1 files changed, 410 insertions, 0 deletions
diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c
new file mode 100644
index 000000000..a9b96b187
--- /dev/null
+++ b/drivers/dma/idxd/cdev.c
@@ -0,0 +1,410 @@
+// 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 <linux/iommu.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" },
+	{ .name = "iax" }
+};
+
+struct idxd_user_context {
+	struct idxd_wq *wq;
+	struct task_struct *task;
+	unsigned int pasid;
+	unsigned int flags;
+	struct iommu_sva *sva;
+};
+
+static void idxd_cdev_dev_release(struct device *dev)
+{
+	struct idxd_cdev *idxd_cdev = dev_to_cdev(dev);
+	struct idxd_cdev_context *cdev_ctx;
+	struct idxd_wq *wq = idxd_cdev->wq;
+
+	cdev_ctx = &ictx[wq->idxd->data->type];
+	ida_simple_remove(&cdev_ctx->minor_ida, idxd_cdev->minor);
+	kfree(idxd_cdev);
+}
+
+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 *inode_wq(struct inode *inode)
+{
+	struct idxd_cdev *idxd_cdev = inode_idxd_cdev(inode);
+
+	return idxd_cdev->wq;
+}
+
+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;
+	int rc = 0;
+	struct iommu_sva *sva;
+	unsigned int pasid;
+
+	wq = inode_wq(inode);
+	idxd = wq->idxd;
+	dev = &idxd->pdev->dev;
+
+	dev_dbg(dev, "%s called: %d\n", __func__, idxd_wq_refcount(wq));
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	mutex_lock(&wq->wq_lock);
+
+	if (idxd_wq_refcount(wq) > 0 && wq_dedicated(wq)) {
+		rc = -EBUSY;
+		goto failed;
+	}
+
+	ctx->wq = wq;
+	filp->private_data = ctx;
+
+	if (device_user_pasid_enabled(idxd)) {
+		sva = iommu_sva_bind_device(dev, current->mm, NULL);
+		if (IS_ERR(sva)) {
+			rc = PTR_ERR(sva);
+			dev_err(dev, "pasid allocation failed: %d\n", rc);
+			goto failed;
+		}
+
+		pasid = iommu_sva_get_pasid(sva);
+		if (pasid == IOMMU_PASID_INVALID) {
+			iommu_sva_unbind_device(sva);
+			rc = -EINVAL;
+			goto failed;
+		}
+
+		ctx->sva = sva;
+		ctx->pasid = pasid;
+
+		if (wq_dedicated(wq)) {
+			rc = idxd_wq_set_pasid(wq, pasid);
+			if (rc < 0) {
+				iommu_sva_unbind_device(sva);
+				dev_err(dev, "wq set pasid failed: %d\n", rc);
+				goto failed;
+			}
+		}
+	}
+
+	idxd_wq_get(wq);
+	mutex_unlock(&wq->wq_lock);
+	return 0;
+
+ failed:
+	mutex_unlock(&wq->wq_lock);
+	kfree(ctx);
+	return rc;
+}
+
+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;
+	int rc;
+
+	dev_dbg(dev, "%s called\n", __func__);
+	filep->private_data = NULL;
+
+	/* Wait for in-flight operations to complete. */
+	if (wq_shared(wq)) {
+		idxd_device_drain_pasid(idxd, ctx->pasid);
+	} else {
+		if (device_user_pasid_enabled(idxd)) {
+			/* The wq disable in the disable pasid function will drain the wq */
+			rc = idxd_wq_disable_pasid(wq);
+			if (rc < 0)
+				dev_err(dev, "wq disable pasid failed.\n");
+		} else {
+			idxd_wq_drain(wq);
+		}
+	}
+
+	if (ctx->sva)
+		iommu_sva_unbind_device(ctx->sva);
+	kfree(ctx);
+	mutex_lock(&wq->wq_lock);
+	idxd_wq_put(wq);
+	mutex_unlock(&wq->wq_lock);
+	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__);
+	if (rc < 0)
+		return rc;
+
+	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;
+	__poll_t out = 0;
+
+	poll_wait(filp, &wq->err_queue, wait);
+	spin_lock(&idxd->dev_lock);
+	if (idxd->sw_err.valid)
+		out = EPOLLIN | EPOLLRDNORM;
+	spin_unlock(&idxd->dev_lock);
+
+	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->data->type].devt);
+}
+
+int idxd_wq_add_cdev(struct idxd_wq *wq)
+{
+	struct idxd_device *idxd = wq->idxd;
+	struct idxd_cdev *idxd_cdev;
+	struct cdev *cdev;
+	struct device *dev;
+	struct idxd_cdev_context *cdev_ctx;
+	int rc, minor;
+
+	idxd_cdev = kzalloc(sizeof(*idxd_cdev), GFP_KERNEL);
+	if (!idxd_cdev)
+		return -ENOMEM;
+
+	idxd_cdev->idxd_dev.type = IDXD_DEV_CDEV;
+	idxd_cdev->wq = wq;
+	cdev = &idxd_cdev->cdev;
+	dev = cdev_dev(idxd_cdev);
+	cdev_ctx = &ictx[wq->idxd->data->type];
+	minor = ida_simple_get(&cdev_ctx->minor_ida, 0, MINORMASK, GFP_KERNEL);
+	if (minor < 0) {
+		kfree(idxd_cdev);
+		return minor;
+	}
+	idxd_cdev->minor = minor;
+
+	device_initialize(dev);
+	dev->parent = wq_confdev(wq);
+	dev->bus = &dsa_bus_type;
+	dev->type = &idxd_cdev_device_type;
+	dev->devt = MKDEV(MAJOR(cdev_ctx->devt), minor);
+
+	rc = dev_set_name(dev, "%s/wq%u.%u", idxd->data->name_prefix, idxd->id, wq->id);
+	if (rc < 0)
+		goto err;
+
+	wq->idxd_cdev = idxd_cdev;
+	cdev_init(cdev, &idxd_cdev_fops);
+	rc = cdev_device_add(cdev, dev);
+	if (rc) {
+		dev_dbg(&wq->idxd->pdev->dev, "cdev_add failed: %d\n", rc);
+		goto err;
+	}
+
+	return 0;
+
+ err:
+	put_device(dev);
+	wq->idxd_cdev = NULL;
+	return rc;
+}
+
+void idxd_wq_del_cdev(struct idxd_wq *wq)
+{
+	struct idxd_cdev *idxd_cdev;
+
+	idxd_cdev = wq->idxd_cdev;
+	wq->idxd_cdev = NULL;
+	cdev_device_del(&idxd_cdev->cdev, cdev_dev(idxd_cdev));
+	put_device(cdev_dev(idxd_cdev));
+}
+
+static int idxd_user_drv_probe(struct idxd_dev *idxd_dev)
+{
+	struct idxd_wq *wq = idxd_dev_to_wq(idxd_dev);
+	struct idxd_device *idxd = wq->idxd;
+	int rc;
+
+	if (idxd->state != IDXD_DEV_ENABLED)
+		return -ENXIO;
+
+	/*
+	 * User type WQ is enabled only when SVA is enabled for two reasons:
+	 *   - If no IOMMU or IOMMU Passthrough without SVA, userspace
+	 *     can directly access physical address through the WQ.
+	 *   - The IDXD cdev driver does not provide any ways to pin
+	 *     user pages and translate the address from user VA to IOVA or
+	 *     PA without IOMMU SVA. Therefore the application has no way
+	 *     to instruct the device to perform DMA function. This makes
+	 *     the cdev not usable for normal application usage.
+	 */
+	if (!device_user_pasid_enabled(idxd)) {
+		idxd->cmd_status = IDXD_SCMD_WQ_USER_NO_IOMMU;
+		dev_dbg(&idxd->pdev->dev,
+			"User type WQ cannot be enabled without SVA.\n");
+
+		return -EOPNOTSUPP;
+	}
+
+	mutex_lock(&wq->wq_lock);
+	wq->type = IDXD_WQT_USER;
+	rc = drv_enable_wq(wq);
+	if (rc < 0)
+		goto err;
+
+	rc = idxd_wq_add_cdev(wq);
+	if (rc < 0) {
+		idxd->cmd_status = IDXD_SCMD_CDEV_ERR;
+		goto err_cdev;
+	}
+
+	idxd->cmd_status = 0;
+	mutex_unlock(&wq->wq_lock);
+	return 0;
+
+err_cdev:
+	drv_disable_wq(wq);
+err:
+	wq->type = IDXD_WQT_NONE;
+	mutex_unlock(&wq->wq_lock);
+	return rc;
+}
+
+static void idxd_user_drv_remove(struct idxd_dev *idxd_dev)
+{
+	struct idxd_wq *wq = idxd_dev_to_wq(idxd_dev);
+
+	mutex_lock(&wq->wq_lock);
+	idxd_wq_del_cdev(wq);
+	drv_disable_wq(wq);
+	wq->type = IDXD_WQT_NONE;
+	mutex_unlock(&wq->wq_lock);
+}
+
+static enum idxd_dev_type dev_types[] = {
+	IDXD_DEV_WQ,
+	IDXD_DEV_NONE,
+};
+
+struct idxd_device_driver idxd_user_drv = {
+	.probe = idxd_user_drv_probe,
+	.remove = idxd_user_drv_remove,
+	.name = "user",
+	.type = dev_types,
+};
+EXPORT_SYMBOL_GPL(idxd_user_drv);
+
+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)
+			goto err_free_chrdev_region;
+	}
+
+	return 0;
+
+err_free_chrdev_region:
+	for (i--; i >= 0; i--)
+		unregister_chrdev_region(ictx[i].devt, MINORMASK);
+
+	return rc;
+}
+
+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);
+	}
+}