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=-7.5 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 F0FD3C48BCD for ; Thu, 10 Jun 2021 02:00:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D624C6140F for ; Thu, 10 Jun 2021 02:00:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229797AbhFJCCJ (ORCPT ); Wed, 9 Jun 2021 22:02:09 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:45207 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229507AbhFJCCG (ORCPT ); Wed, 9 Jun 2021 22:02:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623290410; 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=+xQmp7fuwVh279E0Cth1KC9j6h3TM0sEtu/caMbRU18=; b=a5+CDxhG0+JHuvNib3mWW+zJ/qdjIWa+q9d+Rzw3uOOnUR5fhwZm31ZrvawGxyIjKcpc1q Ysx7FvqPcC8sGd8QZYqjVDi+1UVcNfeQ2V+eS7L74WbDxFkvYPW9gp7PUD7y6bjiPUHOd9 se3AzCL84qRvihJctxIXTDpLv3GbNxg= Received: from mail-pl1-f200.google.com (mail-pl1-f200.google.com [209.85.214.200]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-71-0SSlX-9rNmCA8gMV9b-NqA-1; Wed, 09 Jun 2021 22:00:08 -0400 X-MC-Unique: 0SSlX-9rNmCA8gMV9b-NqA-1 Received: by mail-pl1-f200.google.com with SMTP id d18-20020a170902b712b029010f71d164c6so167027pls.19 for ; Wed, 09 Jun 2021 19:00:08 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=+xQmp7fuwVh279E0Cth1KC9j6h3TM0sEtu/caMbRU18=; b=s505Rhq4GqC+ubdEsQrL4TBv1/PwOD9k1+hT4QZk+LPcVdG/Ib3ew46mBVCkLhoIla P7nvct/1vYysr+qWBNNW3unIoWClc4zqXHeQU5pTlRyBZyMQ79kfODPJplQM0XPMFvzr T7BBDvr78L+ArU2Dp0vcDcl1uEbDZFhJzRh35cFsx74aMH7zygHBCQFhWjfCWtc7B40N DOmBwweKuE/rzaGqrgUEgxiOm4f9fJh7DA0k07/G9VefjoDxrX8CTCrvGMNaY6/Y++vt 5QtJVRUOv8mLFE6+5qs0Q5fimmH/sQSsWaqG36R6rgGI7/jKGz/oMO7wUggE0ybU67XH EmBw== X-Gm-Message-State: AOAM533ThRkivGCUTQAKuFDMcj0gOkisrftI8zydKmwuoa1hBliUnLmk WqayBEd/z6wlq7YOr67rlcNVQ+TwLZKv9Q1LEG9w0SDukxM6aCQZT7/PP4ScSknQOXZMbMwEmuO 6y/geeviMFAiZ2UUikl69ToAZ X-Received: by 2002:a17:90a:2f22:: with SMTP id s31mr743837pjd.62.1623290407727; Wed, 09 Jun 2021 19:00:07 -0700 (PDT) X-Google-Smtp-Source: ABdhPJw65n4JwUpdZlyhZQm9k41Hm7KYINbBHKELAjIO4WceQeGIBYZlAZLwBtr5XPeJivWvj8g7kQ== X-Received: by 2002:a17:90a:2f22:: with SMTP id s31mr743805pjd.62.1623290407512; Wed, 09 Jun 2021 19:00:07 -0700 (PDT) Received: from wangxiaodeMacBook-Air.local ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id 11sm884327pge.57.2021.06.09.19.00.03 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 09 Jun 2021 19:00:06 -0700 (PDT) Subject: Re: [RFC] /dev/ioasid uAPI proposal To: Jason Gunthorpe Cc: "Tian, Kevin" , Lu Baolu , Liu Yi L , "kvm@vger.kernel.org" , Jonathan Corbet , "iommu@lists.linux-foundation.org" , LKML , "Alex Williamson (alex.williamson@redhat.com)\"\"" , David Woodhouse References: <64898584-a482-e6ac-fd71-23549368c508@linux.intel.com> <429d9c2f-3597-eb29-7764-fad3ec9a934f@redhat.com> <05d7f790-870d-5551-1ced-86926a0aa1a6@redhat.com> <42a71462-1abc-0404-156c-60a7ee1ad333@redhat.com> <20210601173138.GM1002214@nvidia.com> <20210602172154.GC1002214@nvidia.com> <20210608132039.GG1002214@nvidia.com> From: Jason Wang Message-ID: Date: Thu, 10 Jun 2021 10:00:01 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210608132039.GG1002214@nvidia.com> Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ÔÚ 2021/6/8 ÏÂÎç9:20, Jason Gunthorpe дµÀ: > On Tue, Jun 08, 2021 at 09:10:42AM +0800, Jason Wang wrote: > >> Well, this sounds like a re-invention of io_uring which has already worked >> for multifds. > How so? io_uring is about sending work to the kernel, not getting > structued events back? Actually it can. Userspace can poll multiple fds via preparing multiple sqes with IORING_OP_ADD flag. > > It is more like one of the perf rings This means another ring and we need introduce ioctl() to add or remove ioasids from the poll. And it still need a kind of fallback like a list if the ring is full. Thanks > > Jason >