On Tue, Sep 10, 2019 at 04:19:35PM +0800, Jason Wang wrote:
> This sample driver creates mdev device that simulate virtio net device
> over virtio mdev transport. The device is implemented through vringh
> and workqueue.
>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> samples/Kconfig | 7 +
> samples/vfio-mdev/Makefile | 1 +
> samples/vfio-mdev/mvnet.c | 766 +++++++++++++++++++++++++++++++++++++
> 3 files changed, 774 insertions(+)
> create mode 100644 samples/vfio-mdev/mvnet.c
So for a POC, this is a bit too rough to be able to judge
whether the approach is workable.
Can you get it a bit more into shape esp wrt UAPI?
> diff --git a/samples/Kconfig b/samples/Kconfig
> index c8dacb4dda80..a1a1ca2c00b7 100644
> --- a/samples/Kconfig
> +++ b/samples/Kconfig
> @@ -131,6 +131,13 @@ config SAMPLE_VFIO_MDEV_MDPY
> mediated device. It is a simple framebuffer and supports
> the region display interface (VFIO_GFX_PLANE_TYPE_REGION).
>
> +config SAMPLE_VIRTIO_MDEV_NET
> + tristate "Build virtio mdev net example mediated device sample code -- loadable modules only"
> + depends on VIRTIO_MDEV_DEVICE && VHOST_RING && m
> + help
> + Build a networking sample device for use as a virtio
> + mediated device.
> +
> config SAMPLE_VFIO_MDEV_MDPY_FB
> tristate "Build VFIO mdpy example guest fbdev driver -- loadable module only"
> depends on FB && m
> diff --git a/samples/vfio-mdev/Makefile b/samples/vfio-mdev/Makefile
> index 10d179c4fdeb..f34af90ed0a0 100644
> --- a/samples/vfio-mdev/Makefile
> +++ b/samples/vfio-mdev/Makefile
> @@ -3,3 +3,4 @@ obj-$(CONFIG_SAMPLE_VFIO_MDEV_MTTY) += mtty.o
> obj-$(CONFIG_SAMPLE_VFIO_MDEV_MDPY) += mdpy.o
> obj-$(CONFIG_SAMPLE_VFIO_MDEV_MDPY_FB) += mdpy-fb.o
> obj-$(CONFIG_SAMPLE_VFIO_MDEV_MBOCHS) += mbochs.o
> +obj-$(CONFIG_SAMPLE_VIRTIO_MDEV_NET) += mvnet.o
> diff --git a/samples/vfio-mdev/mvnet.c b/samples/vfio-mdev/mvnet.c
> new file mode 100644
> index 000000000000..da295b41955e
> --- /dev/null
> +++ b/samples/vfio-mdev/mvnet.c
> @@ -0,0 +1,766 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Mediated virtual virtio-net device driver.
> + *
> + * Copyright (c) 2019, Red Hat Inc. All rights reserved.
> + * Author: Jason Wang <jasowang@xxxxxxxxxx>
> + *
> + * Sample driver
Documentation on how to use this?
> that creates mdev device that simulates ethernet
> + * device virtio mdev transport.
Well not exactly. What it seems to do is short-circuit
RX and TX rings.
> + */
> +
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/fs.h>
> +#include <linux/poll.h>
> +#include <linux/slab.h>
> +#include <linux/sched.h>
> +#include <linux/wait.h>
> +#include <linux/uuid.h>
> +#include <linux/iommu.h>
> +#include <linux/sysfs.h>
> +#include <linux/file.h>
> +#include <linux/etherdevice.h>
> +#include <linux/mdev.h>
> +#include <uapi/linux/virtio_mdev.h>
> +
> +#define VERSION_STRING "0.1"
> +#define DRIVER_AUTHOR "NVIDIA Corporation"
> +
> +#define MVNET_CLASS_NAME "mvnet"
> +
> +#define MVNET_NAME "mvnet"
> +
> +/*
> + * Global Structures
> + */
> +
> +static struct mvnet_dev {
> + struct class *vd_class;
> + struct idr vd_idr;
> + struct device dev;
> +} mvnet_dev;
> +
> +struct mvnet_virtqueue {
> + struct vringh vring;
> + struct vringh_kiov iov;
> + unsigned short head;
> + bool ready;
> + u32 desc_addr_lo;
> + u32 desc_addr_hi;
> + u32 device_addr_lo;
> + u32 device_addr_hi;
> + u32 driver_addr_lo;
> + u32 driver_addr_hi;
> + u64 desc_addr;
> + u64 device_addr;
> + u64 driver_addr;
> + void *private;
> + irqreturn_t (*cb)(void *);
> +};
> +
> +#define MVNET_QUEUE_ALIGN PAGE_SIZE
> +#define MVNET_QUEUE_MAX 256
> +#define MVNET_MAGIC_VALUE ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)
> +#define MVNET_VERSION 0x1 /* Implies virtio 1.0 */
> +#define MVNET_DEVICE_ID 0x1 /* network card */
> +#define MVNET_VENDOR_ID 0 /* is this correct ? */
> +#define MVNET_DEVICE_FEATURES VIRTIO_F_VERSION_1
> +
> +u64 mvnet_features = (1ULL << VIRTIO_F_ANY_LAYOUT) |
> + (1ULL << VIRTIO_F_VERSION_1) |
> + (1ULL << VIRTIO_F_IOMMU_PLATFORM) ;
> +
> +/* State of each mdev device */
> +struct mvnet_state {
> + struct mvnet_virtqueue vqs[2];
> + struct work_struct work;
> + spinlock_t lock;
> + struct mdev_device *mdev;
> + struct virtio_net_config config;
> + struct virtio_mdev_callback *cbs;
> + void *buffer;
> + u32 queue_sel;
> + u32 driver_features_sel;
> + u32 driver_features[2];
> + u32 device_features_sel;
> + u32 status;
> + u32 generation;
> + u32 num;
> + struct list_head next;
> +};
> +
> +static struct mutex mdev_list_lock;
> +static struct list_head mdev_devices_list;
> +
> +static void mvnet_queue_ready(struct mvnet_state *mvnet, unsigned idx)
> +{
> + struct mvnet_virtqueue *vq = &mvnet->vqs[idx];
> + int ret;
> +
> + vq->desc_addr = (u64)vq->desc_addr_hi << 32 | vq->desc_addr_lo;
> + vq->device_addr = (u64)vq->device_addr_hi << 32 | vq->device_addr_lo;
> + vq->driver_addr = (u64)vq->driver_addr_hi << 32 | vq->driver_addr_lo;
> +
> + ret = vringh_init_kern(&vq->vring, mvnet_features, MVNET_QUEUE_MAX,
> + false, (struct vring_desc *)vq->desc_addr,
> + (struct vring_avail *)vq->driver_addr,
> + (struct vring_used *)vq->device_addr);
> +}
> +
> +static ssize_t mvnet_read_config(struct mdev_device *mdev,
> + u32 *val, loff_t pos)
> +{
> + struct mvnet_state *mvnet;
> + struct mvnet_virtqueue *vq;
> + u32 queue_sel;
> +
> + if (!mdev || !val)
> + return -EINVAL;
> +
> + mvnet = mdev_get_drvdata(mdev);
> + if (!mvnet) {
> + pr_err("%s mvnet not found\n", __func__);
> + return -EINVAL;
> + }
> +
> + queue_sel = mvnet->queue_sel;
> + vq = &mvnet->vqs[queue_sel];
> +
> + switch (pos) {
> + case VIRTIO_MDEV_MAGIC_VALUE:
> + *val = MVNET_MAGIC_VALUE;
> + break;
> + case VIRTIO_MDEV_VERSION:
> + *val = MVNET_VERSION;
> + break;
> + case VIRTIO_MDEV_DEVICE_ID:
> + *val = MVNET_DEVICE_ID;
> + break;
> + case VIRTIO_MDEV_VENDOR_ID:
> + *val = MVNET_VENDOR_ID;
> + break;
> + case VIRTIO_MDEV_DEVICE_FEATURES:
> + if (mvnet->device_features_sel)
> + *val = mvnet_features >> 32;
> + else
> + *val = mvnet_features;
> + break;
> + case VIRTIO_MDEV_QUEUE_NUM_MAX:
> + *val = MVNET_QUEUE_MAX;
> + break;
> + case VIRTIO_MDEV_QUEUE_READY:
> + *val = vq->ready;
> + break;
> + case VIRTIO_MDEV_QUEUE_ALIGN:
> + *val = MVNET_QUEUE_ALIGN;
> + break;
> + case VIRTIO_MDEV_STATUS:
> + *val = mvnet->status;
> + break;
> + case VIRTIO_MDEV_QUEUE_DESC_LOW:
> + *val = vq->desc_addr_lo;
> + break;
> + case VIRTIO_MDEV_QUEUE_DESC_HIGH:
> + *val = vq->desc_addr_hi;
> + break;
> + case VIRTIO_MDEV_QUEUE_AVAIL_LOW:
> + *val = vq->driver_addr_lo;
> + break;
> + case VIRTIO_MDEV_QUEUE_AVAIL_HIGH:
> + *val = vq->driver_addr_hi;
> + break;
> + case VIRTIO_MDEV_QUEUE_USED_LOW:
> + *val = vq->device_addr_lo;
> + break;
> + case VIRTIO_MDEV_QUEUE_USED_HIGH:
> + *val = vq->device_addr_hi;
> + break;
> + case VIRTIO_MDEV_CONFIG_GENERATION:
> + *val = 1;
> + break;
> + default:
> + pr_err("Unsupported mdev read offset at 0x%x\n", pos);
> + break;
> + }
> +
> + return 4;
> +}
> +
> +static ssize_t mvnet_read_net_config(struct mdev_device *mdev,
> + char *buf, size_t count, loff_t pos)
> +{
> + struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
> +
> + if (!mvnet) {
> + pr_err("%s mvnet not found\n", __func__);
> + return -EINVAL;
> + }
> +
> + if (pos + count > sizeof(mvnet->config))
> + return -EINVAL;
> +
> + memcpy(buf, &mvnet->config + (unsigned)pos, count);
> +
> + return count;
> +}
> +
> +static void mvnet_vq_reset(struct mvnet_virtqueue *vq)
> +{
> + vq->ready = 0;
> + vq->desc_addr_lo = vq->desc_addr_hi = 0;
> + vq->device_addr_lo = vq->device_addr_hi = 0;
> + vq->driver_addr_lo = vq->driver_addr_hi = 0;
> + vq->desc_addr = 0;
> + vq->driver_addr = 0;
> + vq->device_addr = 0;
> + vringh_init_kern(&vq->vring, mvnet_features, MVNET_QUEUE_MAX,
> + false, 0, 0, 0);
> +}
> +
> +static void mvnet_reset(struct mvnet_state *mvnet)
> +{
> + int i;
> +
> + for (i = 0; i < 2; i++)
> + mvnet_vq_reset(&mvnet->vqs[i]);
> +
> + mvnet->queue_sel = 0;
> + mvnet->driver_features_sel = 0;
> + mvnet->device_features_sel = 0;
> + mvnet->status = 0;
> + ++mvnet->generation;
> +}
> +
> +static ssize_t mvnet_write_config(struct mdev_device *mdev,
> + u32 *val, loff_t pos)
> +{
> + struct mvnet_state *mvnet;
> + struct mvnet_virtqueue *vq;
> + u32 queue_sel;
> +
> + if (!mdev || !val)
> + return -EINVAL;
> +
> + mvnet = mdev_get_drvdata(mdev);
> + if (!mvnet) {
> + pr_err("%s mvnet not found\n", __func__);
> + return -EINVAL;
> + }
> +
> + queue_sel = mvnet->queue_sel;
> + vq = &mvnet->vqs[queue_sel];
> +
> + switch (pos) {
> + case VIRTIO_MDEV_DEVICE_FEATURES_SEL:
> + mvnet->device_features_sel = *val;
> + break;
> + case VIRTIO_MDEV_DRIVER_FEATURES:
> + mvnet->driver_features[mvnet->driver_features_sel] = *val;
> + break;
> + case VIRTIO_MDEV_DRIVER_FEATURES_SEL:
> + mvnet->driver_features_sel = *val;
> + break;
> + case VIRTIO_MDEV_QUEUE_SEL:
> + mvnet->queue_sel = *val;
> + break;
> + case VIRTIO_MDEV_QUEUE_NUM:
> + mvnet->num = *val;
> + break;
> + case VIRTIO_MDEV_QUEUE_READY:
> + vq->ready = *val;
> + if (vq->ready) {
> + spin_lock(&mvnet->lock);
> + mvnet_queue_ready(mvnet, queue_sel);
> + spin_unlock(&mvnet->lock);
> + }
> + break;
> + case VIRTIO_MDEV_QUEUE_NOTIFY:
> + if (vq->ready)
> + schedule_work(&mvnet->work);
> + break;
> + case VIRTIO_MDEV_STATUS:
> + mvnet->status = *val;
> + if (*val == 0) {
> + spin_lock(&mvnet->lock);
> + mvnet_reset(mvnet);
> + spin_unlock(&mvnet->lock);
> + }
> + break;
> + case VIRTIO_MDEV_QUEUE_DESC_LOW:
> + vq->desc_addr_lo = *val;
> + break;
> + case VIRTIO_MDEV_QUEUE_DESC_HIGH:
> + vq->desc_addr_hi = *val;
> + break;
> + case VIRTIO_MDEV_QUEUE_AVAIL_LOW:
> + vq->driver_addr_lo = *val;
> + break;
> + case VIRTIO_MDEV_QUEUE_AVAIL_HIGH:
> + vq->driver_addr_hi = *val;
> + break;
> + case VIRTIO_MDEV_QUEUE_USED_LOW:
> + vq->device_addr_lo = *val;
> + break;
> + case VIRTIO_MDEV_QUEUE_USED_HIGH:
> + vq->device_addr_hi = *val;
> + break;
> + default:
> + pr_err("Unsupported write offset! 0x%x\n", pos);
> + break;
> + }
> + spin_unlock(&mvnet->lock);
> +
> + return 4;
> +}
> +
> +static void mvnet_work(struct work_struct *work)
> +{
> + struct mvnet_state *mvnet = container_of(work, struct
> + mvnet_state, work);
> + struct mvnet_virtqueue *txq = &mvnet->vqs[1];
> + struct mvnet_virtqueue *rxq = &mvnet->vqs[0];
> + size_t read, write, total_write;
> + unsigned long flags;
> + int err;
> + int pkts = 0;
> +
> + spin_lock(&mvnet->lock);
> +
> + if (!txq->ready || !rxq->ready)
> + goto out;
> +
> + while (true) {
> + total_write = 0;
> + err = vringh_getdesc_kern(&txq->vring, &txq->iov, NULL,
> + &txq->head, GFP_KERNEL);
> + if (err <= 0)
> + break;
> +
> + err = vringh_getdesc_kern(&rxq->vring, NULL, &rxq->iov,
> + &rxq->head, GFP_KERNEL);
GFP_KERNEL under a spin_lock will cause deadlocks.
> + if (err <= 0) {
> + vringh_complete_kern(&txq->vring, txq->head, 0);
> + break;
> + }
> +
> + while (true) {
> + read = vringh_iov_pull_kern(&txq->iov, mvnet->buffer,
> + PAGE_SIZE);
> + if (read <= 0)
> + break;
> +
> + write = vringh_iov_push_kern(&rxq->iov, mvnet->buffer,
> + read);
> + if (write <= 0)
> + break;
> +
> + total_write += write;
> + }
> +
> + /* Make sure data is wrote before advancing index */
> + smp_wmb();
> +
> + vringh_complete_kern(&txq->vring, txq->head, 0);
> + vringh_complete_kern(&rxq->vring, rxq->head, total_write);
> +
> + /* Make sure used is visible before rasing the
> + interrupt */
> + smp_wmb();
> +
> + local_bh_disable();
> + if (txq->cb)
> + txq->cb(txq->private);
> + if (rxq->cb)
> + rxq->cb(rxq->private);
> + local_bh_enable();
> +
> + pkts ++;
coding style problem
> + if (pkts > 4) {
> + schedule_work(&mvnet->work);
> + goto out;
> + }
> + }
> +
> +out:
> + spin_unlock(&mvnet->lock);
> +}
> +
> +static dma_addr_t mvnet_map_page(struct device *dev, struct page *page,
> + unsigned long offset, size_t size,
> + enum dma_data_direction dir,
> + unsigned long attrs)
> +{
> + /* Vringh can only use VA */
> + return page_address(page) + offset;
> +}
> +
> +static void mvnet_unmap_page(struct device *dev, dma_addr_t dma_addr,
> + size_t size, enum dma_data_direction dir,
> + unsigned long attrs)
> +{
> + return ;
> +}
> +
> +static void *mvnet_alloc_coherent(struct device *dev, size_t size,
> + dma_addr_t *dma_addr, gfp_t flag,
> + unsigned long attrs)
> +{
> + void *ret = kmalloc(size, flag);
> +
> + if (ret == NULL)
!ret is nicer
> + *dma_addr = DMA_MAPPING_ERROR;
> + else
> + *dma_addr = ret;
Not sure how does this build ... don't we need a cast?
> +
> + return ret;
> +}
> +
> +static void mvnet_free_coherent(struct device *dev, size_t size,
> + void *vaddr, dma_addr_t dma_addr,
> + unsigned long attrs)
> +{
> + kfree(dma_addr);
> +}
> +
> +static const struct dma_map_ops mvnet_dma_ops = {
> + .map_page = mvnet_map_page,
> + .unmap_page = mvnet_unmap_page,
> + .alloc = mvnet_alloc_coherent,
> + .free = mvnet_free_coherent,
> +};
> +
> +static int mvnet_create(struct kobject *kobj, struct mdev_device *mdev)
> +{
> + struct mvnet_state *mvnet;
> + struct virtio_net_config *config;
> +
> + if (!mdev)
> + return -EINVAL;
> +
> + mvnet = kzalloc(sizeof(struct mvnet_state), GFP_KERNEL);
> + if (mvnet == NULL)
> + return -ENOMEM;
> +
> + mvnet->buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
> + if (!mvnet->buffer) {
> + kfree(mvnet);
> + return -ENOMEM;
> + }
> +
> + config = &mvnet->config;
> + config->mtu = 1500;
> + config->status = VIRTIO_NET_S_LINK_UP;
> + eth_random_addr(config->mac);
> +
> + INIT_WORK(&mvnet->work, mvnet_work);
> +
> + spin_lock_init(&mvnet->lock);
> + mvnet->mdev = mdev;
> + mdev_set_drvdata(mdev, mvnet);
> +
> + mutex_lock(&mdev_list_lock);
> + list_add(&mvnet->next, &mdev_devices_list);
> + mutex_unlock(&mdev_list_lock);
> +
> + mdev_set_dma_ops(mdev, &mvnet_dma_ops);
> +
> + return 0;
> +}
> +
> +static int mvnet_remove(struct mdev_device *mdev)
> +{
> + struct mvnet_state *mds, *tmp_mds;
> + struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
> + int ret = -EINVAL;
> +
> + mutex_lock(&mdev_list_lock);
> + list_for_each_entry_safe(mds, tmp_mds, &mdev_devices_list, next) {
> + if (mvnet == mds) {
> + list_del(&mvnet->next);
> + mdev_set_drvdata(mdev, NULL);
> + kfree(mvnet->buffer);
> + kfree(mvnet);
> + ret = 0;
> + break;
> + }
> + }
> + mutex_unlock(&mdev_list_lock);
> +
> + return ret;
> +}
> +
> +static ssize_t mvnet_read(struct mdev_device *mdev, char __user *buf,
> + size_t count, loff_t *ppos)
> +{
> + ssize_t ret;
> +
> + if (*ppos < VIRTIO_MDEV_CONFIG) {
> + if (count == 4)
> + ret = mvnet_read_config(mdev, (u32 *)buf, *ppos);
> + else
> + ret = -EINVAL;
> + *ppos += 4;
> + } else if (*ppos < VIRTIO_MDEV_CONFIG + sizeof(struct virtio_net_config)) {
> + ret = mvnet_read_net_config(mdev, buf, count,
> + *ppos - VIRTIO_MDEV_CONFIG);
> + *ppos += count;
> + } else {
> + ret = -EINVAL;
> + }
> +
> + return ret;
> +}
> +
> +static ssize_t mvnet_write(struct mdev_device *mdev, const char __user *buf,
> + size_t count, loff_t *ppos)
> +{
> + int ret;
> +
> + if (*ppos < VIRTIO_MDEV_CONFIG) {
> + if (count == 4)
> + ret = mvnet_write_config(mdev, (u32 *)buf, *ppos);
> + else
> + ret = -EINVAL;
> + *ppos += 4;
> + } else {
> + /* No writable net config */
> + ret = -EINVAL;
> + }
> +
> + return ret;
> +}
> +
> +static long mvnet_ioctl(struct mdev_device *mdev, unsigned int cmd,
> + unsigned long arg)
> +{
> + int ret = 0;
> + struct mvnet_state *mvnet;
> + struct virtio_mdev_callback *cb;
> +
> + if (!mdev)
> + return -EINVAL;
> +
> + mvnet = mdev_get_drvdata(mdev);
> + if (!mvnet)
> + return -ENODEV;
> +
> + spin_lock(&mvnet->lock);
> +
> + switch (cmd) {
> + case VIRTIO_MDEV_SET_VQ_CALLBACK:
> + cb = (struct virtio_mdev_callback *)arg;
> + mvnet->vqs[mvnet->queue_sel].cb = cb->callback;
> + mvnet->vqs[mvnet->queue_sel].private = cb->private;
> + break;
> + case VIRTIO_MDEV_SET_CONFIG_CALLBACK:
> + break;
success, but nothing happens.
> + default:
> + pr_err("Not supportted ioctl cmd 0x%x\n", cmd);
> + ret = -ENOTTY;
> + break;
> + }
> +
> + spin_unlock(&mvnet->lock);
> +
> + return ret;
> +}
> +
> +static int mvnet_open(struct mdev_device *mdev)
> +{
> + pr_info("%s\n", __func__);
> + return 0;
> +}
> +
> +static void mvnet_close(struct mdev_device *mdev)
> +{
> + pr_info("%s\n", __func__);
> +}
> +
> +static ssize_t
> +sample_mvnet_dev_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + return sprintf(buf, "This is phy device\n");
what's this?
> +}
> +
> +static DEVICE_ATTR_RO(sample_mvnet_dev);
> +
> +static struct attribute *mvnet_dev_attrs[] = {
> + &dev_attr_sample_mvnet_dev.attr,
> + NULL,
> +};
> +
> +static const struct attribute_group mvnet_dev_group = {
> + .name = "mvnet_dev",
> + .attrs = mvnet_dev_attrs,
> +};
> +
> +static const struct attribute_group *mvnet_dev_groups[] = {
> + &mvnet_dev_group,
> + NULL,
> +};
> +
> +static ssize_t
> +sample_mdev_dev_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + if (mdev_from_dev(dev))
> + return sprintf(buf, "This is MDEV %s\n", dev_name(dev));
> +
> + return sprintf(buf, "\n");
> +}
> +
> +static DEVICE_ATTR_RO(sample_mdev_dev);
> +
> +static struct attribute *mdev_dev_attrs[] = {
> + &dev_attr_sample_mdev_dev.attr,
> + NULL,
> +};
> +
> +static const struct attribute_group mdev_dev_group = {
> + .name = "vendor",
> + .attrs = mdev_dev_attrs,
> +};
> +
> +static const struct attribute_group *mdev_dev_groups[] = {
> + &mdev_dev_group,
> + NULL,
> +};
> +
> +#define MVNET_STRING_LEN 16
> +
> +static ssize_t
> +name_show(struct kobject *kobj, struct device *dev, char *buf)
> +{
> + char name[MVNET_STRING_LEN];
> + const char *name_str = "virtio-net";
> +
> + snprintf(name, MVNET_STRING_LEN, "%s", dev_driver_string(dev));
> + if (!strcmp(kobj->name, name))
> + return sprintf(buf, "%s\n", name_str);
> +
> + return -EINVAL;
> +}
> +
> +static MDEV_TYPE_ATTR_RO(name);
> +
> +static ssize_t
> +available_instances_show(struct kobject *kobj, struct device *dev, char *buf)
> +{
> + return sprintf(buf, "%d\n", INT_MAX);
> +}
> +
> +static MDEV_TYPE_ATTR_RO(available_instances);
?
> +
> +static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
> + char *buf)
> +{
> + return sprintf(buf, "%s\n", VIRTIO_MDEV_DEVICE_API_STRING);
> +}
> +
> +static MDEV_TYPE_ATTR_RO(device_api);
> +
> +static struct attribute *mdev_types_attrs[] = {
> + &mdev_type_attr_name.attr,
> + &mdev_type_attr_device_api.attr,
> + &mdev_type_attr_available_instances.attr,
> + NULL,
> +};
> +
> +static struct attribute_group mdev_type_group = {
> + .name = "",
> + .attrs = mdev_types_attrs,
> +};
> +
> +static struct attribute_group *mdev_type_groups[] = {
> + &mdev_type_group,
> + NULL,
> +};
> +
> +static const struct mdev_parent_ops mdev_fops = {
> + .owner = THIS_MODULE,
> + .dev_attr_groups = mvnet_dev_groups,
> + .mdev_attr_groups = mdev_dev_groups,
> + .supported_type_groups = mdev_type_groups,
> + .create = mvnet_create,
> + .remove = mvnet_remove,
> + .open = mvnet_open,
> + .release = mvnet_close,
> + .read = mvnet_read,
> + .write = mvnet_write,
> + .ioctl = mvnet_ioctl,
> +};
> +
> +static void mvnet_device_release(struct device *dev)
> +{
> + dev_dbg(dev, "mvnet: released\n");
> +}
> +
> +static int __init mvnet_dev_init(void)
> +{
> + int ret = 0;
> +
> + pr_info("mvnet_dev: %s\n", __func__);
> +
> + memset(&mvnet_dev, 0, sizeof(mvnet_dev));
> +
> + idr_init(&mvnet_dev.vd_idr);
> +
> + mvnet_dev.vd_class = class_create(THIS_MODULE, MVNET_CLASS_NAME);
> +
> + if (IS_ERR(mvnet_dev.vd_class)) {
> + pr_err("Error: failed to register mvnet_dev class\n");
> + ret = PTR_ERR(mvnet_dev.vd_class);
> + goto failed1;
> + }
> +
> + mvnet_dev.dev.class = mvnet_dev.vd_class;
> + mvnet_dev.dev.release = mvnet_device_release;
> + dev_set_name(&mvnet_dev.dev, "%s", MVNET_NAME);
> +
> + ret = device_register(&mvnet_dev.dev);
> + if (ret)
> + goto failed2;
> +
> + ret = mdev_register_device(&mvnet_dev.dev, &mdev_fops);
> + if (ret)
> + goto failed3;
> +
> + mutex_init(&mdev_list_lock);
> + INIT_LIST_HEAD(&mdev_devices_list);
> +
> + goto all_done;
> +
> +failed3:
> +
> + device_unregister(&mvnet_dev.dev);
> +failed2:
> + class_destroy(mvnet_dev.vd_class);
> +
> +failed1:
> +all_done:
> + return ret;
> +}
> +
> +static void __exit mvnet_dev_exit(void)
> +{
> + mvnet_dev.dev.bus = NULL;
> + mdev_unregister_device(&mvnet_dev.dev);
> +
> + device_unregister(&mvnet_dev.dev);
> + idr_destroy(&mvnet_dev.vd_idr);
> + class_destroy(mvnet_dev.vd_class);
> + mvnet_dev.vd_class = NULL;
> + pr_info("mvnet_dev: Unloaded!\n");
> +}
> +
> +module_init(mvnet_dev_init)
> +module_exit(mvnet_dev_exit)
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_INFO(supported, "Test driver that simulate serial port over PCI");
> +MODULE_VERSION(VERSION_STRING);
> +MODULE_AUTHOR(DRIVER_AUTHOR);
> --
> 2.19.1
