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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 880E4C433EF for ; Mon, 17 Jan 2022 13:24:50 +0000 (UTC) Received: from localhost ([::1]:37002 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1n9S09-0001ao-Et for qemu-devel@archiver.kernel.org; Mon, 17 Jan 2022 08:24:49 -0500 Received: from eggs.gnu.org ([209.51.188.92]:57130) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n9RDz-0002Wd-91 for qemu-devel@nongnu.org; Mon, 17 Jan 2022 07:35:03 -0500 Received: from szxga03-in.huawei.com ([45.249.212.189]:4178) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n9RDv-0000eM-Iq for qemu-devel@nongnu.org; Mon, 17 Jan 2022 07:35:02 -0500 Received: from dggpeml500026.china.huawei.com (unknown [172.30.72.54]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4JcrrM1fRFz8wPR; Mon, 17 Jan 2022 20:32:03 +0800 (CST) Received: from dggpeml100016.china.huawei.com (7.185.36.216) by dggpeml500026.china.huawei.com (7.185.36.106) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Mon, 17 Jan 2022 20:34:51 +0800 Received: from dggpeml100016.china.huawei.com ([7.185.36.216]) by dggpeml100016.china.huawei.com ([7.185.36.216]) with mapi id 15.01.2308.020; Mon, 17 Jan 2022 20:34:50 +0800 To: Stefan Hajnoczi CC: "mst@redhat.com" , "jasowang@redhat.com" , "sgarzare@redhat.com" , "cohuck@redhat.com" , "pbonzini@redhat.com" , "Gonglei (Arei)" , Yechuan , Huangzhichao , "qemu-devel@nongnu.org" Subject: RE: [RFC 05/10] vdpa-dev: implement the realize interface Thread-Topic: [RFC 05/10] vdpa-dev: implement the realize interface Thread-Index: AQHYAc9x2eZeGsh4c02Kkb+31MnmdqxTsSqAgAGZVyCAAA54gIAR4AbQ Date: Mon, 17 Jan 2022 12:34:50 +0000 Message-ID: <99584ad9258745e1a9d1ba2e7ee4239d@huawei.com> References: <20220105005900.860-1-longpeng2@huawei.com> <20220105005900.860-6-longpeng2@huawei.com> <8abbe9c2599247599aec2d0d7ff01c32@huawei.com> In-Reply-To: Accept-Language: zh-CN, en-US Content-Language: zh-CN X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.174.148.223] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-CFilter-Loop: Reflected Received-SPF: pass client-ip=45.249.212.189; envelope-from=longpeng2@huawei.com; helo=szxga03-in.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Reply-to: "Longpeng (Mike, Cloud Infrastructure Service Product Dept.)" From: longpeng2--- via > -----Original Message----- > From: Stefan Hajnoczi [mailto:stefanha@redhat.com] > Sent: Thursday, January 6, 2022 7:34 PM > To: Longpeng (Mike, Cloud Infrastructure Service Product Dept.) > > Cc: mst@redhat.com; jasowang@redhat.com; sgarzare@redhat.com; > cohuck@redhat.com; pbonzini@redhat.com; Gonglei (Arei) > ; Yechuan ; Huangzhichao > ; qemu-devel@nongnu.org > Subject: Re: [RFC 05/10] vdpa-dev: implement the realize interface >=20 > On Thu, Jan 06, 2022 at 03:02:37AM +0000, Longpeng (Mike, Cloud Infrastru= cture > Service Product Dept.) wrote: > > > > > > > -----Original Message----- > > > From: Stefan Hajnoczi [mailto:stefanha@redhat.com] > > > Sent: Wednesday, January 5, 2022 6:18 PM > > > To: Longpeng (Mike, Cloud Infrastructure Service Product Dept.) > > > > > > Cc: mst@redhat.com; jasowang@redhat.com; sgarzare@redhat.com; > > > cohuck@redhat.com; pbonzini@redhat.com; Gonglei (Arei) > > > ; Yechuan ; Huangzhichao > > > ; qemu-devel@nongnu.org > > > Subject: Re: [RFC 05/10] vdpa-dev: implement the realize interface > > > > > > On Wed, Jan 05, 2022 at 08:58:55AM +0800, Longpeng(Mike) wrote: > > > > From: Longpeng > > > > > > > > Implements the .realize interface. > > > > > > > > Signed-off-by: Longpeng > > > > --- > > > > hw/virtio/vdpa-dev.c | 114 +++++++++++++++++++++++++++++++= ++++ > > > > include/hw/virtio/vdpa-dev.h | 8 +++ > > > > 2 files changed, 122 insertions(+) > > > > > > > > diff --git a/hw/virtio/vdpa-dev.c b/hw/virtio/vdpa-dev.c > > > > index 790117fb3b..2d534d837a 100644 > > > > --- a/hw/virtio/vdpa-dev.c > > > > +++ b/hw/virtio/vdpa-dev.c > > > > @@ -15,9 +15,122 @@ > > > > #include "sysemu/sysemu.h" > > > > #include "sysemu/runstate.h" > > > > > > > > +static void > > > > +vhost_vdpa_device_dummy_handle_output(VirtIODevice *vdev, VirtQueu= e > *vq) > > > > +{ > > > > + /* Nothing to do */ > > > > +} > > > > + > > > > +static int vdpa_dev_get_info_by_fd(int fd, uint64_t cmd, Error **e= rrp) > > > > > > This looks similar to the helper function in a previous patch but thi= s > > > time the return value type is int instead of uint32_t. Please make th= e > > > types consistent. > > > > > > > OK. > > > > > > +{ > > > > + int val; > > > > + > > > > + if (ioctl(fd, cmd, &val) < 0) { > > > > + error_setg(errp, "vhost-vdpa-device: cmd 0x%lx failed: %s"= , > > > > + cmd, strerror(errno)); > > > > + return -1; > > > > + } > > > > + > > > > + return val; > > > > +} > > > > + > > > > +static inline int vdpa_dev_get_queue_size(int fd, Error **errp) > > > > +{ > > > > + return vdpa_dev_get_info_by_fd(fd, VHOST_VDPA_GET_VRING_NUM, e= rrp); > > > > +} > > > > + > > > > +static inline int vdpa_dev_get_vqs_num(int fd, Error **errp) > > > > +{ > > > > + return vdpa_dev_get_info_by_fd(fd, VHOST_VDPA_GET_VQS_NUM, err= p); > > > > +} > > > > + > > > > +static inline int vdpa_dev_get_config_size(int fd, Error **errp) > > > > +{ > > > > + return vdpa_dev_get_info_by_fd(fd, VHOST_VDPA_GET_CONFIG_SIZE, > errp); > > > > +} > > > > + > > > > static void vhost_vdpa_device_realize(DeviceState *dev, Error **er= rp) > > > > { > > > > + VirtIODevice *vdev =3D VIRTIO_DEVICE(dev); > > > > + VhostVdpaDevice *s =3D VHOST_VDPA_DEVICE(vdev); > > > > + uint32_t device_id; > > > > + int max_queue_size; > > > > + int fd; > > > > + int i, ret; > > > > + > > > > + fd =3D qemu_open(s->vdpa_dev, O_RDWR, errp); > > > > + if (fd =3D=3D -1) { > > > > + return; > > > > + } > > > > + s->vdpa.device_fd =3D fd; > > > > > > This is the field I suggest exposing as a QOM property so it can be s= et > > > from the proxy object (e.g. when the PCI proxy opens the vdpa device > > > before our .realize() function is called). > > > > > > > OK. > > > > > > + > > > > + max_queue_size =3D vdpa_dev_get_queue_size(fd, errp); > > > > + if (*errp) { > > > > + goto out; > > > > + } > > > > + > > > > + if (s->queue_size > max_queue_size) { > > > > + error_setg(errp, "vhost-vdpa-device: invalid queue_size: %= d > > > (max:%d)", > > > > + s->queue_size, max_queue_size); > > > > + goto out; > > > > + } else if (!s->queue_size) { > > > > + s->queue_size =3D max_queue_size; > > > > + } > > > > + > > > > + ret =3D vdpa_dev_get_vqs_num(fd, errp); > > > > + if (*errp) { > > > > + goto out; > > > > + } > > > > + > > > > + s->dev.nvqs =3D ret; > > > > > > There is no input validation because we trust the kernel vDPA return > > > values. That seems okay for now but if there is a vhost-user version = of > > > this in the future then input validation will be necessary to achieve > > > isolation between QEMU and the vhost-user processes. I suggest includ= ing > > > input validation code right away because it's harder to audit the cod= e > > > and fix missing input validation later on. > > > > > > > Make sense! > > > > Should we only need to validate the upper boundary (e.g. =20 > Careful, ret is currently an int so negative values would bypass the < > VIRTIO_QUEUE_MAX check. >=20 > > > > > > + s->dev.vqs =3D g_new0(struct vhost_virtqueue, s->dev.nvqs); > > > > + s->dev.vq_index =3D 0; > > > > + s->dev.vq_index_end =3D s->dev.nvqs; > > > > + s->dev.backend_features =3D 0; > > > > + s->started =3D false; > > > > + > > > > + ret =3D vhost_dev_init(&s->dev, &s->vdpa, VHOST_BACKEND_TYPE_V= DPA, 0, > > > NULL); > > > > + if (ret < 0) { > > > > + error_setg(errp, "vhost-vdpa-device: vhost initialization > > > failed: %s", > > > > + strerror(-ret)); > > > > + goto out; > > > > + } > > > > + > > > > + ret =3D s->dev.vhost_ops->vhost_get_device_id(&s->dev, &device= _id); > > > > > > The vhost_*() API abstracts the ioctl calls but this source file and = the > > > PCI proxy have ioctl calls. I wonder if it's possible to move the ioc= tls > > > calls into the vhost_*() API? That would be cleaner and also make it > > > easier to add vhost-user vDPA support in the future. > > > > We need these ioctls calls because we need invoke them before the vhost= -dev > > object is initialized. >=20 > It may be possible to clean this up by changing how vhost_dev_init() > works but I haven't investigated. The issue is that the vhost_dev_init() > API requires information from the caller that has to be fetched from the > vDPA device. This forces the caller to communicate directly with the > vDPA device before calling vhost_dev_init(). It may be possible to move > this setup code inside vhost_dev_init() (and vhost_ops callbacks). >=20 Hmm, this is still not clear to me, so let's continue to discuss this in v2 if you think it's necessary. > Stefan