From patchwork Mon Feb 27 11:11:29 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yi Liu X-Patchwork-Id: 13153251 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 3178AC64ED6 for ; Mon, 27 Feb 2023 11:12:18 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id BEB0110E3DA; Mon, 27 Feb 2023 11:12:17 +0000 (UTC) Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by gabe.freedesktop.org (Postfix) with ESMTPS id 93B3A10E3BE; Mon, 27 Feb 2023 11:11:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1677496307; x=1709032307; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=TnrlnqPITmFu04vuqNlTbI4Gcrw9Bgh9GHe8hfhk1Vw=; b=Js5nBh2pPfDaZPtHTRWaP6oMsKTt/ZvapJvwGh3pybclRNyCMEtJ1OZv 2ISKOMj7ynetWW5r196qgyo1ZOuSfSl+1A52y31u4EYUiGLr7UhxtZZwg bZXoQV/tGozAZkCoKcPh8gEfiFvH/Dn4i7HAL9QnrkFRbRhxzH55caf69 k4UmeST6bg3qzHtlgDrG2cmP8U3CvpkK2NziMxPNensxHy5h2Mm26oBZ3 oLUeonDqLdr1bLrP72zcB6xX48hD47V+oSIPM0ouRRw2fjmsOKSam9sAw qjrAqReetc+3kJ/fcRMPKySUYF95DJlP9WzasDPKygieYaYZLGGLtG31V g==; X-IronPort-AV: E=McAfee;i="6500,9779,10633"; a="420097714" X-IronPort-AV: E=Sophos;i="5.97,331,1669104000"; d="scan'208";a="420097714" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Feb 2023 03:11:47 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10633"; a="651189573" X-IronPort-AV: E=Sophos;i="5.97,331,1669104000"; d="scan'208";a="651189573" Received: from 984fee00a4c6.jf.intel.com ([10.165.58.231]) by orsmga006.jf.intel.com with ESMTP; 27 Feb 2023 03:11:46 -0800 From: Yi Liu To: alex.williamson@redhat.com, jgg@nvidia.com, kevin.tian@intel.com Date: Mon, 27 Feb 2023 03:11:29 -0800 Message-Id: <20230227111135.61728-14-yi.l.liu@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230227111135.61728-1-yi.l.liu@intel.com> References: <20230227111135.61728-1-yi.l.liu@intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH v5 13/19] vfio: Add cdev_device_open_cnt to vfio_group X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-s390@vger.kernel.org, yi.l.liu@intel.com, yi.y.sun@linux.intel.com, mjrosato@linux.ibm.com, kvm@vger.kernel.org, intel-gvt-dev@lists.freedesktop.org, joro@8bytes.org, cohuck@redhat.com, xudong.hao@intel.com, peterx@redhat.com, yan.y.zhao@intel.com, eric.auger@redhat.com, terrence.xu@intel.com, nicolinc@nvidia.com, shameerali.kolothum.thodi@huawei.com, suravee.suthikulpanit@amd.com, intel-gfx@lists.freedesktop.org, chao.p.peng@linux.intel.com, lulu@redhat.com, robin.murphy@arm.com, jasowang@redhat.com Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" for counting the devices that are opened via the cdev path. This count is increased and decreased by the cdev path. The group path checks it to achieve exclusion with the cdev path. With this, only one path (group path or cdev path) will claim DMA ownership. This avoids scenarios in which devices within the same group may be opened via different paths. Signed-off-by: Yi Liu Reviewed-by: Kevin Tian Reviewed-by: Jason Gunthorpe --- drivers/vfio/group.c | 33 +++++++++++++++++++++++++++++++++ drivers/vfio/vfio.h | 3 +++ 2 files changed, 36 insertions(+) diff --git a/drivers/vfio/group.c b/drivers/vfio/group.c index e44232551448..d4d78d63db06 100644 --- a/drivers/vfio/group.c +++ b/drivers/vfio/group.c @@ -387,6 +387,33 @@ static long vfio_group_fops_unl_ioctl(struct file *filep, } } +int vfio_device_block_group(struct vfio_device *device) +{ + struct vfio_group *group = device->group; + int ret = 0; + + mutex_lock(&group->group_lock); + if (group->opened_file) { + ret = -EBUSY; + goto out_unlock; + } + + group->cdev_device_open_cnt++; + +out_unlock: + mutex_unlock(&group->group_lock); + return ret; +} + +void vfio_device_unblock_group(struct vfio_device *device) +{ + struct vfio_group *group = device->group; + + mutex_lock(&group->group_lock); + group->cdev_device_open_cnt--; + mutex_unlock(&group->group_lock); +} + static int vfio_group_fops_open(struct inode *inode, struct file *filep) { struct vfio_group *group = @@ -409,6 +436,11 @@ static int vfio_group_fops_open(struct inode *inode, struct file *filep) goto out_unlock; } + if (group->cdev_device_open_cnt) { + ret = -EBUSY; + goto out_unlock; + } + /* * Do we need multiple instances of the group open? Seems not. */ @@ -483,6 +515,7 @@ static void vfio_group_release(struct device *dev) mutex_destroy(&group->device_lock); mutex_destroy(&group->group_lock); WARN_ON(group->iommu_group); + WARN_ON(group->cdev_device_open_cnt); ida_free(&vfio.group_ida, MINOR(group->dev.devt)); kfree(group); } diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h index 04d2bd2e314d..a61d4df30716 100644 --- a/drivers/vfio/vfio.h +++ b/drivers/vfio/vfio.h @@ -84,8 +84,11 @@ struct vfio_group { struct blocking_notifier_head notifier; struct iommufd_ctx *iommufd; spinlock_t kvm_ref_lock; + unsigned int cdev_device_open_cnt; }; +int vfio_device_block_group(struct vfio_device *device); +void vfio_device_unblock_group(struct vfio_device *device); int vfio_device_set_group(struct vfio_device *device, enum vfio_group_type type); void vfio_device_remove_group(struct vfio_device *device);