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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,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 6F02FC433DF for ; Mon, 29 Jun 2020 19:30:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 44DD720663 for ; Mon, 29 Jun 2020 19:30:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="QZlxROUU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732808AbgF2TaI (ORCPT ); Mon, 29 Jun 2020 15:30:08 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:29392 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729266AbgF2TaE (ORCPT ); Mon, 29 Jun 2020 15:30:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593459002; 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=VTBCMk9G4XAJKBAXCLARkHS+UIPi+qyk4DaOQIxioJ0=; b=QZlxROUU1wgv/VdWfomVQPBihwFCZD9Z49tYplSFDRzJQjLn8ErRMKMNbO8CrMrw7Q/+on gOqTWuYzCcz1HnX7NxVt8p08MgdSdA51daYsC47jRYMEyetUGqVIMVolmiM/A0Vxfs1VpM WOg514z2HQMOozMxpjPm/nKUOV/rq9M= 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-321-wYp5EyKcP4qIXcC_HjmluA-1; Mon, 29 Jun 2020 05:26:17 -0400 X-MC-Unique: wYp5EyKcP4qIXcC_HjmluA-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 75543107ACCA; Mon, 29 Jun 2020 09:26:15 +0000 (UTC) Received: from [10.72.12.64] (ovpn-12-64.pek2.redhat.com [10.72.12.64]) by smtp.corp.redhat.com (Postfix) with ESMTP id 00A1110013C1; Mon, 29 Jun 2020 09:26:04 +0000 (UTC) Subject: Re: [PATCH RFC 4/5] vhost-vdpa: support IOTLB batching hints 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: <20200618055626.25660-1-jasowang@redhat.com> <20200618055626.25660-5-jasowang@redhat.com> <20200628054940-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: Date: Mon, 29 Jun 2020 17:26:03 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200628054940-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 10.5.11.22 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/6/28 下午5:58, Michael S. Tsirkin wrote: > On Thu, Jun 18, 2020 at 01:56:25PM +0800, Jason Wang wrote: >> This patches extend the vhost IOTLB API to accept batch updating hints >> form userspace. When userspace wants update the device IOTLB in a >> batch, it may do: >> >> 1) Write vhost_iotlb_msg with VHOST_IOTLB_BATCH_BEGIN flag >> 2) Perform a batch of IOTLB updating via VHOST_IOTLB_UPDATE/INVALIDATE >> 3) Write vhost_iotlb_msg with VHOST_IOTLB_BATCH_END flag > As long as we are extending the interface, > is there some way we could cut down the number of system calls needed > here? I'm not sure it's worth to do that since usually we only have less than 10 regions. A possible method is to carry multiple vhost_iotlb_message in one system call. > > >> Vhost-vdpa may decide to batch the IOMMU/IOTLB updating in step 3 when >> vDPA device support set_map() ops. This is useful for the vDPA device >> that want to know all the mappings to tweak their own DMA translation >> logic. >> >> For vDPA device that doesn't require set_map(), no behavior changes. >> >> This capability is advertised via VHOST_BACKEND_F_IOTLB_BATCH capability. >> >> Signed-off-by: Jason Wang >> --- >> drivers/vhost/vdpa.c | 30 +++++++++++++++++++++++------- >> include/uapi/linux/vhost.h | 2 ++ >> include/uapi/linux/vhost_types.h | 7 +++++++ >> 3 files changed, 32 insertions(+), 7 deletions(-) >> >> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c >> index 453057421f80..8f624bbafee7 100644 >> --- a/drivers/vhost/vdpa.c >> +++ b/drivers/vhost/vdpa.c >> @@ -56,7 +56,9 @@ enum { >> }; >> >> enum { >> - VHOST_VDPA_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2) >> + VHOST_VDPA_BACKEND_FEATURES = >> + (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2) | >> + (1ULL << VHOST_BACKEND_F_IOTLB_BATCH), >> }; >> >> /* Currently, only network backend w/o multiqueue is supported. */ >> @@ -77,6 +79,7 @@ struct vhost_vdpa { >> int virtio_id; >> int minor; >> struct eventfd_ctx *config_ctx; >> + int in_batch; >> }; >> >> static DEFINE_IDA(vhost_vdpa_ida); >> @@ -125,6 +128,7 @@ static void vhost_vdpa_reset(struct vhost_vdpa *v) >> const struct vdpa_config_ops *ops = vdpa->config; >> >> ops->set_status(vdpa, 0); >> + v->in_batch = 0; >> } >> >> static long vhost_vdpa_get_device_id(struct vhost_vdpa *v, u8 __user *argp) >> @@ -540,9 +544,10 @@ static int vhost_vdpa_map(struct vhost_vdpa *v, >> >> if (ops->dma_map) >> r = ops->dma_map(vdpa, iova, size, pa, perm); >> - else if (ops->set_map) >> - r = ops->set_map(vdpa, dev->iotlb); >> - else >> + else if (ops->set_map) { >> + if (!v->in_batch) >> + r = ops->set_map(vdpa, dev->iotlb); >> + } else >> r = iommu_map(v->domain, iova, pa, size, >> perm_to_iommu_flags(perm)); >> >> @@ -559,9 +564,10 @@ static void vhost_vdpa_unmap(struct vhost_vdpa *v, u64 iova, u64 size) >> >> if (ops->dma_map) >> ops->dma_unmap(vdpa, iova, size); >> - else if (ops->set_map) >> - ops->set_map(vdpa, dev->iotlb); >> - else >> + else if (ops->set_map) { >> + if (!v->in_batch) >> + ops->set_map(vdpa, dev->iotlb); >> + } else >> iommu_unmap(v->domain, iova, size); >> } >> >> @@ -655,6 +661,8 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev, >> struct vhost_iotlb_msg *msg) >> { >> struct vhost_vdpa *v = container_of(dev, struct vhost_vdpa, vdev); >> + struct vdpa_device *vdpa = v->vdpa; >> + const struct vdpa_config_ops *ops = vdpa->config; >> int r = 0; >> >> r = vhost_dev_check_owner(dev); >> @@ -668,6 +676,14 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev, >> case VHOST_IOTLB_INVALIDATE: >> vhost_vdpa_unmap(v, msg->iova, msg->size); >> break; >> + case VHOST_IOTLB_BATCH_BEGIN: >> + v->in_batch = true; >> + break; >> + case VHOST_IOTLB_BATCH_END: >> + if (v->in_batch && ops->set_map) >> + ops->set_map(vdpa, dev->iotlb); >> + v->in_batch = false; >> + break; >> default: >> r = -EINVAL; >> break; >> diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h >> index 0c2349612e77..565da96f55d5 100644 >> --- a/include/uapi/linux/vhost.h >> +++ b/include/uapi/linux/vhost.h >> @@ -91,6 +91,8 @@ >> >> /* Use message type V2 */ >> #define VHOST_BACKEND_F_IOTLB_MSG_V2 0x1 >> +/* IOTLB can accpet batching hints */ > typo Will fix. > >> +#define VHOST_BACKEND_F_IOTLB_BATCH 0x2 >> >> #define VHOST_SET_BACKEND_FEATURES _IOW(VHOST_VIRTIO, 0x25, __u64) >> #define VHOST_GET_BACKEND_FEATURES _IOR(VHOST_VIRTIO, 0x26, __u64) >> diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h >> index 669457ce5c48..5c12faffdde9 100644 >> --- a/include/uapi/linux/vhost_types.h >> +++ b/include/uapi/linux/vhost_types.h >> @@ -60,6 +60,13 @@ struct vhost_iotlb_msg { >> #define VHOST_IOTLB_UPDATE 2 >> #define VHOST_IOTLB_INVALIDATE 3 >> #define VHOST_IOTLB_ACCESS_FAIL 4 >> +/* VHOST_IOTLB_BATCH_BEGIN is a hint that userspace will update >> + * several mappings afterwards. VHOST_IOTLB_BATCH_END is a hint that >> + * userspace had finished the mapping updating. > > Well not just hints - in fact updates do not take place > until _END. > > How about: > > /* VHOST_IOTLB_BATCH_BEGIN and VHOST_IOTLB_BATCH_END allow modifying > * multiple mappings in one go: beginning with > * VHOST_IOTLB_BATCH_BEGIN, followed by any number of > VHOST_IOTLB_UPDATE messages, and ending with VHOST_IOTLB_BATCH_END. > */ That's better. > > >> When those two flags >> + * were set, kernel will ignore the rest fileds of the IOTLB message. > how about: > > when one of these two values is used as the message type, the > rest of the fields in the message are ignored. Yes. Will fix. Thanks > >> + */ >> +#define VHOST_IOTLB_BATCH_BEGIN 5 >> +#define VHOST_IOTLB_BATCH_END 6 >> __u8 type; >> }; >> >> -- >> 2.20.1