// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Virtio PCI driver - common functionality for all device versions
 *
 * This module allows virtio devices to be used over a virtual PCI device.
 * This can be used with QEMU based VMMs like KVM or Xen.
 *
 * Copyright IBM Corp. 2007
 * Copyright Red Hat, Inc. 2014
 *
 * Authors:
 *  Anthony Liguori  <aliguori@us.ibm.com>
 *  Rusty Russell <rusty@rustcorp.com.au>
 *  Michael S. Tsirkin <mst@redhat.com>
 */

#include "virtio_pci_common.h"

static bool force_legacy = false;

#if IS_ENABLED(CONFIG_VIRTIO_PCI_LEGACY)
module_param(force_legacy, bool, 0444);
MODULE_PARM_DESC(force_legacy,
                 "Force legacy mode for transitional virtio 1 devices");
#endif

bool vp_is_avq(struct virtio_device *vdev, unsigned int index)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);

        if (!virtio_has_feature(vdev, VIRTIO_F_ADMIN_VQ))
                return false;

        return index == vp_dev->admin_vq.vq_index;
}

/* wait for pending irq handlers */
void vp_synchronize_vectors(struct virtio_device *vdev)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
        int i;

        if (vp_dev->intx_enabled)
                synchronize_irq(vp_dev->pci_dev->irq);

        for (i = 0; i < vp_dev->msix_vectors; ++i)
                synchronize_irq(pci_irq_vector(vp_dev->pci_dev, i));
}

/* the notify function used when creating a virt queue */
bool vp_notify(struct virtqueue *vq)
{
        /* we write the queue's selector into the notification register to
         * signal the other end */
        iowrite16(vq->index, (void __iomem *)vq->priv);
        return true;
}

/* Notify all slow path virtqueues on an interrupt. */
static void vp_vring_slow_path_interrupt(int irq,
                                         struct virtio_pci_device *vp_dev)
{
        struct virtio_pci_vq_info *info;
        unsigned long flags;

        spin_lock_irqsave(&vp_dev->lock, flags);
        list_for_each_entry(info, &vp_dev->slow_virtqueues, node)
                vring_interrupt(irq, info->vq);
        spin_unlock_irqrestore(&vp_dev->lock, flags);
}

/* Handle a configuration change: Tell driver if it wants to know. */
static irqreturn_t vp_config_changed(int irq, void *opaque)
{
        struct virtio_pci_device *vp_dev = opaque;

        virtio_config_changed(&vp_dev->vdev);
        vp_vring_slow_path_interrupt(irq, vp_dev);
        return IRQ_HANDLED;
}

/* Notify all virtqueues on an interrupt. */
static irqreturn_t vp_vring_interrupt(int irq, void *opaque)
{
        struct virtio_pci_device *vp_dev = opaque;
        struct virtio_pci_vq_info *info;
        irqreturn_t ret = IRQ_NONE;
        unsigned long flags;

        spin_lock_irqsave(&vp_dev->lock, flags);
        list_for_each_entry(info, &vp_dev->virtqueues, node) {
                if (vring_interrupt(irq, info->vq) == IRQ_HANDLED)
                        ret = IRQ_HANDLED;
        }
        spin_unlock_irqrestore(&vp_dev->lock, flags);

        return ret;
}

/* A small wrapper to also acknowledge the interrupt when it's handled.
 * I really need an EIO hook for the vring so I can ack the interrupt once we
 * know that we'll be handling the IRQ but before we invoke the callback since
 * the callback may notify the host which results in the host attempting to
 * raise an interrupt that we would then mask once we acknowledged the
 * interrupt. */
static irqreturn_t vp_interrupt(int irq, void *opaque)
{
        struct virtio_pci_device *vp_dev = opaque;
        u8 isr;

        /* reading the ISR has the effect of also clearing it so it's very
         * important to save off the value. */
        isr = ioread8(vp_dev->isr);

        /* It's definitely not us if the ISR was not high */
        if (!isr)
                return IRQ_NONE;

        /* Configuration change?  Tell driver if it wants to know. */
        if (isr & VIRTIO_PCI_ISR_CONFIG)
                vp_config_changed(irq, opaque);

        return vp_vring_interrupt(irq, opaque);
}

static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
                                   bool per_vq_vectors, struct irq_affinity *desc)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
        const char *name = dev_name(&vp_dev->vdev.dev);
        unsigned int flags = PCI_IRQ_MSIX;
        unsigned int i, v;
        int err = -ENOMEM;

        vp_dev->msix_vectors = nvectors;

        vp_dev->msix_names = kmalloc_objs(*vp_dev->msix_names, nvectors);
        if (!vp_dev->msix_names)
                goto error;
        vp_dev->msix_affinity_masks
                = kzalloc_objs(*vp_dev->msix_affinity_masks, nvectors);
        if (!vp_dev->msix_affinity_masks)
                goto error;
        for (i = 0; i < nvectors; ++i)
                if (!alloc_cpumask_var(&vp_dev->msix_affinity_masks[i],
                                        GFP_KERNEL))
                        goto error;

        if (!per_vq_vectors)
                desc = NULL;

        if (desc) {
                flags |= PCI_IRQ_AFFINITY;
                desc->pre_vectors++; /* virtio config vector */
        }

        err = pci_alloc_irq_vectors_affinity(vp_dev->pci_dev, nvectors,
                                             nvectors, flags, desc);
        if (err < 0)
                goto error;
        vp_dev->msix_enabled = 1;

        /* Set the vector used for configuration */
        v = vp_dev->msix_used_vectors;
        snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names,
                 "%s-config", name);
        err = request_irq(pci_irq_vector(vp_dev->pci_dev, v),
                          vp_config_changed, 0, vp_dev->msix_names[v],
                          vp_dev);
        if (err)
                goto error;
        ++vp_dev->msix_used_vectors;

        v = vp_dev->config_vector(vp_dev, v);
        /* Verify we had enough resources to assign the vector */
        if (v == VIRTIO_MSI_NO_VECTOR) {
                err = -EBUSY;
                goto error;
        }

        if (!per_vq_vectors) {
                /* Shared vector for all VQs */
                v = vp_dev->msix_used_vectors;
                snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names,
                         "%s-virtqueues", name);
                err = request_irq(pci_irq_vector(vp_dev->pci_dev, v),
                                  vp_vring_interrupt, 0, vp_dev->msix_names[v],
                                  vp_dev);
                if (err)
                        goto error;
                ++vp_dev->msix_used_vectors;
        }
        return 0;
error:
        return err;
}

static bool vp_is_slow_path_vector(u16 msix_vec)
{
        return msix_vec == VP_MSIX_CONFIG_VECTOR;
}

static struct virtqueue *vp_setup_vq(struct virtio_device *vdev, unsigned int index,
                                     void (*callback)(struct virtqueue *vq),
                                     const char *name,
                                     bool ctx,
                                     u16 msix_vec,
                                     struct virtio_pci_vq_info **p_info)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
        struct virtio_pci_vq_info *info = kmalloc_obj(*info);
        struct virtqueue *vq;
        unsigned long flags;

        /* fill out our structure that represents an active queue */
        if (!info)
                return ERR_PTR(-ENOMEM);

        vq = vp_dev->setup_vq(vp_dev, info, index, callback, name, ctx,
                              msix_vec);
        if (IS_ERR(vq))
                goto out_info;

        info->vq = vq;
        if (callback) {
                spin_lock_irqsave(&vp_dev->lock, flags);
                if (!vp_is_slow_path_vector(msix_vec))
                        list_add(&info->node, &vp_dev->virtqueues);
                else
                        list_add(&info->node, &vp_dev->slow_virtqueues);
                spin_unlock_irqrestore(&vp_dev->lock, flags);
        } else {
                INIT_LIST_HEAD(&info->node);
        }

        *p_info = info;
        return vq;

out_info:
        kfree(info);
        return vq;
}

static void vp_del_vq(struct virtqueue *vq, struct virtio_pci_vq_info *info)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
        unsigned long flags;

        /*
         * If it fails during re-enable reset vq. This way we won't rejoin
         * info->node to the queue. Prevent unexpected irqs.
         */
        if (!vq->reset) {
                spin_lock_irqsave(&vp_dev->lock, flags);
                list_del(&info->node);
                spin_unlock_irqrestore(&vp_dev->lock, flags);
        }

        vp_dev->del_vq(info);
        kfree(info);
}

/* the config->del_vqs() implementation */
void vp_del_vqs(struct virtio_device *vdev)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
        struct virtio_pci_vq_info *info;
        struct virtqueue *vq, *n;
        int i;

        list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
                info = vp_is_avq(vdev, vq->index) ? vp_dev->admin_vq.info :
                                                    vp_dev->vqs[vq->index];

                if (vp_dev->per_vq_vectors) {
                        int v = info->msix_vector;
                        if (v != VIRTIO_MSI_NO_VECTOR &&
                            !vp_is_slow_path_vector(v)) {
                                int irq = pci_irq_vector(vp_dev->pci_dev, v);

                                irq_update_affinity_hint(irq, NULL);
                                free_irq(irq, vq);
                        }
                }
                vp_del_vq(vq, info);
        }
        vp_dev->per_vq_vectors = false;

        if (vp_dev->intx_enabled) {
                free_irq(vp_dev->pci_dev->irq, vp_dev);
                vp_dev->intx_enabled = 0;
        }

        for (i = 0; i < vp_dev->msix_used_vectors; ++i)
                free_irq(pci_irq_vector(vp_dev->pci_dev, i), vp_dev);

        if (vp_dev->msix_affinity_masks) {
                for (i = 0; i < vp_dev->msix_vectors; i++)
                        free_cpumask_var(vp_dev->msix_affinity_masks[i]);
        }

        if (vp_dev->msix_enabled) {
                /* Disable the vector used for configuration */
                vp_dev->config_vector(vp_dev, VIRTIO_MSI_NO_VECTOR);

                pci_free_irq_vectors(vp_dev->pci_dev);
                vp_dev->msix_enabled = 0;
        }

        vp_dev->msix_vectors = 0;
        vp_dev->msix_used_vectors = 0;
        kfree(vp_dev->msix_names);
        vp_dev->msix_names = NULL;
        kfree(vp_dev->msix_affinity_masks);
        vp_dev->msix_affinity_masks = NULL;
        kfree(vp_dev->vqs);
        vp_dev->vqs = NULL;
}

enum vp_vq_vector_policy {
        VP_VQ_VECTOR_POLICY_EACH,
        VP_VQ_VECTOR_POLICY_SHARED_SLOW,
        VP_VQ_VECTOR_POLICY_SHARED,
};

static struct virtqueue *
vp_find_one_vq_msix(struct virtio_device *vdev, int queue_idx,
                    vq_callback_t *callback, const char *name, bool ctx,
                    bool slow_path, int *allocated_vectors,
                    enum vp_vq_vector_policy vector_policy,
                    struct virtio_pci_vq_info **p_info)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
        struct virtqueue *vq;
        u16 msix_vec;
        int err;

        if (!callback)
                msix_vec = VIRTIO_MSI_NO_VECTOR;
        else if (vector_policy == VP_VQ_VECTOR_POLICY_EACH ||
                 (vector_policy == VP_VQ_VECTOR_POLICY_SHARED_SLOW &&
                 !slow_path))
                msix_vec = (*allocated_vectors)++;
        else if (vector_policy != VP_VQ_VECTOR_POLICY_EACH &&
                 slow_path)
                msix_vec = VP_MSIX_CONFIG_VECTOR;
        else
                msix_vec = VP_MSIX_VQ_VECTOR;
        vq = vp_setup_vq(vdev, queue_idx, callback, name, ctx, msix_vec,
                         p_info);
        if (IS_ERR(vq))
                return vq;

        if (vector_policy == VP_VQ_VECTOR_POLICY_SHARED ||
            msix_vec == VIRTIO_MSI_NO_VECTOR ||
            vp_is_slow_path_vector(msix_vec))
                return vq;

        /* allocate per-vq irq if available and necessary */
        snprintf(vp_dev->msix_names[msix_vec], sizeof(*vp_dev->msix_names),
                 "%s-%s", dev_name(&vp_dev->vdev.dev), name);
        err = request_irq(pci_irq_vector(vp_dev->pci_dev, msix_vec),
                          vring_interrupt, 0,
                          vp_dev->msix_names[msix_vec], vq);
        if (err) {
                vp_del_vq(vq, *p_info);
                return ERR_PTR(err);
        }

        return vq;
}

static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned int nvqs,
                            struct virtqueue *vqs[],
                            struct virtqueue_info vqs_info[],
                            enum vp_vq_vector_policy vector_policy,
                            struct irq_affinity *desc)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
        struct virtio_pci_admin_vq *avq = &vp_dev->admin_vq;
        struct virtqueue_info *vqi;
        int i, err, nvectors, allocated_vectors, queue_idx = 0;
        struct virtqueue *vq;
        bool per_vq_vectors;
        u16 avq_num = 0;

        vp_dev->vqs = kzalloc_objs(*vp_dev->vqs, nvqs);
        if (!vp_dev->vqs)
                return -ENOMEM;

        if (vp_dev->avq_index) {
                err = vp_dev->avq_index(vdev, &avq->vq_index, &avq_num);
                if (err)
                        goto error_find;
        }

        per_vq_vectors = vector_policy != VP_VQ_VECTOR_POLICY_SHARED;

        if (per_vq_vectors) {
                /* Best option: one for change interrupt, one per vq. */
                nvectors = 1;
                for (i = 0; i < nvqs; ++i) {
                        vqi = &vqs_info[i];
                        if (vqi->name && vqi->callback)
                                ++nvectors;
                }
                if (avq_num && vector_policy == VP_VQ_VECTOR_POLICY_EACH)
                        ++nvectors;
        } else {
                /* Second best: one for change, shared for all vqs. */
                nvectors = 2;
        }

        err = vp_request_msix_vectors(vdev, nvectors, per_vq_vectors, desc);
        if (err)
                goto error_find;

        vp_dev->per_vq_vectors = per_vq_vectors;
        allocated_vectors = vp_dev->msix_used_vectors;
        for (i = 0; i < nvqs; ++i) {
                vqi = &vqs_info[i];
                if (!vqi->name) {
                        vqs[i] = NULL;
                        continue;
                }
                vqs[i] = vp_find_one_vq_msix(vdev, queue_idx++, vqi->callback,
                                             vqi->name, vqi->ctx, false,
                                             &allocated_vectors, vector_policy,
                                             &vp_dev->vqs[i]);
                if (IS_ERR(vqs[i])) {
                        err = PTR_ERR(vqs[i]);
                        goto error_find;
                }
        }

        if (!avq_num)
                return 0;
        sprintf(avq->name, "avq.%u", avq->vq_index);
        vq = vp_find_one_vq_msix(vdev, avq->vq_index, vp_modern_avq_done,
                                 avq->name, false, true, &allocated_vectors,
                                 vector_policy, &vp_dev->admin_vq.info);
        if (IS_ERR(vq)) {
                err = PTR_ERR(vq);
                goto error_find;
        }

        return 0;

error_find:
        vp_del_vqs(vdev);
        return err;
}

static int vp_find_vqs_intx(struct virtio_device *vdev, unsigned int nvqs,
                            struct virtqueue *vqs[],
                            struct virtqueue_info vqs_info[])
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
        struct virtio_pci_admin_vq *avq = &vp_dev->admin_vq;
        int i, err, queue_idx = 0;
        struct virtqueue *vq;
        u16 avq_num = 0;

        vp_dev->vqs = kzalloc_objs(*vp_dev->vqs, nvqs);
        if (!vp_dev->vqs)
                return -ENOMEM;

        if (vp_dev->avq_index) {
                err = vp_dev->avq_index(vdev, &avq->vq_index, &avq_num);
                if (err)
                        goto out_del_vqs;
        }

        err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED,
                        dev_name(&vdev->dev), vp_dev);
        if (err)
                goto out_del_vqs;

        vp_dev->intx_enabled = 1;
        vp_dev->per_vq_vectors = false;
        for (i = 0; i < nvqs; ++i) {
                struct virtqueue_info *vqi = &vqs_info[i];

                if (!vqi->name) {
                        vqs[i] = NULL;
                        continue;
                }
                vqs[i] = vp_setup_vq(vdev, queue_idx++, vqi->callback,
                                     vqi->name, vqi->ctx,
                                     VIRTIO_MSI_NO_VECTOR, &vp_dev->vqs[i]);
                if (IS_ERR(vqs[i])) {
                        err = PTR_ERR(vqs[i]);
                        goto out_del_vqs;
                }
        }

        if (!avq_num)
                return 0;
        sprintf(avq->name, "avq.%u", avq->vq_index);
        vq = vp_setup_vq(vdev, queue_idx++, vp_modern_avq_done, avq->name,
                         false, VIRTIO_MSI_NO_VECTOR,
                         &vp_dev->admin_vq.info);
        if (IS_ERR(vq)) {
                err = PTR_ERR(vq);
                goto out_del_vqs;
        }

        return 0;
out_del_vqs:
        vp_del_vqs(vdev);
        return err;
}

/* the config->find_vqs() implementation */
int vp_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
                struct virtqueue *vqs[], struct virtqueue_info vqs_info[],
                struct irq_affinity *desc)
{
        int err;

        /* Try MSI-X with one vector per queue. */
        err = vp_find_vqs_msix(vdev, nvqs, vqs, vqs_info,
                               VP_VQ_VECTOR_POLICY_EACH, desc);
        if (!err)
                return 0;
        /* Fallback: MSI-X with one shared vector for config and
         * slow path queues, one vector per queue for the rest.
         */
        err = vp_find_vqs_msix(vdev, nvqs, vqs, vqs_info,
                               VP_VQ_VECTOR_POLICY_SHARED_SLOW, desc);
        if (!err)
                return 0;
        /* Fallback: MSI-X with one vector for config, one shared for queues. */
        err = vp_find_vqs_msix(vdev, nvqs, vqs, vqs_info,
                               VP_VQ_VECTOR_POLICY_SHARED, desc);
        if (!err)
                return 0;
        /* Is there an interrupt? If not give up. */
        if (!(to_vp_device(vdev)->pci_dev->irq))
                return err;
        /* Finally fall back to regular interrupts. */
        return vp_find_vqs_intx(vdev, nvqs, vqs, vqs_info);
}

const char *vp_bus_name(struct virtio_device *vdev)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);

        return pci_name(vp_dev->pci_dev);
}

/* Setup the affinity for a virtqueue:
 * - force the affinity for per vq vector
 * - OR over all affinities for shared MSI
 * - ignore the affinity request if we're using INTX
 */
int vp_set_vq_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask)
{
        struct virtio_device *vdev = vq->vdev;
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
        struct virtio_pci_vq_info *info = vp_dev->vqs[vq->index];
        struct cpumask *mask;
        unsigned int irq;

        if (!vq->callback)
                return -EINVAL;

        if (vp_dev->msix_enabled) {
                mask = vp_dev->msix_affinity_masks[info->msix_vector];
                irq = pci_irq_vector(vp_dev->pci_dev, info->msix_vector);
                if (!cpu_mask)
                        irq_update_affinity_hint(irq, NULL);
                else {
                        cpumask_copy(mask, cpu_mask);
                        irq_set_affinity_and_hint(irq, mask);
                }
        }
        return 0;
}

const struct cpumask *vp_get_vq_affinity(struct virtio_device *vdev, int index)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);

        if (!vp_dev->per_vq_vectors ||
            vp_dev->vqs[index]->msix_vector == VIRTIO_MSI_NO_VECTOR ||
            vp_is_slow_path_vector(vp_dev->vqs[index]->msix_vector))
                return NULL;

        return pci_irq_get_affinity(vp_dev->pci_dev,
                                    vp_dev->vqs[index]->msix_vector);
}

#ifdef CONFIG_PM_SLEEP
static int virtio_pci_freeze(struct device *dev)
{
        struct pci_dev *pci_dev = to_pci_dev(dev);
        struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
        int ret;

        ret = virtio_device_freeze(&vp_dev->vdev);

        if (!ret)
                pci_disable_device(pci_dev);
        return ret;
}

static int virtio_pci_restore(struct device *dev)
{
        struct pci_dev *pci_dev = to_pci_dev(dev);
        struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
        int ret;

        ret = pci_enable_device(pci_dev);
        if (ret)
                return ret;

        pci_set_master(pci_dev);
        return virtio_device_restore(&vp_dev->vdev);
}

static bool vp_supports_pm_no_reset(struct device *dev)
{
        struct pci_dev *pci_dev = to_pci_dev(dev);
        u16 pmcsr;

        if (!pci_dev->pm_cap)
                return false;

        pci_read_config_word(pci_dev, pci_dev->pm_cap + PCI_PM_CTRL, &pmcsr);
        if (PCI_POSSIBLE_ERROR(pmcsr)) {
                dev_err(dev, "Unable to query pmcsr");
                return false;
        }

        return pmcsr & PCI_PM_CTRL_NO_SOFT_RESET;
}

static int virtio_pci_suspend(struct device *dev)
{
        return vp_supports_pm_no_reset(dev) ? 0 : virtio_pci_freeze(dev);
}

static int virtio_pci_resume(struct device *dev)
{
        return vp_supports_pm_no_reset(dev) ? 0 : virtio_pci_restore(dev);
}

static const struct dev_pm_ops virtio_pci_pm_ops = {
        .suspend = virtio_pci_suspend,
        .resume = virtio_pci_resume,
        .freeze = virtio_pci_freeze,
        .thaw = virtio_pci_restore,
        .poweroff = virtio_pci_freeze,
        .restore = virtio_pci_restore,
};
#endif


/* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */
static const struct pci_device_id virtio_pci_id_table[] = {
        { PCI_DEVICE(PCI_VENDOR_ID_REDHAT_QUMRANET, PCI_ANY_ID) },
        { 0 }
};

MODULE_DEVICE_TABLE(pci, virtio_pci_id_table);

static void virtio_pci_release_dev(struct device *_d)
{
        struct virtio_device *vdev = dev_to_virtio(_d);
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);

        /* As struct device is a kobject, it's not safe to
         * free the memory (including the reference counter itself)
         * until it's release callback. */
        kfree(vp_dev);
}

static int virtio_pci_probe(struct pci_dev *pci_dev,
                            const struct pci_device_id *id)
{
        struct virtio_pci_device *vp_dev, *reg_dev = NULL;
        int rc;

        /* allocate our structure and fill it out */
        vp_dev = kzalloc_obj(struct virtio_pci_device);
        if (!vp_dev)
                return -ENOMEM;

        pci_set_drvdata(pci_dev, vp_dev);
        vp_dev->vdev.dev.parent = &pci_dev->dev;
        vp_dev->vdev.dev.release = virtio_pci_release_dev;
        vp_dev->pci_dev = pci_dev;
        INIT_LIST_HEAD(&vp_dev->virtqueues);
        INIT_LIST_HEAD(&vp_dev->slow_virtqueues);
        spin_lock_init(&vp_dev->lock);

        /* enable the device */
        rc = pci_enable_device(pci_dev);
        if (rc)
                goto err_enable_device;

        if (force_legacy) {
                rc = virtio_pci_legacy_probe(vp_dev);
                /* Also try modern mode if we can't map BAR0 (no IO space). */
                if (rc == -ENODEV || rc == -ENOMEM)
                        rc = virtio_pci_modern_probe(vp_dev);
                if (rc)
                        goto err_probe;
        } else {
                rc = virtio_pci_modern_probe(vp_dev);
                if (rc == -ENODEV)
                        rc = virtio_pci_legacy_probe(vp_dev);
                if (rc)
                        goto err_probe;
        }

        pci_set_master(pci_dev);

        rc = register_virtio_device(&vp_dev->vdev);
        reg_dev = vp_dev;
        if (rc)
                goto err_register;

        return 0;

err_register:
        if (vp_dev->is_legacy)
                virtio_pci_legacy_remove(vp_dev);
        else
                virtio_pci_modern_remove(vp_dev);
err_probe:
        pci_disable_device(pci_dev);
err_enable_device:
        if (reg_dev)
                put_device(&vp_dev->vdev.dev);
        else
                kfree(vp_dev);
        return rc;
}

static void virtio_pci_remove(struct pci_dev *pci_dev)
{
        struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
        struct device *dev = get_device(&vp_dev->vdev.dev);

        /*
         * Device is marked broken on surprise removal so that virtio upper
         * layers can abort any ongoing operation.
         */
        if (!pci_device_is_present(pci_dev))
                virtio_break_device(&vp_dev->vdev);

        pci_disable_sriov(pci_dev);

        unregister_virtio_device(&vp_dev->vdev);

        if (vp_dev->is_legacy)
                virtio_pci_legacy_remove(vp_dev);
        else
                virtio_pci_modern_remove(vp_dev);

        pci_disable_device(pci_dev);
        put_device(dev);
}

static int virtio_pci_sriov_configure(struct pci_dev *pci_dev, int num_vfs)
{
        struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
        struct virtio_device *vdev = &vp_dev->vdev;
        int ret;

        if (!(vdev->config->get_status(vdev) & VIRTIO_CONFIG_S_DRIVER_OK))
                return -EBUSY;

        if (!__virtio_test_bit(vdev, VIRTIO_F_SR_IOV))
                return -EINVAL;

        if (pci_vfs_assigned(pci_dev))
                return -EPERM;

        if (num_vfs == 0) {
                pci_disable_sriov(pci_dev);
                return 0;
        }

        ret = pci_enable_sriov(pci_dev, num_vfs);
        if (ret < 0)
                return ret;

        return num_vfs;
}

static void virtio_pci_reset_prepare(struct pci_dev *pci_dev)
{
        struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
        int ret = 0;

        ret = virtio_device_reset_prepare(&vp_dev->vdev);
        if (ret) {
                if (ret != -EOPNOTSUPP)
                        dev_warn(&pci_dev->dev, "Reset prepare failure: %d",
                                 ret);
                return;
        }

        if (pci_is_enabled(pci_dev))
                pci_disable_device(pci_dev);
}

static void virtio_pci_reset_done(struct pci_dev *pci_dev)
{
        struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
        int ret;

        if (pci_is_enabled(pci_dev))
                return;

        ret = pci_enable_device(pci_dev);
        if (!ret) {
                pci_set_master(pci_dev);
                ret = virtio_device_reset_done(&vp_dev->vdev);
        }

        if (ret && ret != -EOPNOTSUPP)
                dev_warn(&pci_dev->dev, "Reset done failure: %d", ret);
}

static const struct pci_error_handlers virtio_pci_err_handler = {
        .reset_prepare  = virtio_pci_reset_prepare,
        .reset_done     = virtio_pci_reset_done,
};

static struct pci_driver virtio_pci_driver = {
        .name           = "virtio-pci",
        .id_table       = virtio_pci_id_table,
        .probe          = virtio_pci_probe,
        .remove         = virtio_pci_remove,
#ifdef CONFIG_PM_SLEEP
        .driver.pm      = &virtio_pci_pm_ops,
#endif
        .sriov_configure = virtio_pci_sriov_configure,
        .err_handler    = &virtio_pci_err_handler,
};

struct virtio_device *virtio_pci_vf_get_pf_dev(struct pci_dev *pdev)
{
        struct virtio_pci_device *pf_vp_dev;

        pf_vp_dev = pci_iov_get_pf_drvdata(pdev, &virtio_pci_driver);
        if (IS_ERR(pf_vp_dev))
                return NULL;

        return &pf_vp_dev->vdev;
}

module_pci_driver(virtio_pci_driver);

MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>");
MODULE_DESCRIPTION("virtio-pci");
MODULE_LICENSE("GPL");
MODULE_VERSION("1");