root/drivers/virtio/virtio_pci_modern_dev.c 
// SPDX-License-Identifier: GPL-2.0-or-later

#include <linux/virtio_pci_modern.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/delay.h>

/*
 * vp_modern_map_capability - map a part of virtio pci capability
 * @mdev: the modern virtio-pci device
 * @off: offset of the capability
 * @minlen: minimal length of the capability
 * @align: align requirement
 * @start: start from the capability
 * @size: map size
 * @len: the length that is actually mapped
 * @pa: physical address of the capability
 *
 * Returns the io address of for the part of the capability
 */
static void __iomem *
vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off,
                         size_t minlen, u32 align, u32 start, u32 size,
                         size_t *len, resource_size_t *pa)
{
        struct pci_dev *dev = mdev->pci_dev;
        u8 bar;
        u32 offset, length;
        void __iomem *p;

        pci_read_config_byte(dev, off + offsetof(struct virtio_pci_cap,
                                                 bar),
                             &bar);
        pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, offset),
                             &offset);
        pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length),
                              &length);

        /* Check if the BAR may have changed since we requested the region. */
        if (bar >= PCI_STD_NUM_BARS || !(mdev->modern_bars & (1 << bar))) {
                dev_err(&dev->dev,
                        "virtio_pci: bar unexpectedly changed to %u\n", bar);
                return NULL;
        }

        if (length <= start) {
                dev_err(&dev->dev,
                        "virtio_pci: bad capability len %u (>%u expected)\n",
                        length, start);
                return NULL;
        }

        if (length - start < minlen) {
                dev_err(&dev->dev,
                        "virtio_pci: bad capability len %u (>=%zu expected)\n",
                        length, minlen);
                return NULL;
        }

        length -= start;

        if (start + offset < offset) {
                dev_err(&dev->dev,
                        "virtio_pci: map wrap-around %u+%u\n",
                        start, offset);
                return NULL;
        }

        offset += start;

        if (offset & (align - 1)) {
                dev_err(&dev->dev,
                        "virtio_pci: offset %u not aligned to %u\n",
                        offset, align);
                return NULL;
        }

        if (length > size)
                length = size;

        if (len)
                *len = length;

        if (minlen + offset < minlen ||
            minlen + offset > pci_resource_len(dev, bar)) {
                dev_err(&dev->dev,
                        "virtio_pci: map virtio %zu@%u "
                        "out of range on bar %i length %lu\n",
                        minlen, offset,
                        bar, (unsigned long)pci_resource_len(dev, bar));
                return NULL;
        }

        p = pci_iomap_range(dev, bar, offset, length);
        if (!p)
                dev_err(&dev->dev,
                        "virtio_pci: unable to map virtio %u@%u on bar %i\n",
                        length, offset, bar);
        else if (pa)
                *pa = pci_resource_start(dev, bar) + offset;

        return p;
}

/**
 * virtio_pci_find_capability - walk capabilities to find device info.
 * @dev: the pci device
 * @cfg_type: the VIRTIO_PCI_CAP_* value we seek
 * @ioresource_types: IORESOURCE_MEM and/or IORESOURCE_IO.
 * @bars: the bitmask of BARs
 *
 * Returns offset of the capability, or 0.
 */
static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type,
                                             u32 ioresource_types, int *bars)
{
        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, bar;
                pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
                                                         cfg_type),
                                     &type);
                pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
                                                         bar),
                                     &bar);

                /* Ignore structures with reserved BAR values */
                if (bar >= PCI_STD_NUM_BARS)
                        continue;

                if (type == cfg_type) {
                        if (pci_resource_len(dev, bar) &&
                            pci_resource_flags(dev, bar) & ioresource_types) {
                                *bars |= (1 << bar);
                                return pos;
                        }
                }
        }
        return 0;
}

/* This is part of the ABI.  Don't screw with it. */
static inline void check_offsets(void)
{
        /* Note: disk space was harmed in compilation of this function. */
        BUILD_BUG_ON(VIRTIO_PCI_CAP_VNDR !=
                     offsetof(struct virtio_pci_cap, cap_vndr));
        BUILD_BUG_ON(VIRTIO_PCI_CAP_NEXT !=
                     offsetof(struct virtio_pci_cap, cap_next));
        BUILD_BUG_ON(VIRTIO_PCI_CAP_LEN !=
                     offsetof(struct virtio_pci_cap, cap_len));
        BUILD_BUG_ON(VIRTIO_PCI_CAP_CFG_TYPE !=
                     offsetof(struct virtio_pci_cap, cfg_type));
        BUILD_BUG_ON(VIRTIO_PCI_CAP_BAR !=
                     offsetof(struct virtio_pci_cap, bar));
        BUILD_BUG_ON(VIRTIO_PCI_CAP_OFFSET !=
                     offsetof(struct virtio_pci_cap, offset));
        BUILD_BUG_ON(VIRTIO_PCI_CAP_LENGTH !=
                     offsetof(struct virtio_pci_cap, length));
        BUILD_BUG_ON(VIRTIO_PCI_NOTIFY_CAP_MULT !=
                     offsetof(struct virtio_pci_notify_cap,
                              notify_off_multiplier));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_DFSELECT !=
                     offsetof(struct virtio_pci_common_cfg,
                              device_feature_select));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_DF !=
                     offsetof(struct virtio_pci_common_cfg, device_feature));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_GFSELECT !=
                     offsetof(struct virtio_pci_common_cfg,
                              guest_feature_select));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_GF !=
                     offsetof(struct virtio_pci_common_cfg, guest_feature));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_MSIX !=
                     offsetof(struct virtio_pci_common_cfg, msix_config));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_NUMQ !=
                     offsetof(struct virtio_pci_common_cfg, num_queues));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_STATUS !=
                     offsetof(struct virtio_pci_common_cfg, device_status));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_CFGGENERATION !=
                     offsetof(struct virtio_pci_common_cfg, config_generation));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SELECT !=
                     offsetof(struct virtio_pci_common_cfg, queue_select));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SIZE !=
                     offsetof(struct virtio_pci_common_cfg, queue_size));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_MSIX !=
                     offsetof(struct virtio_pci_common_cfg, queue_msix_vector));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_ENABLE !=
                     offsetof(struct virtio_pci_common_cfg, queue_enable));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_NOFF !=
                     offsetof(struct virtio_pci_common_cfg, queue_notify_off));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCLO !=
                     offsetof(struct virtio_pci_common_cfg, queue_desc_lo));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCHI !=
                     offsetof(struct virtio_pci_common_cfg, queue_desc_hi));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILLO !=
                     offsetof(struct virtio_pci_common_cfg, queue_avail_lo));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILHI !=
                     offsetof(struct virtio_pci_common_cfg, queue_avail_hi));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDLO !=
                     offsetof(struct virtio_pci_common_cfg, queue_used_lo));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDHI !=
                     offsetof(struct virtio_pci_common_cfg, queue_used_hi));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_NDATA !=
                     offsetof(struct virtio_pci_modern_common_cfg, queue_notify_data));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_RESET !=
                     offsetof(struct virtio_pci_modern_common_cfg, queue_reset));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_ADM_Q_IDX !=
                     offsetof(struct virtio_pci_modern_common_cfg, admin_queue_index));
        BUILD_BUG_ON(VIRTIO_PCI_COMMON_ADM_Q_NUM !=
                     offsetof(struct virtio_pci_modern_common_cfg, admin_queue_num));
}

/*
 * vp_modern_probe: probe the modern virtio pci device, note that the
 * caller is required to enable PCI device before calling this function.
 * @mdev: the modern virtio-pci device
 *
 * Return 0 on succeed otherwise fail
 */
int vp_modern_probe(struct virtio_pci_modern_device *mdev)
{
        struct pci_dev *pci_dev = mdev->pci_dev;
        int err, common, isr, notify, device;
        u32 notify_length;
        u32 notify_offset;
        int devid;

        check_offsets();

        if (mdev->device_id_check) {
                devid = mdev->device_id_check(pci_dev);
                if (devid < 0)
                        return devid;
                mdev->id.device = devid;
        } else {
                /* We only own devices >= 0x1000 and <= 0x107f: leave the rest. */
                if (pci_dev->device < 0x1000 || pci_dev->device > 0x107f)
                        return -ENODEV;

                if (pci_dev->device < 0x1040) {
                        /* Transitional devices: use the PCI subsystem device id as
                         * virtio device id, same as legacy driver always did.
                         */
                        mdev->id.device = pci_dev->subsystem_device;
                } else {
                        /* Modern devices: simply use PCI device id, but start from 0x1040. */
                        mdev->id.device = pci_dev->device - 0x1040;
                }
        }
        mdev->id.vendor = pci_dev->subsystem_vendor;

        /* check for a common config: if not, use legacy mode (bar 0). */
        common = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_COMMON_CFG,
                                            IORESOURCE_IO | IORESOURCE_MEM,
                                            &mdev->modern_bars);
        if (!common) {
                dev_info(&pci_dev->dev,
                         "virtio_pci: leaving for legacy driver\n");
                return -ENODEV;
        }

        /* If common is there, these should be too... */
        isr = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_ISR_CFG,
                                         IORESOURCE_IO | IORESOURCE_MEM,
                                         &mdev->modern_bars);
        notify = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_NOTIFY_CFG,
                                            IORESOURCE_IO | IORESOURCE_MEM,
                                            &mdev->modern_bars);
        if (!isr || !notify) {
                dev_err(&pci_dev->dev,
                        "virtio_pci: missing capabilities %i/%i/%i\n",
                        common, isr, notify);
                return -EINVAL;
        }

        err = dma_set_mask_and_coherent(&pci_dev->dev,
                                        mdev->dma_mask ? : DMA_BIT_MASK(64));
        if (err)
                err = dma_set_mask_and_coherent(&pci_dev->dev,
                                                DMA_BIT_MASK(32));
        if (err)
                dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");

        /* Device capability is only mandatory for devices that have
         * device-specific configuration.
         */
        device = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_DEVICE_CFG,
                                            IORESOURCE_IO | IORESOURCE_MEM,
                                            &mdev->modern_bars);

        err = pci_request_selected_regions(pci_dev, mdev->modern_bars,
                                           "virtio-pci-modern");
        if (err)
                return err;

        err = -EINVAL;
        mdev->common = vp_modern_map_capability(mdev, common,
                              sizeof(struct virtio_pci_common_cfg), 4, 0,
                              offsetofend(struct virtio_pci_modern_common_cfg,
                                          admin_queue_num),
                              &mdev->common_len, NULL);
        if (!mdev->common)
                goto err_map_common;
        mdev->isr = vp_modern_map_capability(mdev, isr, sizeof(u8), 1,
                                             0, 1,
                                             NULL, NULL);
        if (!mdev->isr)
                goto err_map_isr;

        /* Read notify_off_multiplier from config space. */
        pci_read_config_dword(pci_dev,
                              notify + offsetof(struct virtio_pci_notify_cap,
                                                notify_off_multiplier),
                              &mdev->notify_offset_multiplier);
        /* Read notify length and offset from config space. */
        pci_read_config_dword(pci_dev,
                              notify + offsetof(struct virtio_pci_notify_cap,
                                                cap.length),
                              &notify_length);

        pci_read_config_dword(pci_dev,
                              notify + offsetof(struct virtio_pci_notify_cap,
                                                cap.offset),
                              &notify_offset);

        /* We don't know how many VQs we'll map, ahead of the time.
         * If notify length is small, map it all now.
         * Otherwise, map each VQ individually later.
         */
        if ((u64)notify_length + (notify_offset % PAGE_SIZE) <= PAGE_SIZE) {
                mdev->notify_base = vp_modern_map_capability(mdev, notify,
                                                             2, 2,
                                                             0, notify_length,
                                                             &mdev->notify_len,
                                                             &mdev->notify_pa);
                if (!mdev->notify_base)
                        goto err_map_notify;
        } else {
                mdev->notify_map_cap = notify;
        }

        /* Again, we don't know how much we should map, but PAGE_SIZE
         * is more than enough for all existing devices.
         */
        if (device) {
                mdev->device = vp_modern_map_capability(mdev, device, 0, 4,
                                                        0, PAGE_SIZE,
                                                        &mdev->device_len,
                                                        NULL);
                if (!mdev->device)
                        goto err_map_device;
        }

        return 0;

err_map_device:
        if (mdev->notify_base)
                pci_iounmap(pci_dev, mdev->notify_base);
err_map_notify:
        pci_iounmap(pci_dev, mdev->isr);
err_map_isr:
        pci_iounmap(pci_dev, mdev->common);
err_map_common:
        pci_release_selected_regions(pci_dev, mdev->modern_bars);
        return err;
}
EXPORT_SYMBOL_GPL(vp_modern_probe);

/*
 * vp_modern_remove: remove and cleanup the modern virtio pci device
 * @mdev: the modern virtio-pci device
 */
void vp_modern_remove(struct virtio_pci_modern_device *mdev)
{
        struct pci_dev *pci_dev = mdev->pci_dev;

        if (mdev->device)
                pci_iounmap(pci_dev, mdev->device);
        if (mdev->notify_base)
                pci_iounmap(pci_dev, mdev->notify_base);
        pci_iounmap(pci_dev, mdev->isr);
        pci_iounmap(pci_dev, mdev->common);
        pci_release_selected_regions(pci_dev, mdev->modern_bars);
}
EXPORT_SYMBOL_GPL(vp_modern_remove);

/*
 * vp_modern_get_extended_features - get features from device
 * @mdev: the modern virtio-pci device
 * @features: the features array to be filled
 *
 * Fill the specified features array with the features read from the device
 */
void vp_modern_get_extended_features(struct virtio_pci_modern_device *mdev,
                                     u64 *features)
{
        struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
        int i;

        virtio_features_zero(features);
        for (i = 0; i < VIRTIO_FEATURES_BITS / 32; i++) {
                u64 cur;

                vp_iowrite32(i, &cfg->device_feature_select);
                cur = vp_ioread32(&cfg->device_feature);
                features[i >> 1] |= cur << (32 * (i & 1));
        }
}
EXPORT_SYMBOL_GPL(vp_modern_get_extended_features);

/*
 * vp_modern_get_driver_features - get driver features from device
 * @mdev: the modern virtio-pci device
 * @features: the features array to be filled
 *
 * Fill the specified features array with the driver features read from the
 * device
 */
void
vp_modern_get_driver_extended_features(struct virtio_pci_modern_device *mdev,
                                       u64 *features)
{
        struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
        int i;

        virtio_features_zero(features);
        for (i = 0; i < VIRTIO_FEATURES_BITS / 32; i++) {
                u64 cur;

                vp_iowrite32(i, &cfg->guest_feature_select);
                cur = vp_ioread32(&cfg->guest_feature);
                features[i >> 1] |= cur << (32 * (i & 1));
        }
}
EXPORT_SYMBOL_GPL(vp_modern_get_driver_extended_features);

/*
 * vp_modern_set_extended_features - set features to device
 * @mdev: the modern virtio-pci device
 * @features: the features set to device
 */
void vp_modern_set_extended_features(struct virtio_pci_modern_device *mdev,
                                     const u64 *features)
{
        struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
        int i;

        for (i = 0; i < VIRTIO_FEATURES_BITS / 32; i++) {
                u32 cur = features[i >> 1] >> (32 * (i & 1));

                vp_iowrite32(i, &cfg->guest_feature_select);
                vp_iowrite32(cur, &cfg->guest_feature);
        }
}
EXPORT_SYMBOL_GPL(vp_modern_set_extended_features);

/*
 * vp_modern_generation - get the device genreation
 * @mdev: the modern virtio-pci device
 *
 * Returns the genreation read from device
 */
u32 vp_modern_generation(struct virtio_pci_modern_device *mdev)
{
        struct virtio_pci_common_cfg __iomem *cfg = mdev->common;

        return vp_ioread8(&cfg->config_generation);
}
EXPORT_SYMBOL_GPL(vp_modern_generation);

/*
 * vp_modern_get_status - get the device status
 * @mdev: the modern virtio-pci device
 *
 * Returns the status read from device
 */
u8 vp_modern_get_status(struct virtio_pci_modern_device *mdev)
{
        struct virtio_pci_common_cfg __iomem *cfg = mdev->common;

        return vp_ioread8(&cfg->device_status);
}
EXPORT_SYMBOL_GPL(vp_modern_get_status);

/*
 * vp_modern_set_status - set status to device
 * @mdev: the modern virtio-pci device
 * @status: the status set to device
 */
void vp_modern_set_status(struct virtio_pci_modern_device *mdev,
                                 u8 status)
{
        struct virtio_pci_common_cfg __iomem *cfg = mdev->common;

        /*
         * Per memory-barriers.txt, wmb() is not needed to guarantee
         * that the cache coherent memory writes have completed
         * before writing to the MMIO region.
         */
        vp_iowrite8(status, &cfg->device_status);
}
EXPORT_SYMBOL_GPL(vp_modern_set_status);

/*
 * vp_modern_get_queue_reset - get the queue reset status
 * @mdev: the modern virtio-pci device
 * @index: queue index
 */
int vp_modern_get_queue_reset(struct virtio_pci_modern_device *mdev, u16 index)
{
        struct virtio_pci_modern_common_cfg __iomem *cfg;

        cfg = (struct virtio_pci_modern_common_cfg __iomem *)mdev->common;

        vp_iowrite16(index, &cfg->cfg.queue_select);
        return vp_ioread16(&cfg->queue_reset);
}
EXPORT_SYMBOL_GPL(vp_modern_get_queue_reset);

/*
 * vp_modern_set_queue_reset - reset the queue
 * @mdev: the modern virtio-pci device
 * @index: queue index
 */
void vp_modern_set_queue_reset(struct virtio_pci_modern_device *mdev, u16 index)
{
        struct virtio_pci_modern_common_cfg __iomem *cfg;

        cfg = (struct virtio_pci_modern_common_cfg __iomem *)mdev->common;

        vp_iowrite16(index, &cfg->cfg.queue_select);
        vp_iowrite16(1, &cfg->queue_reset);

        while (vp_ioread16(&cfg->queue_reset))
                msleep(1);

        while (vp_ioread16(&cfg->cfg.queue_enable))
                msleep(1);
}
EXPORT_SYMBOL_GPL(vp_modern_set_queue_reset);

/*
 * vp_modern_queue_vector - set the MSIX vector for a specific virtqueue
 * @mdev: the modern virtio-pci device
 * @index: queue index
 * @vector: the queue vector
 *
 * Returns the queue vector read from the device
 */
u16 vp_modern_queue_vector(struct virtio_pci_modern_device *mdev,
                           u16 index, u16 vector)
{
        struct virtio_pci_common_cfg __iomem *cfg = mdev->common;

        vp_iowrite16(index, &cfg->queue_select);
        vp_iowrite16(vector, &cfg->queue_msix_vector);
        /* Flush the write out to device */
        return vp_ioread16(&cfg->queue_msix_vector);
}
EXPORT_SYMBOL_GPL(vp_modern_queue_vector);

/*
 * vp_modern_config_vector - set the vector for config interrupt
 * @mdev: the modern virtio-pci device
 * @vector: the config vector
 *
 * Returns the config vector read from the device
 */
u16 vp_modern_config_vector(struct virtio_pci_modern_device *mdev,
                            u16 vector)
{
        struct virtio_pci_common_cfg __iomem *cfg = mdev->common;

        /* Setup the vector used for configuration events */
        vp_iowrite16(vector, &cfg->msix_config);
        /* Verify we had enough resources to assign the vector */
        /* Will also flush the write out to device */
        return vp_ioread16(&cfg->msix_config);
}
EXPORT_SYMBOL_GPL(vp_modern_config_vector);

/*
 * vp_modern_queue_address - set the virtqueue address
 * @mdev: the modern virtio-pci device
 * @index: the queue index
 * @desc_addr: address of the descriptor area
 * @driver_addr: address of the driver area
 * @device_addr: address of the device area
 */
void vp_modern_queue_address(struct virtio_pci_modern_device *mdev,
                             u16 index, u64 desc_addr, u64 driver_addr,
                             u64 device_addr)
{
        struct virtio_pci_common_cfg __iomem *cfg = mdev->common;

        vp_iowrite16(index, &cfg->queue_select);

        vp_iowrite64_twopart(desc_addr, &cfg->queue_desc_lo,
                             &cfg->queue_desc_hi);
        vp_iowrite64_twopart(driver_addr, &cfg->queue_avail_lo,
                             &cfg->queue_avail_hi);
        vp_iowrite64_twopart(device_addr, &cfg->queue_used_lo,
                             &cfg->queue_used_hi);
}
EXPORT_SYMBOL_GPL(vp_modern_queue_address);

/*
 * vp_modern_set_queue_enable - enable a virtqueue
 * @mdev: the modern virtio-pci device
 * @index: the queue index
 * @enable: whether the virtqueue is enable or not
 */
void vp_modern_set_queue_enable(struct virtio_pci_modern_device *mdev,
                                u16 index, bool enable)
{
        vp_iowrite16(index, &mdev->common->queue_select);
        vp_iowrite16(enable, &mdev->common->queue_enable);
}
EXPORT_SYMBOL_GPL(vp_modern_set_queue_enable);

/*
 * vp_modern_get_queue_enable - enable a virtqueue
 * @mdev: the modern virtio-pci device
 * @index: the queue index
 *
 * Returns whether a virtqueue is enabled or not
 */
bool vp_modern_get_queue_enable(struct virtio_pci_modern_device *mdev,
                                u16 index)
{
        vp_iowrite16(index, &mdev->common->queue_select);

        return vp_ioread16(&mdev->common->queue_enable);
}
EXPORT_SYMBOL_GPL(vp_modern_get_queue_enable);

/*
 * vp_modern_set_queue_size - set size for a virtqueue
 * @mdev: the modern virtio-pci device
 * @index: the queue index
 * @size: the size of the virtqueue
 */
void vp_modern_set_queue_size(struct virtio_pci_modern_device *mdev,
                              u16 index, u16 size)
{
        vp_iowrite16(index, &mdev->common->queue_select);
        vp_iowrite16(size, &mdev->common->queue_size);

}
EXPORT_SYMBOL_GPL(vp_modern_set_queue_size);

/*
 * vp_modern_get_queue_size - get size for a virtqueue
 * @mdev: the modern virtio-pci device
 * @index: the queue index
 *
 * Returns the size of the virtqueue
 */
u16 vp_modern_get_queue_size(struct virtio_pci_modern_device *mdev,
                             u16 index)
{
        vp_iowrite16(index, &mdev->common->queue_select);

        return vp_ioread16(&mdev->common->queue_size);

}
EXPORT_SYMBOL_GPL(vp_modern_get_queue_size);

/*
 * vp_modern_get_num_queues - get the number of virtqueues
 * @mdev: the modern virtio-pci device
 *
 * Returns the number of virtqueues
 */
u16 vp_modern_get_num_queues(struct virtio_pci_modern_device *mdev)
{
        return vp_ioread16(&mdev->common->num_queues);
}
EXPORT_SYMBOL_GPL(vp_modern_get_num_queues);

/*
 * vp_modern_get_queue_notify_off - get notification offset for a virtqueue
 * @mdev: the modern virtio-pci device
 * @index: the queue index
 *
 * Returns the notification offset for a virtqueue
 */
static u16 vp_modern_get_queue_notify_off(struct virtio_pci_modern_device *mdev,
                                          u16 index)
{
        vp_iowrite16(index, &mdev->common->queue_select);

        return vp_ioread16(&mdev->common->queue_notify_off);
}

/*
 * vp_modern_map_vq_notify - map notification area for a
 * specific virtqueue
 * @mdev: the modern virtio-pci device
 * @index: the queue index
 * @pa: the pointer to the physical address of the nofity area
 *
 * Returns the address of the notification area
 */
void __iomem *vp_modern_map_vq_notify(struct virtio_pci_modern_device *mdev,
                                      u16 index, resource_size_t *pa)
{
        u16 off = vp_modern_get_queue_notify_off(mdev, index);

        if (mdev->notify_base) {
                /* offset should not wrap */
                if ((u64)off * mdev->notify_offset_multiplier + 2
                        > mdev->notify_len) {
                        dev_warn(&mdev->pci_dev->dev,
                                 "bad notification offset %u (x %u) "
                                 "for queue %u > %zd",
                                 off, mdev->notify_offset_multiplier,
                                 index, mdev->notify_len);
                        return NULL;
                }
                if (pa)
                        *pa = mdev->notify_pa +
                              off * mdev->notify_offset_multiplier;
                return mdev->notify_base + off * mdev->notify_offset_multiplier;
        } else {
                return vp_modern_map_capability(mdev,
                                       mdev->notify_map_cap, 2, 2,
                                       off * mdev->notify_offset_multiplier, 2,
                                       NULL, pa);
        }
}
EXPORT_SYMBOL_GPL(vp_modern_map_vq_notify);

u16 vp_modern_avq_num(struct virtio_pci_modern_device *mdev)
{
        struct virtio_pci_modern_common_cfg __iomem *cfg;

        cfg = (struct virtio_pci_modern_common_cfg __iomem *)mdev->common;
        return vp_ioread16(&cfg->admin_queue_num);
}
EXPORT_SYMBOL_GPL(vp_modern_avq_num);

u16 vp_modern_avq_index(struct virtio_pci_modern_device *mdev)
{
        struct virtio_pci_modern_common_cfg __iomem *cfg;

        cfg = (struct virtio_pci_modern_common_cfg __iomem *)mdev->common;
        return vp_ioread16(&cfg->admin_queue_index);
}
EXPORT_SYMBOL_GPL(vp_modern_avq_index);

MODULE_VERSION("0.1");
MODULE_DESCRIPTION("Modern Virtio PCI Device");
MODULE_AUTHOR("Jason Wang <jasowang@redhat.com>");
MODULE_LICENSE("GPL");