO8C84PwetDznfU2L7X89x+c0RVfNlfHgZn+rRsRjBGlbXaxc2eHknoAc gVeZKXfNg9p19+agnfR6PE6yLllkiBk= 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-346-EWkCYCeNMcm4t8G3QDakkQ-1; Wed, 05 Aug 2020 23:27:33 -0400 X-MC-Unique: EWkCYCeNMcm4t8G3QDakkQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4C0D1106B242; Thu, 6 Aug 2020 03:27:31 +0000 (UTC) Received: from [10.72.13.140] (ovpn-13-140.pek2.redhat.com [10.72.13.140]) by smtp.corp.redhat.com (Postfix) with ESMTP id E19EA19D81; Thu, 6 Aug 2020 03:27:17 +0000 (UTC) Subject: Re: [PATCH 3/4] vdpa: get_iova_range() is mandatory for device specific DMA translation To: "Michael S. Tsirkin" 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, eli@mellanox.com References: <20200617032947.6371-1-jasowang@redhat.com> <20200617032947.6371-4-jasowang@redhat.com> <20200805085217-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: Date: Thu, 6 Aug 2020 11:27:16 +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: <20200805085217-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 2.84 on 10.5.11.23 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/8/5 下午8:55, Michael S. Tsirkin wrote: > On Wed, Jun 17, 2020 at 11:29:46AM +0800, Jason Wang wrote: >> In order to let userspace work correctly, get_iova_range() is a must >> for the device that has its own DMA translation logic. > I guess you mean for a device. > > However in absence of ths op, I don't see what is wrong with just > assuming device can access any address. It's just for safe, if you want, we can assume any address without this op. > >> Signed-off-by: Jason Wang >> --- >> drivers/vdpa/vdpa.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c >> index de211ef3738c..ab7af978ef70 100644 >> --- a/drivers/vdpa/vdpa.c >> +++ b/drivers/vdpa/vdpa.c >> @@ -82,6 +82,10 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent, >> if (!!config->dma_map != !!config->dma_unmap) >> goto err; >> >> + if ((config->dma_map || config->set_map) && >> + !config->get_iova_range) >> + goto err; >> + >> err = -ENOMEM; >> vdev = kzalloc(size, GFP_KERNEL); >> if (!vdev) > What about devices using an IOMMU for translation? > IOMMUs generally have a limited IOVA range too, right? See patch 4 which query the IOMMU geometry in this case: +        iommu_domain_get_attr(v->domain, +                      DOMAIN_ATTR_GEOMETRY, &geo); +        range.start = geo.aperture_start; +        range.end = geo.aperture_end; Thanks > > > >> -- >> 2.20.1