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=-5.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 23817C33CB3 for ; Fri, 17 Jan 2020 03:03:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E0A6B206D7 for ; Fri, 17 Jan 2020 03:03:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gS9JXooK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389235AbgAQDDl (ORCPT ); Thu, 16 Jan 2020 22:03:41 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:44467 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2388298AbgAQDDh (ORCPT ); Thu, 16 Jan 2020 22:03:37 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579230215; 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=ZHZAudpQ7YKqVHyEOwRamq1WK1H7U3kwvTz/1r/Y/lU=; b=gS9JXooKQ6njC2mjiEuvDFSMpDEY8KWgPGd3A9B8iufRriaQpYCxyme6ZYZ9PvzOLL9N5K y4e2pe8lmZq8dXjIBZOERel0Yi89Xl0+Do7K16Jo9Hq77/qRC4arTsTQ6wQG9i/KwTVppi sd2CQEISWNkqCu2TP6XkFf/zeffRPW0= 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-275-CkGX8257OWK3y6RbnjmjLQ-1; Thu, 16 Jan 2020 22:03:33 -0500 X-MC-Unique: CkGX8257OWK3y6RbnjmjLQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2E08FDBA3; Fri, 17 Jan 2020 03:03:30 +0000 (UTC) Received: from [10.72.12.168] (ovpn-12-168.pek2.redhat.com [10.72.12.168]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8EA4E19C5B; Fri, 17 Jan 2020 03:03:14 +0000 (UTC) Subject: Re: [PATCH 3/5] vDPA: introduce vDPA bus To: Jason Gunthorpe Cc: "mst@redhat.com" , "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" , "virtualization@lists.linux-foundation.org" , "netdev@vger.kernel.org" , "tiwei.bie@intel.com" , "maxime.coquelin@redhat.com" , "cunming.liang@intel.com" , "zhihong.wang@intel.com" , "rob.miller@broadcom.com" , "xiao.w.wang@intel.com" , "haotian.wang@sifive.com" , "lingshan.zhu@intel.com" , "eperezma@redhat.com" , "lulu@redhat.com" , Parav Pandit , "kevin.tian@intel.com" , "stefanha@redhat.com" , "rdunlap@infradead.org" , "hch@infradead.org" , "aadam@redhat.com" , "jakub.kicinski@netronome.com" , Jiri Pirko , Shahaf Shuler , "hanand@xilinx.com" , "mhabets@solarflare.com" References: <20200116124231.20253-1-jasowang@redhat.com> <20200116124231.20253-4-jasowang@redhat.com> <20200116152209.GH20978@mellanox.com> From: Jason Wang Message-ID: <03cfbcc2-fef0-c9d8-0b08-798b2a293b8c@redhat.com> Date: Fri, 17 Jan 2020 11:03:12 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20200116152209.GH20978@mellanox.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Content-Transfer-Encoding: quoted-printable Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 2020/1/16 =E4=B8=8B=E5=8D=8811:22, Jason Gunthorpe wrote: > On Thu, Jan 16, 2020 at 08:42:29PM +0800, Jason Wang wrote: >> vDPA device is a device that uses a datapath which complies with the >> virtio specifications with vendor specific control path. vDPA devices >> can be both physically located on the hardware or emulated by >> software. vDPA hardware devices are usually implemented through PCIE >> with the following types: >> >> - PF (Physical Function) - A single Physical Function >> - VF (Virtual Function) - Device that supports single root I/O >> virtualization (SR-IOV). Its Virtual Function (VF) represents a >> virtualized instance of the device that can be assigned to differen= t >> partitions >> - VDEV (Virtual Device) - With technologies such as Intel Scalable >> IOV, a virtual device composed by host OS utilizing one or more >> ADIs. >> - SF (Sub function) - Vendor specific interface to slice the Physical >> Function to multiple sub functions that can be assigned to differen= t >> partitions as virtual devices. > I really hope we don't end up with two different ways to spell this > same thing. I think you meant ADI vs SF. It looks to me that ADI is limited to the=20 scope of scalable IOV but SF not. > >> @@ -0,0 +1,2 @@ >> +# SPDX-License-Identifier: GPL-2.0 >> +obj-$(CONFIG_VDPA) +=3D vdpa.o >> diff --git a/drivers/virtio/vdpa/vdpa.c b/drivers/virtio/vdpa/vdpa.c >> new file mode 100644 >> index 000000000000..2b0e4a9f105d >> +++ b/drivers/virtio/vdpa/vdpa.c >> @@ -0,0 +1,141 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * vDPA bus. >> + * >> + * Copyright (c) 2019, Red Hat. All rights reserved. >> + * Author: Jason Wang > 2020 tests days Will fix. > >> + * >> + */ >> + >> +#include >> +#include >> +#include >> + >> +#define MOD_VERSION "0.1" > I think module versions are discouraged these days Will remove. > >> +#define MOD_DESC "vDPA bus" >> +#define MOD_AUTHOR "Jason Wang " >> +#define MOD_LICENSE "GPL v2" >> + >> +static DEFINE_IDA(vdpa_index_ida); >> + >> +struct device *vdpa_get_parent(struct vdpa_device *vdpa) >> +{ >> + return vdpa->dev.parent; >> +} >> +EXPORT_SYMBOL(vdpa_get_parent); >> + >> +void vdpa_set_parent(struct vdpa_device *vdpa, struct device *parent) >> +{ >> + vdpa->dev.parent =3D parent; >> +} >> +EXPORT_SYMBOL(vdpa_set_parent); >> + >> +struct vdpa_device *dev_to_vdpa(struct device *_dev) >> +{ >> + return container_of(_dev, struct vdpa_device, dev); >> +} >> +EXPORT_SYMBOL_GPL(dev_to_vdpa); >> + >> +struct device *vdpa_to_dev(struct vdpa_device *vdpa) >> +{ >> + return &vdpa->dev; >> +} >> +EXPORT_SYMBOL_GPL(vdpa_to_dev); > Why these trivial assessors? Seems unnecessary, or should at least be > static inlines in a header Will fix. > >> +int register_vdpa_device(struct vdpa_device *vdpa) >> +{ > Usually we want to see symbols consistently prefixed with vdpa_*, is > there a reason why register/unregister are swapped? I follow the name from virtio. I will switch to vdpa_*. > >> + int err; >> + >> + if (!vdpa_get_parent(vdpa)) >> + return -EINVAL; >> + >> + if (!vdpa->config) >> + return -EINVAL; >> + >> + err =3D ida_simple_get(&vdpa_index_ida, 0, 0, GFP_KERNEL); >> + if (err < 0) >> + return -EFAULT; >> + >> + vdpa->dev.bus =3D &vdpa_bus; >> + device_initialize(&vdpa->dev); > IMHO device_initialize should not be called inside something called > register, toooften we find out that the caller drivers need the device > to be initialized earlier, ie to use the kref, or something. > > I find the best flow is to have some init function that does the > device_initialize and sets the device_name that the driver can call > early. Ok, will do. > > Shouldn't there be a device/driver matching process of some kind? The question is what do we want do match here. 1) "virtio" vs "vhost", I implemented matching method for this in mdev=20 series, but it looks unnecessary for vDPA device driver to know about=20 this. Anyway we can use sysfs driver bind/unbind to switch drivers 2) virtio device id and vendor id. I'm not sure we need this consider=20 the two drivers so far (virtio/vhost) are all bus drivers. Thanks > > Jason >