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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CDBCBC77B71 for ; Tue, 25 Apr 2023 08:08:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233393AbjDYIIp (ORCPT ); Tue, 25 Apr 2023 04:08:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38706 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232203AbjDYIIo (ORCPT ); Tue, 25 Apr 2023 04:08:44 -0400 Received: from out30-113.freemail.mail.aliyun.com (out30-113.freemail.mail.aliyun.com [115.124.30.113]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 690EBA2; Tue, 25 Apr 2023 01:08:42 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R181e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045176;MF=xuanzhuo@linux.alibaba.com;NM=1;PH=DS;RN=13;SR=0;TI=SMTPD_---0VgzLxx7_1682410117; Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0VgzLxx7_1682410117) by smtp.aliyun-inc.com; Tue, 25 Apr 2023 16:08:38 +0800 Message-ID: <1682409903.8734658-2-xuanzhuo@linux.alibaba.com> Subject: Re: [PATCH vhost v7 00/11] virtio core prepares for AF_XDP Date: Tue, 25 Apr 2023 16:05:03 +0800 From: Xuan Zhuo To: "Michael S. Tsirkin" Cc: virtualization@lists.linux-foundation.org, Jason Wang , Alexei Starovoitov , Daniel Borkmann , "David S. Miller" , Jesper Dangaard Brouer , John Fastabend , netdev@vger.kernel.org, bpf@vger.kernel.org, Christoph Hellwig , Jakub Kicinski , Alexander Lobakin References: <20230425073613.8839-1-xuanzhuo@linux.alibaba.com> <20230425034700-mutt-send-email-mst@kernel.org> In-Reply-To: <20230425034700-mutt-send-email-mst@kernel.org> Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Tue, 25 Apr 2023 03:51:47 -0400, "Michael S. Tsirkin" wrote: > On Tue, Apr 25, 2023 at 03:36:02PM +0800, Xuan Zhuo wrote: > > ## About DMA APIs > > > > Now, virtio may can not work with DMA APIs when virtio features do not have > > VIRTIO_F_ACCESS_PLATFORM. > > > > 1. I tried to let DMA APIs return phy address by virtio-device. But DMA APIs just > > work with the "real" devices. > > 2. I tried to let xsk support callballs to get phy address from virtio-net > > driver as the dma address. But the maintainers of xsk may want to use dma-buf > > to replace the DMA APIs. I think that may be a larger effort. We will wait > > too long. > > > > So rethinking this, firstly, we can support premapped-dma only for devices with > > VIRTIO_F_ACCESS_PLATFORM. In the case of af-xdp, if the users want to use it, > > they have to update the device to support VIRTIO_F_RING_RESET, and they can also > > enable the device's VIRTIO_F_ACCESS_PLATFORM feature by the way. > > I don't understand this last sentence. If you think ring > reset can change device features then the answer is no, it can't. Sorry, I should remove "by the way". > > If you are saying device has to set VIRTIO_F_ACCESS_PLATFORM to > benefit from this work, that's fine at least as a first approach. > Note that setting VIRTIO_F_ACCESS_PLATFORM breaks old guests > (it's a secirity boundary), e.g. it is not available for > transitional devices. > So to support transitional devices, we might want to find another way to > address this down the road, Maybe dma-buf is a way. I'll look into it, especially some practice on xsk. > but as a first step, I agree just going with > DMA is fine. Thanks. > > > > Thanks for the help from Christoph. > > > > ================= > > > > XDP socket(AF_XDP) is an excellent bypass kernel network framework. The zero > > copy feature of xsk (XDP socket) needs to be supported by the driver. The > > performance of zero copy is very good. > > > > ENV: Qemu with vhost. > > > > vhost cpu | Guest APP CPU |Guest Softirq CPU | PPS > > -----------------------------|---------------|------------------|------------ > > xmit by sockperf: 90% | 100% | | 318967 > > xmit by xsk: 100% | 30% | 33% | 1192064 > > recv by sockperf: 100% | 68% | 100% | 692288 > > recv by xsk: 100% | 33% | 43% | 771670 > > > > Before achieving the function of Virtio-Net, we also have to let virtio core > > support these features: > > > > 1. virtio core support premapped > > 2. virtio core support reset per-queue > > 3. introduce DMA APIs to virtio core > > > > Please review. > > > > Thanks. > > > > v7: > > 1. virtqueue_dma_dev() return NULL when virtio is without DMA API. > > > > v6: > > 1. change the size of the flags to u32. > > > > v5: > > 1. fix for error handler > > 2. add flags to record internal dma mapping > > > > v4: > > 1. rename map_inter to dma_map_internal > > 2. fix: Excess function parameter 'vq' description in 'virtqueue_dma_dev' > > > > v3: > > 1. add map_inter to struct desc state to reocrd whether virtio core do dma map > > > > v2: > > 1. based on sgs[0]->dma_address to judgment is premapped > > 2. based on extra.addr to judgment to do unmap for no-indirect desc > > 3. based on indir_desc to judgment to do unmap for indirect desc > > 4. rename virtqueue_get_dma_dev to virtqueue_dma_dev > > > > v1: > > 1. expose dma device. NO introduce the api for dma and sync > > 2. split some commit for review. > > > > Xuan Zhuo (11): > > virtio_ring: split: separate dma codes > > virtio_ring: packed: separate dma codes > > virtio_ring: packed-indirect: separate dma codes > > virtio_ring: split: support premapped > > virtio_ring: packed: support premapped > > virtio_ring: packed-indirect: support premapped > > virtio_ring: update document for virtqueue_add_* > > virtio_ring: introduce virtqueue_dma_dev() > > virtio_ring: correct the expression of the description of > > virtqueue_resize() > > virtio_ring: separate the logic of reset/enable from virtqueue_resize > > virtio_ring: introduce virtqueue_reset() > > > > drivers/virtio/virtio_ring.c | 352 +++++++++++++++++++++++++---------- > > include/linux/virtio.h | 4 + > > 2 files changed, 259 insertions(+), 97 deletions(-) > > > > -- > > 2.32.0.3.g01195cf9f > 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 Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9141EC77B61 for ; Tue, 25 Apr 2023 08:09:07 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 2E82760D4C; Tue, 25 Apr 2023 08:09:07 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp3.osuosl.org 2E82760D4C X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id mhecF3Gf6bcA; Tue, 25 Apr 2023 08:09:05 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp3.osuosl.org (Postfix) with ESMTPS id 12E8660739; Tue, 25 Apr 2023 08:09:05 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp3.osuosl.org 12E8660739 Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id EB50AC0036; Tue, 25 Apr 2023 08:09:04 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id EC55DC002A for ; Tue, 25 Apr 2023 08:09:03 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id B449B60AE4 for ; Tue, 25 Apr 2023 08:09:03 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp3.osuosl.org B449B60AE4 X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id E3g6xH7toSCa for ; Tue, 25 Apr 2023 08:09:03 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp3.osuosl.org 9F6DC60739 Received: from out30-101.freemail.mail.aliyun.com (out30-101.freemail.mail.aliyun.com [115.124.30.101]) by smtp3.osuosl.org (Postfix) with ESMTPS id 9F6DC60739 for ; Tue, 25 Apr 2023 08:09:00 +0000 (UTC) X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R181e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=ay29a033018045176; MF=xuanzhuo@linux.alibaba.com; NM=1; PH=DS; RN=13; SR=0; TI=SMTPD_---0VgzLxx7_1682410117; Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0VgzLxx7_1682410117) by smtp.aliyun-inc.com; Tue, 25 Apr 2023 16:08:38 +0800 Message-ID: <1682409903.8734658-2-xuanzhuo@linux.alibaba.com> Subject: Re: [PATCH vhost v7 00/11] virtio core prepares for AF_XDP Date: Tue, 25 Apr 2023 16:05:03 +0800 From: Xuan Zhuo To: "Michael S. Tsirkin" References: <20230425073613.8839-1-xuanzhuo@linux.alibaba.com> <20230425034700-mutt-send-email-mst@kernel.org> In-Reply-To: <20230425034700-mutt-send-email-mst@kernel.org> Cc: Jesper Dangaard Brouer , Daniel Borkmann , netdev@vger.kernel.org, John Fastabend , Alexei Starovoitov , virtualization@lists.linux-foundation.org, Christoph Hellwig , Alexander Lobakin , Jakub Kicinski , bpf@vger.kernel.org, "David S. Miller" X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" On Tue, 25 Apr 2023 03:51:47 -0400, "Michael S. Tsirkin" wrote: > On Tue, Apr 25, 2023 at 03:36:02PM +0800, Xuan Zhuo wrote: > > ## About DMA APIs > > > > Now, virtio may can not work with DMA APIs when virtio features do not have > > VIRTIO_F_ACCESS_PLATFORM. > > > > 1. I tried to let DMA APIs return phy address by virtio-device. But DMA APIs just > > work with the "real" devices. > > 2. I tried to let xsk support callballs to get phy address from virtio-net > > driver as the dma address. But the maintainers of xsk may want to use dma-buf > > to replace the DMA APIs. I think that may be a larger effort. We will wait > > too long. > > > > So rethinking this, firstly, we can support premapped-dma only for devices with > > VIRTIO_F_ACCESS_PLATFORM. In the case of af-xdp, if the users want to use it, > > they have to update the device to support VIRTIO_F_RING_RESET, and they can also > > enable the device's VIRTIO_F_ACCESS_PLATFORM feature by the way. > > I don't understand this last sentence. If you think ring > reset can change device features then the answer is no, it can't. Sorry, I should remove "by the way". > > If you are saying device has to set VIRTIO_F_ACCESS_PLATFORM to > benefit from this work, that's fine at least as a first approach. > Note that setting VIRTIO_F_ACCESS_PLATFORM breaks old guests > (it's a secirity boundary), e.g. it is not available for > transitional devices. > So to support transitional devices, we might want to find another way to > address this down the road, Maybe dma-buf is a way. I'll look into it, especially some practice on xsk. > but as a first step, I agree just going with > DMA is fine. Thanks. > > > > Thanks for the help from Christoph. > > > > ================= > > > > XDP socket(AF_XDP) is an excellent bypass kernel network framework. The zero > > copy feature of xsk (XDP socket) needs to be supported by the driver. The > > performance of zero copy is very good. > > > > ENV: Qemu with vhost. > > > > vhost cpu | Guest APP CPU |Guest Softirq CPU | PPS > > -----------------------------|---------------|------------------|------------ > > xmit by sockperf: 90% | 100% | | 318967 > > xmit by xsk: 100% | 30% | 33% | 1192064 > > recv by sockperf: 100% | 68% | 100% | 692288 > > recv by xsk: 100% | 33% | 43% | 771670 > > > > Before achieving the function of Virtio-Net, we also have to let virtio core > > support these features: > > > > 1. virtio core support premapped > > 2. virtio core support reset per-queue > > 3. introduce DMA APIs to virtio core > > > > Please review. > > > > Thanks. > > > > v7: > > 1. virtqueue_dma_dev() return NULL when virtio is without DMA API. > > > > v6: > > 1. change the size of the flags to u32. > > > > v5: > > 1. fix for error handler > > 2. add flags to record internal dma mapping > > > > v4: > > 1. rename map_inter to dma_map_internal > > 2. fix: Excess function parameter 'vq' description in 'virtqueue_dma_dev' > > > > v3: > > 1. add map_inter to struct desc state to reocrd whether virtio core do dma map > > > > v2: > > 1. based on sgs[0]->dma_address to judgment is premapped > > 2. based on extra.addr to judgment to do unmap for no-indirect desc > > 3. based on indir_desc to judgment to do unmap for indirect desc > > 4. rename virtqueue_get_dma_dev to virtqueue_dma_dev > > > > v1: > > 1. expose dma device. NO introduce the api for dma and sync > > 2. split some commit for review. > > > > Xuan Zhuo (11): > > virtio_ring: split: separate dma codes > > virtio_ring: packed: separate dma codes > > virtio_ring: packed-indirect: separate dma codes > > virtio_ring: split: support premapped > > virtio_ring: packed: support premapped > > virtio_ring: packed-indirect: support premapped > > virtio_ring: update document for virtqueue_add_* > > virtio_ring: introduce virtqueue_dma_dev() > > virtio_ring: correct the expression of the description of > > virtqueue_resize() > > virtio_ring: separate the logic of reset/enable from virtqueue_resize > > virtio_ring: introduce virtqueue_reset() > > > > drivers/virtio/virtio_ring.c | 352 +++++++++++++++++++++++++---------- > > include/linux/virtio.h | 4 + > > 2 files changed, 259 insertions(+), 97 deletions(-) > > > > -- > > 2.32.0.3.g01195cf9f > _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization