misc: mic: Enable VOP host side functionality

This patch moves virtio functionality from the MIC host driver into a
separate hardware independent Virtio Over PCIe (VOP) driver. This
functionality was introduced in commit f69bcbf3b4c4 ("Intel MIC Host
Driver Changes for Virtio Devices.") in
drivers/misc/mic/host/mic_virtio.c. Apart from being moved into a
separate driver the functionality is essentially unchanged. See the
above mentioned commit for a description of this functionality.

Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Sudeep Dutt <sudeep.dutt@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 1164 insertions, 0 deletions

diff --git a/drivers/misc/mic/vop/vop_vringh.c b/drivers/misc/mic/vop/vop_vringh.c
new file mode 100644
index 000000000000..c1dd000f042b
--- /dev/null
+++ b/drivers/misc/mic/vop/vop_vringh.c
@@ -0,0 +1,1164 @@
+/*
+ * Intel MIC Platform Software Stack (MPSS)
+ *
+ * Copyright(c) 2016 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * The full GNU General Public License is included in this distribution in
+ * the file called "COPYING".
+ *
+ * Intel Virtio Over PCIe (VOP) driver.
+ *
+ */
+#include <linux/sched.h>
+#include <linux/poll.h>
+#include <linux/dma-mapping.h>
+
+#include <linux/mic_common.h>
+#include "../common/mic_dev.h"
+
+#include <linux/mic_ioctl.h>
+#include "vop_main.h"
+
+/* Helper API to obtain the VOP PCIe device */
+static inline struct device *vop_dev(struct vop_vdev *vdev)
+{
+        return vdev->vpdev->dev.parent;
+}
+
+/* Helper API to check if a virtio device is initialized */
+static inline int vop_vdev_inited(struct vop_vdev *vdev)
+{
+        if (!vdev)
+                return -EINVAL;
+        /* Device has not been created yet */
+        if (!vdev->dd || !vdev->dd->type) {
+                dev_err(vop_dev(vdev), "%s %d err %d\n",
+                        __func__, __LINE__, -EINVAL);
+                return -EINVAL;
+        }
+        /* Device has been removed/deleted */
+        if (vdev->dd->type == -1) {
+                dev_dbg(vop_dev(vdev), "%s %d err %d\n",
+                        __func__, __LINE__, -ENODEV);
+                return -ENODEV;
+        }
+        return 0;
+}
+
+static void _vop_notify(struct vringh *vrh)
+{
+        struct vop_vringh *vvrh = container_of(vrh, struct vop_vringh, vrh);
+        struct vop_vdev *vdev = vvrh->vdev;
+        struct vop_device *vpdev = vdev->vpdev;
+        s8 db = vdev->dc->h2c_vdev_db;
+
+        if (db != -1)
+                vpdev->hw_ops->send_intr(vpdev, db);
+}
+
+static void vop_virtio_init_post(struct vop_vdev *vdev)
+{
+        struct mic_vqconfig *vqconfig = mic_vq_config(vdev->dd);
+        struct vop_device *vpdev = vdev->vpdev;
+        int i, used_size;
+
+        for (i = 0; i < vdev->dd->num_vq; i++) {
+                used_size = PAGE_ALIGN(sizeof(u16) * 3 +
+                                sizeof(struct vring_used_elem) *
+                                le16_to_cpu(vqconfig->num));
+                if (!le64_to_cpu(vqconfig[i].used_address)) {
+                        dev_warn(vop_dev(vdev), "used_address zero??\n");
+                        continue;
+                }
+                vdev->vvr[i].vrh.vring.used =
+                        (void __force *)vpdev->hw_ops->ioremap(
+                        vpdev,
+                        le64_to_cpu(vqconfig[i].used_address),
+                        used_size);
+        }
+
+        vdev->dc->used_address_updated = 0;
+
+        dev_info(vop_dev(vdev), "%s: device type %d LINKUP\n",
+                 __func__, vdev->virtio_id);
+}
+
+static inline void vop_virtio_device_reset(struct vop_vdev *vdev)
+{
+        int i;
+
+        dev_dbg(vop_dev(vdev), "%s: status %d device type %d RESET\n",
+                __func__, vdev->dd->status, vdev->virtio_id);
+
+        for (i = 0; i < vdev->dd->num_vq; i++)
+                /*
+                 * Avoid lockdep false positive. The + 1 is for the vop
+                 * mutex which is held in the reset devices code path.
+                 */
+                mutex_lock_nested(&vdev->vvr[i].vr_mutex, i + 1);
+
+        /* 0 status means "reset" */
+        vdev->dd->status = 0;
+        vdev->dc->vdev_reset = 0;
+        vdev->dc->host_ack = 1;
+
+        for (i = 0; i < vdev->dd->num_vq; i++) {
+                struct vringh *vrh = &vdev->vvr[i].vrh;
+
+                vdev->vvr[i].vring.info->avail_idx = 0;
+                vrh->completed = 0;
+                vrh->last_avail_idx = 0;
+                vrh->last_used_idx = 0;
+        }
+
+        for (i = 0; i < vdev->dd->num_vq; i++)
+                mutex_unlock(&vdev->vvr[i].vr_mutex);
+}
+
+static void vop_virtio_reset_devices(struct vop_info *vi)
+{
+        struct list_head *pos, *tmp;
+        struct vop_vdev *vdev;
+
+        list_for_each_safe(pos, tmp, &vi->vdev_list) {
+                vdev = list_entry(pos, struct vop_vdev, list);
+                vop_virtio_device_reset(vdev);
+                vdev->poll_wake = 1;
+                wake_up(&vdev->waitq);
+        }
+}
+
+static void vop_bh_handler(struct work_struct *work)
+{
+        struct vop_vdev *vdev = container_of(work, struct vop_vdev,
+                        virtio_bh_work);
+
+        if (vdev->dc->used_address_updated)
+                vop_virtio_init_post(vdev);
+
+        if (vdev->dc->vdev_reset)
+                vop_virtio_device_reset(vdev);
+
+        vdev->poll_wake = 1;
+        wake_up(&vdev->waitq);
+}
+
+static irqreturn_t _vop_virtio_intr_handler(int irq, void *data)
+{
+        struct vop_vdev *vdev = data;
+        struct vop_device *vpdev = vdev->vpdev;
+
+        vpdev->hw_ops->ack_interrupt(vpdev, vdev->virtio_db);
+        schedule_work(&vdev->virtio_bh_work);
+        return IRQ_HANDLED;
+}
+
+static int vop_virtio_config_change(struct vop_vdev *vdev, void *argp)
+{
+        DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake);
+        int ret = 0, retry, i;
+        struct vop_device *vpdev = vdev->vpdev;
+        struct vop_info *vi = dev_get_drvdata(&vpdev->dev);
+        struct mic_bootparam *bootparam = vpdev->hw_ops->get_dp(vpdev);
+        s8 db = bootparam->h2c_config_db;
+
+        mutex_lock(&vi->vop_mutex);
+        for (i = 0; i < vdev->dd->num_vq; i++)
+                mutex_lock_nested(&vdev->vvr[i].vr_mutex, i + 1);
+
+        if (db == -1 || vdev->dd->type == -1) {
+                ret = -EIO;
+                goto exit;
+        }
+
+        memcpy(mic_vq_configspace(vdev->dd), argp, vdev->dd->config_len);
+        vdev->dc->config_change = MIC_VIRTIO_PARAM_CONFIG_CHANGED;
+        vpdev->hw_ops->send_intr(vpdev, db);
+
+        for (retry = 100; retry--;) {
+                ret = wait_event_timeout(wake, vdev->dc->guest_ack,
+                                         msecs_to_jiffies(100));
+                if (ret)
+                        break;
+        }
+
+        dev_dbg(vop_dev(vdev),
+                "%s %d retry: %d\n", __func__, __LINE__, retry);
+        vdev->dc->config_change = 0;
+        vdev->dc->guest_ack = 0;
+exit:
+        for (i = 0; i < vdev->dd->num_vq; i++)
+                mutex_unlock(&vdev->vvr[i].vr_mutex);
+        mutex_unlock(&vi->vop_mutex);
+        return ret;
+}
+
+static int vop_copy_dp_entry(struct vop_vdev *vdev,
+                             struct mic_device_desc *argp, __u8 *type,
+                             struct mic_device_desc **devpage)
+{
+        struct vop_device *vpdev = vdev->vpdev;
+        struct mic_device_desc *devp;
+        struct mic_vqconfig *vqconfig;
+        int ret = 0, i;
+        bool slot_found = false;
+
+        vqconfig = mic_vq_config(argp);
+        for (i = 0; i < argp->num_vq; i++) {
+                if (le16_to_cpu(vqconfig[i].num) > MIC_MAX_VRING_ENTRIES) {
+                        ret =  -EINVAL;
+                        dev_err(vop_dev(vdev), "%s %d err %d\n",
+                                __func__, __LINE__, ret);
+                        goto exit;
+                }
+        }
+
+        /* Find the first free device page entry */
+        for (i = sizeof(struct mic_bootparam);
+                i < MIC_DP_SIZE - mic_total_desc_size(argp);
+                i += mic_total_desc_size(devp)) {
+                devp = vpdev->hw_ops->get_dp(vpdev) + i;
+                if (devp->type == 0 || devp->type == -1) {
+                        slot_found = true;
+                        break;
+                }
+        }
+        if (!slot_found) {
+                ret =  -EINVAL;
+                dev_err(vop_dev(vdev), "%s %d err %d\n",
+                        __func__, __LINE__, ret);
+                goto exit;
+        }
+        /*
+         * Save off the type before doing the memcpy. Type will be set in the
+         * end after completing all initialization for the new device.
+         */
+        *type = argp->type;
+        argp->type = 0;
+        memcpy(devp, argp, mic_desc_size(argp));
+
+        *devpage = devp;
+exit:
+        return ret;
+}
+
+static void vop_init_device_ctrl(struct vop_vdev *vdev,
+                                 struct mic_device_desc *devpage)
+{
+        struct mic_device_ctrl *dc;
+
+        dc = (void *)devpage + mic_aligned_desc_size(devpage);
+
+        dc->config_change = 0;
+        dc->guest_ack = 0;
+        dc->vdev_reset = 0;
+        dc->host_ack = 0;
+        dc->used_address_updated = 0;
+        dc->c2h_vdev_db = -1;
+        dc->h2c_vdev_db = -1;
+        vdev->dc = dc;
+}
+
+static int vop_virtio_add_device(struct vop_vdev *vdev,
+                                 struct mic_device_desc *argp)
+{
+        struct vop_info *vi = vdev->vi;
+        struct vop_device *vpdev = vi->vpdev;
+        struct mic_device_desc *dd = NULL;
+        struct mic_vqconfig *vqconfig;
+        int vr_size, i, j, ret;
+        u8 type = 0;
+        s8 db = -1;
+        char irqname[16];
+        struct mic_bootparam *bootparam;
+        u16 num;
+        dma_addr_t vr_addr;
+
+        bootparam = vpdev->hw_ops->get_dp(vpdev);
+        init_waitqueue_head(&vdev->waitq);
+        INIT_LIST_HEAD(&vdev->list);
+        vdev->vpdev = vpdev;
+
+        ret = vop_copy_dp_entry(vdev, argp, &type, &dd);
+        if (ret) {
+                kfree(vdev);
+                dev_err(vop_dev(vdev), "%s %d err %d\n",
+                        __func__, __LINE__, ret);
+                return ret;
+        }
+
+        vop_init_device_ctrl(vdev, dd);
+
+        vdev->dd = dd;
+        vdev->virtio_id = type;
+        vqconfig = mic_vq_config(dd);
+        INIT_WORK(&vdev->virtio_bh_work, vop_bh_handler);
+
+        for (i = 0; i < dd->num_vq; i++) {
+                struct vop_vringh *vvr = &vdev->vvr[i];
+                struct mic_vring *vr = &vdev->vvr[i].vring;
+
+                num = le16_to_cpu(vqconfig[i].num);
+                mutex_init(&vvr->vr_mutex);
+                vr_size = PAGE_ALIGN(vring_size(num, MIC_VIRTIO_RING_ALIGN) +
+                        sizeof(struct _mic_vring_info));
+                vr->va = (void *)
+                        __get_free_pages(GFP_KERNEL | __GFP_ZERO,
+                                         get_order(vr_size));
+                if (!vr->va) {
+                        ret = -ENOMEM;
+                        dev_err(vop_dev(vdev), "%s %d err %d\n",
+                                __func__, __LINE__, ret);
+                        goto err;
+                }
+                vr->len = vr_size;
+                vr->info = vr->va + vring_size(num, MIC_VIRTIO_RING_ALIGN);
+                vr->info->magic = cpu_to_le32(MIC_MAGIC + vdev->virtio_id + i);
+                vr_addr = dma_map_single(&vpdev->dev, vr->va, vr_size,
+                                         DMA_BIDIRECTIONAL);
+                if (dma_mapping_error(&vpdev->dev, vr_addr)) {
+                        free_pages((unsigned long)vr->va, get_order(vr_size));
+                        ret = -ENOMEM;
+                        dev_err(vop_dev(vdev), "%s %d err %d\n",
+                                __func__, __LINE__, ret);
+                        goto err;
+                }
+                vqconfig[i].address = cpu_to_le64(vr_addr);
+
+                vring_init(&vr->vr, num, vr->va, MIC_VIRTIO_RING_ALIGN);
+                ret = vringh_init_kern(&vvr->vrh,
+                                       *(u32 *)mic_vq_features(vdev->dd),
+                                       num, false, vr->vr.desc, vr->vr.avail,
+                                       vr->vr.used);
+                if (ret) {
+                        dev_err(vop_dev(vdev), "%s %d err %d\n",
+                                __func__, __LINE__, ret);
+                        goto err;
+                }
+                vringh_kiov_init(&vvr->riov, NULL, 0);
+                vringh_kiov_init(&vvr->wiov, NULL, 0);
+                vvr->head = USHRT_MAX;
+                vvr->vdev = vdev;
+                vvr->vrh.notify = _vop_notify;
+                dev_dbg(&vpdev->dev,
+                        "%s %d index %d va %p info %p vr_size 0x%x\n",
+                        __func__, __LINE__, i, vr->va, vr->info, vr_size);
+                vvr->buf = (void *)__get_free_pages(GFP_KERNEL,
+                                        get_order(VOP_INT_DMA_BUF_SIZE));
+                vvr->buf_da = dma_map_single(&vpdev->dev,
+                                          vvr->buf, VOP_INT_DMA_BUF_SIZE,
+                                          DMA_BIDIRECTIONAL);
+        }
+
+        snprintf(irqname, sizeof(irqname), "vop%dvirtio%d", vpdev->index,
+                 vdev->virtio_id);
+        vdev->virtio_db = vpdev->hw_ops->next_db(vpdev);
+        vdev->virtio_cookie = vpdev->hw_ops->request_irq(vpdev,
+                        _vop_virtio_intr_handler, irqname, vdev,
+                        vdev->virtio_db);
+        if (IS_ERR(vdev->virtio_cookie)) {
+                ret = PTR_ERR(vdev->virtio_cookie);
+                dev_dbg(&vpdev->dev, "request irq failed\n");
+                goto err;
+        }
+
+        vdev->dc->c2h_vdev_db = vdev->virtio_db;
+
+        /*
+         * Order the type update with previous stores. This write barrier
+         * is paired with the corresponding read barrier before the uncached
+         * system memory read of the type, on the card while scanning the
+         * device page.
+         */
+        smp_wmb();
+        dd->type = type;
+        argp->type = type;
+
+        if (bootparam) {
+                db = bootparam->h2c_config_db;
+                if (db != -1)
+                        vpdev->hw_ops->send_intr(vpdev, db);
+        }
+        dev_dbg(&vpdev->dev, "Added virtio id %d db %d\n", dd->type, db);
+        return 0;
+err:
+        vqconfig = mic_vq_config(dd);
+        for (j = 0; j < i; j++) {
+                struct vop_vringh *vvr = &vdev->vvr[j];
+
+                dma_unmap_single(&vpdev->dev, le64_to_cpu(vqconfig[j].address),
+                                 vvr->vring.len, DMA_BIDIRECTIONAL);
+                free_pages((unsigned long)vvr->vring.va,
+                           get_order(vvr->vring.len));
+        }
+        return ret;
+}
+
+static void vop_dev_remove(struct vop_info *pvi, struct mic_device_ctrl *devp,
+                           struct vop_device *vpdev)
+{
+        struct mic_bootparam *bootparam = vpdev->hw_ops->get_dp(vpdev);
+        s8 db;
+        int ret, retry;
+        DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake);
+
+        devp->config_change = MIC_VIRTIO_PARAM_DEV_REMOVE;
+        db = bootparam->h2c_config_db;
+        if (db != -1)
+                vpdev->hw_ops->send_intr(vpdev, db);
+        else
+                goto done;
+        for (retry = 15; retry--;) {
+                ret = wait_event_timeout(wake, devp->guest_ack,
+                                         msecs_to_jiffies(1000));
+                if (ret)
+                        break;
+        }
+done:
+        devp->config_change = 0;
+        devp->guest_ack = 0;
+}
+
+static void vop_virtio_del_device(struct vop_vdev *vdev)
+{
+        struct vop_info *vi = vdev->vi;
+        struct vop_device *vpdev = vdev->vpdev;
+        int i;
+        struct mic_vqconfig *vqconfig;
+        struct mic_bootparam *bootparam = vpdev->hw_ops->get_dp(vpdev);
+
+        if (!bootparam)
+                goto skip_hot_remove;
+        vop_dev_remove(vi, vdev->dc, vpdev);
+skip_hot_remove:
+        vpdev->hw_ops->free_irq(vpdev, vdev->virtio_cookie, vdev);
+        flush_work(&vdev->virtio_bh_work);
+        vqconfig = mic_vq_config(vdev->dd);
+        for (i = 0; i < vdev->dd->num_vq; i++) {
+                struct vop_vringh *vvr = &vdev->vvr[i];
+
+                dma_unmap_single(&vpdev->dev,
+                                 vvr->buf_da, VOP_INT_DMA_BUF_SIZE,
+                                 DMA_BIDIRECTIONAL);
+                free_pages((unsigned long)vvr->buf,
+                           get_order(VOP_INT_DMA_BUF_SIZE));
+                vringh_kiov_cleanup(&vvr->riov);
+                vringh_kiov_cleanup(&vvr->wiov);
+                dma_unmap_single(&vpdev->dev, le64_to_cpu(vqconfig[i].address),
+                                 vvr->vring.len, DMA_BIDIRECTIONAL);
+                free_pages((unsigned long)vvr->vring.va,
+                           get_order(vvr->vring.len));
+        }
+        /*
+         * Order the type update with previous stores. This write barrier
+         * is paired with the corresponding read barrier before the uncached
+         * system memory read of the type, on the card while scanning the
+         * device page.
+         */
+        smp_wmb();
+        vdev->dd->type = -1;
+}
+
+/*
+ * vop_sync_dma - Wrapper for synchronous DMAs.
+ *
+ * @dev - The address of the pointer to the device instance used
+ * for DMA registration.
+ * @dst - destination DMA address.
+ * @src - source DMA address.
+ * @len - size of the transfer.
+ *
+ * Return DMA_SUCCESS on success
+ */
+static int vop_sync_dma(struct vop_vdev *vdev, dma_addr_t dst, dma_addr_t src,
+                        size_t len)
+{
+        int err = 0;
+        struct dma_device *ddev;
+        struct dma_async_tx_descriptor *tx;
+        struct vop_info *vi = dev_get_drvdata(&vdev->vpdev->dev);
+        struct dma_chan *vop_ch = vi->dma_ch;
+
+        if (!vop_ch) {
+                err = -EBUSY;
+                goto error;
+        }
+        ddev = vop_ch->device;
+        tx = ddev->device_prep_dma_memcpy(vop_ch, dst, src, len,
+                DMA_PREP_FENCE);
+        if (!tx) {
+                err = -ENOMEM;
+                goto error;
+        } else {
+                dma_cookie_t cookie;
+
+                cookie = tx->tx_submit(tx);
+                if (dma_submit_error(cookie)) {
+                        err = -ENOMEM;
+                        goto error;
+                }
+                dma_async_issue_pending(vop_ch);
+                err = dma_sync_wait(vop_ch, cookie);
+        }
+error:
+        if (err)
+                dev_err(&vi->vpdev->dev, "%s %d err %d\n",
+                        __func__, __LINE__, err);
+        return err;
+}
+
+#define VOP_USE_DMA true
+
+/*
+ * Initiates the copies across the PCIe bus from card memory to a user
+ * space buffer. When transfers are done using DMA, source/destination
+ * addresses and transfer length must follow the alignment requirements of
+ * the MIC DMA engine.
+ */
+static int vop_virtio_copy_to_user(struct vop_vdev *vdev, void __user *ubuf,
+                                   size_t len, u64 daddr, size_t dlen,
+                                   int vr_idx)
+{
+        struct vop_device *vpdev = vdev->vpdev;
+        void __iomem *dbuf = vpdev->hw_ops->ioremap(vpdev, daddr, len);
+        struct vop_vringh *vvr = &vdev->vvr[vr_idx];
+        struct vop_info *vi = dev_get_drvdata(&vpdev->dev);
+        size_t dma_alignment = 1 << vi->dma_ch->device->copy_align;
+        bool x200 = is_dma_copy_aligned(vi->dma_ch->device, 1, 1, 1);
+        size_t dma_offset, partlen;
+        int err;
+
+        if (!VOP_USE_DMA) {
+                if (copy_to_user(ubuf, (void __force *)dbuf, len)) {
+                        err = -EFAULT;
+                        dev_err(vop_dev(vdev), "%s %d err %d\n",
+                                __func__, __LINE__, err);
+                        goto err;
+                }
+                vdev->in_bytes += len;
+                err = 0;
+                goto err;
+        }
+
+        dma_offset = daddr - round_down(daddr, dma_alignment);
+        daddr -= dma_offset;
+        len += dma_offset;
+        /*
+         * X100 uses DMA addresses as seen by the card so adding
+         * the aperture base is not required for DMA. However x200
+         * requires DMA addresses to be an offset into the bar so
+         * add the aperture base for x200.
+         */
+        if (x200)
+                daddr += vpdev->aper->pa;
+        while (len) {
+                partlen = min_t(size_t, len, VOP_INT_DMA_BUF_SIZE);
+                err = vop_sync_dma(vdev, vvr->buf_da, daddr,
+                                   ALIGN(partlen, dma_alignment));
+                if (err) {
+                        dev_err(vop_dev(vdev), "%s %d err %d\n",
+                                __func__, __LINE__, err);
+                        goto err;
+                }
+                if (copy_to_user(ubuf, vvr->buf + dma_offset,
+                                 partlen - dma_offset)) {
+                        err = -EFAULT;
+                        dev_err(vop_dev(vdev), "%s %d err %d\n",
+                                __func__, __LINE__, err);
+                        goto err;
+                }
+                daddr += partlen;
+                ubuf += partlen;
+                dbuf += partlen;
+                vdev->in_bytes_dma += partlen;
+                vdev->in_bytes += partlen;
+                len -= partlen;
+                dma_offset = 0;
+        }
+        err = 0;
+err:
+        vpdev->hw_ops->iounmap(vpdev, dbuf);
+        dev_dbg(vop_dev(vdev),
+                "%s: ubuf %p dbuf %p len 0x%lx vr_idx 0x%x\n",
+                __func__, ubuf, dbuf, len, vr_idx);
+        return err;
+}
+
+/*
+ * Initiates copies across the PCIe bus from a user space buffer to card
+ * memory. When transfers are done using DMA, source/destination addresses
+ * and transfer length must follow the alignment requirements of the MIC
+ * DMA engine.
+ */
+static int vop_virtio_copy_from_user(struct vop_vdev *vdev, void __user *ubuf,
+                                     size_t len, u64 daddr, size_t dlen,
+                                     int vr_idx)
+{
+        struct vop_device *vpdev = vdev->vpdev;
+        void __iomem *dbuf = vpdev->hw_ops->ioremap(vpdev, daddr, len);
+        struct vop_vringh *vvr = &vdev->vvr[vr_idx];
+        struct vop_info *vi = dev_get_drvdata(&vdev->vpdev->dev);
+        size_t dma_alignment = 1 << vi->dma_ch->device->copy_align;
+        bool x200 = is_dma_copy_aligned(vi->dma_ch->device, 1, 1, 1);
+        size_t partlen;
+        bool dma = VOP_USE_DMA;
+        int err = 0;
+
+        if (daddr & (dma_alignment - 1)) {
+                vdev->tx_dst_unaligned += len;
+                dma = false;
+        } else if (ALIGN(len, dma_alignment) > dlen) {
+                vdev->tx_len_unaligned += len;
+                dma = false;
+        }
+
+        if (!dma)
+                goto memcpy;
+
+        /*
+         * X100 uses DMA addresses as seen by the card so adding
+         * the aperture base is not required for DMA. However x200
+         * requires DMA addresses to be an offset into the bar so
+         * add the aperture base for x200.
+         */
+        if (x200)
+                daddr += vpdev->aper->pa;
+        while (len) {
+                partlen = min_t(size_t, len, VOP_INT_DMA_BUF_SIZE);
+
+                if (copy_from_user(vvr->buf, ubuf, partlen)) {
+                        err = -EFAULT;
+                        dev_err(vop_dev(vdev), "%s %d err %d\n",
+                                __func__, __LINE__, err);
+                        goto err;
+                }
+                err = vop_sync_dma(vdev, daddr, vvr->buf_da,
+                                   ALIGN(partlen, dma_alignment));
+                if (err) {
+                        dev_err(vop_dev(vdev), "%s %d err %d\n",
+                                __func__, __LINE__, err);
+                        goto err;
+                }
+                daddr += partlen;
+                ubuf += partlen;
+                dbuf += partlen;
+                vdev->out_bytes_dma += partlen;
+                vdev->out_bytes += partlen;
+                len -= partlen;
+        }
+memcpy:
+        /*
+         * We are copying to IO below and should ideally use something
+         * like copy_from_user_toio(..) if it existed.
+         */
+        if (copy_from_user((void __force *)dbuf, ubuf, len)) {
+                err = -EFAULT;
+                dev_err(vop_dev(vdev), "%s %d err %d\n",
+                        __func__, __LINE__, err);
+                goto err;
+        }
+        vdev->out_bytes += len;
+        err = 0;
+err:
+        vpdev->hw_ops->iounmap(vpdev, dbuf);
+        dev_dbg(vop_dev(vdev),
+                "%s: ubuf %p dbuf %p len 0x%lx vr_idx 0x%x\n",
+                __func__, ubuf, dbuf, len, vr_idx);
+        return err;
+}
+
+#define MIC_VRINGH_READ true
+
+/* Determine the total number of bytes consumed in a VRINGH KIOV */
+static inline u32 vop_vringh_iov_consumed(struct vringh_kiov *iov)
+{
+        int i;
+        u32 total = iov->consumed;
+
+        for (i = 0; i < iov->i; i++)
+                total += iov->iov[i].iov_len;
+        return total;
+}
+
+/*
+ * Traverse the VRINGH KIOV and issue the APIs to trigger the copies.
+ * This API is heavily based on the vringh_iov_xfer(..) implementation
+ * in vringh.c. The reason we cannot reuse vringh_iov_pull_kern(..)
+ * and vringh_iov_push_kern(..) directly is because there is no
+ * way to override the VRINGH xfer(..) routines as of v3.10.
+ */
+static int vop_vringh_copy(struct vop_vdev *vdev, struct vringh_kiov *iov,
+                           void __user *ubuf, size_t len, bool read, int vr_idx,
+                           size_t *out_len)
+{
+        int ret = 0;
+        size_t partlen, tot_len = 0;
+
+        while (len && iov->i < iov->used) {
+                struct kvec *kiov = &iov->iov[iov->i];
+
+                partlen = min(kiov->iov_len, len);
+                if (read)
+                        ret = vop_virtio_copy_to_user(vdev, ubuf, partlen,
+                                                      (u64)kiov->iov_base,
+                                                      kiov->iov_len,
+                                                      vr_idx);
+                else
+                        ret = vop_virtio_copy_from_user(vdev, ubuf, partlen,
+                                                        (u64)kiov->iov_base,
+                                                        kiov->iov_len,
+                                                        vr_idx);
+                if (ret) {
+                        dev_err(vop_dev(vdev), "%s %d err %d\n",
+                                __func__, __LINE__, ret);
+                        break;
+                }
+                len -= partlen;
+                ubuf += partlen;
+                tot_len += partlen;
+                iov->consumed += partlen;
+                kiov->iov_len -= partlen;
+                kiov->iov_base += partlen;
+                if (!kiov->iov_len) {
+                        /* Fix up old iov element then increment. */
+                        kiov->iov_len = iov->consumed;
+                        kiov->iov_base -= iov->consumed;
+
+                        iov->consumed = 0;
+                        iov->i++;
+                }
+        }
+        *out_len = tot_len;
+        return ret;
+}
+
+/*
+ * Use the standard VRINGH infrastructure in the kernel to fetch new
+ * descriptors, initiate the copies and update the used ring.
+ */
+static int _vop_virtio_copy(struct vop_vdev *vdev, struct mic_copy_desc *copy)
+{
+        int ret = 0;
+        u32 iovcnt = copy->iovcnt;
+        struct iovec iov;
+        struct iovec __user *u_iov = copy->iov;
+        void __user *ubuf = NULL;
+        struct vop_vringh *vvr = &vdev->vvr[copy->vr_idx];
+        struct vringh_kiov *riov = &vvr->riov;
+        struct vringh_kiov *wiov = &vvr->wiov;
+        struct vringh *vrh = &vvr->vrh;
+        u16 *head = &vvr->head;
+        struct mic_vring *vr = &vvr->vring;
+        size_t len = 0, out_len;
+
+        copy->out_len = 0;
+        /* Fetch a new IOVEC if all previous elements have been processed */
+        if (riov->i == riov->used && wiov->i == wiov->used) {
+                ret = vringh_getdesc_kern(vrh, riov, wiov,
+                                          head, GFP_KERNEL);
+                /* Check if there are available descriptors */
+                if (ret <= 0)
+                        return ret;
+        }
+        while (iovcnt) {
+                if (!len) {
+                        /* Copy over a new iovec from user space. */
+                        ret = copy_from_user(&iov, u_iov, sizeof(*u_iov));
+                        if (ret) {
+                                ret = -EINVAL;
+                                dev_err(vop_dev(vdev), "%s %d err %d\n",
+                                        __func__, __LINE__, ret);
+                                break;
+                        }
+                        len = iov.iov_len;
+                        ubuf = iov.iov_base;
+                }
+                /* Issue all the read descriptors first */
+                ret = vop_vringh_copy(vdev, riov, ubuf, len,
+                                      MIC_VRINGH_READ, copy->vr_idx, &out_len);
+                if (ret) {
+                        dev_err(vop_dev(vdev), "%s %d err %d\n",
+                                __func__, __LINE__, ret);
+                        break;
+                }
+                len -= out_len;
+                ubuf += out_len;
+                copy->out_len += out_len;
+                /* Issue the write descriptors next */
+                ret = vop_vringh_copy(vdev, wiov, ubuf, len,
+                                      !MIC_VRINGH_READ, copy->vr_idx, &out_len);
+                if (ret) {
+                        dev_err(vop_dev(vdev), "%s %d err %d\n",
+                                __func__, __LINE__, ret);
+                        break;
+                }
+                len -= out_len;
+                ubuf += out_len;
+                copy->out_len += out_len;
+                if (!len) {
+                        /* One user space iovec is now completed */
+                        iovcnt--;
+                        u_iov++;
+                }
+                /* Exit loop if all elements in KIOVs have been processed. */
+                if (riov->i == riov->used && wiov->i == wiov->used)
+                        break;
+        }
+        /*
+         * Update the used ring if a descriptor was available and some data was
+         * copied in/out and the user asked for a used ring update.
+         */
+        if (*head != USHRT_MAX && copy->out_len && copy->update_used) {
+                u32 total = 0;
+
+                /* Determine the total data consumed */
+                total += vop_vringh_iov_consumed(riov);
+                total += vop_vringh_iov_consumed(wiov);
+                vringh_complete_kern(vrh, *head, total);
+                *head = USHRT_MAX;
+                if (vringh_need_notify_kern(vrh) > 0)
+                        vringh_notify(vrh);
+                vringh_kiov_cleanup(riov);
+                vringh_kiov_cleanup(wiov);
+                /* Update avail idx for user space */
+                vr->info->avail_idx = vrh->last_avail_idx;
+        }
+        return ret;
+}
+
+static inline int vop_verify_copy_args(struct vop_vdev *vdev,
+                                       struct mic_copy_desc *copy)
+{
+        if (!vdev || copy->vr_idx >= vdev->dd->num_vq)
+                return -EINVAL;
+        return 0;
+}
+
+/* Copy a specified number of virtio descriptors in a chain */
+static int vop_virtio_copy_desc(struct vop_vdev *vdev,
+                                struct mic_copy_desc *copy)
+{
+        int err;
+        struct vop_vringh *vvr = &vdev->vvr[copy->vr_idx];
+
+        err = vop_verify_copy_args(vdev, copy);
+        if (err)
+                return err;
+
+        mutex_lock(&vvr->vr_mutex);
+        if (!vop_vdevup(vdev)) {
+                err = -ENODEV;
+                dev_err(vop_dev(vdev), "%s %d err %d\n",
+                        __func__, __LINE__, err);
+                goto err;
+        }
+        err = _vop_virtio_copy(vdev, copy);
+        if (err) {
+                dev_err(vop_dev(vdev), "%s %d err %d\n",
+                        __func__, __LINE__, err);
+        }
+err:
+        mutex_unlock(&vvr->vr_mutex);
+        return err;
+}
+
+static int vop_open(struct inode *inode, struct file *f)
+{
+        struct vop_vdev *vdev;
+        struct vop_info *vi = container_of(f->private_data,
+                struct vop_info, miscdev);
+
+        vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
+        if (!vdev)
+                return -ENOMEM;
+        vdev->vi = vi;
+        mutex_init(&vdev->vdev_mutex);
+        f->private_data = vdev;
+        init_completion(&vdev->destroy);
+        complete(&vdev->destroy);
+        return 0;
+}
+
+static int vop_release(struct inode *inode, struct file *f)
+{
+        struct vop_vdev *vdev = f->private_data, *vdev_tmp;
+        struct vop_info *vi = vdev->vi;
+        struct list_head *pos, *tmp;
+        bool found = false;
+
+        mutex_lock(&vdev->vdev_mutex);
+        if (vdev->deleted)
+                goto unlock;
+        mutex_lock(&vi->vop_mutex);
+        list_for_each_safe(pos, tmp, &vi->vdev_list) {
+                vdev_tmp = list_entry(pos, struct vop_vdev, list);
+                if (vdev == vdev_tmp) {
+                        vop_virtio_del_device(vdev);
+                        list_del(pos);
+                        found = true;
+                        break;
+                }
+        }
+        mutex_unlock(&vi->vop_mutex);
+unlock:
+        mutex_unlock(&vdev->vdev_mutex);
+        if (!found)
+                wait_for_completion(&vdev->destroy);
+        f->private_data = NULL;
+        kfree(vdev);
+        return 0;
+}
+
+static long vop_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
+{
+        struct vop_vdev *vdev = f->private_data;
+        struct vop_info *vi = vdev->vi;
+        void __user *argp = (void __user *)arg;
+        int ret;
+
+        switch (cmd) {
+        case MIC_VIRTIO_ADD_DEVICE:
+        {
+                struct mic_device_desc dd, *dd_config;
+
+                if (copy_from_user(&dd, argp, sizeof(dd)))
+                        return -EFAULT;
+
+                if (mic_aligned_desc_size(&dd) > MIC_MAX_DESC_BLK_SIZE ||
+                    dd.num_vq > MIC_MAX_VRINGS)
+                        return -EINVAL;
+
+                dd_config = kzalloc(mic_desc_size(&dd), GFP_KERNEL);
+                if (!dd_config)
+                        return -ENOMEM;
+                if (copy_from_user(dd_config, argp, mic_desc_size(&dd))) {
+                        ret = -EFAULT;
+                        goto free_ret;
+                }
+                mutex_lock(&vdev->vdev_mutex);
+                mutex_lock(&vi->vop_mutex);
+                ret = vop_virtio_add_device(vdev, dd_config);
+                if (ret)
+                        goto unlock_ret;
+                list_add_tail(&vdev->list, &vi->vdev_list);
+unlock_ret:
+                mutex_unlock(&vi->vop_mutex);
+                mutex_unlock(&vdev->vdev_mutex);
+free_ret:
+                kfree(dd_config);
+                return ret;
+        }
+        case MIC_VIRTIO_COPY_DESC:
+        {
+                struct mic_copy_desc copy;
+
+                mutex_lock(&vdev->vdev_mutex);
+                ret = vop_vdev_inited(vdev);
+                if (ret)
+                        goto _unlock_ret;
+
+                if (copy_from_user(&copy, argp, sizeof(copy))) {
+                        ret = -EFAULT;
+                        goto _unlock_ret;
+                }
+
+                ret = vop_virtio_copy_desc(vdev, &copy);
+                if (ret < 0)
+                        goto _unlock_ret;
+                if (copy_to_user(
+                        &((struct mic_copy_desc __user *)argp)->out_len,
+                        &copy.out_len, sizeof(copy.out_len)))
+                        ret = -EFAULT;
+_unlock_ret:
+                mutex_unlock(&vdev->vdev_mutex);
+                return ret;
+        }
+        case MIC_VIRTIO_CONFIG_CHANGE:
+        {
+                void *buf;
+
+                mutex_lock(&vdev->vdev_mutex);
+                ret = vop_vdev_inited(vdev);
+                if (ret)
+                        goto __unlock_ret;
+                buf = kzalloc(vdev->dd->config_len, GFP_KERNEL);
+                if (!buf) {
+                        ret = -ENOMEM;
+                        goto __unlock_ret;
+                }
+                if (copy_from_user(buf, argp, vdev->dd->config_len)) {
+                        ret = -EFAULT;
+                        goto done;
+                }
+                ret = vop_virtio_config_change(vdev, buf);
+done:
+                kfree(buf);
+__unlock_ret:
+                mutex_unlock(&vdev->vdev_mutex);
+                return ret;
+        }
+        default:
+                return -ENOIOCTLCMD;
+        };
+        return 0;
+}
+
+/*
+ * We return POLLIN | POLLOUT from poll when new buffers are enqueued, and
+ * not when previously enqueued buffers may be available. This means that
+ * in the card->host (TX) path, when userspace is unblocked by poll it
+ * must drain all available descriptors or it can stall.
+ */
+static unsigned int vop_poll(struct file *f, poll_table *wait)
+{
+        struct vop_vdev *vdev = f->private_data;
+        int mask = 0;
+
+        mutex_lock(&vdev->vdev_mutex);
+        if (vop_vdev_inited(vdev)) {
+                mask = POLLERR;
+                goto done;
+        }
+        poll_wait(f, &vdev->waitq, wait);
+        if (vop_vdev_inited(vdev)) {
+                mask = POLLERR;
+        } else if (vdev->poll_wake) {
+                vdev->poll_wake = 0;
+                mask = POLLIN | POLLOUT;
+        }
+done:
+        mutex_unlock(&vdev->vdev_mutex);
+        return mask;
+}
+
+static inline int
+vop_query_offset(struct vop_vdev *vdev, unsigned long offset,
+                 unsigned long *size, unsigned long *pa)
+{
+        struct vop_device *vpdev = vdev->vpdev;
+        unsigned long start = MIC_DP_SIZE;
+        int i;
+
+        /*
+         * MMAP interface is as follows:
+         * offset                               region
+         * 0x0                                  virtio device_page
+         * 0x1000                               first vring
+         * 0x1000 + size of 1st vring           second vring
+         * ....
+         */
+        if (!offset) {
+                *pa = virt_to_phys(vpdev->hw_ops->get_dp(vpdev));
+                *size = MIC_DP_SIZE;
+                return 0;
+        }
+
+        for (i = 0; i < vdev->dd->num_vq; i++) {
+                struct vop_vringh *vvr = &vdev->vvr[i];
+
+                if (offset == start) {
+                        *pa = virt_to_phys(vvr->vring.va);
+                        *size = vvr->vring.len;
+                        return 0;
+                }
+                start += vvr->vring.len;
+        }
+        return -1;
+}
+
+/*
+ * Maps the device page and virtio rings to user space for readonly access.
+ */
+static int vop_mmap(struct file *f, struct vm_area_struct *vma)
+{
+        struct vop_vdev *vdev = f->private_data;
+        unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
+        unsigned long pa, size = vma->vm_end - vma->vm_start, size_rem = size;
+        int i, err;
+
+        err = vop_vdev_inited(vdev);
+        if (err)
+                goto ret;
+        if (vma->vm_flags & VM_WRITE) {
+                err = -EACCES;
+                goto ret;
+        }
+        while (size_rem) {
+                i = vop_query_offset(vdev, offset, &size, &pa);
+                if (i < 0) {
+                        err = -EINVAL;
+                        goto ret;
+                }
+                err = remap_pfn_range(vma, vma->vm_start + offset,
+                                      pa >> PAGE_SHIFT, size,
+                                      vma->vm_page_prot);
+                if (err)
+                        goto ret;
+                size_rem -= size;
+                offset += size;
+        }
+ret:
+        return err;
+}
+
+static const struct file_operations vop_fops = {
+        .open = vop_open,
+        .release = vop_release,
+        .unlocked_ioctl = vop_ioctl,
+        .poll = vop_poll,
+        .mmap = vop_mmap,
+        .owner = THIS_MODULE,
+};
+
+int vop_host_init(struct vop_info *vi)
+{
+        int rc;
+        struct miscdevice *mdev;
+        struct vop_device *vpdev = vi->vpdev;
+
+        INIT_LIST_HEAD(&vi->vdev_list);
+        vi->dma_ch = vpdev->dma_ch;
+        mdev = &vi->miscdev;
+        mdev->minor = MISC_DYNAMIC_MINOR;
+        snprintf(vi->name, sizeof(vi->name), "vop_virtio%d", vpdev->index);
+        mdev->name = vi->name;
+        mdev->fops = &vop_fops;
+        mdev->parent = &vpdev->dev;
+
+        rc = misc_register(mdev);
+        if (rc)
+                dev_err(&vpdev->dev, "%s failed rc %d\n", __func__, rc);
+        return rc;
+}
+
+void vop_host_uninit(struct vop_info *vi)
+{
+        struct list_head *pos, *tmp;
+        struct vop_vdev *vdev;
+
+        mutex_lock(&vi->vop_mutex);
+        vop_virtio_reset_devices(vi);
+        list_for_each_safe(pos, tmp, &vi->vdev_list) {
+                vdev = list_entry(pos, struct vop_vdev, list);
+                list_del(pos);
+                reinit_completion(&vdev->destroy);
+                mutex_unlock(&vi->vop_mutex);
+                mutex_lock(&vdev->vdev_mutex);
+                vop_virtio_del_device(vdev);
+                vdev->deleted = true;
+                mutex_unlock(&vdev->vdev_mutex);
+                complete(&vdev->destroy);
+                mutex_lock(&vi->vop_mutex);
+        }
+        mutex_unlock(&vi->vop_mutex);
+        misc_deregister(&vi->miscdev);
+}