virtio-loopback-driver - multi-device supportHEADmaster

Updates [v1]:
- The driver to handle multiple adapter instances.
- The source code is restructured and splitted into:
  "virtio_loopback_driver.c" and "virtio_loopback_device.c".
- Notification mechanism is based on workqueues

Updates [v2]:
- Update module final name to 'virtio_loopback'
- Update the README file, add tested platforms
- Fix indents, typos

Bug-AGL: SPEC-4834

Change-Id: Ifef4cb222652c3e8584849d257d84abc7c7ba1b5
Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>

1 files changed, 0 insertions, 1148 deletions

diff --git a/loopback_driver.c b/loopback_driver.c
deleted file mode 100644
index 989b865..0000000
--- a/loopback_driver.c
+++ /dev/null
@@ -1,1148 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * Based on virtio_mmio.c
- *   Copyright 2011-2014, ARM Ltd.
- *
- * Copyright 2022-2024 Virtual Open Systems SAS
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software Foundation,
- * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- */
-
-#define pr_fmt(fmt) "virtio-loopback: " fmt
-
-#include <linux/cdev.h>
-#include <linux/eventfd.h>
-#include <linux/fdtable.h>
-#include <linux/init.h>
-#include <linux/module.h>
-#include <linux/platform_device.h>
-#include <linux/kernel.h>
-#include <linux/device.h>
-#include <linux/version.h>
-#include <linux/slab.h>
-
-/* Virtio-loopback includes */
-#include <linux/dma-mapping.h>
-#include <linux/list.h>
-#include <linux/spinlock.h>
-#include <linux/mutex.h>
-#include <linux/virtio.h>
-#include <linux/virtio_config.h>
-#include <uapi/linux/virtio_mmio.h>
-#include <linux/virtio_ring.h>
-#include <linux/pid.h>
-#include <linux/kthread.h>
-
-/* Loopback header file */
-#include "loopback_driver.h"
-
-/* Features */
-MODULE_LICENSE("GPL v2");
-
-/* function declaration */
-static uint64_t read_adapter(uint64_t fn_id, uint64_t size);
-static void write_adapter(uint64_t data, uint64_t fn_id, uint64_t size);
-
-struct mmap_info *info;
-int mmap_index;
-uint64_t sum_pgfaults;
-
-/* Waitq */
-wait_queue_head_t wq;
-wait_queue_head_t wq_notify;
-
-/* Read write mutex */
-struct mutex read_write_lock;
-struct mutex interrupt_lock;
-
-/* Notification spinlock */
-spinlock_t notify_q_spinlock;
-
-bool share_communication_struct;
-uint32_t vq_index;
-uint64_t vq_pfns[16], vq_pfn;
-
-struct virtio_mmio_device *vm_dev_irq;
-
-struct virtqueue *global_vq;
-const struct vring *global_vring;
-
-/* counters */
-static int interrupt_cnt;
-static int notify_sent, notify_received;
-
-/* Define a notification list */
-static struct list_head *notify_list;
-
-static struct platform_device *virtio_loopback_device;
-
-/* Virio-loopback device funcitonality */
-struct eventfd_ctx *efd_ctx;
-static struct task_struct *start_loopback_thread;
-static struct task_struct *start_notification_thread;
-
-/* global storage for device Major number */
-static int dev_major;
-/* sysfs class structure */
-static struct class *loopback_class;
-/* array of loopback_device_data for */
-static struct loopback_device_data *loopback_data;
-
-/* Allow only one process to open the driver */
-unsigned long loopback_flags;
-
-/* Current ram index */
-int cur_ram_idx;
-
-/*
- * If this variable is true then read/write should wait
- * the adapter to unlock this opertion by sending an
- * eventfd. If it's equal to "false" then the oparetion
- * does not wait for adapter's confirmation.
- */
-bool valid_eventfd;
-
-/* Create a mapping array */
-struct share_mmap share_mmap_list[MMAP_LIMIT];
-
-/* Configuration interface */
-
-static u64 vm_get_features(struct virtio_device *vdev)
-{
-	u64 features;
-
-	/* Take feature bits 0-31 */
-	write_adapter(1, VIRTIO_MMIO_DEVICE_FEATURES_SEL, 4);
-	features = read_adapter(VIRTIO_MMIO_DEVICE_FEATURES, 4);
-	features <<= 32;
-
-	/* Take feature bits 32-63 */
-	write_adapter(0, VIRTIO_MMIO_DEVICE_FEATURES_SEL, 4);
-	features |= read_adapter(VIRTIO_MMIO_DEVICE_FEATURES, 4);
-
-	return features;
-}
-
-static int vm_finalize_features(struct virtio_device *vdev)
-{
-	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
-
-	/* Give virtio_ring a chance to accept features. */
-	vring_transport_features(vdev);
-
-	/* Make sure there are no mixed devices */
-	if (vm_dev->version == 2 &&
-		!__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
-		dev_err(&vdev->dev, "New virtio-mmio devices (version 2) "
-				"must provide VIRTIO_F_VERSION_1 feature!\n");
-		return -EINVAL;
-	}
-
-	write_adapter(1, VIRTIO_MMIO_DRIVER_FEATURES_SEL, 4);
-	write_adapter((u32)(vdev->features >> 32), VIRTIO_MMIO_DRIVER_FEATURES, 4);
-
-	write_adapter(0, VIRTIO_MMIO_DRIVER_FEATURES_SEL, 4);
-	write_adapter((u32)vdev->features, VIRTIO_MMIO_DRIVER_FEATURES, 4);
-
-	return 0;
-}
-
-static void vm_get(struct virtio_device *vdev, unsigned int offset,
-				   void *buf, unsigned int len)
-{
-	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
-	u8 b;
-	__le16 w;
-	__le32 l;
-
-	if (vm_dev->version == 1) {
-		u8 *ptr = buf;
-		int i;
-
-		for (i = 0; i < len; i++)
-			ptr[i] = read_adapter(VIRTIO_MMIO_CONFIG + offset + i, 1);
-		return;
-	}
-
-	switch (len) {
-	case 1:
-		b = read_adapter(VIRTIO_MMIO_CONFIG + offset, 1);
-		memcpy(buf, &b, sizeof(b));
-		break;
-	case 2:
-		w = cpu_to_le16(read_adapter(VIRTIO_MMIO_CONFIG + offset, 2));
-		memcpy(buf, &w, sizeof(w));
-		break;
-	case 4:
-		l = cpu_to_le32(read_adapter(VIRTIO_MMIO_CONFIG + offset, 4));
-		memcpy(buf, &l, sizeof(l));
-		break;
-	case 8:
-		l = cpu_to_le32(read_adapter(VIRTIO_MMIO_CONFIG + offset, 4));
-		memcpy(buf, &l, sizeof(l));
-		l = cpu_to_le32(read_adapter(VIRTIO_MMIO_CONFIG + offset + sizeof(l), 4));
-		memcpy(buf + sizeof(l), &l, sizeof(l));
-		break;
-	default:
-		BUG();
-	}
-}
-
-static void vm_set(struct virtio_device *vdev, unsigned int offset,
-				   const void *buf, unsigned int len)
-{
-	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
-	u8 b;
-	__le16 w;
-	__le32 l;
-
-	if (vm_dev->version == 1) {
-		const u8 *ptr = buf;
-		int i;
-
-		for (i = 0; i < len; i++)
-			write_adapter(ptr[i], VIRTIO_MMIO_CONFIG + offset + i, 1);
-
-		return;
-	}
-
-	switch (len) {
-	case 1:
-		memcpy(&b, buf, sizeof(b));
-		write_adapter(b, VIRTIO_MMIO_CONFIG + offset, 1);
-		break;
-	case 2:
-		memcpy(&w, buf, sizeof(w));
-		write_adapter(le16_to_cpu(w), VIRTIO_MMIO_CONFIG + offset, 2);
-		break;
-	case 4:
-		memcpy(&l, buf, sizeof(l));
-		write_adapter(le32_to_cpu(l), VIRTIO_MMIO_CONFIG + offset, 4);
-		break;
-	case 8:
-		memcpy(&l, buf, sizeof(l));
-		write_adapter(le32_to_cpu(l), VIRTIO_MMIO_CONFIG + offset, 4);
-		memcpy(&l, buf + sizeof(l), sizeof(l));
-		write_adapter(le32_to_cpu(l), VIRTIO_MMIO_CONFIG + offset + sizeof(l), 4);
-		break;
-	default:
-		BUG();
-	}
-}
-
-static u32 vm_generation(struct virtio_device *vdev)
-{
-	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
-
-	if (vm_dev->version == 1)
-		return 0;
-	else
-		return read_adapter(VIRTIO_MMIO_CONFIG_GENERATION, 4);
-}
-
-static u8 vm_get_status(struct virtio_device *vdev)
-{
-	return read_adapter(VIRTIO_MMIO_STATUS, 4) & 0xff;
-}
-
-static void vm_set_status(struct virtio_device *vdev, u8 status)
-{
-	write_adapter(status, VIRTIO_MMIO_STATUS, 4);
-}
-
-static void vm_reset(struct virtio_device *vdev)
-{
-	/* 0 status means a reset. */
-	write_adapter(0, VIRTIO_MMIO_STATUS, 4);
-}
-
-int start_notification(void *data)
-{
-	struct notify_data *first_notification;
-	uint32_t index;
-
-	DBG("Start notification\n");
-
-	(void)data;
-
-	while(1) {
-
-		spin_lock(&notify_q_spinlock);
-		while (valid_eventfd && list_empty(notify_list) == 1) {
-			spin_unlock(&notify_q_spinlock);
-			wait_event_timeout(wq_notify, list_empty(notify_list) != 1, 1 * HZ);
-			spin_lock(&notify_q_spinlock);
-		}
-
-		first_notification = list_first_entry(notify_list, struct notify_data, list);
-		index = first_notification->index;
-		list_del(&first_notification->list);
-
-		DBG("notify_received: %d, VQ: %d\n", notify_received++, index);
-		spin_unlock(&notify_q_spinlock);
-		write_adapter(index, VIRTIO_MMIO_QUEUE_NOTIFY, 4);
-
-		if (!valid_eventfd) {
-			DBG("Exit notification thread\n");
-			return 0;
-		}
-	}
-}
-
-/* the notify function used when creating a virt queue */
-static bool vm_notify(struct virtqueue *vq)
-{
-	struct notify_data *data;
-	/*
-	 * We write the queue's selector into
-	 * the notification register to signal
-	 * the other end
-	 */
-	spin_lock(&notify_q_spinlock);
-	DBG("vm_notify\n");
-
-	data = kmalloc(sizeof(struct notify_data), GFP_KERNEL);
-	data->index = vq->index;
-	INIT_LIST_HEAD(&data->list);
-	list_add_tail(&data->list, notify_list);
-	spin_unlock(&notify_q_spinlock);
-
-	wake_up(&wq_notify);
-
-	return true;
-}
-
-/* Notify all virtqueues on an interrupt. */
-static void vm_interrupt(struct work_struct *work)
-{
-	struct virtio_mmio_device *vm_dev = vm_dev_irq;
-	struct virtio_mmio_vq_info *info;
-	int irq = 44;
-	unsigned long status;
-
-	/* STATUS and ACK should ne done without any intermediate status change */
-	mutex_lock(&interrupt_lock);
-	DBG("interrupt_cnt: %d\n", interrupt_cnt++);
-
-	/* Read and acknowledge interrupts */
-	status = read_adapter(VIRTIO_MMIO_INTERRUPT_STATUS, 4);
-	write_adapter(status, VIRTIO_MMIO_INTERRUPT_ACK, 4);
-
-	if (unlikely(status & VIRTIO_MMIO_INT_CONFIG))
-		virtio_config_changed(&vm_dev->vdev);
-
-	if (likely(status & VIRTIO_MMIO_INT_VRING)) {
-		spin_lock(&vm_dev->lock);
-		list_for_each_entry(info, &vm_dev->virtqueues, node) {
-			(void)vring_interrupt(irq, info->vq);
-		}
-		spin_unlock(&vm_dev->lock);
-	}
-	mutex_unlock(&interrupt_lock);
-}
-
-static void vm_del_vq(struct virtqueue *vq)
-{
-	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
-	struct virtio_mmio_vq_info *info = vq->priv;
-	unsigned long flags;
-	unsigned int index = vq->index;
-
-	spin_lock_irqsave(&vm_dev->lock, flags);
-	list_del(&info->node);
-	spin_unlock_irqrestore(&vm_dev->lock, flags);
-
-	/* Select and deactivate the queue */
-	write_adapter(index, VIRTIO_MMIO_QUEUE_SEL, 4);
-
-	if (vm_dev->version == 1) {
-		write_adapter(0, VIRTIO_MMIO_QUEUE_PFN, 4);
-	} else {
-		write_adapter(0, VIRTIO_MMIO_QUEUE_READY, 4);
-		WARN_ON(read_adapter(VIRTIO_MMIO_QUEUE_READY, 4));
-	}
-
-	vring_del_virtqueue(vq);
-	kfree(info);
-}
-
-static void vm_del_vqs(struct virtio_device *vdev)
-{
-	struct virtqueue *vq, *n;
-
-	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
-		vm_del_vq(vq);
-}
-
-static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int index,
-				  void (*callback)(struct virtqueue *vq),
-				  const char *name, bool ctx)
-{
-	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
-	struct virtio_mmio_vq_info *info;
-	struct virtqueue *vq;
-	unsigned long flags;
-	unsigned int num;
-	int err;
-
-	if (!name)
-		return NULL;
-
-	/* Select the queue we're interested in */
-	write_adapter(index, VIRTIO_MMIO_QUEUE_SEL, 4);
-
-	/* Queue shouldn't already be set up. */
-	if (read_adapter((vm_dev->version == 1 ?
-			VIRTIO_MMIO_QUEUE_PFN : VIRTIO_MMIO_QUEUE_READY), 4)) {
-		err = -ENOENT;
-		goto error_available;
-	}
-
-	/* Allocate and fill out our active queue description */
-	info = kmalloc(sizeof(*info), GFP_KERNEL);
-	if (!info) {
-		err = -ENOMEM;
-		goto error_kmalloc;
-	}
-
-	num = read_adapter(VIRTIO_MMIO_QUEUE_NUM_MAX, 4);
-	if (num == 0) {
-		err = -ENOENT;
-		goto error_new_virtqueue;
-	}
-
-	/* Create the vring */
-	vq = vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALIGN, vdev,
-					 true, true, ctx, vm_notify, callback, name);
-	if (!vq) {
-		err = -ENOMEM;
-		goto error_new_virtqueue;
-	}
-
-
-#if LINUX_VERSION_CODE >  KERNEL_VERSION(6,0,0)
-	vq->num_max = num;
-#endif
-	/* Activate the queue */
-	write_adapter(virtqueue_get_vring_size(vq), VIRTIO_MMIO_QUEUE_NUM, 4);
-	if (vm_dev->version == 1) {
-		u64 q_pfn = virtqueue_get_desc_addr(vq);
-
-		q_pfn = q_pfn >> PAGE_SHIFT;
-
-		/* Copy the physical address and enable the mmap */
-		vq_pfn = q_pfn;
-		vq_pfns[vq_index++] = q_pfn;
-
-		/* Save the virtqueue in a global variable */
-		global_vq = vq;
-		global_vring = virtqueue_get_vring(vq);
-
-		/*
-		 * virtio-mmio v1 uses a 32bit QUEUE PFN. If we have something
-		 * that doesn't fit in 32bit, fail the setup rather than
-		 * pretending to be successful.
-		 */
-		if (q_pfn >> 32) {
-			dev_err(&vdev->dev,
-				"platform bug: legacy virtio-mmio must not "
-				"be used with RAM above 0x%llxGB\n",
-				0x1ULL << (32 + PAGE_SHIFT - 30));
-			err = -E2BIG;
-			goto error_bad_pfn;
-		}
-
-		write_adapter(PAGE_SIZE, VIRTIO_MMIO_QUEUE_ALIGN, 4);
-		write_adapter(q_pfn, VIRTIO_MMIO_QUEUE_PFN, 4);
-	} else {
-		u64 addr;
-
-		addr = virtqueue_get_desc_addr(vq);
-		write_adapter((u32)addr, VIRTIO_MMIO_QUEUE_DESC_LOW, 4);
-		write_adapter((u32)(addr >> 32), VIRTIO_MMIO_QUEUE_DESC_HIGH, 4);
-
-		addr = virtqueue_get_avail_addr(vq);
-		write_adapter((u32)addr, VIRTIO_MMIO_QUEUE_AVAIL_LOW, 4);
-		write_adapter((u32)(addr >> 32), VIRTIO_MMIO_QUEUE_AVAIL_HIGH, 4);
-
-		addr = virtqueue_get_used_addr(vq);
-		write_adapter((u32)addr, VIRTIO_MMIO_QUEUE_USED_LOW, 4);
-		write_adapter((u32)(addr >> 32), VIRTIO_MMIO_QUEUE_USED_HIGH, 4);
-
-		write_adapter(1, VIRTIO_MMIO_QUEUE_READY, 4);
-	}
-
-	vq->priv = info;
-	info->vq = vq;
-
-	spin_lock_irqsave(&vm_dev->lock, flags);
-	list_add(&info->node, &vm_dev->virtqueues);
-	spin_unlock_irqrestore(&vm_dev->lock, flags);
-
-	return vq;
-
-error_bad_pfn:
-	vring_del_virtqueue(vq);
-error_new_virtqueue:
-	if (vm_dev->version == 1) {
-		write_adapter(0, VIRTIO_MMIO_QUEUE_PFN, 4);
-	} else {
-		write_adapter(0, VIRTIO_MMIO_QUEUE_READY, 4);
-		WARN_ON(read_adapter(VIRTIO_MMIO_QUEUE_READY, 4));
-	}
-	kfree(info);
-error_kmalloc:
-error_available:
-	return ERR_PTR(err);
-}
-
-static int vm_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
-					   struct virtqueue *vqs[],
-					   vq_callback_t *callbacks[],
-					   const char * const names[],
-					   const bool *ctx,
-					   struct irq_affinity *desc)
-{
-	int i, queue_idx = 0;
-
-	for (i = 0; i < nvqs; ++i) {
-		if (!names[i]) {
-			vqs[i] = NULL;
-			continue;
-		}
-
-		vqs[i] = vm_setup_vq(vdev, queue_idx++, callbacks[i], names[i],
-							 ctx ? ctx[i] : false);
-		if (IS_ERR(vqs[i])) {
-			vm_del_vqs(vdev);
-			return PTR_ERR(vqs[i]);
-		}
-	}
-
-	return 0;
-}
-
-static const char *vm_bus_name(struct virtio_device *vdev)
-{
-	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
-
-	return vm_dev->pdev->name;
-}
-
-static bool vm_get_shm_region(struct virtio_device *vdev,
-				  struct virtio_shm_region *region, u8 id)
-{
-	u64 len, addr;
-
-	/* Select the region we're interested in */
-	write_adapter(id, VIRTIO_MMIO_SHM_SEL, 4);
-
-	/* Read the region size */
-	len = (u64) read_adapter(VIRTIO_MMIO_SHM_LEN_LOW, 4);
-	len |= (u64) read_adapter(VIRTIO_MMIO_SHM_LEN_HIGH, 4) << 32;
-
-	region->len = len;
-
-	/* Check if region length is -1. If that's the case, the shared memory
-	 * region does not exist and there is no need to proceed further.
-	 */
-	if (len == ~(u64)0)
-		return false;
-
-	/* Read the region base address */
-	addr = (u64) read_adapter(VIRTIO_MMIO_SHM_BASE_LOW, 4);
-	addr |= (u64) read_adapter(VIRTIO_MMIO_SHM_BASE_HIGH, 4) << 32;
-
-	region->addr = addr;
-
-	return true;
-}
-
-static const struct virtio_config_ops virtio_mmio_config_ops = {
-	.get			= vm_get,
-	.set			= vm_set,
-	.generation		= vm_generation,
-	.get_status		= vm_get_status,
-	.set_status		= vm_set_status,
-	.reset			= vm_reset,
-	.find_vqs		= vm_find_vqs,
-	.del_vqs		= vm_del_vqs,
-	.get_features		= vm_get_features,
-	.finalize_features	= vm_finalize_features,
-	.bus_name		= vm_bus_name,
-	.get_shm_region		= vm_get_shm_region,
-};
-
-static void virtio_mmio_release_dev(struct device *_d)
-{
-	struct virtio_device *vdev = container_of(_d, struct virtio_device, dev);
-	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
-	struct platform_device *pdev = vm_dev->pdev;
-
-	devm_kfree(&pdev->dev, vm_dev);
-}
-
-static int virtio_mmio_probe(struct platform_device *pdev)
-{
-	struct virtio_mmio_device *vm_dev;
-	unsigned long magic;
-	int rc;
-
-	vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL);
-	if (!vm_dev)
-		return -ENOMEM;
-
-	/* Save the device pointer globally */
-	vm_dev_irq = vm_dev;
-
-	vm_dev->vdev.dev.parent = &pdev->dev;
-	vm_dev->vdev.dev.release = virtio_mmio_release_dev;
-	vm_dev->vdev.config = &virtio_mmio_config_ops;
-	vm_dev->pdev = pdev;
-	INIT_LIST_HEAD(&vm_dev->virtqueues);
-	spin_lock_init(&vm_dev->lock);
-
-	/* Check magic value */
-	magic = read_adapter(VIRTIO_MMIO_MAGIC_VALUE, 4);
-
-	if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
-		dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
-		return -ENODEV;
-	}
-
-	/* Check device version */
-	vm_dev->version = read_adapter(VIRTIO_MMIO_VERSION, 4);
-
-	if (vm_dev->version < 1 || vm_dev->version > 2) {
-		dev_err(&pdev->dev, "Version %ld not supported!\n",
-							vm_dev->version);
-		return -ENXIO;
-	}
-
-	vm_dev->vdev.id.device = read_adapter(VIRTIO_MMIO_DEVICE_ID, 4);
-
-	if (vm_dev->vdev.id.device == 0) {
-		/*
-		 * virtio-mmio device with an ID 0 is a (dummy) placeholder
-		 * with no function. End probing now with no error reported.
-		 */
-		return -ENODEV;
-	}
-
-	vm_dev->vdev.id.vendor = read_adapter(VIRTIO_MMIO_VENDOR_ID, 4);
-
-	if (vm_dev->version == 1) {
-		write_adapter(PAGE_SIZE, VIRTIO_MMIO_GUEST_PAGE_SIZE, 4);
-
-		rc = dma_set_mask(&pdev->dev, DMA_BIT_MASK(64));
-		/*
-		 * In the legacy case, ensure our coherently-allocated virtio
-		 * ring will be at an address expressable as a 32-bit PFN.
-		 */
-		if (!rc)
-			dma_set_coherent_mask(&pdev->dev,
-				  DMA_BIT_MASK(32 + PAGE_SHIFT));
-	} else {
-		rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
-	}
-	if (rc)
-		rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
-	if (rc)
-		dev_warn(&pdev->dev, "Failed to enable 64-bit or 32-bit DMA."
-				"Trying to continue, but this might not work.\n");
-
-	platform_set_drvdata(pdev, vm_dev);
-
-	rc = register_virtio_device(&vm_dev->vdev);
-
-	if (rc)
-		put_device(&vm_dev->vdev.dev);
-
-	return rc;
-}
-
-static int virtio_mmio_remove(struct platform_device *pdev)
-{
-	struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
-
-	unregister_virtio_device(&vm_dev->vdev);
-	DBG("unregister_virtio_device!\n");
-	return 0;
-}
-
-/* Not need of DTS and ACPI */
-static struct platform_driver virtio_mmio_driver = {
-	.probe	 = virtio_mmio_probe,
-	.remove	 = virtio_mmio_remove,
-	.driver	 = {
-		.name   = "loopback-transport",
-	},
-};
-
-void pf_mmap_close(struct vm_area_struct *vma)
-{
-	DBG("unmap\t-> vma->vm_start: 0x%lx\n", vma->vm_start);
-	DBG("unmap\t-> size: %lu\n", vma->vm_end - vma->vm_start);
-	share_mmap_rem(vma, share_mmap_list);
-}
-
-vm_fault_t pf_mmap_fault(struct vm_fault *vmf)
-{
-	uint64_t corrected_pfn;
-	pfn_t corr_pfn_struct;
-	struct page *page;
-	int ret = 0;
-
-	DBG("----- Page fault: %lld -----\n", sum_pgfaults++);
-
-	/* Find the corrected pfn */
-	corrected_pfn = share_mmap_exist_vma_return_correct_pfn(vmf->address, share_mmap_list);
-	corr_pfn_struct.val = corrected_pfn;
-
-	/* Some debug prints */
-	DBG("vma->vm_start: 0x%lx\n", vmf->vma->vm_start);
-	DBG("vma->vm_pgoff: 0x%lx\n", vmf->vma->vm_pgoff);
-	DBG("vmf->address: 0x%lx\n", vmf->address);
-	DBG("corrected_pfn: 0x%llx\n", corrected_pfn);
-	DBG("pfn_valid(corrected_pfn): 0x%x\n", pfn_valid(corrected_pfn));
-
-	BUG_ON(!pfn_valid(corrected_pfn));
-
-	/* After finding the page, correct the vmf->page */
-	page = pfn_to_page(corrected_pfn);
-	BUG_ON(!virt_addr_valid(page_address(page)));
-
-	/* Insert the correct page */
-	ret = vmf_insert_pfn(vmf->vma, vmf->address, corrected_pfn);
-	DBG("vmf_insert_pfn -> ret: %d\n", ret);
-
-	return ret;
-}
-
-const struct vm_operations_struct pf_mmap_ops = {
-	.close = pf_mmap_close,
-	.fault = pf_mmap_fault,
-};
-
-int pf_mmap_vm_page(struct file *filp, struct vm_area_struct *vma)
-{
-	uint64_t size = (unsigned long)(vma->vm_end - vma->vm_start);
-	uint64_t pfn = ((cur_ram_idx++) * 0x40000);
-
-#if LINUX_VERSION_CODE <  KERNEL_VERSION(6,3,0)
-	vma->vm_flags |= VM_PFNMAP;
-#else
-	vm_flags_set(vma, VM_PFNMAP);
-#endif
-	add_share_mmap(filp, pfn, vma->vm_start, size, share_mmap_list, &mmap_index);
-	return 0;
-}
-
-int op_mmap(struct file *filp, struct vm_area_struct *vma)
-{
-	int ret = 0;
-	uint64_t size = (unsigned long)(vma->vm_end - vma->vm_start);
-
-	DBG("op_mmap -> vma->vm_pgoff: 0x%lx", vma->vm_pgoff);
-
-	if (share_communication_struct) {
-		DBG("MMAP communication struct\n");
-		ret = mmap_communication_shared_space(filp, vma, share_mmap_list, &mmap_index);
-		share_communication_struct = false;
-		goto out;
-	}
-
-	if (size > PAGE_SIZE * 100) {
-		ret = pf_mmap_vm_page(filp, vma);
-		goto out;
-	}
-
-	ret = mmap_mix(filp, vma, share_mmap_list, &mmap_index, vq_pfn);
-
-out:
-	vma->vm_ops = &pf_mmap_ops;
-	return ret;
-}
-
-static uint64_t read_adapter(uint64_t fn_id, uint64_t size)
-{
-	uint64_t result;
-
-	mutex_lock(&read_write_lock);
-
-	/*
-	 * By enabling the following line all
-	 * read messages will be printed:
-	 *
-	 * print_neg_flag(fn_id, 1);
-	 */
-	print_neg_flag(fn_id, 1);
-
-	((virtio_neg_t *)(info->data))->notification = fn_id;
-	((virtio_neg_t *)(info->data))->data = 0;
-	((virtio_neg_t *)(info->data))->size = size;
-	((virtio_neg_t *)(info->data))->read = true;
-
-	atomic_set(&((virtio_neg_t *)(info->data))->done, 0);
-
-	eventfd_signal(efd_ctx, 1);
-
-	/*
-	 * There is a chance virtio-loopback adapter to call "wake_up"
-	 * before the current thread sleep. This is the reason that
-	 * "wait_event_timeout" is used instead of "wait_event". In this
-	 * way, virtio-loopback driver will wake up even if has missed the
-	 * "wake_up" kick, check the updated "done" value and return.
-	 */
-
-	while (valid_eventfd && atomic_read(&((virtio_neg_t *)(info->data))->done) != 1)
-		wait_event_timeout(wq, atomic_read(&((virtio_neg_t *)(info->data))->done) == 1, 1 * HZ);
-
-	result = ((virtio_neg_t *)(info->data))->data;
-
-	mutex_unlock(&read_write_lock);
-
-	return result;
-}
-
-static void write_adapter(uint64_t data, uint64_t fn_id, uint64_t size)
-{
-
-	mutex_lock(&read_write_lock);
-
-	/*
-	 * By enabling the following line all
-	 * write messages will be printed:
-	 *
-	 * print_neg_flag(fn_id, 1);
-	 */
-	print_neg_flag(fn_id, 0);
-
-	((virtio_neg_t *)(info->data))->notification = fn_id;
-	((virtio_neg_t *)(info->data))->data = data;
-	((virtio_neg_t *)(info->data))->size = size;
-	((virtio_neg_t *)(info->data))->read = false;
-
-	atomic_set(&((virtio_neg_t *)(info->data))->done, 0);
-
-	eventfd_signal(efd_ctx, 1);
-
-	/*
-	 * There is a chance virtio-loopback adapter to call "wake_up"
-	 * before the current thread sleep. This is the reason that
-	 * "wait_event_timeout" is used instead of "wait_event". In this
-	 * way, virtio-loopback driver will wake up even if has missed the
-	 * "wake_up" kick, check the updated "done" value and return.
-	 */
-	while (valid_eventfd && atomic_read(&((virtio_neg_t *)(info->data))->done) != 1)
-		wait_event_timeout(wq, atomic_read(&((virtio_neg_t *)(info->data))->done) == 1, 1 * HZ);
-
-	mutex_unlock(&read_write_lock);
-}
-
-/* Defined for future work */
-static ssize_t loopback_write(struct file *file,
-				   const char __user *user_buffer,
-				   size_t size,
-				   loff_t *offset)
-{
-	ssize_t len = sizeof(int);
-
-	DBG("loopback write function is called\n");
-	if (len <= 0)
-		return 0;
-
-	return len;
-}
-
-/* Defined for future work */
-static ssize_t loopback_read(struct file *file,
-				 char __user *user_buffer,
-				 size_t size, loff_t *offset)
-{
-	DBG("loopback read function is called\n");
-	return 0;
-}
-
-loff_t loopback_seek(struct file *file, loff_t offset, int whence)
-{
-	loff_t new_pos;
-
-	DBG("loopback seek function!\n");
-	switch (whence) {
-	case SEEK_SET:
-		new_pos = offset;
-		break;
-	case SEEK_CUR:
-		new_pos = file->f_pos + offset;
-		break;
-	case SEEK_END:
-		new_pos = file->f_inode->i_size;
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	if (new_pos < 0 || new_pos > file->f_inode->i_size)
-		return -EINVAL;
-
-	return new_pos;
-}
-
-int start_loopback(void *data)
-{
-	(void)data;
-	/* Register mmio_trasmport */
-	(void)platform_driver_register(&virtio_mmio_driver);
-	return 0;
-}
-
-static long loopback_ioctl(struct file *file,
-				unsigned int cmd, unsigned long arg)
-{
-	efd_data_t efd_data;
-	struct task_struct *userspace_task;
-	struct file *efd_file;
-	int irq;
-	uint32_t queue_sel;
-
-	switch (cmd) {
-	case EFD_INIT:
-		if (copy_from_user(&efd_data, (efd_data_t *) arg,
-						   sizeof(efd_data_t)))
-			return -EFAULT;
-
-		userspace_task = pid_task(find_vpid(efd_data.pid), PIDTYPE_PID);
-
-		rcu_read_lock();
-
-#if LINUX_VERSION_CODE <  KERNEL_VERSION(5,11,220)
-		efd_file = fcheck_files(userspace_task->files, efd_data.efd[0]);
-#else
-		efd_file = files_lookup_fd_rcu(userspace_task->files, efd_data.efd[0]);
-#endif
-
-		rcu_read_unlock();
-
-		efd_ctx = eventfd_ctx_fileget(efd_file);
-		if (!efd_ctx)
-			return -1;
-
-		break;
-	case WAKEUP:
-		atomic_set(&((virtio_neg_t *)(info->data))->done, 1);
-		wake_up(&wq);
-		break;
-	case START_LOOPBACK:
-		start_notification_thread = kthread_run(start_notification, NULL, "start_notification");
-		start_loopback_thread = kthread_run(start_loopback, NULL, "start_loopback");
-		break;
-	case IRQ:
-		if (copy_from_user(&irq, (int *) arg, sizeof(int)))
-			return -EFAULT;
-		DBG("\nIRQ\n");
-		/*
-		 * Both of the interrupt ways work but a) is more stable
-		 * and b) has better performance:
-		 * a) vm_interrupt(NULL);
-		 * b) queue_work(interrupt_workqueue, &async_interrupt);
-		 */
-		vm_interrupt(NULL);
-		break;
-	case SHARE_VQS:
-		if (copy_from_user(&queue_sel, (uint32_t *) arg, sizeof(uint32_t)))
-			return -EFAULT;
-		DBG("\n\nSHARE_VQS: %u\n\n", queue_sel);
-		vq_pfn = vq_pfns[queue_sel];
-		DBG("Selected pfn is: 0x%llx", vq_pfn);
-		break;
-	case SHARE_COM_STRUCT:
-		share_communication_struct = true;
-		break;
-	default:
-		DBG("loopback ioctl: default, %u\n", cmd);
-		return -ENOTTY;
-	}
-
-	return 0;
-}
-
-/*
- * The current implementation of the driver supports
- * exclusive access to one user-space thread. Multi-device
- * support will be added in future implementation.
- */
-static int loopback_open(struct inode *inode, struct file *file)
-{
-	uint32_t val_1gb = 1024 * 1024 * 1024; // 1GB
-	virtio_neg_t device_neg = {.done = ATOMIC_INIT(0)};
-
-	/* Update the global variable, the driver is in use */
-	if (test_and_set_bit(IN_USE_BIT, &loopback_flags)) {
-		DBG("Driver is busy\n");
-		return -EBUSY;
-	}
-
-	/* Set the i_size for the stat SYS_CALL*/
-	file->f_inode->i_size = 10 * val_1gb;
-
-	/* Init mmap funcitonality */
-	info = kmalloc(sizeof(struct mmap_info), GFP_KERNEL);
-	info->data = (void *)get_zeroed_page(GFP_KERNEL);
-	memcpy(info->data, &device_neg, sizeof(virtio_neg_t));
-
-	/* assign this info struct to the file */
-	file->private_data = info;
-
-	/* Init notification list */
-	notify_list = kmalloc(sizeof(struct list_head), GFP_KERNEL);
-	if (!notify_list) {
-		printk(KERN_ERR "Failed to allocate memory for list head\n");
-		return 1;
-	}
-	INIT_LIST_HEAD(notify_list);
-
-	/* Init global variables */
-	mmap_index = 0;
-	sum_pgfaults = 0;
-	share_communication_struct = false;
-	valid_eventfd = true;
-	vq_index = 0;
-	cur_ram_idx = 0;
-	interrupt_cnt = 0;
-	notify_sent = 0;
-	notify_received = 0;
-
-	return 0;
-}
-
-static int loopback_release(struct inode *inode, struct file *file)
-{
-	int i;
-
-	DBG("Release the device\n");
-
-	/*
-	 * This make the read/write do not wait
-	 * for the virtio-loopback-adapter if
-	 * the last has closed the fd
-	 */
-	valid_eventfd = false;
-
-	/* Unegister mmio_trasmport */
-	platform_driver_unregister(&virtio_mmio_driver);
-	DBG("platform_driver_unregister!\n");
-
-	/* free communication structure */
-	free_page((unsigned long)info->data);
-	kfree(info);
-	file->private_data = NULL;
-	DBG("Clean private_data\n");
-
-	/* Clear share_mmap_list */
-	for(i = 0; i < MMAP_LIMIT; i++) {
-		share_mmap_list[i].uid = 0;
-		share_mmap_list[i].pfn = 0;
-		share_mmap_list[i].vm_start = 0;
-		share_mmap_list[i].size = 0;
-	}
-
-	/* Update the global variable, the driver is not in use */
-	smp_mb__before_atomic();
-	clear_bit(IN_USE_BIT, &loopback_flags);
-	DBG("clear_bit!\n");
-
-	return 0;
-}
-
-static const struct file_operations fops = {
-	.owner			= THIS_MODULE,
-	.read			= loopback_read,
-	.write			= loopback_write,
-	.open			= loopback_open,
-	.unlocked_ioctl = loopback_ioctl,
-	.mmap			= op_mmap,
-	.llseek 		= loopback_seek,
-	.release		= loopback_release
-};
-
-static int __init loopback_init(void)
-{
-	int err;
-	dev_t dev;
-
-	err = alloc_chrdev_region(&dev, 0, MAX_DEV, "loopback");
-	dev_major = MAJOR(dev);
-
-#if LINUX_VERSION_CODE <  KERNEL_VERSION(6,4,0)
-	loopback_class = class_create(THIS_MODULE, "loopback");
-#else
-	loopback_class = class_create("loopback");
-#endif
-	if (IS_ERR(loopback_class)) {
-			printk(KERN_ERR "Failed to create class\n");
-			return PTR_ERR(loopback_class);
-	}
-
-	loopback_data = (struct loopback_device_data *)kmalloc(
-						sizeof(struct loopback_device_data), GFP_KERNEL);
-
-	cdev_init(&loopback_data->cdev, &fops);
-	loopback_data->cdev.owner = THIS_MODULE;
-	cdev_add(&loopback_data->cdev, MKDEV(dev_major, 0), 1);
-	device_create(loopback_class, NULL, MKDEV(dev_major, 0), NULL, "loopback");
-
-	/* Init wq */
-	init_waitqueue_head(&wq);
-	init_waitqueue_head(&wq_notify);
-
-	/* Init mutex */
-	mutex_init(&read_write_lock);
-	mutex_init(&interrupt_lock);
-
-	/* Init spinlock */
-	spin_lock_init(&notify_q_spinlock);
-
-	virtio_loopback_device = platform_device_register_simple("loopback-transport", -1, NULL, 0);
-	if (IS_ERR(virtio_loopback_device)) {
-		err = PTR_ERR(virtio_loopback_device);
-		pr_err("failed to register loopback-transport device: %d\n", err);
-		return err;
-	}
-
-	return 0;
-}
-
-void __exit loopback_exit(void)
-{
-	DBG("Exit driver!\n");
-
-	/* Unegister loopback device */
-	platform_device_unregister(virtio_loopback_device);
-	DBG("platform_device_unregister!\n");
-
-	device_destroy(loopback_class, MKDEV(dev_major, 0));
-	cdev_del(&loopback_data->cdev);
-	DBG("device_destroy!\n");
-
-	class_destroy(loopback_class);
-	DBG("class_destroy!\n");
-
-	kfree(loopback_data);
-	DBG("Free resources");
-}
-
-module_init(loopback_init);
-module_exit(loopback_exit);