assigned-dev.c

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/*
 * 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);
        spin_unlock(&assigned_dev->intx_mask_lock);
    } else
        kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,
                vector, 1);
}

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_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_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);

    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);
    }

    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);

    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 irqreturn_t kvm_assigned_dev_msi(int irq, void *dev_id)
{
    return IRQ_WAKE_THREAD;
}

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 irqreturn_t kvm_assigned_dev_msix(int irq, void *dev_id)
{
    return IRQ_WAKE_THREAD;
}

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);
            /*
             * 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_CAP_IRQ_ROUTING
    case KVM_SET_GSI_ROUTING: {
        struct kvm_irq_routing routing;
        struct kvm_irq_routing __user *urouting;
        struct kvm_irq_routing_entry *entries;

        r = -EFAULT;
        if (copy_from_user(&routing, argp, sizeof(routing)))
            goto out;
        r = -EINVAL;
        if (routing.nr >= KVM_MAX_IRQ_ROUTES)
            goto out;
        if (routing.flags)
            goto out;
        r = -ENOMEM;
        entries = vmalloc(routing.nr * sizeof(*entries));
        if (!entries)
            goto out;
        r = -EFAULT;
        urouting = argp;
        if (copy_from_user(entries, urouting->entries,
                   routing.nr * sizeof(*entries)))
            goto out_free_irq_routing;
        r = kvm_set_irq_routing(kvm, entries, routing.nr,
                    routing.flags);
    out_free_irq_routing:
        vfree(entries);
        break;
    }
#endif /* KVM_CAP_IRQ_ROUTING */
#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;
}