1 files changed, 700 insertions, 0 deletions

diff --git a/drivers/misc/mic/host/mic_virtio.c b/drivers/misc/mic/host/mic_virtio.c
new file mode 100644
index 000000000000..5b8494bd1e00
--- /dev/null
+++ b/drivers/misc/mic/host/mic_virtio.c
@@ -0,0 +1,700 @@
+/*
+ * Intel MIC Platform Software Stack (MPSS)
+ *
+ * Copyright(c) 2013 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 MIC Host driver.
+ *
+ */
+#include <linux/pci.h>
+#include <linux/sched.h>
+#include <linux/uaccess.h>
+
+#include <linux/mic_common.h>
+#include "../common/mic_dev.h"
+#include "mic_device.h"
+#include "mic_smpt.h"
+#include "mic_virtio.h"
+
+/*
+ * Initiates the copies across the PCIe bus from card memory to
+ * a user space buffer.
+ */
+static int mic_virtio_copy_to_user(struct mic_vdev *mvdev,
+		void __user *ubuf, size_t len, u64 addr)
+{
+	int err;
+	void __iomem *dbuf = mvdev->mdev->aper.va + addr;
+	/*
+	 * We are copying from IO below an should ideally use something
+	 * like copy_to_user_fromio(..) if it existed.
+	 */
+	if (copy_to_user(ubuf, dbuf, len)) {
+		err = -EFAULT;
+		dev_err(mic_dev(mvdev), "%s %d err %d\n",
+			__func__, __LINE__, err);
+		goto err;
+	}
+	mvdev->in_bytes += len;
+	err = 0;
+err:
+	return err;
+}
+
+/*
+ * Initiates copies across the PCIe bus from a user space
+ * buffer to card memory.
+ */
+static int mic_virtio_copy_from_user(struct mic_vdev *mvdev,
+		void __user *ubuf, size_t len, u64 addr)
+{
+	int err;
+	void __iomem *dbuf = mvdev->mdev->aper.va + addr;
+	/*
+	 * We are copying to IO below and should ideally use something
+	 * like copy_from_user_toio(..) if it existed.
+	 */
+	if (copy_from_user(dbuf, ubuf, len)) {
+		err = -EFAULT;
+		dev_err(mic_dev(mvdev), "%s %d err %d\n",
+			__func__, __LINE__, err);
+		goto err;
+	}
+	mvdev->out_bytes += len;
+	err = 0;
+err:
+	return err;
+}
+
+#define MIC_VRINGH_READ true
+
+/* The function to call to notify the card about added buffers */
+static void mic_notify(struct vringh *vrh)
+{
+	struct mic_vringh *mvrh = container_of(vrh, struct mic_vringh, vrh);
+	struct mic_vdev *mvdev = mvrh->mvdev;
+	s8 db = mvdev->dc->h2c_vdev_db;
+
+	if (db != -1)
+		mvdev->mdev->ops->send_intr(mvdev->mdev, db);
+}
+
+/* Determine the total number of bytes consumed in a VRINGH KIOV */
+static inline u32 mic_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 mic_vringh_copy(struct mic_vdev *mvdev, struct vringh_kiov *iov,
+	void __user *ubuf, size_t len, bool read, size_t *out_len)
+{
+	int ret = 0;
+	size_t partlen, tot_len = 0;
+
+	while (len && iov->i < iov->used) {
+		partlen = min(iov->iov[iov->i].iov_len, len);
+		if (read)
+			ret = mic_virtio_copy_to_user(mvdev,
+				ubuf, partlen,
+				(u64)iov->iov[iov->i].iov_base);
+		else
+			ret = mic_virtio_copy_from_user(mvdev,
+				ubuf, partlen,
+				(u64)iov->iov[iov->i].iov_base);
+		if (ret) {
+			dev_err(mic_dev(mvdev), "%s %d err %d\n",
+				__func__, __LINE__, ret);
+			break;
+		}
+		len -= partlen;
+		ubuf += partlen;
+		tot_len += partlen;
+		iov->consumed += partlen;
+		iov->iov[iov->i].iov_len -= partlen;
+		iov->iov[iov->i].iov_base += partlen;
+		if (!iov->iov[iov->i].iov_len) {
+			/* Fix up old iov element then increment. */
+			iov->iov[iov->i].iov_len = iov->consumed;
+			iov->iov[iov->i].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 _mic_virtio_copy(struct mic_vdev *mvdev,
+	struct mic_copy_desc *copy)
+{
+	int ret = 0, iovcnt = copy->iovcnt;
+	struct iovec iov;
+	struct iovec __user *u_iov = copy->iov;
+	void __user *ubuf = NULL;
+	struct mic_vringh *mvr = &mvdev->mvr[copy->vr_idx];
+	struct vringh_kiov *riov = &mvr->riov;
+	struct vringh_kiov *wiov = &mvr->wiov;
+	struct vringh *vrh = &mvr->vrh;
+	u16 *head = &mvr->head;
+	struct mic_vring *vr = &mvr->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(mic_dev(mvdev), "%s %d err %d\n",
+					__func__, __LINE__, ret);
+				break;
+			}
+			len = iov.iov_len;
+			ubuf = iov.iov_base;
+		}
+		/* Issue all the read descriptors first */
+		ret = mic_vringh_copy(mvdev, riov, ubuf, len,
+			MIC_VRINGH_READ, &out_len);
+		if (ret) {
+			dev_err(mic_dev(mvdev), "%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 = mic_vringh_copy(mvdev, wiov, ubuf, len,
+			!MIC_VRINGH_READ, &out_len);
+		if (ret) {
+			dev_err(mic_dev(mvdev), "%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 += mic_vringh_iov_consumed(riov);
+		total += mic_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 mic_verify_copy_args(struct mic_vdev *mvdev,
+		struct mic_copy_desc *copy)
+{
+	if (copy->vr_idx >= mvdev->dd->num_vq) {
+		dev_err(mic_dev(mvdev), "%s %d err %d\n",
+			__func__, __LINE__, -EINVAL);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/* Copy a specified number of virtio descriptors in a chain */
+int mic_virtio_copy_desc(struct mic_vdev *mvdev,
+		struct mic_copy_desc *copy)
+{
+	int err;
+	struct mic_vringh *mvr = &mvdev->mvr[copy->vr_idx];
+
+	err = mic_verify_copy_args(mvdev, copy);
+	if (err)
+		return err;
+
+	mutex_lock(&mvr->vr_mutex);
+	if (!mic_vdevup(mvdev)) {
+		err = -ENODEV;
+		dev_err(mic_dev(mvdev), "%s %d err %d\n",
+			__func__, __LINE__, err);
+		goto err;
+	}
+	err = _mic_virtio_copy(mvdev, copy);
+	if (err) {
+		dev_err(mic_dev(mvdev), "%s %d err %d\n",
+			__func__, __LINE__, err);
+	}
+err:
+	mutex_unlock(&mvr->vr_mutex);
+	return err;
+}
+
+static void mic_virtio_init_post(struct mic_vdev *mvdev)
+{
+	struct mic_vqconfig *vqconfig = mic_vq_config(mvdev->dd);
+	int i;
+
+	for (i = 0; i < mvdev->dd->num_vq; i++) {
+		if (!le64_to_cpu(vqconfig[i].used_address)) {
+			dev_warn(mic_dev(mvdev), "used_address zero??\n");
+			continue;
+		}
+		mvdev->mvr[i].vrh.vring.used =
+			mvdev->mdev->aper.va +
+			le64_to_cpu(vqconfig[i].used_address);
+	}
+
+	mvdev->dc->used_address_updated = 0;
+
+	dev_dbg(mic_dev(mvdev), "%s: device type %d LINKUP\n",
+		__func__, mvdev->virtio_id);
+}
+
+static inline void mic_virtio_device_reset(struct mic_vdev *mvdev)
+{
+	int i;
+
+	dev_dbg(mic_dev(mvdev), "%s: status %d device type %d RESET\n",
+		__func__, mvdev->dd->status, mvdev->virtio_id);
+
+	for (i = 0; i < mvdev->dd->num_vq; i++)
+		/*
+		 * Avoid lockdep false positive. The + 1 is for the mic
+		 * mutex which is held in the reset devices code path.
+		 */
+		mutex_lock_nested(&mvdev->mvr[i].vr_mutex, i + 1);
+
+	/* 0 status means "reset" */
+	mvdev->dd->status = 0;
+	mvdev->dc->vdev_reset = 0;
+	mvdev->dc->host_ack = 1;
+
+	for (i = 0; i < mvdev->dd->num_vq; i++) {
+		struct vringh *vrh = &mvdev->mvr[i].vrh;
+		mvdev->mvr[i].vring.info->avail_idx = 0;
+		vrh->completed = 0;
+		vrh->last_avail_idx = 0;
+		vrh->last_used_idx = 0;
+	}
+
+	for (i = 0; i < mvdev->dd->num_vq; i++)
+		mutex_unlock(&mvdev->mvr[i].vr_mutex);
+}
+
+void mic_virtio_reset_devices(struct mic_device *mdev)
+{
+	struct list_head *pos, *tmp;
+	struct mic_vdev *mvdev;
+
+	dev_dbg(mdev->sdev->parent, "%s\n",  __func__);
+
+	list_for_each_safe(pos, tmp, &mdev->vdev_list) {
+		mvdev = list_entry(pos, struct mic_vdev, list);
+		mic_virtio_device_reset(mvdev);
+		mvdev->poll_wake = 1;
+		wake_up(&mvdev->waitq);
+	}
+}
+
+void mic_bh_handler(struct work_struct *work)
+{
+	struct mic_vdev *mvdev = container_of(work, struct mic_vdev,
+			virtio_bh_work);
+
+	if (mvdev->dc->used_address_updated)
+		mic_virtio_init_post(mvdev);
+
+	if (mvdev->dc->vdev_reset)
+		mic_virtio_device_reset(mvdev);
+
+	mvdev->poll_wake = 1;
+	wake_up(&mvdev->waitq);
+}
+
+static irqreturn_t mic_virtio_intr_handler(int irq, void *data)
+{
+	struct mic_vdev *mvdev = data;
+	struct mic_device *mdev = mvdev->mdev;
+
+	mdev->ops->ack_interrupt(mdev);
+	schedule_work(&mvdev->virtio_bh_work);
+	return IRQ_HANDLED;
+}
+
+int mic_virtio_config_change(struct mic_vdev *mvdev,
+			void __user *argp)
+{
+	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake);
+	int ret = 0, retry = 100, i;
+	struct mic_bootparam *bootparam = mvdev->mdev->dp;
+	s8 db = bootparam->h2c_config_db;
+
+	mutex_lock(&mvdev->mdev->mic_mutex);
+	for (i = 0; i < mvdev->dd->num_vq; i++)
+		mutex_lock_nested(&mvdev->mvr[i].vr_mutex, i + 1);
+
+	if (db == -1 || mvdev->dd->type == -1) {
+		ret = -EIO;
+		goto exit;
+	}
+
+	if (copy_from_user(mic_vq_configspace(mvdev->dd),
+			   argp, mvdev->dd->config_len)) {
+		dev_err(mic_dev(mvdev), "%s %d err %d\n",
+			__func__, __LINE__, -EFAULT);
+		ret = -EFAULT;
+		goto exit;
+	}
+	mvdev->dc->config_change = MIC_VIRTIO_PARAM_CONFIG_CHANGED;
+	mvdev->mdev->ops->send_intr(mvdev->mdev, db);
+
+	for (i = retry; i--;) {
+		ret = wait_event_timeout(wake,
+			mvdev->dc->guest_ack, msecs_to_jiffies(100));
+		if (ret)
+			break;
+	}
+
+	dev_dbg(mic_dev(mvdev),
+		"%s %d retry: %d\n", __func__, __LINE__, retry);
+	mvdev->dc->config_change = 0;
+	mvdev->dc->guest_ack = 0;
+exit:
+	for (i = 0; i < mvdev->dd->num_vq; i++)
+		mutex_unlock(&mvdev->mvr[i].vr_mutex);
+	mutex_unlock(&mvdev->mdev->mic_mutex);
+	return ret;
+}
+
+static int mic_copy_dp_entry(struct mic_vdev *mvdev,
+					void __user *argp,
+					__u8 *type,
+					struct mic_device_desc **devpage)
+{
+	struct mic_device *mdev = mvdev->mdev;
+	struct mic_device_desc dd, *dd_config, *devp;
+	struct mic_vqconfig *vqconfig;
+	int ret = 0, i;
+	bool slot_found = false;
+
+	if (copy_from_user(&dd, argp, sizeof(dd))) {
+		dev_err(mic_dev(mvdev), "%s %d err %d\n",
+			__func__, __LINE__, -EFAULT);
+		return -EFAULT;
+	}
+
+	if (mic_aligned_desc_size(&dd) > MIC_MAX_DESC_BLK_SIZE ||
+	    dd.num_vq > MIC_MAX_VRINGS) {
+		dev_err(mic_dev(mvdev), "%s %d err %d\n",
+			__func__, __LINE__, -EINVAL);
+		return -EINVAL;
+	}
+
+	dd_config = kmalloc(mic_desc_size(&dd), GFP_KERNEL);
+	if (dd_config == NULL) {
+		dev_err(mic_dev(mvdev), "%s %d err %d\n",
+			__func__, __LINE__, -ENOMEM);
+		return -ENOMEM;
+	}
+	if (copy_from_user(dd_config, argp, mic_desc_size(&dd))) {
+		ret = -EFAULT;
+		dev_err(mic_dev(mvdev), "%s %d err %d\n",
+			__func__, __LINE__, ret);
+		goto exit;
+	}
+
+	vqconfig = mic_vq_config(dd_config);
+	for (i = 0; i < dd.num_vq; i++) {
+		if (le16_to_cpu(vqconfig[i].num) > MIC_MAX_VRING_ENTRIES) {
+			ret =  -EINVAL;
+			dev_err(mic_dev(mvdev), "%s %d err %d\n",
+				__func__, __LINE__, ret);
+			goto exit;
+		}
+	}
+
+	/* Find the first free device page entry */
+	for (i = mic_aligned_size(struct mic_bootparam);
+		i < MIC_DP_SIZE - mic_total_desc_size(dd_config);
+		i += mic_total_desc_size(devp)) {
+		devp = mdev->dp + i;
+		if (devp->type == 0 || devp->type == -1) {
+			slot_found = true;
+			break;
+		}
+	}
+	if (!slot_found) {
+		ret =  -EINVAL;
+		dev_err(mic_dev(mvdev), "%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 = dd_config->type;
+	dd_config->type = 0;
+	memcpy(devp, dd_config, mic_desc_size(dd_config));
+
+	*devpage = devp;
+exit:
+	kfree(dd_config);
+	return ret;
+}
+
+static void mic_init_device_ctrl(struct mic_vdev *mvdev,
+				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;
+	mvdev->dc = dc;
+}
+
+int mic_virtio_add_device(struct mic_vdev *mvdev,
+			void __user *argp)
+{
+	struct mic_device *mdev = mvdev->mdev;
+	struct mic_device_desc *dd = NULL;
+	struct mic_vqconfig *vqconfig;
+	int vr_size, i, j, ret;
+	u8 type = 0;
+	s8 db;
+	char irqname[10];
+	struct mic_bootparam *bootparam = mdev->dp;
+	u16 num;
+
+	mutex_lock(&mdev->mic_mutex);
+
+	ret = mic_copy_dp_entry(mvdev, argp, &type, &dd);
+	if (ret) {
+		mutex_unlock(&mdev->mic_mutex);
+		return ret;
+	}
+
+	mic_init_device_ctrl(mvdev, dd);
+
+	mvdev->dd = dd;
+	mvdev->virtio_id = type;
+	vqconfig = mic_vq_config(dd);
+	INIT_WORK(&mvdev->virtio_bh_work, mic_bh_handler);
+
+	for (i = 0; i < dd->num_vq; i++) {
+		struct mic_vringh *mvr = &mvdev->mvr[i];
+		struct mic_vring *vr = &mvdev->mvr[i].vring;
+		num = le16_to_cpu(vqconfig[i].num);
+		mutex_init(&mvr->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(mic_dev(mvdev), "%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 = MIC_MAGIC + mvdev->virtio_id + i;
+		vqconfig[i].address = mic_map_single(mdev,
+			vr->va, vr_size);
+		if (mic_map_error(vqconfig[i].address)) {
+			free_pages((unsigned long)vr->va, get_order(vr_size));
+			ret = -ENOMEM;
+			dev_err(mic_dev(mvdev), "%s %d err %d\n",
+				__func__, __LINE__, ret);
+			goto err;
+		}
+		vqconfig[i].address = cpu_to_le64(vqconfig[i].address);
+
+		vring_init(&vr->vr, num, vr->va, MIC_VIRTIO_RING_ALIGN);
+		ret = vringh_init_kern(&mvr->vrh,
+			*(u32 *)mic_vq_features(mvdev->dd), num, false,
+			vr->vr.desc, vr->vr.avail, vr->vr.used);
+		if (ret) {
+			dev_err(mic_dev(mvdev), "%s %d err %d\n",
+				__func__, __LINE__, ret);
+			goto err;
+		}
+		vringh_kiov_init(&mvr->riov, NULL, 0);
+		vringh_kiov_init(&mvr->wiov, NULL, 0);
+		mvr->head = USHRT_MAX;
+		mvr->mvdev = mvdev;
+		mvr->vrh.notify = mic_notify;
+		dev_dbg(mdev->sdev->parent,
+			"%s %d index %d va %p info %p vr_size 0x%x\n",
+			__func__, __LINE__, i, vr->va, vr->info, vr_size);
+	}
+
+	snprintf(irqname, sizeof(irqname), "mic%dvirtio%d", mdev->id,
+		 mvdev->virtio_id);
+	mvdev->virtio_db = mic_next_db(mdev);
+	mvdev->virtio_cookie = mic_request_irq(mdev, mic_virtio_intr_handler,
+			irqname, mvdev, mvdev->virtio_db, MIC_INTR_DB);
+	if (IS_ERR(mvdev->virtio_cookie)) {
+		ret = PTR_ERR(mvdev->virtio_cookie);
+		dev_dbg(mdev->sdev->parent, "request irq failed\n");
+		goto err;
+	}
+
+	mvdev->dc->c2h_vdev_db = mvdev->virtio_db;
+
+	list_add_tail(&mvdev->list, &mdev->vdev_list);
+	/*
+	 * 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;
+
+	dev_dbg(mdev->sdev->parent, "Added virtio device id %d\n", dd->type);
+
+	db = bootparam->h2c_config_db;
+	if (db != -1)
+		mdev->ops->send_intr(mdev, db);
+	mutex_unlock(&mdev->mic_mutex);
+	return 0;
+err:
+	vqconfig = mic_vq_config(dd);
+	for (j = 0; j < i; j++) {
+		struct mic_vringh *mvr = &mvdev->mvr[j];
+		mic_unmap_single(mdev, le64_to_cpu(vqconfig[j].address),
+				 mvr->vring.len);
+		free_pages((unsigned long)mvr->vring.va,
+			   get_order(mvr->vring.len));
+	}
+	mutex_unlock(&mdev->mic_mutex);
+	return ret;
+}
+
+void mic_virtio_del_device(struct mic_vdev *mvdev)
+{
+	struct list_head *pos, *tmp;
+	struct mic_vdev *tmp_mvdev;
+	struct mic_device *mdev = mvdev->mdev;
+	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake);
+	int i, ret, retry = 100;
+	struct mic_vqconfig *vqconfig;
+	struct mic_bootparam *bootparam = mdev->dp;
+	s8 db;
+
+	mutex_lock(&mdev->mic_mutex);
+	db = bootparam->h2c_config_db;
+	if (db == -1)
+		goto skip_hot_remove;
+	dev_dbg(mdev->sdev->parent,
+		"Requesting hot remove id %d\n", mvdev->virtio_id);
+	mvdev->dc->config_change = MIC_VIRTIO_PARAM_DEV_REMOVE;
+	mdev->ops->send_intr(mdev, db);
+	for (i = retry; i--;) {
+		ret = wait_event_timeout(wake,
+			mvdev->dc->guest_ack, msecs_to_jiffies(100));
+		if (ret)
+			break;
+	}
+	dev_dbg(mdev->sdev->parent,
+		"Device id %d config_change %d guest_ack %d\n",
+		mvdev->virtio_id, mvdev->dc->config_change,
+		mvdev->dc->guest_ack);
+	mvdev->dc->config_change = 0;
+	mvdev->dc->guest_ack = 0;
+skip_hot_remove:
+	mic_free_irq(mdev, mvdev->virtio_cookie, mvdev);
+	flush_work(&mvdev->virtio_bh_work);
+	vqconfig = mic_vq_config(mvdev->dd);
+	for (i = 0; i < mvdev->dd->num_vq; i++) {
+		struct mic_vringh *mvr = &mvdev->mvr[i];
+		vringh_kiov_cleanup(&mvr->riov);
+		vringh_kiov_cleanup(&mvr->wiov);
+		mic_unmap_single(mdev, le64_to_cpu(vqconfig[i].address),
+				 mvr->vring.len);
+		free_pages((unsigned long)mvr->vring.va,
+			   get_order(mvr->vring.len));
+	}
+
+	list_for_each_safe(pos, tmp, &mdev->vdev_list) {
+		tmp_mvdev = list_entry(pos, struct mic_vdev, list);
+		if (tmp_mvdev == mvdev) {
+			list_del(pos);
+			dev_dbg(mdev->sdev->parent,
+				"Removing virtio device id %d\n",
+				mvdev->virtio_id);
+			break;
+		}
+	}
+	/*
+	 * 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();
+	mvdev->dd->type = -1;
+	mutex_unlock(&mdev->mic_mutex);
+}