]> asedeno.scripts.mit.edu Git - linux.git/commitdiff
dmaengine: idxd: add char driver to expose submission portal to userland
authorDave Jiang <dave.jiang@intel.com>
Tue, 21 Jan 2020 23:44:29 +0000 (16:44 -0700)
committerVinod Koul <vkoul@kernel.org>
Fri, 24 Jan 2020 05:48:45 +0000 (11:18 +0530)
Create a char device region that will allow acquisition of user portals in
order to allow applications to submit DMA operations. A char device will be
created per work queue that gets exposed. The workqueue type "user"
is used to mark a work queue for user char device. For example if the
workqueue 0 of DSA device 0 is marked for char device, then a device node
of /dev/dsa/wq0.0 will be created.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/157965026985.73301.976523230037106742.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
drivers/dma/idxd/Makefile
drivers/dma/idxd/cdev.c [new file with mode: 0644]
drivers/dma/idxd/device.c
drivers/dma/idxd/idxd.h
drivers/dma/idxd/init.c
drivers/dma/idxd/irq.c
drivers/dma/idxd/submit.c
drivers/dma/idxd/sysfs.c

index a036ba0e77d2264989fa4d7ff05baf9574391fb7..8978b898d777075b36da88868a997f2c09f39a22 100644 (file)
@@ -1,2 +1,2 @@
 obj-$(CONFIG_INTEL_IDXD) += idxd.o
-idxd-y := init.o irq.o device.o sysfs.o submit.o dma.o
+idxd-y := init.o irq.o device.o sysfs.o submit.o dma.o cdev.o
diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c
new file mode 100644 (file)
index 0000000..1d73478
--- /dev/null
@@ -0,0 +1,302 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2019 Intel Corporation. All rights rsvd. */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/device.h>
+#include <linux/sched/task.h>
+#include <linux/intel-svm.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/cdev.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <uapi/linux/idxd.h>
+#include "registers.h"
+#include "idxd.h"
+
+struct idxd_cdev_context {
+       const char *name;
+       dev_t devt;
+       struct ida minor_ida;
+};
+
+/*
+ * ictx is an array based off of accelerator types. enum idxd_type
+ * is used as index
+ */
+static struct idxd_cdev_context ictx[IDXD_TYPE_MAX] = {
+       { .name = "dsa" },
+};
+
+struct idxd_user_context {
+       struct idxd_wq *wq;
+       struct task_struct *task;
+       unsigned int flags;
+};
+
+enum idxd_cdev_cleanup {
+       CDEV_NORMAL = 0,
+       CDEV_FAILED,
+};
+
+static void idxd_cdev_dev_release(struct device *dev)
+{
+       dev_dbg(dev, "releasing cdev device\n");
+       kfree(dev);
+}
+
+static struct device_type idxd_cdev_device_type = {
+       .name = "idxd_cdev",
+       .release = idxd_cdev_dev_release,
+};
+
+static inline struct idxd_cdev *inode_idxd_cdev(struct inode *inode)
+{
+       struct cdev *cdev = inode->i_cdev;
+
+       return container_of(cdev, struct idxd_cdev, cdev);
+}
+
+static inline struct idxd_wq *idxd_cdev_wq(struct idxd_cdev *idxd_cdev)
+{
+       return container_of(idxd_cdev, struct idxd_wq, idxd_cdev);
+}
+
+static inline struct idxd_wq *inode_wq(struct inode *inode)
+{
+       return idxd_cdev_wq(inode_idxd_cdev(inode));
+}
+
+static int idxd_cdev_open(struct inode *inode, struct file *filp)
+{
+       struct idxd_user_context *ctx;
+       struct idxd_device *idxd;
+       struct idxd_wq *wq;
+       struct device *dev;
+       struct idxd_cdev *idxd_cdev;
+
+       wq = inode_wq(inode);
+       idxd = wq->idxd;
+       dev = &idxd->pdev->dev;
+       idxd_cdev = &wq->idxd_cdev;
+
+       dev_dbg(dev, "%s called\n", __func__);
+
+       if (idxd_wq_refcount(wq) > 1 && wq_dedicated(wq))
+               return -EBUSY;
+
+       ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+       if (!ctx)
+               return -ENOMEM;
+
+       ctx->wq = wq;
+       filp->private_data = ctx;
+       idxd_wq_get(wq);
+       return 0;
+}
+
+static int idxd_cdev_release(struct inode *node, struct file *filep)
+{
+       struct idxd_user_context *ctx = filep->private_data;
+       struct idxd_wq *wq = ctx->wq;
+       struct idxd_device *idxd = wq->idxd;
+       struct device *dev = &idxd->pdev->dev;
+
+       dev_dbg(dev, "%s called\n", __func__);
+       filep->private_data = NULL;
+
+       kfree(ctx);
+       idxd_wq_put(wq);
+       return 0;
+}
+
+static int check_vma(struct idxd_wq *wq, struct vm_area_struct *vma,
+                    const char *func)
+{
+       struct device *dev = &wq->idxd->pdev->dev;
+
+       if ((vma->vm_end - vma->vm_start) > PAGE_SIZE) {
+               dev_info_ratelimited(dev,
+                                    "%s: %s: mapping too large: %lu\n",
+                                    current->comm, func,
+                                    vma->vm_end - vma->vm_start);
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+static int idxd_cdev_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+       struct idxd_user_context *ctx = filp->private_data;
+       struct idxd_wq *wq = ctx->wq;
+       struct idxd_device *idxd = wq->idxd;
+       struct pci_dev *pdev = idxd->pdev;
+       phys_addr_t base = pci_resource_start(pdev, IDXD_WQ_BAR);
+       unsigned long pfn;
+       int rc;
+
+       dev_dbg(&pdev->dev, "%s called\n", __func__);
+       rc = check_vma(wq, vma, __func__);
+
+       vma->vm_flags |= VM_DONTCOPY;
+       pfn = (base + idxd_get_wq_portal_full_offset(wq->id,
+                               IDXD_PORTAL_LIMITED)) >> PAGE_SHIFT;
+       vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+       vma->vm_private_data = ctx;
+
+       return io_remap_pfn_range(vma, vma->vm_start, pfn, PAGE_SIZE,
+                       vma->vm_page_prot);
+}
+
+static __poll_t idxd_cdev_poll(struct file *filp,
+                              struct poll_table_struct *wait)
+{
+       struct idxd_user_context *ctx = filp->private_data;
+       struct idxd_wq *wq = ctx->wq;
+       struct idxd_device *idxd = wq->idxd;
+       struct idxd_cdev *idxd_cdev = &wq->idxd_cdev;
+       unsigned long flags;
+       __poll_t out = 0;
+
+       poll_wait(filp, &idxd_cdev->err_queue, wait);
+       spin_lock_irqsave(&idxd->dev_lock, flags);
+       if (idxd->sw_err.valid)
+               out = EPOLLIN | EPOLLRDNORM;
+       spin_unlock_irqrestore(&idxd->dev_lock, flags);
+
+       return out;
+}
+
+static const struct file_operations idxd_cdev_fops = {
+       .owner = THIS_MODULE,
+       .open = idxd_cdev_open,
+       .release = idxd_cdev_release,
+       .mmap = idxd_cdev_mmap,
+       .poll = idxd_cdev_poll,
+};
+
+int idxd_cdev_get_major(struct idxd_device *idxd)
+{
+       return MAJOR(ictx[idxd->type].devt);
+}
+
+static int idxd_wq_cdev_dev_setup(struct idxd_wq *wq)
+{
+       struct idxd_device *idxd = wq->idxd;
+       struct idxd_cdev *idxd_cdev = &wq->idxd_cdev;
+       struct idxd_cdev_context *cdev_ctx;
+       struct device *dev;
+       int minor, rc;
+
+       idxd_cdev->dev = kzalloc(sizeof(*idxd_cdev->dev), GFP_KERNEL);
+       if (!idxd_cdev->dev)
+               return -ENOMEM;
+
+       dev = idxd_cdev->dev;
+       dev->parent = &idxd->pdev->dev;
+       dev_set_name(dev, "%s/wq%u.%u", idxd_get_dev_name(idxd),
+                    idxd->id, wq->id);
+       dev->bus = idxd_get_bus_type(idxd);
+
+       cdev_ctx = &ictx[wq->idxd->type];
+       minor = ida_simple_get(&cdev_ctx->minor_ida, 0, MINORMASK, GFP_KERNEL);
+       if (minor < 0) {
+               rc = minor;
+               goto ida_err;
+       }
+
+       dev->devt = MKDEV(MAJOR(cdev_ctx->devt), minor);
+       dev->type = &idxd_cdev_device_type;
+       rc = device_register(dev);
+       if (rc < 0) {
+               dev_err(&idxd->pdev->dev, "device register failed\n");
+               put_device(dev);
+               goto dev_reg_err;
+       }
+       idxd_cdev->minor = minor;
+
+       return 0;
+
+ dev_reg_err:
+       ida_simple_remove(&cdev_ctx->minor_ida, MINOR(dev->devt));
+ ida_err:
+       kfree(dev);
+       idxd_cdev->dev = NULL;
+       return rc;
+}
+
+static void idxd_wq_cdev_cleanup(struct idxd_wq *wq,
+                                enum idxd_cdev_cleanup cdev_state)
+{
+       struct idxd_cdev *idxd_cdev = &wq->idxd_cdev;
+       struct idxd_cdev_context *cdev_ctx;
+
+       cdev_ctx = &ictx[wq->idxd->type];
+       if (cdev_state == CDEV_NORMAL)
+               cdev_del(&idxd_cdev->cdev);
+       device_unregister(idxd_cdev->dev);
+       /*
+        * The device_type->release() will be called on the device and free
+        * the allocated struct device. We can just forget it.
+        */
+       ida_simple_remove(&cdev_ctx->minor_ida, idxd_cdev->minor);
+       idxd_cdev->dev = NULL;
+       idxd_cdev->minor = -1;
+}
+
+int idxd_wq_add_cdev(struct idxd_wq *wq)
+{
+       struct idxd_cdev *idxd_cdev = &wq->idxd_cdev;
+       struct cdev *cdev = &idxd_cdev->cdev;
+       struct device *dev;
+       int rc;
+
+       rc = idxd_wq_cdev_dev_setup(wq);
+       if (rc < 0)
+               return rc;
+
+       dev = idxd_cdev->dev;
+       cdev_init(cdev, &idxd_cdev_fops);
+       cdev_set_parent(cdev, &dev->kobj);
+       rc = cdev_add(cdev, dev->devt, 1);
+       if (rc) {
+               dev_dbg(&wq->idxd->pdev->dev, "cdev_add failed: %d\n", rc);
+               idxd_wq_cdev_cleanup(wq, CDEV_FAILED);
+               return rc;
+       }
+
+       init_waitqueue_head(&idxd_cdev->err_queue);
+       return 0;
+}
+
+void idxd_wq_del_cdev(struct idxd_wq *wq)
+{
+       idxd_wq_cdev_cleanup(wq, CDEV_NORMAL);
+}
+
+int idxd_cdev_register(void)
+{
+       int rc, i;
+
+       for (i = 0; i < IDXD_TYPE_MAX; i++) {
+               ida_init(&ictx[i].minor_ida);
+               rc = alloc_chrdev_region(&ictx[i].devt, 0, MINORMASK,
+                                        ictx[i].name);
+               if (rc)
+                       return rc;
+       }
+
+       return 0;
+}
+
+void idxd_cdev_remove(void)
+{
+       int i;
+
+       for (i = 0; i < IDXD_TYPE_MAX; i++) {
+               unregister_chrdev_region(ictx[i].devt, MINORMASK);
+               ida_destroy(&ictx[i].minor_ida);
+       }
+}
index b4c4cec489df907a22c39640ada6c5ccba0dcb26..ada69e722f84a7bcfbf462ce98fecf3f79921572 100644 (file)
@@ -539,7 +539,7 @@ static int idxd_wq_config_write(struct idxd_wq *wq)
        wq->wqcfg.wq_thresh = wq->threshold;
 
        /* byte 8-11 */
-       wq->wqcfg.priv = 1; /* kernel, therefore priv */
+       wq->wqcfg.priv = !!(wq->type == IDXD_WQT_KERNEL);
        wq->wqcfg.mode = 1;
 
        wq->wqcfg.priority = wq->priority;
index a36214818d1eab6ccb342a14bda6d3938a483645..b8f8a363b4a71c57213be6d5362228cab8d617b3 100644 (file)
@@ -7,6 +7,7 @@
 #include <linux/dmaengine.h>
 #include <linux/percpu-rwsem.h>
 #include <linux/wait.h>
+#include <linux/cdev.h>
 #include "registers.h"
 
 #define IDXD_DRIVER_VERSION    "1.00"
@@ -63,6 +64,14 @@ enum idxd_wq_flag {
 enum idxd_wq_type {
        IDXD_WQT_NONE = 0,
        IDXD_WQT_KERNEL,
+       IDXD_WQT_USER,
+};
+
+struct idxd_cdev {
+       struct cdev cdev;
+       struct device *dev;
+       int minor;
+       struct wait_queue_head err_queue;
 };
 
 #define IDXD_ALLOCATED_BATCH_SIZE      128U
@@ -82,6 +91,7 @@ enum idxd_complete_type {
 struct idxd_wq {
        void __iomem *dportal;
        struct device conf_dev;
+       struct idxd_cdev idxd_cdev;
        struct idxd_device *idxd;
        int id;
        enum idxd_wq_type type;
@@ -145,6 +155,7 @@ struct idxd_device {
        enum idxd_device_state state;
        unsigned long flags;
        int id;
+       int major;
 
        struct pci_dev *pdev;
        void __iomem *reg_base;
@@ -196,11 +207,29 @@ struct idxd_desc {
 #define confdev_to_idxd(dev) container_of(dev, struct idxd_device, conf_dev)
 #define confdev_to_wq(dev) container_of(dev, struct idxd_wq, conf_dev)
 
+extern struct bus_type dsa_bus_type;
+
 static inline bool wq_dedicated(struct idxd_wq *wq)
 {
        return test_bit(WQ_FLAG_DEDICATED, &wq->flags);
 }
 
+enum idxd_portal_prot {
+       IDXD_PORTAL_UNLIMITED = 0,
+       IDXD_PORTAL_LIMITED,
+};
+
+static inline int idxd_get_wq_portal_offset(enum idxd_portal_prot prot)
+{
+       return prot * 0x1000;
+}
+
+static inline int idxd_get_wq_portal_full_offset(int wq_id,
+                                                enum idxd_portal_prot prot)
+{
+       return ((wq_id * 4) << PAGE_SHIFT) + idxd_get_wq_portal_offset(prot);
+}
+
 static inline void idxd_set_type(struct idxd_device *idxd)
 {
        struct pci_dev *pdev = idxd->pdev;
@@ -233,6 +262,7 @@ int idxd_setup_sysfs(struct idxd_device *idxd);
 void idxd_cleanup_sysfs(struct idxd_device *idxd);
 int idxd_register_driver(void);
 void idxd_unregister_driver(void);
+struct bus_type *idxd_get_bus_type(struct idxd_device *idxd);
 
 /* device interrupt control */
 irqreturn_t idxd_irq_handler(int vec, void *data);
@@ -276,4 +306,11 @@ void idxd_dma_complete_txd(struct idxd_desc *desc,
                           enum idxd_complete_type comp_type);
 dma_cookie_t idxd_dma_tx_submit(struct dma_async_tx_descriptor *tx);
 
+/* cdev */
+int idxd_cdev_register(void);
+void idxd_cdev_remove(void);
+int idxd_cdev_get_major(struct idxd_device *idxd);
+int idxd_wq_add_cdev(struct idxd_wq *wq);
+void idxd_wq_del_cdev(struct idxd_wq *wq);
+
 #endif
index cf6e1d89dd02293e8bc674feae24234b25a3c5a2..7778c05deb5d5f1d0e6971e776360aaab6713c08 100644 (file)
@@ -188,6 +188,7 @@ static int idxd_setup_internals(struct idxd_device *idxd)
                mutex_init(&wq->wq_lock);
                atomic_set(&wq->dq_count, 0);
                init_waitqueue_head(&wq->submit_waitq);
+               wq->idxd_cdev.minor = -1;
                rc = percpu_init_rwsem(&wq->submit_lock);
                if (rc < 0) {
                        idxd_wqs_free_lock(idxd);
@@ -321,6 +322,8 @@ static int idxd_probe(struct idxd_device *idxd)
                goto err_idr_fail;
        }
 
+       idxd->major = idxd_cdev_get_major(idxd);
+
        dev_dbg(dev, "IDXD device %d probed successfully\n", idxd->id);
        return 0;
 
@@ -501,6 +504,10 @@ static int __init idxd_init_module(void)
        if (err < 0)
                goto err_idxd_driver_register;
 
+       err = idxd_cdev_register();
+       if (err)
+               goto err_cdev_register;
+
        err = pci_register_driver(&idxd_pci_driver);
        if (err)
                goto err_pci_register;
@@ -508,6 +515,8 @@ static int __init idxd_init_module(void)
        return 0;
 
 err_pci_register:
+       idxd_cdev_remove();
+err_cdev_register:
        idxd_unregister_driver();
 err_idxd_driver_register:
        idxd_unregister_bus_type();
@@ -518,6 +527,7 @@ module_init(idxd_init_module);
 static void __exit idxd_exit_module(void)
 {
        pci_unregister_driver(&idxd_pci_driver);
+       idxd_cdev_remove();
        idxd_unregister_bus_type();
 }
 module_exit(idxd_exit_module);
index 770d408470dbd1a15369af0095b1b32ed41b1b7c..d6fcd2e601034323123255280923b60e616cab2a 100644 (file)
@@ -89,6 +89,24 @@ irqreturn_t idxd_misc_thread(int vec, void *data)
                        idxd->sw_err.bits[i] = ioread64(idxd->reg_base +
                                        IDXD_SWERR_OFFSET + i * sizeof(u64));
                iowrite64(IDXD_SWERR_ACK, idxd->reg_base + IDXD_SWERR_OFFSET);
+
+               if (idxd->sw_err.valid && idxd->sw_err.wq_idx_valid) {
+                       int id = idxd->sw_err.wq_idx;
+                       struct idxd_wq *wq = &idxd->wqs[id];
+
+                       if (wq->type == IDXD_WQT_USER)
+                               wake_up_interruptible(&wq->idxd_cdev.err_queue);
+               } else {
+                       int i;
+
+                       for (i = 0; i < idxd->max_wqs; i++) {
+                               struct idxd_wq *wq = &idxd->wqs[i];
+
+                               if (wq->type == IDXD_WQT_USER)
+                                       wake_up_interruptible(&wq->idxd_cdev.err_queue);
+                       }
+               }
+
                spin_unlock_bh(&idxd->dev_lock);
                val |= IDXD_INTC_ERR;
 
index e16cab37dda827ed100bb73330bf014f4e592dee..45a0c5869a0aff2ae129988d75ddc03eb428f34d 100644 (file)
@@ -69,17 +69,19 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
 {
        struct idxd_device *idxd = wq->idxd;
        int vec = desc->hw->int_handle;
+       void __iomem *portal;
 
        if (idxd->state != IDXD_DEV_ENABLED)
                return -EIO;
 
+       portal = wq->dportal + idxd_get_wq_portal_offset(IDXD_PORTAL_UNLIMITED);
        /*
         * The wmb() flushes writes to coherent DMA data before possibly
         * triggering a DMA read. The wmb() is necessary even on UP because
         * the recipient is a device.
         */
        wmb();
-       iosubmit_cmds512(wq->dportal, desc->hw, 1);
+       iosubmit_cmds512(portal, desc->hw, 1);
 
        /*
         * Pending the descriptor to the lockless list for the irq_entry
index f5e3f962ee6aadd7995ed02f6817b1ae3fd5a005..849c50ab939adb5c818798f1e9954a74a5d06e77 100644 (file)
@@ -13,6 +13,7 @@
 static char *idxd_wq_type_names[] = {
        [IDXD_WQT_NONE]         = "none",
        [IDXD_WQT_KERNEL]       = "kernel",
+       [IDXD_WQT_USER]         = "user",
 };
 
 static void idxd_conf_device_release(struct device *dev)
@@ -63,6 +64,11 @@ static inline bool is_idxd_wq_dmaengine(struct idxd_wq *wq)
        return false;
 }
 
+static inline bool is_idxd_wq_cdev(struct idxd_wq *wq)
+{
+       return wq->type == IDXD_WQT_USER ? true : false;
+}
+
 static int idxd_config_bus_match(struct device *dev,
                                 struct device_driver *drv)
 {
@@ -109,6 +115,9 @@ static int idxd_config_bus_probe(struct device *dev)
                        return -EBUSY;
                }
 
+               if (!try_module_get(THIS_MODULE))
+                       return -ENXIO;
+
                spin_lock_irqsave(&idxd->dev_lock, flags);
 
                /* Perform IDXD configuration and enabling */
@@ -216,6 +225,13 @@ static int idxd_config_bus_probe(struct device *dev)
                                mutex_unlock(&wq->wq_lock);
                                return rc;
                        }
+               } else if (is_idxd_wq_cdev(wq)) {
+                       rc = idxd_wq_add_cdev(wq);
+                       if (rc < 0) {
+                               dev_dbg(dev, "Cdev creation failed\n");
+                               mutex_unlock(&wq->wq_lock);
+                               return rc;
+                       }
                }
 
                mutex_unlock(&wq->wq_lock);
@@ -241,6 +257,8 @@ static void disable_wq(struct idxd_wq *wq)
 
        if (is_idxd_wq_dmaengine(wq))
                idxd_unregister_dma_channel(wq);
+       else if (is_idxd_wq_cdev(wq))
+               idxd_wq_del_cdev(wq);
 
        if (idxd_wq_refcount(wq))
                dev_warn(dev, "Clients has claim on wq %d: %d\n",
@@ -295,10 +313,12 @@ static int idxd_config_bus_remove(struct device *dev)
                spin_lock_irqsave(&idxd->dev_lock, flags);
                rc = idxd_device_disable(idxd);
                spin_unlock_irqrestore(&idxd->dev_lock, flags);
+               module_put(THIS_MODULE);
                if (rc < 0)
                        dev_warn(dev, "Device disable failed\n");
                else
                        dev_info(dev, "Device %s disabled\n", dev_name(dev));
+
        }
 
        return 0;
@@ -309,7 +329,7 @@ static void idxd_config_bus_shutdown(struct device *dev)
        dev_dbg(dev, "%s called\n", __func__);
 }
 
-static struct bus_type dsa_bus_type = {
+struct bus_type dsa_bus_type = {
        .name = "dsa",
        .match = idxd_config_bus_match,
        .probe = idxd_config_bus_probe,
@@ -334,7 +354,7 @@ static struct idxd_device_driver *idxd_drvs[] = {
        &dsa_drv
 };
 
-static struct bus_type *idxd_get_bus_type(struct idxd_device *idxd)
+struct bus_type *idxd_get_bus_type(struct idxd_device *idxd)
 {
        return idxd_bus_types[idxd->type];
 }
@@ -956,6 +976,9 @@ static ssize_t wq_type_show(struct device *dev,
        case IDXD_WQT_KERNEL:
                return sprintf(buf, "%s\n",
                               idxd_wq_type_names[IDXD_WQT_KERNEL]);
+       case IDXD_WQT_USER:
+               return sprintf(buf, "%s\n",
+                              idxd_wq_type_names[IDXD_WQT_USER]);
        case IDXD_WQT_NONE:
        default:
                return sprintf(buf, "%s\n",
@@ -978,6 +1001,8 @@ static ssize_t wq_type_store(struct device *dev,
        old_type = wq->type;
        if (sysfs_streq(buf, idxd_wq_type_names[IDXD_WQT_KERNEL]))
                wq->type = IDXD_WQT_KERNEL;
+       else if (sysfs_streq(buf, idxd_wq_type_names[IDXD_WQT_USER]))
+               wq->type = IDXD_WQT_USER;
        else
                wq->type = IDXD_WQT_NONE;
 
@@ -1020,6 +1045,17 @@ static ssize_t wq_name_store(struct device *dev,
 static struct device_attribute dev_attr_wq_name =
                __ATTR(name, 0644, wq_name_show, wq_name_store);
 
+static ssize_t wq_cdev_minor_show(struct device *dev,
+                                 struct device_attribute *attr, char *buf)
+{
+       struct idxd_wq *wq = container_of(dev, struct idxd_wq, conf_dev);
+
+       return sprintf(buf, "%d\n", wq->idxd_cdev.minor);
+}
+
+static struct device_attribute dev_attr_wq_cdev_minor =
+               __ATTR(cdev_minor, 0444, wq_cdev_minor_show, NULL);
+
 static struct attribute *idxd_wq_attributes[] = {
        &dev_attr_wq_clients.attr,
        &dev_attr_wq_state.attr,
@@ -1029,6 +1065,7 @@ static struct attribute *idxd_wq_attributes[] = {
        &dev_attr_wq_priority.attr,
        &dev_attr_wq_type.attr,
        &dev_attr_wq_name.attr,
+       &dev_attr_wq_cdev_minor.attr,
        NULL,
 };
 
@@ -1242,6 +1279,16 @@ static ssize_t token_limit_store(struct device *dev,
 }
 static DEVICE_ATTR_RW(token_limit);
 
+static ssize_t cdev_major_show(struct device *dev,
+                              struct device_attribute *attr, char *buf)
+{
+       struct idxd_device *idxd =
+               container_of(dev, struct idxd_device, conf_dev);
+
+       return sprintf(buf, "%u\n", idxd->major);
+}
+static DEVICE_ATTR_RO(cdev_major);
+
 static struct attribute *idxd_device_attributes[] = {
        &dev_attr_max_groups.attr,
        &dev_attr_max_work_queues.attr,
@@ -1257,6 +1304,7 @@ static struct attribute *idxd_device_attributes[] = {
        &dev_attr_errors.attr,
        &dev_attr_max_tokens.attr,
        &dev_attr_token_limit.attr,
+       &dev_attr_cdev_major.attr,
        NULL,
 };