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=-7.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 35674C433ED for ; Thu, 22 Apr 2021 08:20:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 021CD613C4 for ; Thu, 22 Apr 2021 08:20:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235245AbhDVIUk (ORCPT ); Thu, 22 Apr 2021 04:20:40 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:37694 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235379AbhDVIUe (ORCPT ); Thu, 22 Apr 2021 04:20:34 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619079574; 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=xHywtxI3pNGHCs9NAnF/msLigH9rjPmkvDS5057lzus=; b=ezgcRXJBhYP5LGUHi30bWG7jM6XZrPuSx+VHawkGAVjJOJg1SfxsDXHNtXZZXVO4m4azF5 8vJ0SIJA1FldOTUA+TcxPRUezBgxleL6E1VeSBPxC9hewjaxqwy/Q/ydmbdWaBBP799kPN Z01tkfPPrn4ENBE4HgaFJsHuDH58Dfk= 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-47-yyTTz9KuMi29o3s8dGVJbQ-1; Thu, 22 Apr 2021 04:19:30 -0400 X-MC-Unique: yyTTz9KuMi29o3s8dGVJbQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D5692107ACC7; Thu, 22 Apr 2021 08:19:28 +0000 (UTC) Received: from wangxiaodeMacBook-Air.local (ovpn-13-214.pek2.redhat.com [10.72.13.214]) by smtp.corp.redhat.com (Postfix) with ESMTP id 95228100AE2C; Thu, 22 Apr 2021 08:19:18 +0000 (UTC) Subject: Re: [RFC PATCH 0/7] Untrusted device support for virtio To: Christoph Hellwig Cc: mst@redhat.com, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, xieyongji@bytedance.com, stefanha@redhat.com, file@sect.tu-berlin.de, ashish.kalra@amd.com, martin.radev@aisec.fraunhofer.de, konrad.wilk@oracle.com, kvm@vger.kernel.org References: <20210421032117.5177-1-jasowang@redhat.com> <20210422063128.GB4176641@infradead.org> From: Jason Wang Message-ID: <0c61dcbb-ac5b-9815-a4a1-5f93ae640011@redhat.com> Date: Thu, 22 Apr 2021 16:19:16 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.9.1 MIME-Version: 1.0 In-Reply-To: <20210422063128.GB4176641@infradead.org> Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ÔÚ 2021/4/22 ÏÂÎç2:31, Christoph Hellwig дµÀ: > On Wed, Apr 21, 2021 at 11:21:10AM +0800, Jason Wang wrote: >> The behaivor for non DMA API is kept for minimizing the performance >> impact. > NAK. Everyone should be using the DMA API in a modern world. So > treating the DMA API path worse than the broken legacy path does not > make any sense whatsoever. I think the goal is not treat DMA API path worse than legacy. The issue is that the management layer should guarantee that ACCESS_PLATFORM is set so DMA API is guaranteed to be used by the driver. So I'm not sure how much value we can gain from trying to 'fix' the legacy path. But I can change the behavior of legacy path to match DMA API path. Thanks