From patchwork Wed Jul 6 07:42:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 12907467 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 DB6D3C433EF for ; Wed, 6 Jul 2022 07:43:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231491AbiGFHnb (ORCPT ); Wed, 6 Jul 2022 03:43:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59576 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231892AbiGFHnW (ORCPT ); Wed, 6 Jul 2022 03:43:22 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A4D4C22BE8; Wed, 6 Jul 2022 00:43:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=5Ajl/tFHQLoMgXVwluAwsv9O0zp854GlZxbgDKDVmRU=; b=AyNV0saI6ntcLSexk38muaff4w gHfeRwS1JxURyRhHf1veWhiGQ43FIGKRwnAPCQN+M+KVjy9ZFzRzyV8ZRtq3pqz0IhTcPfWSf391x it1WNgEurWWLsHXSpiQOqec38ncknzsmcz9hi57p/u1RurkbDHAf6k+T4eSmCKJgkd3RF/XiNWFt6 kqkuDWHIosk+AG1JUwfbf0WohhogDZTcMHFuN8KWVCvUj/+QTNvdzQuVgQa16CvMLp157feDX/nha eV2F1FWwEAEu2xtlebPNxO9GaD6JAtE5TM+AyKwZwbQrqKU/edTvrMgmCNLuS/nFRQrmi7eFWMeZX NRjlKKbg==; Received: from [2001:4bb8:189:3c4a:34cd:2d1d:8766:aad] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1o8zgg-0079yt-00; Wed, 06 Jul 2022 07:43:06 +0000 From: Christoph Hellwig To: Kirti Wankhede , Tony Krowiak , Halil Pasic , Jason Herne , Eric Farman , Matthew Rosato , Zhenyu Wang , Zhi Wang , Alex Williamson Cc: Jason Gunthorpe , kvm@vger.kernel.org, linux-s390@vger.kernel.org, intel-gvt-dev@lists.freedesktop.org, Kevin Tian Subject: [PATCH 14/15] vfio/mdev: add mdev available instance checking to the core Date: Wed, 6 Jul 2022 09:42:18 +0200 Message-Id: <20220706074219.3614-15-hch@lst.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220706074219.3614-1-hch@lst.de> References: <20220706074219.3614-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Many of the mdev drivers use a simple counter for keeping track of the available instances. Move this code to the core code and store the counter in the mdev_parent. Implement it using correct locking, fixing mdpy. Drivers just provide the value in the mdev_driver at registration time and the core code takes care of maintaining it and exposing the value in sysfs. Signed-off-by: Jason Gunthorpe [count instances per-parent instead of per-type] Signed-off-by: Christoph Hellwig Reviewed-by: Kevin Tian Reviewed-by: Kirti Wankhede --- drivers/s390/cio/vfio_ccw_drv.c | 1 - drivers/s390/cio/vfio_ccw_ops.c | 14 +------------- drivers/s390/cio/vfio_ccw_private.h | 2 -- drivers/s390/crypto/vfio_ap_ops.c | 21 +++------------------ drivers/s390/crypto/vfio_ap_private.h | 2 -- drivers/vfio/mdev/mdev_core.c | 18 +++++++++++++++--- include/linux/mdev.h | 3 +++ samples/vfio-mdev/mdpy.c | 23 ++++------------------- 8 files changed, 26 insertions(+), 58 deletions(-) diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c index 750d0315f1f5b..449c76b29a3b5 100644 --- a/drivers/s390/cio/vfio_ccw_drv.c +++ b/drivers/s390/cio/vfio_ccw_drv.c @@ -149,7 +149,6 @@ static struct vfio_ccw_private *vfio_ccw_alloc_private(struct subchannel *sch) INIT_LIST_HEAD(&private->crw); INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo); INIT_WORK(&private->crw_work, vfio_ccw_crw_todo); - atomic_set(&private->avail, 1); private->cp.guest_cp = kcalloc(CCWCHAIN_LEN_MAX, sizeof(struct ccw1), GFP_KERNEL); diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c index 6f6a0f2695059..c05d80add7be2 100644 --- a/drivers/s390/cio/vfio_ccw_ops.c +++ b/drivers/s390/cio/vfio_ccw_ops.c @@ -70,13 +70,6 @@ static int vfio_ccw_mdev_notifier(struct notifier_block *nb, return NOTIFY_DONE; } -static unsigned int vfio_ccw_get_available(struct mdev_type *mtype) -{ - struct vfio_ccw_private *private = dev_get_drvdata(mtype->parent->dev); - - return atomic_read(&private->avail); -} - static int vfio_ccw_mdev_probe(struct mdev_device *mdev) { struct vfio_ccw_private *private = dev_get_drvdata(mdev->dev.parent); @@ -85,9 +78,6 @@ static int vfio_ccw_mdev_probe(struct mdev_device *mdev) if (private->state == VFIO_CCW_STATE_NOT_OPER) return -ENODEV; - if (atomic_dec_if_positive(&private->avail) < 0) - return -EPERM; - memset(&private->vdev, 0, sizeof(private->vdev)); vfio_init_group_dev(&private->vdev, &mdev->dev, &vfio_ccw_dev_ops); @@ -108,7 +98,6 @@ static int vfio_ccw_mdev_probe(struct mdev_device *mdev) err_atomic: vfio_uninit_group_dev(&private->vdev); - atomic_inc(&private->avail); private->mdev = NULL; private->state = VFIO_CCW_STATE_IDLE; return ret; @@ -135,7 +124,6 @@ static void vfio_ccw_mdev_remove(struct mdev_device *mdev) vfio_uninit_group_dev(&private->vdev); cp_free(&private->cp); private->mdev = NULL; - atomic_inc(&private->avail); } static int vfio_ccw_mdev_open_device(struct vfio_device *vdev) @@ -613,6 +601,7 @@ static const struct vfio_device_ops vfio_ccw_dev_ops = { struct mdev_driver vfio_ccw_mdev_driver = { .device_api = VFIO_DEVICE_API_CCW_STRING, + .max_instances = 1, .driver = { .name = "vfio_ccw_mdev", .owner = THIS_MODULE, @@ -620,7 +609,6 @@ struct mdev_driver vfio_ccw_mdev_driver = { }, .probe = vfio_ccw_mdev_probe, .remove = vfio_ccw_mdev_remove, - .get_available = vfio_ccw_get_available, }; int vfio_ccw_mdev_reg(struct subchannel *sch) diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h index b7163bac8cc75..9be5baed0cb7f 100644 --- a/drivers/s390/cio/vfio_ccw_private.h +++ b/drivers/s390/cio/vfio_ccw_private.h @@ -72,7 +72,6 @@ struct vfio_ccw_crw { * @sch: pointer to the subchannel * @state: internal state of the device * @completion: synchronization helper of the I/O completion - * @avail: available for creating a mediated device * @mdev: pointer to the mediated device * @nb: notifier for vfio events * @io_region: MMIO region to input/output I/O arguments/results @@ -96,7 +95,6 @@ struct vfio_ccw_private { struct subchannel *sch; int state; struct completion *completion; - atomic_t avail; struct mdev_device *mdev; struct notifier_block nb; struct ccw_io_region *io_region; diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c index edeec11c56560..69ed88fdaf383 100644 --- a/drivers/s390/crypto/vfio_ap_ops.c +++ b/drivers/s390/crypto/vfio_ap_ops.c @@ -461,14 +461,9 @@ static int vfio_ap_mdev_probe(struct mdev_device *mdev) struct ap_matrix_mdev *matrix_mdev; int ret; - if ((atomic_dec_if_positive(&matrix_dev->available_instances) < 0)) - return -EPERM; - matrix_mdev = kzalloc(sizeof(*matrix_mdev), GFP_KERNEL); - if (!matrix_mdev) { - ret = -ENOMEM; - goto err_dec_available; - } + if (!matrix_mdev) + return -ENOMEM; vfio_init_group_dev(&matrix_mdev->vdev, &mdev->dev, &vfio_ap_matrix_dev_ops); @@ -491,8 +486,6 @@ static int vfio_ap_mdev_probe(struct mdev_device *mdev) mutex_unlock(&matrix_dev->lock); vfio_uninit_group_dev(&matrix_mdev->vdev); kfree(matrix_mdev); -err_dec_available: - atomic_inc(&matrix_dev->available_instances); return ret; } @@ -508,12 +501,6 @@ static void vfio_ap_mdev_remove(struct mdev_device *mdev) mutex_unlock(&matrix_dev->lock); vfio_uninit_group_dev(&matrix_mdev->vdev); kfree(matrix_mdev); - atomic_inc(&matrix_dev->available_instances); -} - -static unsigned int vfio_ap_mdev_get_available(struct mdev_type *mtype) -{ - return atomic_read(&matrix_dev->available_instances); } struct vfio_ap_queue_reserved { @@ -1427,6 +1414,7 @@ static const struct vfio_device_ops vfio_ap_matrix_dev_ops = { static struct mdev_driver vfio_ap_matrix_driver = { .device_api = VFIO_DEVICE_API_AP_STRING, + .max_instances = MAX_ZDEV_ENTRIES_EXT, .driver = { .name = "vfio_ap_mdev", .owner = THIS_MODULE, @@ -1435,15 +1423,12 @@ static struct mdev_driver vfio_ap_matrix_driver = { }, .probe = vfio_ap_mdev_probe, .remove = vfio_ap_mdev_remove, - .get_available = vfio_ap_mdev_get_available, }; int vfio_ap_mdev_register(void) { int ret; - atomic_set(&matrix_dev->available_instances, MAX_ZDEV_ENTRIES_EXT); - ret = mdev_register_driver(&vfio_ap_matrix_driver); if (ret) return ret; diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h index 5dc5050d03791..b808b343b771f 100644 --- a/drivers/s390/crypto/vfio_ap_private.h +++ b/drivers/s390/crypto/vfio_ap_private.h @@ -28,7 +28,6 @@ * struct ap_matrix_dev - Contains the data for the matrix device. * * @device: generic device structure associated with the AP matrix device - * @available_instances: number of mediated matrix devices that can be created * @info: the struct containing the output from the PQAP(QCI) instruction * @mdev_list: the list of mediated matrix devices created * @lock: mutex for locking the AP matrix device. This lock will be @@ -40,7 +39,6 @@ */ struct ap_matrix_dev { struct device device; - atomic_t available_instances; struct ap_config_info info; struct list_head mdev_list; struct mutex lock; diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c index 93f8caf2e5f77..9bc897235c492 100644 --- a/drivers/vfio/mdev/mdev_core.c +++ b/drivers/vfio/mdev/mdev_core.c @@ -70,6 +70,7 @@ int mdev_register_parent(struct mdev_parent *parent, struct device *dev, parent->mdev_driver = mdev_driver; parent->types = types; parent->nr_types = nr_types; + parent->available_instances = mdev_driver->max_instances; if (!mdev_bus_compat_class) { mdev_bus_compat_class = class_compat_register("mdev_bus"); @@ -115,14 +116,17 @@ EXPORT_SYMBOL(mdev_unregister_parent); static void mdev_device_release(struct device *dev) { struct mdev_device *mdev = to_mdev_device(dev); - - /* Pairs with the get in mdev_device_create() */ - kobject_put(&mdev->type->kobj); + struct mdev_parent *parent = mdev->type->parent; mutex_lock(&mdev_list_lock); list_del(&mdev->next); + if (!parent->mdev_driver->get_available) + parent->available_instances++; mutex_unlock(&mdev_list_lock); + /* Pairs with the get in mdev_device_create() */ + kobject_put(&mdev->type->kobj); + dev_dbg(&mdev->dev, "MDEV: destroying\n"); kfree(mdev); } @@ -144,6 +148,14 @@ int mdev_device_create(struct mdev_type *type, const guid_t *uuid) } } + if (!drv->get_available) { + if (!parent->available_instances) { + mutex_unlock(&mdev_list_lock); + return -EUSERS; + } + parent->available_instances--; + } + mdev = kzalloc(sizeof(*mdev), GFP_KERNEL); if (!mdev) { mutex_unlock(&mdev_list_lock); diff --git a/include/linux/mdev.h b/include/linux/mdev.h index dc38ad2b07883..641ed18a61247 100644 --- a/include/linux/mdev.h +++ b/include/linux/mdev.h @@ -45,6 +45,7 @@ struct mdev_parent { struct rw_semaphore unreg_sem; struct mdev_type **types; unsigned int nr_types; + unsigned int available_instances; }; static inline struct mdev_device *to_mdev_device(struct device *dev) @@ -55,6 +56,7 @@ static inline struct mdev_device *to_mdev_device(struct device *dev) /** * struct mdev_driver - Mediated device driver * @device_api: string to return for the device_api sysfs + * @max_instances: maximum number of instances supported (optional) * @probe: called when new device created * @remove: called when device removed * @get_available: Return the max number of instances that can be created @@ -63,6 +65,7 @@ static inline struct mdev_device *to_mdev_device(struct device *dev) **/ struct mdev_driver { const char *device_api; + unsigned int max_instances; int (*probe)(struct mdev_device *dev); void (*remove)(struct mdev_device *dev); unsigned int (*get_available)(struct mdev_type *mtype); diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c index 250b7ea2df2e4..7f7ac5491407e 100644 --- a/samples/vfio-mdev/mdpy.c +++ b/samples/vfio-mdev/mdpy.c @@ -42,11 +42,6 @@ MODULE_LICENSE("GPL v2"); -static int max_devices = 4; -module_param_named(count, max_devices, int, 0444); -MODULE_PARM_DESC(count, "number of " MDPY_NAME " devices"); - - #define MDPY_TYPE_1 "vga" #define MDPY_TYPE_2 "xga" #define MDPY_TYPE_3 "hd" @@ -93,7 +88,6 @@ static struct class *mdpy_class; static struct cdev mdpy_cdev; static struct device mdpy_dev; static struct mdev_parent mdpy_parent; -static u32 mdpy_count; static const struct vfio_device_ops mdpy_dev_ops; /* State of each mdev device */ @@ -234,9 +228,6 @@ static int mdpy_probe(struct mdev_device *mdev) u32 fbsize; int ret; - if (mdpy_count >= max_devices) - return -ENOMEM; - mdev_state = kzalloc(sizeof(struct mdev_state), GFP_KERNEL); if (mdev_state == NULL) return -ENOMEM; @@ -265,8 +256,6 @@ static int mdpy_probe(struct mdev_device *mdev) mdpy_create_config_space(mdev_state); mdpy_reset(mdev_state); - mdpy_count++; - ret = vfio_register_emulated_iommu_dev(&mdev_state->vdev); if (ret) goto err_mem; @@ -293,8 +282,6 @@ static void mdpy_remove(struct mdev_device *mdev) kfree(mdev_state->vconfig); vfio_uninit_group_dev(&mdev_state->vdev); kfree(mdev_state); - - mdpy_count--; } static ssize_t mdpy_read(struct vfio_device *vdev, char __user *buf, @@ -658,11 +645,6 @@ static ssize_t mdpy_show_description(struct mdev_type *mtype, char *buf) type->width, type->height); } -static unsigned int mdpy_get_available(struct mdev_type *mtype) -{ - return max_devices - mdpy_count; -} - static const struct vfio_device_ops mdpy_dev_ops = { .read = mdpy_read, .write = mdpy_write, @@ -672,6 +654,7 @@ static const struct vfio_device_ops mdpy_dev_ops = { static struct mdev_driver mdpy_driver = { .device_api = VFIO_DEVICE_API_PCI_STRING, + .max_instances = 4, .driver = { .name = "mdpy", .owner = THIS_MODULE, @@ -680,7 +663,6 @@ static struct mdev_driver mdpy_driver = { }, .probe = mdpy_probe, .remove = mdpy_remove, - .get_available = mdpy_get_available, .show_description = mdpy_show_description, }; @@ -757,5 +739,8 @@ static void __exit mdpy_dev_exit(void) mdpy_class = NULL; } +module_param_named(count, mdpy_driver.max_instances, int, 0444); +MODULE_PARM_DESC(count, "number of " MDPY_NAME " devices"); + module_init(mdpy_dev_init) module_exit(mdpy_dev_exit)