/*
 * Kernel-based Virtual Machine - device assignment support
 *
 * Copyright (C) 2010 Red Hat, Inc. and/or its affiliates.
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 *
 */

#include <linux/kvm_host.h>
#include <linux/kvm.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
#include <linux/errno.h>
#include <linux/spinlock.h>
#include <linux/pci.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/fs.h>
#include "irq.h"

static struct kvm_assigned_dev_kernel *kvm_find_assigned_dev(struct list_head *head,
                                                      int assigned_dev_id)
{
        struct list_head *ptr;
        struct kvm_assigned_dev_kernel *match;

        list_for_each(ptr, head) {
                match = list_entry(ptr, struct kvm_assigned_dev_kernel, list);
                if (match->assigned_dev_id == assigned_dev_id)
                        return match;
        }
        return NULL;
}

static int find_index_from_host_irq(struct kvm_assigned_dev_kernel
                                    *assigned_dev, int irq)
{
        int i, index;
        struct msix_entry *host_msix_entries;

        host_msix_entries = assigned_dev->host_msix_entries;

        index = -1;
        for (i = 0; i < assigned_dev->entries_nr; i++)
                if (irq == host_msix_entries[i].vector) {
                        index = i;
                        break;
                }
        if (index < 0)
                printk(KERN_WARNING "Fail to find correlated MSI-X entry!\n");

        return index;
}

static irqreturn_t kvm_assigned_dev_intx(int irq, void *dev_id)
{
        struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
        int ret;

        spin_lock(&assigned_dev->intx_lock);
        if (pci_check_and_mask_intx(assigned_dev->dev)) {
                assigned_dev->host_irq_disabled = true;
                ret = IRQ_WAKE_THREAD;
        } else
                ret = IRQ_NONE;
        spin_unlock(&assigned_dev->intx_lock);

        return ret;
}

static void
kvm_assigned_dev_raise_guest_irq(struct kvm_assigned_dev_kernel *assigned_dev,
                                 int vector)
{
        if (unlikely(assigned_dev->irq_requested_type &
                     KVM_DEV_IRQ_GUEST_INTX)) {
                spin_lock(&assigned_dev->intx_mask_lock);
                if (!(assigned_dev->flags & KVM_DEV_ASSIGN_MASK_INTX))
                        kvm_set_irq(assigned_dev->kvm,
                                    assigned_dev->irq_source_id, vector, 1,
                                    false);
                spin_unlock(&assigned_dev->intx_mask_lock);
        } else
                kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,
                            vector, 1, false);
}

static irqreturn_t kvm_assigned_dev_thread_intx(int irq, void *dev_id)
{
        struct kvm_assigned_dev_kernel *assigned_dev = dev_id;

        if (!(assigned_dev->flags & KVM_DEV_ASSIGN_PCI_2_3)) {
                spin_lock_irq(&assigned_dev->intx_lock);
                disable_irq_nosync(irq);
                assigned_dev->host_irq_disabled = true;
                spin_unlock_irq(&assigned_dev->intx_lock);
        }

        kvm_assigned_dev_raise_guest_irq(assigned_dev,
                                         assigned_dev->guest_irq);

        return IRQ_HANDLED;
}

#ifdef __KVM_HAVE_MSI
static irqreturn_t kvm_assigned_dev_msi(int irq, void *dev_id)
{
        struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
        int ret = kvm_set_irq_inatomic(assigned_dev->kvm,
                                       assigned_dev->irq_source_id,
                                       assigned_dev->guest_irq, 1);
        return unlikely(ret == -EWOULDBLOCK) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
}

static irqreturn_t kvm_assigned_dev_thread_msi(int irq, void *dev_id)
{
        struct kvm_assigned_dev_kernel *assigned_dev = dev_id;

        kvm_assigned_dev_raise_guest_irq(assigned_dev,
                                         assigned_dev->guest_irq);

        return IRQ_HANDLED;
}
#endif

#ifdef __KVM_HAVE_MSIX
static irqreturn_t kvm_assigned_dev_msix(int irq, void *dev_id)
{
        struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
        int index = find_index_from_host_irq(assigned_dev, irq);
        u32 vector;
        int ret = 0;

        if (index >= 0) {
                vector = assigned_dev->guest_msix_entries[index].vector;
                ret = kvm_set_irq_inatomic(assigned_dev->kvm,
                                           assigned_dev->irq_source_id,
                                           vector, 1);
        }

        return unlikely(ret == -EWOULDBLOCK) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
}

static irqreturn_t kvm_assigned_dev_thread_msix(int irq, void *dev_id)
{
        struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
        int index = find_index_from_host_irq(assigned_dev, irq);
        u32 vector;

        if (index >= 0) {
                vector = assigned_dev->guest_msix_entries[index].vector;
                kvm_assigned_dev_raise_guest_irq(assigned_dev, vector);
        }

        return IRQ_HANDLED;
}
#endif

/* Ack the irq line for an assigned device */
static void kvm_assigned_dev_ack_irq(struct kvm_irq_ack_notifier *kian)
{
        struct kvm_assigned_dev_kernel *dev =
                container_of(kian, struct kvm_assigned_dev_kernel,
                             ack_notifier);

        kvm_set_irq(dev->kvm, dev->irq_source_id, dev->guest_irq, 0, false);

        spin_lock(&dev->intx_mask_lock);

        if (!(dev->flags & KVM_DEV_ASSIGN_MASK_INTX)) {
                bool reassert = false;

                spin_lock_irq(&dev->intx_lock);
                /*
                 * The guest IRQ may be shared so this ack can come from an
                 * IRQ for another guest device.
                 */
                if (dev->host_irq_disabled) {
                        if (!(dev->flags & KVM_DEV_ASSIGN_PCI_2_3))
                                enable_irq(dev->host_irq);
                        else if (!pci_check_and_unmask_intx(dev->dev))
                                reassert = true;
                        dev->host_irq_disabled = reassert;
                }
                spin_unlock_irq(&dev->intx_lock);

                if (reassert)
                        kvm_set_irq(dev->kvm, dev->irq_source_id,
                                    dev->guest_irq, 1, false);
        }

        spin_unlock(&dev->intx_mask_lock);
}

static void deassign_guest_irq(struct kvm *kvm,
                               struct kvm_assigned_dev_kernel *assigned_dev)
{
        if (assigned_dev->ack_notifier.gsi != -1)
                kvm_unregister_irq_ack_notifier(kvm,
                                                &assigned_dev->ack_notifier);

        kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,
                    assigned_dev->guest_irq, 0, false);

        if (assigned_dev->irq_source_id != -1)
                kvm_free_irq_source_id(kvm, assigned_dev->irq_source_id);
        assigned_dev->irq_source_id = -1;
        assigned_dev->irq_requested_type &= ~(KVM_DEV_IRQ_GUEST_MASK);
}

/* The function implicit hold kvm->lock mutex due to cancel_work_sync() */
static void deassign_host_irq(struct kvm *kvm,
                              struct kvm_assigned_dev_kernel *assigned_dev)
{
        /*
         * We disable irq here to prevent further events.
         *
         * Notice this maybe result in nested disable if the interrupt type is
         * INTx, but it's OK for we are going to free it.
         *
         * If this function is a part of VM destroy, please ensure that till
         * now, the kvm state is still legal for probably we also have to wait
         * on a currently running IRQ handler.
         */
        if (assigned_dev->irq_requested_type & KVM_DEV_IRQ_HOST_MSIX) {
                int i;
                for (i = 0; i < assigned_dev->entries_nr; i++)
                        disable_irq(assigned_dev->host_msix_entries[i].vector);

                for (i = 0; i < assigned_dev->entries_nr; i++)
                        free_irq(assigned_dev->host_msix_entries[i].vector,
                                 assigned_dev);

                assigned_dev->entries_nr = 0;
                kfree(assigned_dev->host_msix_entries);
                kfree(assigned_dev->guest_msix_entries);
                pci_disable_msix(assigned_dev->dev);
        } else {
                /* Deal with MSI and INTx */
                if ((assigned_dev->irq_requested_type &
                     KVM_DEV_IRQ_HOST_INTX) &&
                    (assigned_dev->flags & KVM_DEV_ASSIGN_PCI_2_3)) {
                        spin_lock_irq(&assigned_dev->intx_lock);
                        pci_intx(assigned_dev->dev, false);
                        spin_unlock_irq(&assigned_dev->intx_lock);
                        synchronize_irq(assigned_dev->host_irq);
                } else
                        disable_irq(assigned_dev->host_irq);

                free_irq(assigned_dev->host_irq, assigned_dev);

                if (assigned_dev->irq_requested_type & KVM_DEV_IRQ_HOST_MSI)
                        pci_disable_msi(assigned_dev->dev);
        }

        assigned_dev->irq_requested_type &= ~(KVM_DEV_IRQ_HOST_MASK);
}

static int kvm_deassign_irq(struct kvm *kvm,
                            struct kvm_assigned_dev_kernel *assigned_dev,
                            unsigned long irq_requested_type)
{
        unsigned long guest_irq_type, host_irq_type;

        if (!irqchip_in_kernel(kvm))
                return -EINVAL;
        /* no irq assignment to deassign */
        if (!assigned_dev->irq_requested_type)
                return -ENXIO;

        host_irq_type = irq_requested_type & KVM_DEV_IRQ_HOST_MASK;
        guest_irq_type = irq_requested_type & KVM_DEV_IRQ_GUEST_MASK;

        if (host_irq_type)
                deassign_host_irq(kvm, assigned_dev);
        if (guest_irq_type)
                deassign_guest_irq(kvm, assigned_dev);

        return 0;
}

static void kvm_free_assigned_irq(struct kvm *kvm,
                                  struct kvm_assigned_dev_kernel *assigned_dev)
{
        kvm_deassign_irq(kvm, assigned_dev, assigned_dev->irq_requested_type);
}

static void kvm_free_assigned_device(struct kvm *kvm,
                                     struct kvm_assigned_dev_kernel
                                     *assigned_dev)
{
        kvm_free_assigned_irq(kvm, assigned_dev);

        pci_reset_function(assigned_dev->dev);
        if (pci_load_and_free_saved_state(assigned_dev->dev,
                                          &assigned_dev->pci_saved_state))
                printk(KERN_INFO "%s: Couldn't reload %s saved state\n",
                       __func__, dev_name(&assigned_dev->dev->dev));
        else
                pci_restore_state(assigned_dev->dev);

        assigned_dev->dev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;

        pci_release_regions(assigned_dev->dev);
        pci_disable_device(assigned_dev->dev);
        pci_dev_put(assigned_dev->dev);

        list_del(&assigned_dev->list);
        kfree(assigned_dev);
}

void kvm_free_all_assigned_devices(struct kvm *kvm)
{
        struct list_head *ptr, *ptr2;
        struct kvm_assigned_dev_kernel *assigned_dev;

        list_for_each_safe(ptr, ptr2, &kvm->arch.assigned_dev_head) {
                assigned_dev = list_entry(ptr,
                                          struct kvm_assigned_dev_kernel,
                                          list);

                kvm_free_assigned_device(kvm, assigned_dev);
        }
}

static int assigned_device_enable_host_intx(struct kvm *kvm,
                                            struct kvm_assigned_dev_kernel *dev)
{
        irq_handler_t irq_handler;
        unsigned long flags;

        dev->host_irq = dev->dev->irq;

        /*
         * We can only share the IRQ line with other host devices if we are
         * able to disable the IRQ source at device-level - independently of
         * the guest driver. Otherwise host devices may suffer from unbounded
         * IRQ latencies when the guest keeps the line asserted.
         */
        if (dev->flags & KVM_DEV_ASSIGN_PCI_2_3) {
                irq_handler = kvm_assigned_dev_intx;
                flags = IRQF_SHARED;
        } else {
                irq_handler = NULL;
                flags = IRQF_ONESHOT;
        }
        if (request_threaded_irq(dev->host_irq, irq_handler,
                                 kvm_assigned_dev_thread_intx, flags,
                                 dev->irq_name, dev))
                return -EIO;

        if (dev->flags & KVM_DEV_ASSIGN_PCI_2_3) {
                spin_lock_irq(&dev->intx_lock);
                pci_intx(dev->dev, true);
                spin_unlock_irq(&dev->intx_lock);
        }
        return 0;
}

#ifdef __KVM_HAVE_MSI
static int assigned_device_enable_host_msi(struct kvm *kvm,
                                           struct kvm_assigned_dev_kernel *dev)
{
        int r;

        if (!dev->dev->msi_enabled) {
                r = pci_enable_msi(dev->dev);
                if (r)
                        return r;
        }

        dev->host_irq = dev->dev->irq;
        if (request_threaded_irq(dev->host_irq, kvm_assigned_dev_msi,
                                 kvm_assigned_dev_thread_msi, 0,
                                 dev->irq_name, dev)) {
                pci_disable_msi(dev->dev);
                return -EIO;
        }

        return 0;
}
#endif

#ifdef __KVM_HAVE_MSIX
static int assigned_device_enable_host_msix(struct kvm *kvm,
                                            struct kvm_assigned_dev_kernel *dev)
{
        int i, r = -EINVAL;

        /* host_msix_entries and guest_msix_entries should have been
         * initialized */
        if (dev->entries_nr == 0)
                return r;

        r = pci_enable_msix(dev->dev, dev->host_msix_entries, dev->entries_nr);
        if (r)
                return r;

        for (i = 0; i < dev->entries_nr; i++) {
                r = request_threaded_irq(dev->host_msix_entries[i].vector,
                                         kvm_assigned_dev_msix,
                                         kvm_assigned_dev_thread_msix,
                                         0, dev->irq_name, dev);
                if (r)
                        goto err;
        }

        return 0;
err:
        for (i -= 1; i >= 0; i--)
                free_irq(dev->host_msix_entries[i].vector, dev);
        pci_disable_msix(dev->dev);
        return r;
}

#endif

static int assigned_device_enable_guest_intx(struct kvm *kvm,
                                struct kvm_assigned_dev_kernel *dev,
                                struct kvm_assigned_irq *irq)
{
        dev->guest_irq = irq->guest_irq;
        dev->ack_notifier.gsi = irq->guest_irq;
        return 0;
}

#ifdef __KVM_HAVE_MSI
static int assigned_device_enable_guest_msi(struct kvm *kvm,
                        struct kvm_assigned_dev_kernel *dev,
                        struct kvm_assigned_irq *irq)
{
        dev->guest_irq = irq->guest_irq;
        dev->ack_notifier.gsi = -1;
        return 0;
}
#endif

#ifdef __KVM_HAVE_MSIX
static int assigned_device_enable_guest_msix(struct kvm *kvm,
                        struct kvm_assigned_dev_kernel *dev,
                        struct kvm_assigned_irq *irq)
{
        dev->guest_irq = irq->guest_irq;
        dev->ack_notifier.gsi = -1;
        return 0;
}
#endif

static int assign_host_irq(struct kvm *kvm,
                           struct kvm_assigned_dev_kernel *dev,
                           __u32 host_irq_type)
{
        int r = -EEXIST;

        if (dev->irq_requested_type & KVM_DEV_IRQ_HOST_MASK)
                return r;

        snprintf(dev->irq_name, sizeof(dev->irq_name), "kvm:%s",
                 pci_name(dev->dev));

        switch (host_irq_type) {
        case KVM_DEV_IRQ_HOST_INTX:
                r = assigned_device_enable_host_intx(kvm, dev);
                break;
#ifdef __KVM_HAVE_MSI
        case KVM_DEV_IRQ_HOST_MSI:
                r = assigned_device_enable_host_msi(kvm, dev);
                break;
#endif
#ifdef __KVM_HAVE_MSIX
        case KVM_DEV_IRQ_HOST_MSIX:
                r = assigned_device_enable_host_msix(kvm, dev);
                break;
#endif
        default:
                r = -EINVAL;
        }
        dev->host_irq_disabled = false;

        if (!r)
                dev->irq_requested_type |= host_irq_type;

        return r;
}

static int assign_guest_irq(struct kvm *kvm,
                            struct kvm_assigned_dev_kernel *dev,
                            struct kvm_assigned_irq *irq,
                            unsigned long guest_irq_type)
{
        int id;
        int r = -EEXIST;

        if (dev->irq_requested_type & KVM_DEV_IRQ_GUEST_MASK)
                return r;

        id = kvm_request_irq_source_id(kvm);
        if (id < 0)
                return id;

        dev->irq_source_id = id;

        switch (guest_irq_type) {
        case KVM_DEV_IRQ_GUEST_INTX:
                r = assigned_device_enable_guest_intx(kvm, dev, irq);
                break;
#ifdef __KVM_HAVE_MSI
        case KVM_DEV_IRQ_GUEST_MSI:
                r = assigned_device_enable_guest_msi(kvm, dev, irq);
                break;
#endif
#ifdef __KVM_HAVE_MSIX
        case KVM_DEV_IRQ_GUEST_MSIX:
                r = assigned_device_enable_guest_msix(kvm, dev, irq);
                break;
#endif
        default:
                r = -EINVAL;
        }

        if (!r) {
                dev->irq_requested_type |= guest_irq_type;
                if (dev->ack_notifier.gsi != -1)
                        kvm_register_irq_ack_notifier(kvm, &dev->ack_notifier);
        } else
                kvm_free_irq_source_id(kvm, dev->irq_source_id);

        return r;
}

/* TODO Deal with KVM_DEV_IRQ_ASSIGNED_MASK_MSIX */
static int kvm_vm_ioctl_assign_irq(struct kvm *kvm,
                                   struct kvm_assigned_irq *assigned_irq)
{
        int r = -EINVAL;
        struct kvm_assigned_dev_kernel *match;
        unsigned long host_irq_type, guest_irq_type;

        if (!irqchip_in_kernel(kvm))
                return r;

        mutex_lock(&kvm->lock);
        r = -ENODEV;
        match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
                                      assigned_irq->assigned_dev_id);
        if (!match)
                goto out;

        host_irq_type = (assigned_irq->flags & KVM_DEV_IRQ_HOST_MASK);
        guest_irq_type = (assigned_irq->flags & KVM_DEV_IRQ_GUEST_MASK);

        r = -EINVAL;
        /* can only assign one type at a time */
        if (hweight_long(host_irq_type) > 1)
                goto out;
        if (hweight_long(guest_irq_type) > 1)
                goto out;
        if (host_irq_type == 0 && guest_irq_type == 0)
                goto out;

        r = 0;
        if (host_irq_type)
                r = assign_host_irq(kvm, match, host_irq_type);
        if (r)
                goto out;

        if (guest_irq_type)
                r = assign_guest_irq(kvm, match, assigned_irq, guest_irq_type);
out:
        mutex_unlock(&kvm->lock);
        return r;
}

static int kvm_vm_ioctl_deassign_dev_irq(struct kvm *kvm,
                                         struct kvm_assigned_irq
                                         *assigned_irq)
{
        int r = -ENODEV;
        struct kvm_assigned_dev_kernel *match;
        unsigned long irq_type;

        mutex_lock(&kvm->lock);

        match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
                                      assigned_irq->assigned_dev_id);
        if (!match)
                goto out;

        irq_type = assigned_irq->flags & (KVM_DEV_IRQ_HOST_MASK |
                                          KVM_DEV_IRQ_GUEST_MASK);
        r = kvm_deassign_irq(kvm, match, irq_type);
out:
        mutex_unlock(&kvm->lock);
        return r;
}

/*
 * We want to test whether the caller has been granted permissions to
 * use this device.  To be able to configure and control the device,
 * the user needs access to PCI configuration space and BAR resources.
 * These are accessed through PCI sysfs.  PCI config space is often
 * passed to the process calling this ioctl via file descriptor, so we
 * can't rely on access to that file.  We can check for permissions
 * on each of the BAR resource files, which is a pretty clear
 * indicator that the user has been granted access to the device.
 */
static int probe_sysfs_permissions(struct pci_dev *dev)
{
#ifdef CONFIG_SYSFS
        int i;
        bool bar_found = false;

        for (i = PCI_STD_RESOURCES; i <= PCI_STD_RESOURCE_END; i++) {
                char *kpath, *syspath;
                struct path path;
                struct inode *inode;
                int r;

                if (!pci_resource_len(dev, i))
                        continue;

                kpath = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
                if (!kpath)
                        return -ENOMEM;

                /* Per sysfs-rules, sysfs is always at /sys */
                syspath = kasprintf(GFP_KERNEL, "/sys%s/resource%d", kpath, i);
                kfree(kpath);
                if (!syspath)
                        return -ENOMEM;

                r = kern_path(syspath, LOOKUP_FOLLOW, &path);
                kfree(syspath);
                if (r)
                        return r;

                inode = path.dentry->d_inode;

                r = inode_permission(inode, MAY_READ | MAY_WRITE | MAY_ACCESS);
                path_put(&path);
                if (r)
                        return r;

                bar_found = true;
        }

        /* If no resources, probably something special */
        if (!bar_found)
                return -EPERM;

        return 0;
#else
        return -EINVAL; /* No way to control the device without sysfs */
#endif
}

static int kvm_vm_ioctl_assign_device(struct kvm *kvm,
                                      struct kvm_assigned_pci_dev *assigned_dev)
{
        int r = 0, idx;
        struct kvm_assigned_dev_kernel *match;
        struct pci_dev *dev;

        if (!(assigned_dev->flags & KVM_DEV_ASSIGN_ENABLE_IOMMU))
                return -EINVAL;

        mutex_lock(&kvm->lock);
        idx = srcu_read_lock(&kvm->srcu);

        match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
                                      assigned_dev->assigned_dev_id);
        if (match) {
                /* device already assigned */
                r = -EEXIST;
                goto out;
        }

        match = kzalloc(sizeof(struct kvm_assigned_dev_kernel), GFP_KERNEL);
        if (match == NULL) {
                printk(KERN_INFO "%s: Couldn't allocate memory\n",
                       __func__);
                r = -ENOMEM;
                goto out;
        }
        dev = pci_get_domain_bus_and_slot(assigned_dev->segnr,
                                   assigned_dev->busnr,
                                   assigned_dev->devfn);
        if (!dev) {
                printk(KERN_INFO "%s: host device not found\n", __func__);
                r = -EINVAL;
                goto out_free;
        }

        /* Don't allow bridges to be assigned */
        if (dev->hdr_type != PCI_HEADER_TYPE_NORMAL) {
                r = -EPERM;
                goto out_put;
        }

        r = probe_sysfs_permissions(dev);
        if (r)
                goto out_put;

        if (pci_enable_device(dev)) {
                printk(KERN_INFO "%s: Could not enable PCI device\n", __func__);
                r = -EBUSY;
                goto out_put;
        }
        r = pci_request_regions(dev, "kvm_assigned_device");
        if (r) {
                printk(KERN_INFO "%s: Could not get access to device regions\n",
                       __func__);
                goto out_disable;
        }

        pci_reset_function(dev);
        pci_save_state(dev);
        match->pci_saved_state = pci_store_saved_state(dev);
        if (!match->pci_saved_state)
                printk(KERN_DEBUG "%s: Couldn't store %s saved state\n",
                       __func__, dev_name(&dev->dev));

        if (!pci_intx_mask_supported(dev))
                assigned_dev->flags &= ~KVM_DEV_ASSIGN_PCI_2_3;

        match->assigned_dev_id = assigned_dev->assigned_dev_id;
        match->host_segnr = assigned_dev->segnr;
        match->host_busnr = assigned_dev->busnr;
        match->host_devfn = assigned_dev->devfn;
        match->flags = assigned_dev->flags;
        match->dev = dev;
        spin_lock_init(&match->intx_lock);
        spin_lock_init(&match->intx_mask_lock);
        match->irq_source_id = -1;
        match->kvm = kvm;
        match->ack_notifier.irq_acked = kvm_assigned_dev_ack_irq;

        list_add(&match->list, &kvm->arch.assigned_dev_head);

        if (!kvm->arch.iommu_domain) {
                r = kvm_iommu_map_guest(kvm);
                if (r)
                        goto out_list_del;
        }
        r = kvm_assign_device(kvm, match);
        if (r)
                goto out_list_del;

out:
        srcu_read_unlock(&kvm->srcu, idx);
        mutex_unlock(&kvm->lock);
        return r;
out_list_del:
        if (pci_load_and_free_saved_state(dev, &match->pci_saved_state))
                printk(KERN_INFO "%s: Couldn't reload %s saved state\n",
                       __func__, dev_name(&dev->dev));
        list_del(&match->list);
        pci_release_regions(dev);
out_disable:
        pci_disable_device(dev);
out_put:
        pci_dev_put(dev);
out_free:
        kfree(match);
        srcu_read_unlock(&kvm->srcu, idx);
        mutex_unlock(&kvm->lock);
        return r;
}

static int kvm_vm_ioctl_deassign_device(struct kvm *kvm,
                struct kvm_assigned_pci_dev *assigned_dev)
{
        int r = 0;
        struct kvm_assigned_dev_kernel *match;

        mutex_lock(&kvm->lock);

        match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
                                      assigned_dev->assigned_dev_id);
        if (!match) {
                printk(KERN_INFO "%s: device hasn't been assigned before, "
                  "so cannot be deassigned\n", __func__);
                r = -EINVAL;
                goto out;
        }

        kvm_deassign_device(kvm, match);

        kvm_free_assigned_device(kvm, match);

out:
        mutex_unlock(&kvm->lock);
        return r;
}


#ifdef __KVM_HAVE_MSIX
static int kvm_vm_ioctl_set_msix_nr(struct kvm *kvm,
                                    struct kvm_assigned_msix_nr *entry_nr)
{
        int r = 0;
        struct kvm_assigned_dev_kernel *adev;

        mutex_lock(&kvm->lock);

        adev = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
                                      entry_nr->assigned_dev_id);
        if (!adev) {
                r = -EINVAL;
                goto msix_nr_out;
        }

        if (adev->entries_nr == 0) {
                adev->entries_nr = entry_nr->entry_nr;
                if (adev->entries_nr == 0 ||
                    adev->entries_nr > KVM_MAX_MSIX_PER_DEV) {
                        r = -EINVAL;
                        goto msix_nr_out;
                }

                adev->host_msix_entries = kzalloc(sizeof(struct msix_entry) *
                                                entry_nr->entry_nr,
                                                GFP_KERNEL);
                if (!adev->host_msix_entries) {
                        r = -ENOMEM;
                        goto msix_nr_out;
                }
                adev->guest_msix_entries =
                        kzalloc(sizeof(struct msix_entry) * entry_nr->entry_nr,
                                GFP_KERNEL);
                if (!adev->guest_msix_entries) {
                        kfree(adev->host_msix_entries);
                        r = -ENOMEM;
                        goto msix_nr_out;
                }
        } else /* Not allowed set MSI-X number twice */
                r = -EINVAL;
msix_nr_out:
        mutex_unlock(&kvm->lock);
        return r;
}

static int kvm_vm_ioctl_set_msix_entry(struct kvm *kvm,
                                       struct kvm_assigned_msix_entry *entry)
{
        int r = 0, i;
        struct kvm_assigned_dev_kernel *adev;

        mutex_lock(&kvm->lock);

        adev = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
                                      entry->assigned_dev_id);

        if (!adev) {
                r = -EINVAL;
                goto msix_entry_out;
        }

        for (i = 0; i < adev->entries_nr; i++)
                if (adev->guest_msix_entries[i].vector == 0 ||
                    adev->guest_msix_entries[i].entry == entry->entry) {
                        adev->guest_msix_entries[i].entry = entry->entry;
                        adev->guest_msix_entries[i].vector = entry->gsi;
                        adev->host_msix_entries[i].entry = entry->entry;
                        break;
                }
        if (i == adev->entries_nr) {
                r = -ENOSPC;
                goto msix_entry_out;
        }

msix_entry_out:
        mutex_unlock(&kvm->lock);

        return r;
}
#endif

static int kvm_vm_ioctl_set_pci_irq_mask(struct kvm *kvm,
                struct kvm_assigned_pci_dev *assigned_dev)
{
        int r = 0;
        struct kvm_assigned_dev_kernel *match;

        mutex_lock(&kvm->lock);

        match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
                                      assigned_dev->assigned_dev_id);
        if (!match) {
                r = -ENODEV;
                goto out;
        }

        spin_lock(&match->intx_mask_lock);

        match->flags &= ~KVM_DEV_ASSIGN_MASK_INTX;
        match->flags |= assigned_dev->flags & KVM_DEV_ASSIGN_MASK_INTX;

        if (match->irq_requested_type & KVM_DEV_IRQ_GUEST_INTX) {
                if (assigned_dev->flags & KVM_DEV_ASSIGN_MASK_INTX) {
                        kvm_set_irq(match->kvm, match->irq_source_id,
                                    match->guest_irq, 0, false);
                        /*
                         * Masking at hardware-level is performed on demand,
                         * i.e. when an IRQ actually arrives at the host.
                         */
                } else if (!(assigned_dev->flags & KVM_DEV_ASSIGN_PCI_2_3)) {
                        /*
                         * Unmask the IRQ line if required. Unmasking at
                         * device level will be performed by user space.
                         */
                        spin_lock_irq(&match->intx_lock);
                        if (match->host_irq_disabled) {
                                enable_irq(match->host_irq);
                                match->host_irq_disabled = false;
                        }
                        spin_unlock_irq(&match->intx_lock);
                }
        }

        spin_unlock(&match->intx_mask_lock);

out:
        mutex_unlock(&kvm->lock);
        return r;
}

long kvm_vm_ioctl_assigned_device(struct kvm *kvm, unsigned ioctl,
                                  unsigned long arg)
{
        void __user *argp = (void __user *)arg;
        int r;

        switch (ioctl) {
        case KVM_ASSIGN_PCI_DEVICE: {
                struct kvm_assigned_pci_dev assigned_dev;

                r = -EFAULT;
                if (copy_from_user(&assigned_dev, argp, sizeof assigned_dev))
                        goto out;
                r = kvm_vm_ioctl_assign_device(kvm, &assigned_dev);
                if (r)
                        goto out;
                break;
        }
        case KVM_ASSIGN_IRQ: {
                r = -EOPNOTSUPP;
                break;
        }
        case KVM_ASSIGN_DEV_IRQ: {
                struct kvm_assigned_irq assigned_irq;

                r = -EFAULT;
                if (copy_from_user(&assigned_irq, argp, sizeof assigned_irq))
                        goto out;
                r = kvm_vm_ioctl_assign_irq(kvm, &assigned_irq);
                if (r)
                        goto out;
                break;
        }
        case KVM_DEASSIGN_DEV_IRQ: {
                struct kvm_assigned_irq assigned_irq;

                r = -EFAULT;
                if (copy_from_user(&assigned_irq, argp, sizeof assigned_irq))
                        goto out;
                r = kvm_vm_ioctl_deassign_dev_irq(kvm, &assigned_irq);
                if (r)
                        goto out;
                break;
        }
        case KVM_DEASSIGN_PCI_DEVICE: {
                struct kvm_assigned_pci_dev assigned_dev;

                r = -EFAULT;
                if (copy_from_user(&assigned_dev, argp, sizeof assigned_dev))
                        goto out;
                r = kvm_vm_ioctl_deassign_device(kvm, &assigned_dev);
                if (r)
                        goto out;
                break;
        }
#ifdef __KVM_HAVE_MSIX
        case KVM_ASSIGN_SET_MSIX_NR: {
                struct kvm_assigned_msix_nr entry_nr;
                r = -EFAULT;
                if (copy_from_user(&entry_nr, argp, sizeof entry_nr))
                        goto out;
                r = kvm_vm_ioctl_set_msix_nr(kvm, &entry_nr);
                if (r)
                        goto out;
                break;
        }
        case KVM_ASSIGN_SET_MSIX_ENTRY: {
                struct kvm_assigned_msix_entry entry;
                r = -EFAULT;
                if (copy_from_user(&entry, argp, sizeof entry))

                        goto out;
                r = kvm_vm_ioctl_set_msix_entry(kvm, &entry);
                if (r)
                        goto out;
                break;
        }
#endif
        case KVM_ASSIGN_SET_INTX_MASK: {
                struct kvm_assigned_pci_dev assigned_dev;

                r = -EFAULT;
                if (copy_from_user(&assigned_dev, argp, sizeof assigned_dev))
                        goto out;
                r = kvm_vm_ioctl_set_pci_irq_mask(kvm, &assigned_dev);
                break;
        }
        default:
                r = -ENOTTY;
                break;
        }
out:
        return r;
}