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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,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 39EAEC4360C for ; Fri, 27 Sep 2019 03:27:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 14C9620835 for ; Fri, 27 Sep 2019 03:27:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729067AbfI0D12 (ORCPT ); Thu, 26 Sep 2019 23:27:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38514 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726145AbfI0D11 (ORCPT ); Thu, 26 Sep 2019 23:27:27 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 890AE58; Fri, 27 Sep 2019 03:27:27 +0000 (UTC) Received: from [10.72.12.160] (ovpn-12-160.pek2.redhat.com [10.72.12.160]) by smtp.corp.redhat.com (Postfix) with ESMTP id B8DEF60BE2; Fri, 27 Sep 2019 03:27:14 +0000 (UTC) Subject: Re: [PATCH] vhost: introduce mdev based hardware backend To: Tiwei Bie , "Michael S. Tsirkin" Cc: alex.williamson@redhat.com, maxime.coquelin@redhat.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, dan.daly@intel.com, cunming.liang@intel.com, zhihong.wang@intel.com, lingshan.zhu@intel.com References: <20190926045427.4973-1-tiwei.bie@intel.com> <20190926042156-mutt-send-email-mst@kernel.org> <20190926131439.GA11652@___> From: Jason Wang Message-ID: <8ab5a8d9-284d-bba5-803d-08523c0814e1@redhat.com> Date: Fri, 27 Sep 2019 11:27:12 +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: <20190926131439.GA11652@___> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Fri, 27 Sep 2019 03:27:27 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/9/26 下午9:14, Tiwei Bie wrote: > On Thu, Sep 26, 2019 at 04:35:18AM -0400, Michael S. Tsirkin wrote: >> On Thu, Sep 26, 2019 at 12:54:27PM +0800, Tiwei Bie wrote: > [...] >>> diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h >>> index 40d028eed645..5afbc2f08fa3 100644 >>> --- a/include/uapi/linux/vhost.h >>> +++ b/include/uapi/linux/vhost.h >>> @@ -116,4 +116,12 @@ >>> #define VHOST_VSOCK_SET_GUEST_CID _IOW(VHOST_VIRTIO, 0x60, __u64) >>> #define VHOST_VSOCK_SET_RUNNING _IOW(VHOST_VIRTIO, 0x61, int) >>> >>> +/* VHOST_MDEV specific defines */ >>> + >>> +#define VHOST_MDEV_SET_STATE _IOW(VHOST_VIRTIO, 0x70, __u64) >>> + >>> +#define VHOST_MDEV_S_STOPPED 0 >>> +#define VHOST_MDEV_S_RUNNING 1 >>> +#define VHOST_MDEV_S_MAX 2 >>> + >>> #endif >> So assuming we have an underlying device that behaves like virtio: > I think they are really good questions/suggestions. Thanks! > >> 1. Should we use SET_STATUS maybe? > I like this idea. I will give it a try. > >> 2. Do we want a reset ioctl? > I think it is helpful. If we use SET_STATUS, maybe we > can use it to support the reset. > >> 3. Do we want ability to enable rings individually? > I will make it possible at least in the vhost layer. Note the API support e.g set_vq_ready(). > >> 4. Does device need to limit max ring size? >> 5. Does device need to limit max number of queues? > I think so. It's helpful to have ioctls to report the max > ring size and max number of queues. An issue is the max number of queues is done through a device specific way, usually device configuration space. This is supported by the transport API, but how to expose it to userspace may need more thought. Thanks > > Thanks!