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=-5.9 required=3.0 tests=BAYES_00, 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 BABA0C47092 for ; Tue, 1 Jun 2021 12:30:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9BF6461009 for ; Tue, 1 Jun 2021 12:30:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233698AbhFAMca (ORCPT ); Tue, 1 Jun 2021 08:32:30 -0400 Received: from mga17.intel.com ([192.55.52.151]:60719 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231219AbhFAMc2 (ORCPT ); Tue, 1 Jun 2021 08:32:28 -0400 IronPort-SDR: aVjDwVqi+d3RUg37IKw3LHd0pWMA70a4JVQMTICrzeeGrSx95i71zhNlezAAyEM6tFGO72EOGQ SNoEFnxJ+/OA== X-IronPort-AV: E=McAfee;i="6200,9189,10001"; a="183897135" X-IronPort-AV: E=Sophos;i="5.83,239,1616482800"; d="scan'208";a="183897135" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jun 2021 05:30:44 -0700 IronPort-SDR: pmRj6eQl7X0Fy7iIH1MbbbVkU0DGVu7qw6nbeDY/T4pbyT5C2VCpozjuvAh/HOtbhAPZWRXLJ7 5LEqbVipItug== X-IronPort-AV: E=Sophos;i="5.83,239,1616482800"; d="scan'208";a="479260607" Received: from blu2-mobl3.ccr.corp.intel.com (HELO [10.254.213.9]) ([10.254.213.9]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jun 2021 05:30:37 -0700 Cc: baolu.lu@linux.intel.com, Eric Auger , Jonathan Corbet , "Raj, Ashok" , "Liu, Yi L" , "Wu, Hao" , "Jiang, Dave" , Jacob Pan , Jean-Philippe Brucker , David Gibson , Kirti Wankhede , Robin Murphy , Zenghui Yu , "wanghaibin.wang@huawei.com" Subject: Re: [RFC] /dev/ioasid uAPI proposal To: Shenming Lu , "Tian, Kevin" , LKML , Joerg Roedel , Jason Gunthorpe , David Woodhouse , "iommu@lists.linux-foundation.org" , "kvm@vger.kernel.org" , "Alex Williamson (alex.williamson@redhat.com)" , Jason Wang References: From: Lu Baolu Message-ID: <01fe5034-42c8-6923-32f1-e287cc36bccc@linux.intel.com> Date: Tue, 1 Jun 2021 20:30:35 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/6/1 15:15, Shenming Lu wrote: > On 2021/6/1 13:10, Lu Baolu wrote: >> Hi Shenming, >> >> On 6/1/21 12:31 PM, Shenming Lu wrote: >>> On 2021/5/27 15:58, Tian, Kevin wrote: >>>> /dev/ioasid provides an unified interface for managing I/O page tables for >>>> devices assigned to userspace. Device passthrough frameworks (VFIO, vDPA, >>>> etc.) are expected to use this interface instead of creating their own logic to >>>> isolate untrusted device DMAs initiated by userspace. >>>> >>>> This proposal describes the uAPI of /dev/ioasid and also sample sequences >>>> with VFIO as example in typical usages. The driver-facing kernel API provided >>>> by the iommu layer is still TBD, which can be discussed after consensus is >>>> made on this uAPI. >>>> >>>> It's based on a lengthy discussion starting from here: >>>> https://lore.kernel.org/linux-iommu/20210330132830.GO2356281@nvidia.com/ >>>> >>>> It ends up to be a long writing due to many things to be summarized and >>>> non-trivial effort required to connect them into a complete proposal. >>>> Hope it provides a clean base to converge. >>>> >>> [..] >>> >>>> /* >>>>    * Page fault report and response >>>>    * >>>>    * This is TBD. Can be added after other parts are cleared up. Likely it >>>>    * will be a ring buffer shared between user/kernel, an eventfd to notify >>>>    * the user and an ioctl to complete the fault. >>>>    * >>>>    * The fault data is per I/O address space, i.e.: IOASID + faulting_addr >>>>    */ >>> Hi, >>> >>> It seems that the ioasid has different usage in different situation, it could >>> be directly used in the physical routing, or just a virtual handle that indicates >>> a page table or a vPASID table (such as the GPA address space, in the simple >>> passthrough case, the DMA input to IOMMU will just contain a Stream ID, no >>> Substream ID), right? >>> >>> And Baolu suggested that since one device might consume multiple page tables, >>> it's more reasonable to have one fault handler per page table. By this, do we >>> have to maintain such an ioasid info list in the IOMMU layer? >> As discussed earlier, the I/O page fault and cache invalidation paths >> will have "device labels" so that the information could be easily >> translated and routed. >> >> So it's likely the per-device fault handler registering API in iommu >> core can be kept, but /dev/ioasid will be grown with a layer to >> translate and propagate I/O page fault information to the right >> consumers. > Yeah, having a general preprocessing of the faults in IOASID seems to be > a doable direction. But since there may be more than one consumer at the > same time, who is responsible for registering the per-device fault handler? The drivers register per page table fault handlers to /dev/ioasid which will then register itself to iommu core to listen and route the per- device I/O page faults. This is just a top level thought. Haven't gone through the details yet. Need to wait and see what /dev/ioasid finally looks like. Best regards, baolu 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=-5.9 required=3.0 tests=BAYES_00, 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 83E5AC47080 for ; Tue, 1 Jun 2021 12:30:48 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 13922613B1 for ; Tue, 1 Jun 2021 12:30:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 13922613B1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id CF08840266; Tue, 1 Jun 2021 12:30:47 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id jorUu_TBBebw; Tue, 1 Jun 2021 12:30:47 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp2.osuosl.org (Postfix) with ESMTP id AC50D40004; Tue, 1 Jun 2021 12:30:46 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 8F3ECC000D; Tue, 1 Jun 2021 12:30:46 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 8D5D7C0001 for ; Tue, 1 Jun 2021 12:30:45 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 647844047A for ; Tue, 1 Jun 2021 12:30:45 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id SI4BskfDFT5G for ; Tue, 1 Jun 2021 12:30:44 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by smtp4.osuosl.org (Postfix) with ESMTPS id 331634045D for ; Tue, 1 Jun 2021 12:30:44 +0000 (UTC) IronPort-SDR: 6I1t2ld5Lz8g+S3ogo+NeC/SUGVkARjzbOAf41HVXiUG6S1zr+7LEuU2KeiuIpr4ptq53tQEoj kZDmaBrFDVZA== X-IronPort-AV: E=McAfee;i="6200,9189,10001"; a="203533455" X-IronPort-AV: E=Sophos;i="5.83,239,1616482800"; d="scan'208";a="203533455" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jun 2021 05:30:43 -0700 IronPort-SDR: pmRj6eQl7X0Fy7iIH1MbbbVkU0DGVu7qw6nbeDY/T4pbyT5C2VCpozjuvAh/HOtbhAPZWRXLJ7 5LEqbVipItug== X-IronPort-AV: E=Sophos;i="5.83,239,1616482800"; d="scan'208";a="479260607" Received: from blu2-mobl3.ccr.corp.intel.com (HELO [10.254.213.9]) ([10.254.213.9]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jun 2021 05:30:37 -0700 Subject: Re: [RFC] /dev/ioasid uAPI proposal To: Shenming Lu , "Tian, Kevin" , LKML , Joerg Roedel , Jason Gunthorpe , David Woodhouse , "iommu@lists.linux-foundation.org" , "kvm@vger.kernel.org" , "Alex Williamson (alex.williamson@redhat.com)" , Jason Wang References: From: Lu Baolu Message-ID: <01fe5034-42c8-6923-32f1-e287cc36bccc@linux.intel.com> Date: Tue, 1 Jun 2021 20:30:35 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US Cc: Jean-Philippe Brucker , "Jiang, Dave" , "Raj, Ashok" , Jonathan Corbet , Kirti Wankhede , David Gibson , "wanghaibin.wang@huawei.com" , Robin Murphy X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: base64 Content-Type: text/plain; charset="utf-8"; Format="flowed" Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" T24gMjAyMS82LzEgMTU6MTUsIFNoZW5taW5nIEx1IHdyb3RlOgo+IE9uIDIwMjEvNi8xIDEzOjEw LCBMdSBCYW9sdSB3cm90ZToKPj4gSGkgU2hlbm1pbmcsCj4+Cj4+IE9uIDYvMS8yMSAxMjozMSBQ TSwgU2hlbm1pbmcgTHUgd3JvdGU6Cj4+PiBPbiAyMDIxLzUvMjcgMTU6NTgsIFRpYW4sIEtldmlu IHdyb3RlOgo+Pj4+IC9kZXYvaW9hc2lkIHByb3ZpZGVzIGFuIHVuaWZpZWQgaW50ZXJmYWNlIGZv ciBtYW5hZ2luZyBJL08gcGFnZSB0YWJsZXMgZm9yCj4+Pj4gZGV2aWNlcyBhc3NpZ25lZCB0byB1 c2Vyc3BhY2UuIERldmljZSBwYXNzdGhyb3VnaCBmcmFtZXdvcmtzIChWRklPLCB2RFBBLAo+Pj4+ IGV0Yy4pIGFyZSBleHBlY3RlZCB0byB1c2UgdGhpcyBpbnRlcmZhY2UgaW5zdGVhZCBvZiBjcmVh dGluZyB0aGVpciBvd24gbG9naWMgdG8KPj4+PiBpc29sYXRlIHVudHJ1c3RlZCBkZXZpY2UgRE1B cyBpbml0aWF0ZWQgYnkgdXNlcnNwYWNlLgo+Pj4+Cj4+Pj4gVGhpcyBwcm9wb3NhbCBkZXNjcmli ZXMgdGhlIHVBUEkgb2YgL2Rldi9pb2FzaWQgYW5kIGFsc28gc2FtcGxlIHNlcXVlbmNlcwo+Pj4+ IHdpdGggVkZJTyBhcyBleGFtcGxlIGluIHR5cGljYWwgdXNhZ2VzLiBUaGUgZHJpdmVyLWZhY2lu ZyBrZXJuZWwgQVBJIHByb3ZpZGVkCj4+Pj4gYnkgdGhlIGlvbW11IGxheWVyIGlzIHN0aWxsIFRC RCwgd2hpY2ggY2FuIGJlIGRpc2N1c3NlZCBhZnRlciBjb25zZW5zdXMgaXMKPj4+PiBtYWRlIG9u IHRoaXMgdUFQSS4KPj4+Pgo+Pj4+IEl0J3MgYmFzZWQgb24gYSBsZW5ndGh5IGRpc2N1c3Npb24g c3RhcnRpbmcgZnJvbSBoZXJlOgo+Pj4+ICAgICAgaHR0cHM6Ly9sb3JlLmtlcm5lbC5vcmcvbGlu dXgtaW9tbXUvMjAyMTAzMzAxMzI4MzAuR08yMzU2MjgxQG52aWRpYS5jb20vCj4+Pj4KPj4+PiBJ dCBlbmRzIHVwIHRvIGJlIGEgbG9uZyB3cml0aW5nIGR1ZSB0byBtYW55IHRoaW5ncyB0byBiZSBz dW1tYXJpemVkIGFuZAo+Pj4+IG5vbi10cml2aWFsIGVmZm9ydCByZXF1aXJlZCB0byBjb25uZWN0 IHRoZW0gaW50byBhIGNvbXBsZXRlIHByb3Bvc2FsLgo+Pj4+IEhvcGUgaXQgcHJvdmlkZXMgYSBj bGVhbiBiYXNlIHRvIGNvbnZlcmdlLgo+Pj4+Cj4+PiBbLi5dCj4+Pgo+Pj4+IC8qCj4+Pj4gIMKg wqAgKiBQYWdlIGZhdWx0IHJlcG9ydCBhbmQgcmVzcG9uc2UKPj4+PiAgwqDCoCAqCj4+Pj4gIMKg wqAgKiBUaGlzIGlzIFRCRC4gQ2FuIGJlIGFkZGVkIGFmdGVyIG90aGVyIHBhcnRzIGFyZSBjbGVh cmVkIHVwLiBMaWtlbHkgaXQKPj4+PiAgwqDCoCAqIHdpbGwgYmUgYSByaW5nIGJ1ZmZlciBzaGFy ZWQgYmV0d2VlbiB1c2VyL2tlcm5lbCwgYW4gZXZlbnRmZCB0byBub3RpZnkKPj4+PiAgwqDCoCAq IHRoZSB1c2VyIGFuZCBhbiBpb2N0bCB0byBjb21wbGV0ZSB0aGUgZmF1bHQuCj4+Pj4gIMKgwqAg Kgo+Pj4+ICDCoMKgICogVGhlIGZhdWx0IGRhdGEgaXMgcGVyIEkvTyBhZGRyZXNzIHNwYWNlLCBp LmUuOiBJT0FTSUQgKyBmYXVsdGluZ19hZGRyCj4+Pj4gIMKgwqAgKi8KPj4+IEhpLAo+Pj4KPj4+ IEl0IHNlZW1zIHRoYXQgdGhlIGlvYXNpZCBoYXMgZGlmZmVyZW50IHVzYWdlIGluIGRpZmZlcmVu dCBzaXR1YXRpb24sIGl0IGNvdWxkCj4+PiBiZSBkaXJlY3RseSB1c2VkIGluIHRoZSBwaHlzaWNh bCByb3V0aW5nLCBvciBqdXN0IGEgdmlydHVhbCBoYW5kbGUgdGhhdCBpbmRpY2F0ZXMKPj4+IGEg cGFnZSB0YWJsZSBvciBhIHZQQVNJRCB0YWJsZSAoc3VjaCBhcyB0aGUgR1BBIGFkZHJlc3Mgc3Bh Y2UsIGluIHRoZSBzaW1wbGUKPj4+IHBhc3N0aHJvdWdoIGNhc2UsIHRoZSBETUEgaW5wdXQgdG8g SU9NTVUgd2lsbCBqdXN0IGNvbnRhaW4gYSBTdHJlYW0gSUQsIG5vCj4+PiBTdWJzdHJlYW0gSUQp LCByaWdodD8KPj4+Cj4+PiBBbmQgQmFvbHUgc3VnZ2VzdGVkIHRoYXQgc2luY2Ugb25lIGRldmlj ZSBtaWdodCBjb25zdW1lIG11bHRpcGxlIHBhZ2UgdGFibGVzLAo+Pj4gaXQncyBtb3JlIHJlYXNv bmFibGUgdG8gaGF2ZSBvbmUgZmF1bHQgaGFuZGxlciBwZXIgcGFnZSB0YWJsZS4gQnkgdGhpcywg ZG8gd2UKPj4+IGhhdmUgdG8gbWFpbnRhaW4gc3VjaCBhbiBpb2FzaWQgaW5mbyBsaXN0IGluIHRo ZSBJT01NVSBsYXllcj8KPj4gQXMgZGlzY3Vzc2VkIGVhcmxpZXIsIHRoZSBJL08gcGFnZSBmYXVs dCBhbmQgY2FjaGUgaW52YWxpZGF0aW9uIHBhdGhzCj4+IHdpbGwgaGF2ZSAiZGV2aWNlIGxhYmVs cyIgc28gdGhhdCB0aGUgaW5mb3JtYXRpb24gY291bGQgYmUgZWFzaWx5Cj4+IHRyYW5zbGF0ZWQg YW5kIHJvdXRlZC4KPj4KPj4gU28gaXQncyBsaWtlbHkgdGhlIHBlci1kZXZpY2UgZmF1bHQgaGFu ZGxlciByZWdpc3RlcmluZyBBUEkgaW4gaW9tbXUKPj4gY29yZSBjYW4gYmUga2VwdCwgYnV0IC9k ZXYvaW9hc2lkIHdpbGwgYmUgZ3Jvd24gd2l0aCBhIGxheWVyIHRvCj4+IHRyYW5zbGF0ZSBhbmQg cHJvcGFnYXRlIEkvTyBwYWdlIGZhdWx0IGluZm9ybWF0aW9uIHRvIHRoZSByaWdodAo+PiBjb25z dW1lcnMuCj4gWWVhaCwgaGF2aW5nIGEgZ2VuZXJhbCBwcmVwcm9jZXNzaW5nIG9mIHRoZSBmYXVs dHMgaW4gSU9BU0lEIHNlZW1zIHRvIGJlCj4gYSBkb2FibGUgZGlyZWN0aW9uLiBCdXQgc2luY2Ug dGhlcmUgbWF5IGJlIG1vcmUgdGhhbiBvbmUgY29uc3VtZXIgYXQgdGhlCj4gc2FtZSB0aW1lLCB3 aG8gaXMgcmVzcG9uc2libGUgZm9yIHJlZ2lzdGVyaW5nIHRoZSBwZXItZGV2aWNlIGZhdWx0IGhh bmRsZXI/CgpUaGUgZHJpdmVycyByZWdpc3RlciBwZXIgcGFnZSB0YWJsZSBmYXVsdCBoYW5kbGVy cyB0byAvZGV2L2lvYXNpZCB3aGljaAp3aWxsIHRoZW4gcmVnaXN0ZXIgaXRzZWxmIHRvIGlvbW11 IGNvcmUgdG8gbGlzdGVuIGFuZCByb3V0ZSB0aGUgcGVyLQpkZXZpY2UgSS9PIHBhZ2UgZmF1bHRz LiBUaGlzIGlzIGp1c3QgYSB0b3AgbGV2ZWwgdGhvdWdodC4gSGF2ZW4ndCBnb25lCnRocm91Z2gg dGhlIGRldGFpbHMgeWV0LiBOZWVkIHRvIHdhaXQgYW5kIHNlZSB3aGF0IC9kZXYvaW9hc2lkIGZp bmFsbHkKbG9va3MgbGlrZS4KCkJlc3QgcmVnYXJkcywKYmFvbHUKX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX18KaW9tbXUgbWFpbGluZyBsaXN0CmlvbW11QGxp c3RzLmxpbnV4LWZvdW5kYXRpb24ub3JnCmh0dHBzOi8vbGlzdHMubGludXhmb3VuZGF0aW9uLm9y Zy9tYWlsbWFuL2xpc3RpbmZvL2lvbW11