// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Virtio PCI driver - modern (virtio 1.0) device support
 *
 * 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 <linux/delay.h>
#define VIRTIO_PCI_NO_LEGACY
#define VIRTIO_RING_NO_LEGACY
#include "virtio_pci_common.h"

static u64 vp_get_features(struct virtio_device *vdev)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);

        return vp_modern_get_features(&vp_dev->mdev);
}

static void vp_transport_features(struct virtio_device *vdev, u64 features)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
        struct pci_dev *pci_dev = vp_dev->pci_dev;

        if ((features & BIT_ULL(VIRTIO_F_SR_IOV)) &&
                        pci_find_ext_capability(pci_dev, PCI_EXT_CAP_ID_SRIOV))
                __virtio_set_bit(vdev, VIRTIO_F_SR_IOV);
}

/* virtio config->finalize_features() implementation */
static int vp_finalize_features(struct virtio_device *vdev)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
        u64 features = vdev->features;

        /* Give virtio_ring a chance to accept features. */
        vring_transport_features(vdev);

        /* Give virtio_pci a chance to accept features. */
        vp_transport_features(vdev, features);

        if (!__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
                dev_err(&vdev->dev, "virtio: device uses modern interface "
                        "but does not have VIRTIO_F_VERSION_1\n");
                return -EINVAL;
        }

        vp_modern_set_features(&vp_dev->mdev, vdev->features);

        return 0;
}

/* virtio config->get() implementation */
static void vp_get(struct virtio_device *vdev, unsigned offset,
                   void *buf, unsigned len)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
        struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
        void __iomem *device = mdev->device;
        u8 b;
        __le16 w;
        __le32 l;

        BUG_ON(offset + len > mdev->device_len);

        switch (len) {
        case 1:
                b = ioread8(device + offset);
                memcpy(buf, &b, sizeof b);
                break;
        case 2:
                w = cpu_to_le16(ioread16(device + offset));
                memcpy(buf, &w, sizeof w);
                break;
        case 4:
                l = cpu_to_le32(ioread32(device + offset));
                memcpy(buf, &l, sizeof l);
                break;
        case 8:
                l = cpu_to_le32(ioread32(device + offset));
                memcpy(buf, &l, sizeof l);
                l = cpu_to_le32(ioread32(device + offset + sizeof l));
                memcpy(buf + sizeof l, &l, sizeof l);
                break;
        default:
                BUG();
        }
}

/* the config->set() implementation.  it's symmetric to the config->get()
 * implementation */
static void vp_set(struct virtio_device *vdev, unsigned offset,
                   const void *buf, unsigned len)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
        struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
        void __iomem *device = mdev->device;
        u8 b;
        __le16 w;
        __le32 l;

        BUG_ON(offset + len > mdev->device_len);

        switch (len) {
        case 1:
                memcpy(&b, buf, sizeof b);
                iowrite8(b, device + offset);
                break;
        case 2:
                memcpy(&w, buf, sizeof w);
                iowrite16(le16_to_cpu(w), device + offset);
                break;
        case 4:
                memcpy(&l, buf, sizeof l);
                iowrite32(le32_to_cpu(l), device + offset);
                break;
        case 8:
                memcpy(&l, buf, sizeof l);
                iowrite32(le32_to_cpu(l), device + offset);
                memcpy(&l, buf + sizeof l, sizeof l);
                iowrite32(le32_to_cpu(l), device + offset + sizeof l);
                break;
        default:
                BUG();
        }
}

static u32 vp_generation(struct virtio_device *vdev)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);

        return vp_modern_generation(&vp_dev->mdev);
}

/* config->{get,set}_status() implementations */
static u8 vp_get_status(struct virtio_device *vdev)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);

        return vp_modern_get_status(&vp_dev->mdev);
}

static void vp_set_status(struct virtio_device *vdev, u8 status)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);

        /* We should never be setting status to 0. */
        BUG_ON(status == 0);
        vp_modern_set_status(&vp_dev->mdev, status);
}

static void vp_reset(struct virtio_device *vdev)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
        struct virtio_pci_modern_device *mdev = &vp_dev->mdev;

        /* 0 status means a reset. */
        vp_modern_set_status(mdev, 0);
        /* After writing 0 to device_status, the driver MUST wait for a read of
         * device_status to return 0 before reinitializing the device.
         * This will flush out the status write, and flush in device writes,
         * including MSI-X interrupts, if any.
         */
        while (vp_modern_get_status(mdev))
                msleep(1);
        /* Flush pending VQ/configuration callbacks. */
        vp_synchronize_vectors(vdev);
}

static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
{
        return vp_modern_config_vector(&vp_dev->mdev, vector);
}

static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
                                  struct virtio_pci_vq_info *info,
                                  unsigned index,
                                  void (*callback)(struct virtqueue *vq),
                                  const char *name,
                                  bool ctx,
                                  u16 msix_vec)
{

        struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
        struct virtqueue *vq;
        u16 num;
        int err;

        if (index >= vp_modern_get_num_queues(mdev))
                return ERR_PTR(-ENOENT);

        /* Check if queue is either not available or already active. */
        num = vp_modern_get_queue_size(mdev, index);
        if (!num || vp_modern_get_queue_enable(mdev, index))
                return ERR_PTR(-ENOENT);

        if (num & (num - 1)) {
                dev_warn(&vp_dev->pci_dev->dev, "bad queue size %u", num);
                return ERR_PTR(-EINVAL);
        }

        info->msix_vector = msix_vec;

        /* create the vring */
        vq = vring_create_virtqueue(index, num,
                                    SMP_CACHE_BYTES, &vp_dev->vdev,
                                    true, true, ctx,
                                    vp_notify, callback, name);
        if (!vq)
                return ERR_PTR(-ENOMEM);

        /* activate the queue */
        vp_modern_set_queue_size(mdev, index, virtqueue_get_vring_size(vq));
        vp_modern_queue_address(mdev, index, virtqueue_get_desc_addr(vq),
                                virtqueue_get_avail_addr(vq),
                                virtqueue_get_used_addr(vq));

        vq->priv = (void __force *)vp_modern_map_vq_notify(mdev, index, NULL);
        if (!vq->priv) {
                err = -ENOMEM;
                goto err_map_notify;
        }

        if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
                msix_vec = vp_modern_queue_vector(mdev, index, msix_vec);
                if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
                        err = -EBUSY;
                        goto err_assign_vector;
                }
        }

        return vq;

err_assign_vector:
        if (!mdev->notify_base)
                pci_iounmap(mdev->pci_dev, (void __iomem __force *)vq->priv);
err_map_notify:
        vring_del_virtqueue(vq);
        return ERR_PTR(err);
}

static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,
                              struct virtqueue *vqs[],
                              vq_callback_t *callbacks[],
                              const char * const names[], const bool *ctx,
                              struct irq_affinity *desc)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
        struct virtqueue *vq;
        int rc = vp_find_vqs(vdev, nvqs, vqs, callbacks, names, ctx, desc);

        if (rc)
                return rc;

        /* Select and activate all queues. Has to be done last: once we do
         * this, there's no way to go back except reset.
         */
        list_for_each_entry(vq, &vdev->vqs, list)
                vp_modern_set_queue_enable(&vp_dev->mdev, vq->index, true);

        return 0;
}

static void del_vq(struct virtio_pci_vq_info *info)
{
        struct virtqueue *vq = info->vq;
        struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
        struct virtio_pci_modern_device *mdev = &vp_dev->mdev;

        if (vp_dev->msix_enabled)
                vp_modern_queue_vector(mdev, vq->index,
                                       VIRTIO_MSI_NO_VECTOR);

        if (!mdev->notify_base)
                pci_iounmap(mdev->pci_dev, (void __force __iomem *)vq->priv);

        vring_del_virtqueue(vq);
}

static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,
                                   u8 *bar, u64 *offset, u64 *len)
{
        int pos;

        for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR); pos > 0;
             pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
                u8 type, cap_len, id;
                u32 tmp32;
                u64 res_offset, res_length;

                pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
                                                         cfg_type), &type);
                if (type != VIRTIO_PCI_CAP_SHARED_MEMORY_CFG)
                        continue;

                pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
                                                         cap_len), &cap_len);
                if (cap_len != sizeof(struct virtio_pci_cap64)) {
                        dev_err(&dev->dev, "%s: shm cap with bad size offset:"
                                " %d size: %d\n", __func__, pos, cap_len);
                        continue;
                }

                pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
                                                         id), &id);
                if (id != required_id)
                        continue;

                /* Type, and ID match, looks good */
                pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
                                                         bar), bar);

                /* Read the lower 32bit of length and offset */
                pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap,
                                                          offset), &tmp32);
                res_offset = tmp32;
                pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap,
                                                          length), &tmp32);
                res_length = tmp32;

                /* and now the top half */
                pci_read_config_dword(dev,
                                      pos + offsetof(struct virtio_pci_cap64,
                                                     offset_hi), &tmp32);
                res_offset |= ((u64)tmp32) << 32;
                pci_read_config_dword(dev,
                                      pos + offsetof(struct virtio_pci_cap64,
                                                     length_hi), &tmp32);
                res_length |= ((u64)tmp32) << 32;

                *offset = res_offset;
                *len = res_length;

                return pos;
        }
        return 0;
}

static bool vp_get_shm_region(struct virtio_device *vdev,
                              struct virtio_shm_region *region, u8 id)
{
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
        struct pci_dev *pci_dev = vp_dev->pci_dev;
        u8 bar;
        u64 offset, len;
        phys_addr_t phys_addr;
        size_t bar_len;

        if (!virtio_pci_find_shm_cap(pci_dev, id, &bar, &offset, &len))
                return false;

        phys_addr = pci_resource_start(pci_dev, bar);
        bar_len = pci_resource_len(pci_dev, bar);

        if ((offset + len) < offset) {
                dev_err(&pci_dev->dev, "%s: cap offset+len overflow detected\n",
                        __func__);
                return false;
        }

        if (offset + len > bar_len) {
                dev_err(&pci_dev->dev, "%s: bar shorter than cap offset+len\n",
                        __func__);
                return false;
        }

        region->len = len;
        region->addr = (u64) phys_addr + offset;

        return true;
}

static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
        .get            = NULL,
        .set            = NULL,
        .generation     = vp_generation,
        .get_status     = vp_get_status,
        .set_status     = vp_set_status,
        .reset          = vp_reset,
        .find_vqs       = vp_modern_find_vqs,
        .del_vqs        = vp_del_vqs,
        .get_features   = vp_get_features,
        .finalize_features = vp_finalize_features,
        .bus_name       = vp_bus_name,
        .set_vq_affinity = vp_set_vq_affinity,
        .get_vq_affinity = vp_get_vq_affinity,
        .get_shm_region  = vp_get_shm_region,
};

static const struct virtio_config_ops virtio_pci_config_ops = {
        .get            = vp_get,
        .set            = vp_set,
        .generation     = vp_generation,
        .get_status     = vp_get_status,
        .set_status     = vp_set_status,
        .reset          = vp_reset,
        .find_vqs       = vp_modern_find_vqs,
        .del_vqs        = vp_del_vqs,
        .get_features   = vp_get_features,
        .finalize_features = vp_finalize_features,
        .bus_name       = vp_bus_name,
        .set_vq_affinity = vp_set_vq_affinity,
        .get_vq_affinity = vp_get_vq_affinity,
        .get_shm_region  = vp_get_shm_region,
};

/* the PCI probing function */
int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
{
        struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
        struct pci_dev *pci_dev = vp_dev->pci_dev;
        int err;

        mdev->pci_dev = pci_dev;

        err = vp_modern_probe(mdev);
        if (err)
                return err;

        if (mdev->device)
                vp_dev->vdev.config = &virtio_pci_config_ops;
        else
                vp_dev->vdev.config = &virtio_pci_config_nodev_ops;

        vp_dev->config_vector = vp_config_vector;
        vp_dev->setup_vq = setup_vq;
        vp_dev->del_vq = del_vq;
        vp_dev->isr = mdev->isr;
        vp_dev->vdev.id = mdev->id;

        return 0;
}

void virtio_pci_modern_remove(struct virtio_pci_device *vp_dev)
{
        struct virtio_pci_modern_device *mdev = &vp_dev->mdev;

        vp_modern_remove(mdev);
}