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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A0C8BC7EE23 for ; Tue, 23 May 2023 15:51:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229510AbjEWPvS (ORCPT ); Tue, 23 May 2023 11:51:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50772 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237172AbjEWPvS (ORCPT ); Tue, 23 May 2023 11:51:18 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C6D3121 for ; Tue, 23 May 2023 08:50:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1684857030; 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=wYFl8U0SDWnlIQQFAjgbnzByRprAY7BghMfujkqtBpA=; b=cMuWjnEcXhyevbHA1iv90pSRhUkmgMZ5utfWOj3EKGGFyWVodC49UnJxfBi/ssH6MCyaBa d4VuSbBK3GlOEhKrtSQTSMzsQzWHPOBpqnTONjVVVp9cTCrV33vIQ1CCDNBMsR+YjfKW18 vgVRUc+JBtdY3507xbfUr6Vp7Neqc9o= Received: from mail-il1-f197.google.com (mail-il1-f197.google.com [209.85.166.197]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-330-NLGNrDZmMw2vg3WJQKUrew-1; Tue, 23 May 2023 11:50:29 -0400 X-MC-Unique: NLGNrDZmMw2vg3WJQKUrew-1 Received: by mail-il1-f197.google.com with SMTP id e9e14a558f8ab-331139b46cfso6886785ab.1 for ; Tue, 23 May 2023 08:50:29 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1684857028; x=1687449028; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=wYFl8U0SDWnlIQQFAjgbnzByRprAY7BghMfujkqtBpA=; b=bC3jUAVEtJjyDTG0LfUdNGEmZ1RkQGCzxm3tJh7YLKXlDjkb+4PlhLh1Ifr/U1vY5y K53AI22cYli26xqsNLeYOwDrRJWMNa9Do7U6kKbm+hgIQH6XRuxyR5Ji9sAMWqE2QdOc ckPPHQLkZpz2YVNwb5MkySgHfctg7yF5K4GELy4h0y+nKoK+5TQsS9FC+76SS2e7Ah9p uc9aSNpaSZhFrIe5RwHTk5P4YgbJES1UKglLI0ipAsU4edS3CJUgAwPFcXnOBiWCETmm 4ZSsOK6ZUpJJfeRPzaPFvbmSTVTr1MZeMsOLyPeAcBaHoUNduYJTAbvTRRwIF/sid7YI 6mSQ== X-Gm-Message-State: AC+VfDy6EqaLe7C6r0T185xW2dfNr0EViB/DLqai/Xx/CkGoFbNt0Um4 e7u4O3MYv5wul5HfMPsy0osaaIc8Nrjqr5aYVzAm0lXRD7rfQ62yEGyy+2sUXDpmKy4OyxPQFG1 1W64L/wAnLvnw2zIfTayJ8A== X-Received: by 2002:a92:cc4e:0:b0:338:b887:b674 with SMTP id t14-20020a92cc4e000000b00338b887b674mr7921325ilq.2.1684857028276; Tue, 23 May 2023 08:50:28 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ5L5cxZeYlEeuroxDhVXKppcAZQVL21daMeMkcovyH4v9JrjGeyYnpYWoYxJebm28zcXp2DNQ== X-Received: by 2002:a92:cc4e:0:b0:338:b887:b674 with SMTP id t14-20020a92cc4e000000b00338b887b674mr7921317ilq.2.1684857027956; Tue, 23 May 2023 08:50:27 -0700 (PDT) Received: from redhat.com ([38.15.36.239]) by smtp.gmail.com with ESMTPSA id y2-20020a056638228200b0040fa5258658sm2401119jas.77.2023.05.23.08.50.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 23 May 2023 08:50:27 -0700 (PDT) Date: Tue, 23 May 2023 09:50:25 -0600 From: Alex Williamson To: "Liu, Yi L" Cc: "jgg@nvidia.com" , "Tian, Kevin" , "joro@8bytes.org" , "robin.murphy@arm.com" , "cohuck@redhat.com" , "eric.auger@redhat.com" , "nicolinc@nvidia.com" , "kvm@vger.kernel.org" , "mjrosato@linux.ibm.com" , "chao.p.peng@linux.intel.com" , "yi.y.sun@linux.intel.com" , "peterx@redhat.com" , "jasowang@redhat.com" , "shameerali.kolothum.thodi@huawei.com" , "lulu@redhat.com" , "suravee.suthikulpanit@amd.com" , "intel-gvt-dev@lists.freedesktop.org" , "intel-gfx@lists.freedesktop.org" , "linux-s390@vger.kernel.org" , "Hao, Xudong" , "Zhao, Yan Y" , "Xu, Terrence" , "Jiang, Yanting" , "Duan, Zhenzhong" , "clegoate@redhat.com" Subject: Re: [PATCH v11 20/23] vfio: Add VFIO_DEVICE_[AT|DE]TACH_IOMMUFD_PT Message-ID: <20230523095025.1898297c.alex.williamson@redhat.com> In-Reply-To: References: <20230513132827.39066-1-yi.l.liu@intel.com> <20230513132827.39066-21-yi.l.liu@intel.com> <20230522161534.32f3bf8e.alex.williamson@redhat.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.35; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org On Tue, 23 May 2023 01:20:17 +0000 "Liu, Yi L" wrote: > > From: Alex Williamson > > Sent: Tuesday, May 23, 2023 6:16 AM > >=20 > > On Sat, 13 May 2023 06:28:24 -0700 > > Yi Liu wrote: > > =20 > > > This adds ioctl for userspace to attach device cdev fd to and detach > > > from IOAS/hw_pagetable managed by iommufd. > > > > > > VFIO_DEVICE_ATTACH_IOMMUFD_PT: attach vfio device to IOAS, hw_pag= etable > > > managed by iommufd. Attach can be > > > undo by VFIO_DEVICE_DETACH_IOMMUFD_PT > > > or device fd close. > > > VFIO_DEVICE_DETACH_IOMMUFD_PT: detach vfio device from the curren= t attached > > > IOAS or hw_pagetable managed by iommufd. > > > > > > Tested-by: Yanting Jiang > > > Tested-by: Shameer Kolothum > > > Signed-off-by: Yi Liu > > > --- > > > drivers/vfio/device_cdev.c | 66 ++++++++++++++++++++++++++++++++++++= ++ > > > drivers/vfio/iommufd.c | 18 +++++++++++ > > > drivers/vfio/vfio.h | 18 +++++++++++ > > > drivers/vfio/vfio_main.c | 8 +++++ > > > include/uapi/linux/vfio.h | 52 ++++++++++++++++++++++++++++++ > > > 5 files changed, 162 insertions(+) > > > > > > diff --git a/drivers/vfio/device_cdev.c b/drivers/vfio/device_cdev.c > > > index 291cc678a18b..3f14edb80a93 100644 > > > --- a/drivers/vfio/device_cdev.c > > > +++ b/drivers/vfio/device_cdev.c > > > @@ -174,6 +174,72 @@ long vfio_device_ioctl_bind_iommufd(struct vfio_= device_file =20 > > *df, =20 > > > return ret; > > > } > > > > > > +int vfio_ioctl_device_attach(struct vfio_device_file *df, > > > + struct vfio_device_attach_iommufd_pt __user *arg) > > > +{ > > > + struct vfio_device *device =3D df->device; > > > + struct vfio_device_attach_iommufd_pt attach; > > > + unsigned long minsz; > > > + int ret; > > > + > > > + minsz =3D offsetofend(struct vfio_device_attach_iommufd_pt, pt_id); > > > + > > > + if (copy_from_user(&attach, arg, minsz)) > > > + return -EFAULT; > > > + > > > + if (attach.argsz < minsz || attach.flags) > > > + return -EINVAL; > > > + > > > + /* ATTACH only allowed for cdev fds */ > > > + if (df->group) > > > + return -EINVAL; > > > + > > > + mutex_lock(&device->dev_set->lock); > > > + ret =3D vfio_iommufd_attach(device, &attach.pt_id); > > > + if (ret) > > > + goto out_unlock; > > > + > > > + ret =3D copy_to_user(&arg->pt_id, &attach.pt_id, > > > + sizeof(attach.pt_id)) ? -EFAULT : 0; > > > + if (ret) > > > + goto out_detach; > > > + mutex_unlock(&device->dev_set->lock); > > > + > > > + return 0; > > > + > > > +out_detach: > > > + vfio_iommufd_detach(device); > > > +out_unlock: > > > + mutex_unlock(&device->dev_set->lock); > > > + return ret; > > > +} > > > + > > > +int vfio_ioctl_device_detach(struct vfio_device_file *df, > > > + struct vfio_device_detach_iommufd_pt __user *arg) > > > +{ > > > + struct vfio_device *device =3D df->device; > > > + struct vfio_device_detach_iommufd_pt detach; > > > + unsigned long minsz; > > > + > > > + minsz =3D offsetofend(struct vfio_device_detach_iommufd_pt, flags); > > > + > > > + if (copy_from_user(&detach, arg, minsz)) > > > + return -EFAULT; > > > + > > > + if (detach.argsz < minsz || detach.flags) > > > + return -EINVAL; > > > + > > > + /* DETACH only allowed for cdev fds */ > > > + if (df->group) > > > + return -EINVAL; > > > + > > > + mutex_lock(&device->dev_set->lock); > > > + vfio_iommufd_detach(device); > > > + mutex_unlock(&device->dev_set->lock); > > > + > > > + return 0; > > > +} > > > + > > > static char *vfio_device_devnode(const struct device *dev, umode_t *= mode) > > > { > > > return kasprintf(GFP_KERNEL, "vfio/devices/%s", dev_name(dev)); > > > diff --git a/drivers/vfio/iommufd.c b/drivers/vfio/iommufd.c > > > index 83575b65ea01..799ea322a7d4 100644 > > > --- a/drivers/vfio/iommufd.c > > > +++ b/drivers/vfio/iommufd.c > > > @@ -112,6 +112,24 @@ void vfio_iommufd_unbind(struct vfio_device_file= *df) > > > vdev->ops->unbind_iommufd(vdev); > > > } > > > > > > +int vfio_iommufd_attach(struct vfio_device *vdev, u32 *pt_id) > > > +{ > > > + lockdep_assert_held(&vdev->dev_set->lock); > > > + > > > + if (vfio_device_is_noiommu(vdev)) > > > + return 0; =20 > >=20 > > Isn't this an invalid operation for a noiommu cdev, ie. -EINVAL? We > > return success and copy back the provided pt_id, why would a user not > > consider it a bug that they can't use whatever value was there with > > iommufd? =20 >=20 > Yes, this is the question I asked in [1]. At that time, it appears to me > that better to allow it [2]. Maybe it's more suitable to ask it here. =46rom an API perspective it seems wrong. We return success without doing anything. A user would be right to consider it a bug that the attach operation works but there's not actually any association to the IOAS. Thanks, Alex > [1] https://lore.kernel.org/kvm/c203f11f-4d9f-cf43-03ab-e41a858bdd92@inte= l.com/ > [2] https://lore.kernel.org/kvm/ZFFUyhqID+LtUB%2FD@nvidia.com/ >=20 > > > + > > > + return vdev->ops->attach_ioas(vdev, pt_id); > > > +} > > > + > > > +void vfio_iommufd_detach(struct vfio_device *vdev) > > > +{ > > > + lockdep_assert_held(&vdev->dev_set->lock); > > > + > > > + if (!vfio_device_is_noiommu(vdev)) > > > + vdev->ops->detach_ioas(vdev); > > > +} > > > + > > > struct iommufd_ctx *vfio_iommufd_physical_ictx(struct vfio_device *v= dev) > > > { > > > if (vdev->iommufd_device) > > > diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h > > > index 8b359a7794be..50553f67600f 100644 > > > --- a/drivers/vfio/vfio.h > > > +++ b/drivers/vfio/vfio.h > > > @@ -241,6 +241,8 @@ int vfio_iommufd_bind(struct vfio_device_file *df= ); > > > void vfio_iommufd_unbind(struct vfio_device_file *df); > > > int vfio_iommufd_compat_attach_ioas(struct vfio_device *device, > > > struct iommufd_ctx *ictx); > > > +int vfio_iommufd_attach(struct vfio_device *vdev, u32 *pt_id); > > > +void vfio_iommufd_detach(struct vfio_device *vdev); > > > #else > > > static inline int > > > vfio_iommufd_compat_probe_noiommu(struct vfio_device *device, > > > @@ -282,6 +284,10 @@ int vfio_device_fops_cdev_open(struct inode *ino= de, struct =20 > > file *filep); =20 > > > void vfio_device_cdev_close(struct vfio_device_file *df); > > > long vfio_device_ioctl_bind_iommufd(struct vfio_device_file *df, > > > struct vfio_device_bind_iommufd __user *arg); > > > +int vfio_ioctl_device_attach(struct vfio_device_file *df, > > > + struct vfio_device_attach_iommufd_pt __user *arg); > > > +int vfio_ioctl_device_detach(struct vfio_device_file *df, > > > + struct vfio_device_detach_iommufd_pt __user *arg); > > > int vfio_cdev_init(struct class *device_class); > > > void vfio_cdev_cleanup(void); > > > #else > > > @@ -315,6 +321,18 @@ static inline long vfio_device_ioctl_bind_iommuf= d(struct =20 > > vfio_device_file *df, =20 > > > return -EOPNOTSUPP; > > > } > > > > > > +static inline int vfio_ioctl_device_attach(struct vfio_device_file *= df, > > > + struct vfio_device_attach_iommufd_pt __user =20 > > *arg) =20 > > > +{ > > > + return -EOPNOTSUPP; > > > +} > > > + > > > +static inline int vfio_ioctl_device_detach(struct vfio_device_file *= df, > > > + struct vfio_device_detach_iommufd_pt =20 > > __user *arg) =20 > > > +{ > > > + return -EOPNOTSUPP; > > > +} > > > + > > > static inline int vfio_cdev_init(struct class *device_class) > > > { > > > return 0; > > > diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c > > > index c9fa39ac4b02..8c3f26b4929b 100644 > > > --- a/drivers/vfio/vfio_main.c > > > +++ b/drivers/vfio/vfio_main.c > > > @@ -1165,6 +1165,14 @@ static long vfio_device_fops_unl_ioctl(struct = file *filep, > > > ret =3D vfio_ioctl_device_feature(device, (void __user *)arg); > > > break; > > > > > > + case VFIO_DEVICE_ATTACH_IOMMUFD_PT: > > > + ret =3D vfio_ioctl_device_attach(df, (void __user *)arg); > > > + break; > > > + > > > + case VFIO_DEVICE_DETACH_IOMMUFD_PT: > > > + ret =3D vfio_ioctl_device_detach(df, (void __user *)arg); > > > + break; > > > + > > > default: > > > if (unlikely(!device->ops->ioctl)) > > > ret =3D -EINVAL; > > > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > > > index 07c917de31e9..770f5f949929 100644 > > > --- a/include/uapi/linux/vfio.h > > > +++ b/include/uapi/linux/vfio.h > > > @@ -222,6 +222,58 @@ struct vfio_device_bind_iommufd { > > > > > > #define VFIO_DEVICE_BIND_IOMMUFD _IO(VFIO_TYPE, VFIO_BASE + 19) > > > > > > +/* > > > + * VFIO_DEVICE_ATTACH_IOMMUFD_PT - _IOW(VFIO_TYPE, VFIO_BASE + 20, > > > + * struct vfio_device_attach_iommufd_pt) > > > + * > > > + * Attach a vfio device to an iommufd address space specified by IOAS > > > + * id or hw_pagetable (hwpt) id. > > > + * > > > + * Available only after a device has been bound to iommufd via > > > + * VFIO_DEVICE_BIND_IOMMUFD > > > + * > > > + * Undo by VFIO_DEVICE_DETACH_IOMMUFD_PT or device fd close. > > > + * > > > + * @argsz: User filled size of this data. > > > + * @flags: Must be 0. > > > + * @pt_id: Input the target id which can represent an ioas or a hwpt > > > + * allocated via iommufd subsystem. > > > + * Output the input ioas id or the attached hwpt id which could > > > + * be the specified hwpt itself or a hwpt automatically created > > > + * for the specified ioas by kernel during the attachment. > > > + * > > > + * Return: 0 on success, -errno on failure. > > > + */ > > > +struct vfio_device_attach_iommufd_pt { > > > + __u32 argsz; > > > + __u32 flags; > > > + __u32 pt_id; > > > +}; > > > + > > > +#define VFIO_DEVICE_ATTACH_IOMMUFD_PT _IO(VFIO_TYPE, =20 > > VFIO_BASE + 20) =20 > > > + > > > +/* > > > + * VFIO_DEVICE_DETACH_IOMMUFD_PT - _IOW(VFIO_TYPE, VFIO_BASE + 21, > > > + * struct vfio_device_detach_iommufd_pt) > > > + * > > > + * Detach a vfio device from the iommufd address space it has been > > > + * attached to. After it, device should be in a blocking DMA state. > > > + * > > > + * Available only after a device has been bound to iommufd via > > > + * VFIO_DEVICE_BIND_IOMMUFD. =20 > >=20 > > These "[a]vailable only after" comments are meaningless, if the user > > has the file descriptor the ioctl is available. We can say that ATTACH > > should be used after BIND to associate the device with an address space > > within the bound iommufd and DETACH removes that association, but the > > user is welcome to call everything in the wrong order and we need to be > > prepared for that anyway. Thanks, =20 >=20 > Oh, yes. it's available as long as FD is got. But it is expected to fail = if > the order is not met. This should be what the comment really wants > to deliver. Will have a look at other ioctls as well. >=20 > Regards, > Yi Liu >=20 > >=20 > > Alex > > =20 > > > + * > > > + * @argsz: User filled size of this data. > > > + * @flags: Must be 0. > > > + * > > > + * Return: 0 on success, -errno on failure. > > > + */ > > > +struct vfio_device_detach_iommufd_pt { > > > + __u32 argsz; > > > + __u32 flags; > > > +}; > > > + > > > +#define VFIO_DEVICE_DETACH_IOMMUFD_PT _IO(VFIO_TYPE, =20 > > VFIO_BASE + 21) =20 > > > + > > > /** > > > * VFIO_DEVICE_GET_INFO - _IOR(VFIO_TYPE, VFIO_BASE + 7, > > > * struct vfio_device_info) =20 >=20