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=-15.8 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,SPF_HELO_NONE,SPF_PASS 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 7757DC433E0 for ; Mon, 22 Feb 2021 16:54:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3C48F64EF5 for ; Mon, 22 Feb 2021 16:54:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231499AbhBVQxv (ORCPT ); Mon, 22 Feb 2021 11:53:51 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:41485 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231478AbhBVQxU (ORCPT ); Mon, 22 Feb 2021 11:53:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1614012714; 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=ScOwtZfsBfs3LX8QPLUz2J4hjmFvF5QjW3WOO14yaj8=; b=WEYIcp/rEeAeiIoAPdolDIaF9wgV/NwD0/Nku/k21ZlTBV7G/xg7ZGC8RPBCHBZiZNBnUv yC6xXV16wM7fg0EdgzIoITmwnnM9Bn/pUjUo8WEt1XvmiYrSGiUkICx3NyJ7qz2TRa2GvS U56RhlWTXCl7P//zfNFYdpJ7P5blw1A= 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-360-fHKP-MOyNQOfDhHfKM2YeQ-1; Mon, 22 Feb 2021 11:51:51 -0500 X-MC-Unique: fHKP-MOyNQOfDhHfKM2YeQ-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 35A00CC623; Mon, 22 Feb 2021 16:51:50 +0000 (UTC) Received: from gimli.home (ovpn-112-255.phx2.redhat.com [10.3.112.255]) by smtp.corp.redhat.com (Postfix) with ESMTP id 22A5257; Mon, 22 Feb 2021 16:51:39 +0000 (UTC) Subject: [RFC PATCH 06/10] vfio: Add a device notifier interface From: Alex Williamson To: alex.williamson@redhat.com Cc: cohuck@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, jgg@nvidia.com, peterx@redhat.com Date: Mon, 22 Feb 2021 09:51:38 -0700 Message-ID: <161401269874.16443.4238313694176658818.stgit@gimli.home> In-Reply-To: <161401167013.16443.8389863523766611711.stgit@gimli.home> References: <161401167013.16443.8389863523766611711.stgit@gimli.home> User-Agent: StGit/0.21-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Using a vfio device, a notifier block can be registered to receive select device events. Notifiers can only be registered for contained devices, ie. they are available through a user context. Registration of a notifier increments the reference to that container context therefore notifiers must minimally respond to the release event by asynchronously removing notifiers. Signed-off-by: Alex Williamson --- drivers/vfio/Kconfig | 1 + drivers/vfio/vfio.c | 35 +++++++++++++++++++++++++++++++++++ include/linux/vfio.h | 9 +++++++++ 3 files changed, 45 insertions(+) diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig index 5533df91b257..8ac1601b681b 100644 --- a/drivers/vfio/Kconfig +++ b/drivers/vfio/Kconfig @@ -23,6 +23,7 @@ menuconfig VFIO tristate "VFIO Non-Privileged userspace driver framework" depends on IOMMU_API select VFIO_IOMMU_TYPE1 if (X86 || S390 || ARM || ARM64) + select SRCU help VFIO provides a framework for secure userspace device drivers. See Documentation/driver-api/vfio.rst for more details. diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 399c42b77fbb..1a1b46215ac4 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -105,6 +105,7 @@ struct vfio_device { struct list_head group_next; void *device_data; struct inode *inode; + struct srcu_notifier_head notifier; }; #ifdef CONFIG_VFIO_NOIOMMU @@ -610,6 +611,7 @@ struct vfio_device *vfio_group_create_device(struct vfio_group *group, device->ops = ops; device->device_data = device_data; dev_set_drvdata(dev, device); + srcu_init_notifier_head(&device->notifier); /* No need to get group_lock, caller has group reference */ vfio_group_get(group); @@ -1778,6 +1780,39 @@ static const struct file_operations vfio_device_fops = { .mmap = vfio_device_fops_mmap, }; +int vfio_device_register_notifier(struct vfio_device *device, + struct notifier_block *nb) +{ + int ret; + + /* Container ref persists until unregister on success */ + ret = vfio_group_add_container_user(device->group); + if (ret) + return ret; + + ret = srcu_notifier_chain_register(&device->notifier, nb); + if (ret) + vfio_group_try_dissolve_container(device->group); + + return ret; +} +EXPORT_SYMBOL_GPL(vfio_device_register_notifier); + +void vfio_device_unregister_notifier(struct vfio_device *device, + struct notifier_block *nb) +{ + if (!srcu_notifier_chain_unregister(&device->notifier, nb)) + vfio_group_try_dissolve_container(device->group); +} +EXPORT_SYMBOL_GPL(vfio_device_unregister_notifier); + +int vfio_device_notifier_call(struct vfio_device *device, + enum vfio_device_notify_type event) +{ + return srcu_notifier_call_chain(&device->notifier, event, NULL); +} +EXPORT_SYMBOL_GPL(vfio_device_notifier_call); + /** * External user API, exported by symbols to be linked dynamically. * diff --git a/include/linux/vfio.h b/include/linux/vfio.h index 188c2f3feed9..8217cd4ea53d 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -60,6 +60,15 @@ extern void vfio_device_unmap_mapping_range(struct vfio_device *device, loff_t start, loff_t len); extern void vfio_device_vma_open(struct vm_area_struct *vma); extern struct vfio_device *vfio_device_get_from_vma(struct vm_area_struct *vma); +extern int vfio_device_register_notifier(struct vfio_device *device, + struct notifier_block *nb); +extern void vfio_device_unregister_notifier(struct vfio_device *device, + struct notifier_block *nb); +enum vfio_device_notify_type { + VFIO_DEVICE_RELEASE = 0, +}; +int vfio_device_notifier_call(struct vfio_device *device, + enum vfio_device_notify_type event); /* events for the backend driver notify callback */ enum vfio_iommu_notify_type {