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=-20.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, 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 9E4B4C433DB for ; Wed, 30 Dec 2020 06:51:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5817621973 for ; Wed, 30 Dec 2020 06:51:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726509AbgL3Guq (ORCPT ); Wed, 30 Dec 2020 01:50:46 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:36748 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726412AbgL3Gup (ORCPT ); Wed, 30 Dec 2020 01:50:45 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1609310958; 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=heg1e+a0V0k76vMPfwBRgNJmwNSkeMx7Vj1PPs8FGPE=; b=VKKPcvhHq6gU9fQeXblMMGEbp3CZ6GsWgUTCkToPC0WiIigTK+l3djt2pnO/Ea9xwfEY4x MfzvOD2yJXEdpw1/ZM9Y8Uw7V/5dr0kt6jSMu7Q9NUcpMmG/+P8bQFxeLkDo+9UHw+Bmr1 v8rr/TMiWKeCv3Cyp0dhFO31tJ/f/kc= 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-138-Te43lXXeP_qDJgvLF9ML3Q-1; Wed, 30 Dec 2020 01:49:17 -0500 X-MC-Unique: Te43lXXeP_qDJgvLF9ML3Q-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6C497107ACE6; Wed, 30 Dec 2020 06:49:15 +0000 (UTC) Received: from [10.72.13.30] (ovpn-13-30.pek2.redhat.com [10.72.13.30]) by smtp.corp.redhat.com (Postfix) with ESMTP id E61FA71CBB; Wed, 30 Dec 2020 06:49:04 +0000 (UTC) Subject: Re: [PATCH 12/21] vhost-vdpa: introduce uAPI to get the number of virtqueue groups To: Eli Cohen Cc: mst@redhat.com, eperezma@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, lulu@redhat.com, eli@mellanox.com, lingshan.zhu@intel.com, rob.miller@broadcom.com, stefanha@redhat.com, sgarzare@redhat.com References: <20201216064818.48239-1-jasowang@redhat.com> <20201216064818.48239-13-jasowang@redhat.com> <20201229122455.GF195479@mtl-vdi-166.wap.labs.mlnx> From: Jason Wang Message-ID: Date: Wed, 30 Dec 2020 14:49:03 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201229122455.GF195479@mtl-vdi-166.wap.labs.mlnx> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/12/29 下午8:24, Eli Cohen wrote: > On Wed, Dec 16, 2020 at 02:48:09PM +0800, Jason Wang wrote: >> Follows the vDPA support for multiple address spaces, this patch >> introduce uAPI for the userspace to know the number of virtqueue >> groups supported by the vDPA device. > Can you explain what exactly you mean be userspace? It's the userspace that uses the uAPI introduced in this patch. > Is it just qemu or > is it destined to the virtio_net driver run by the qemu process? It could be Qemu, DPDK or other userspace program. The guest virtio-net driver will not use this but talks to the virtio device emulated by Qemu. > Also can you say for what purpose? This can be used for facilitate the checking of whether the control vq could be supported. E.g if the device support less than 2 groups, qemu won't advertise control vq. Yes, #groups could be inferred from GET_VRING_GROUP. But it's not straightforward as this. Thanks > >> Signed-off-by: Jason Wang >> --- >> drivers/vhost/vdpa.c | 4 ++++ >> include/uapi/linux/vhost.h | 3 +++ >> 2 files changed, 7 insertions(+) >> >> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c >> index 060d5b5b7e64..1ba5901b28e7 100644 >> --- a/drivers/vhost/vdpa.c >> +++ b/drivers/vhost/vdpa.c >> @@ -536,6 +536,10 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep, >> case VHOST_VDPA_GET_VRING_NUM: >> r = vhost_vdpa_get_vring_num(v, argp); >> break; >> + case VHOST_VDPA_GET_GROUP_NUM: >> + r = copy_to_user(argp, &v->vdpa->ngroups, >> + sizeof(v->vdpa->ngroups)); >> + break; >> case VHOST_SET_LOG_BASE: >> case VHOST_SET_LOG_FD: >> r = -ENOIOCTLCMD; >> diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h >> index 59c6c0fbaba1..8a4e6e426bbf 100644 >> --- a/include/uapi/linux/vhost.h >> +++ b/include/uapi/linux/vhost.h >> @@ -145,4 +145,7 @@ >> /* Get the valid iova range */ >> #define VHOST_VDPA_GET_IOVA_RANGE _IOR(VHOST_VIRTIO, 0x78, \ >> struct vhost_vdpa_iova_range) >> +/* Get the number of virtqueue groups. */ >> +#define VHOST_VDPA_GET_GROUP_NUM _IOR(VHOST_VIRTIO, 0x79, unsigned int) >> + >> #endif >> -- >> 2.25.1 >>