diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/hv/Makefile | 2 | ||||
| -rw-r--r-- | drivers/hv/hv_utils_transport.c | 276 | ||||
| -rw-r--r-- | drivers/hv/hv_utils_transport.h | 51 |
3 files changed, 328 insertions, 1 deletions
diff --git a/drivers/hv/Makefile b/drivers/hv/Makefile index 5e4dfa4..39c9b2c 100644 --- a/drivers/hv/Makefile +++ b/drivers/hv/Makefile @@ -5,4 +5,4 @@ obj-$(CONFIG_HYPERV_BALLOON) += hv_balloon.o hv_vmbus-y := vmbus_drv.o \ hv.o connection.o channel.o \ channel_mgmt.o ring_buffer.o -hv_utils-y := hv_util.o hv_kvp.o hv_snapshot.o hv_fcopy.o +hv_utils-y := hv_util.o hv_kvp.o hv_snapshot.o hv_fcopy.o hv_utils_transport.o diff --git a/drivers/hv/hv_utils_transport.c b/drivers/hv/hv_utils_transport.c new file mode 100644 index 0000000..ea7ba5e --- /dev/null +++ b/drivers/hv/hv_utils_transport.c @@ -0,0 +1,276 @@ +/* + * Kernel/userspace transport abstraction for Hyper-V util driver. + * + * Copyright (C) 2015, Vitaly Kuznetsov <vkuznets@redhat.com> + * + * 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, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for more + * details. + * + */ + +#include <linux/slab.h> +#include <linux/fs.h> +#include <linux/poll.h> + +#include "hyperv_vmbus.h" +#include "hv_utils_transport.h" + +static DEFINE_SPINLOCK(hvt_list_lock); +static struct list_head hvt_list = LIST_HEAD_INIT(hvt_list); + +static void hvt_reset(struct hvutil_transport *hvt) +{ + mutex_lock(&hvt->outmsg_lock); + kfree(hvt->outmsg); + hvt->outmsg = NULL; + hvt->outmsg_len = 0; + mutex_unlock(&hvt->outmsg_lock); + if (hvt->on_reset) + hvt->on_reset(); +} + +static ssize_t hvt_op_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + struct hvutil_transport *hvt; + int ret; + + hvt = container_of(file->f_op, struct hvutil_transport, fops); + + if (wait_event_interruptible(hvt->outmsg_q, hvt->outmsg_len > 0)) + return -EINTR; + + mutex_lock(&hvt->outmsg_lock); + if (!hvt->outmsg) { + ret = -EAGAIN; + goto out_unlock; + } + + if (count < hvt->outmsg_len) { + ret = -EINVAL; + goto out_unlock; + } + + if (!copy_to_user(buf, hvt->outmsg, hvt->outmsg_len)) + ret = hvt->outmsg_len; + else + ret = -EFAULT; + + kfree(hvt->outmsg); + hvt->outmsg = NULL; + hvt->outmsg_len = 0; + +out_unlock: + mutex_unlock(&hvt->outmsg_lock); + return ret; +} + +static ssize_t hvt_op_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct hvutil_transport *hvt; + u8 *inmsg; + + hvt = container_of(file->f_op, struct hvutil_transport, fops); + + inmsg = kzalloc(count, GFP_KERNEL); + if (copy_from_user(inmsg, buf, count)) { + kfree(inmsg); + return -EFAULT; + } + if (hvt->on_msg(inmsg, count)) + return -EFAULT; + kfree(inmsg); + + return count; +} + +static unsigned int hvt_op_poll(struct file *file, poll_table *wait) +{ + struct hvutil_transport *hvt; + + hvt = container_of(file->f_op, struct hvutil_transport, fops); + + poll_wait(file, &hvt->outmsg_q, wait); + if (hvt->outmsg_len > 0) + return POLLIN | POLLRDNORM; + + return 0; +} + +static int hvt_op_open(struct inode *inode, struct file *file) +{ + struct hvutil_transport *hvt; + + hvt = container_of(file->f_op, struct hvutil_transport, fops); + + /* + * Switching to CHARDEV mode. We switch bach to INIT when device + * gets released. + */ + if (hvt->mode == HVUTIL_TRANSPORT_INIT) + hvt->mode = HVUTIL_TRANSPORT_CHARDEV; + else if (hvt->mode == HVUTIL_TRANSPORT_NETLINK) { + /* + * We're switching from netlink communication to using char + * device. Issue the reset first. + */ + hvt_reset(hvt); + hvt->mode = HVUTIL_TRANSPORT_CHARDEV; + } else + return -EBUSY; + + return 0; +} + +static int hvt_op_release(struct inode *inode, struct file *file) +{ + struct hvutil_transport *hvt; + + hvt = container_of(file->f_op, struct hvutil_transport, fops); + + hvt->mode = HVUTIL_TRANSPORT_INIT; + /* + * Cleanup message buffers to avoid spurious messages when the daemon + * connects back. + */ + hvt_reset(hvt); + + return 0; +} + +static void hvt_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp) +{ + struct hvutil_transport *hvt, *hvt_found = NULL; + + spin_lock(&hvt_list_lock); + list_for_each_entry(hvt, &hvt_list, list) { + if (hvt->cn_id.idx == msg->id.idx && + hvt->cn_id.val == msg->id.val) { + hvt_found = hvt; + break; + } + } + spin_unlock(&hvt_list_lock); + if (!hvt_found) { + pr_warn("hvt_cn_callback: spurious message received!\n"); + return; + } + + /* + * Switching to NETLINK mode. Switching to CHARDEV happens when someone + * opens the device. + */ + if (hvt->mode == HVUTIL_TRANSPORT_INIT) + hvt->mode = HVUTIL_TRANSPORT_NETLINK; + + if (hvt->mode == HVUTIL_TRANSPORT_NETLINK) + hvt_found->on_msg(msg->data, msg->len); + else + pr_warn("hvt_cn_callback: unexpected netlink message!\n"); +} + +int hvutil_transport_send(struct hvutil_transport *hvt, void *msg, int len) +{ + struct cn_msg *cn_msg; + int ret = 0; + + if (hvt->mode == HVUTIL_TRANSPORT_INIT) { + return -EINVAL; + } else if (hvt->mode == HVUTIL_TRANSPORT_NETLINK) { + cn_msg = kzalloc(sizeof(*cn_msg) + len, GFP_ATOMIC); + if (!msg) + return -ENOMEM; + cn_msg->id.idx = hvt->cn_id.idx; + cn_msg->id.val = hvt->cn_id.val; + cn_msg->len = len; + memcpy(cn_msg->data, msg, len); + ret = cn_netlink_send(cn_msg, 0, 0, GFP_ATOMIC); + kfree(cn_msg); + return ret; + } + /* HVUTIL_TRANSPORT_CHARDEV */ + mutex_lock(&hvt->outmsg_lock); + if (hvt->outmsg) { + /* Previous message wasn't received */ + ret = -EFAULT; + goto out_unlock; + } + hvt->outmsg = kzalloc(len, GFP_KERNEL); + memcpy(hvt->outmsg, msg, len); + hvt->outmsg_len = len; + wake_up_interruptible(&hvt->outmsg_q); +out_unlock: + mutex_unlock(&hvt->outmsg_lock); + return ret; +} + +struct hvutil_transport *hvutil_transport_init(const char *name, + u32 cn_idx, u32 cn_val, + int (*on_msg)(void *, int), + void (*on_reset)(void)) +{ + struct hvutil_transport *hvt; + + hvt = kzalloc(sizeof(*hvt), GFP_KERNEL); + if (!hvt) + return NULL; + + hvt->cn_id.idx = cn_idx; + hvt->cn_id.val = cn_val; + + hvt->mdev.minor = MISC_DYNAMIC_MINOR; + hvt->mdev.name = name; + + hvt->fops.owner = THIS_MODULE; + hvt->fops.read = hvt_op_read; + hvt->fops.write = hvt_op_write; + hvt->fops.poll = hvt_op_poll; + hvt->fops.open = hvt_op_open; + hvt->fops.release = hvt_op_release; + + hvt->mdev.fops = &hvt->fops; + + init_waitqueue_head(&hvt->outmsg_q); + mutex_init(&hvt->outmsg_lock); + + spin_lock(&hvt_list_lock); + list_add(&hvt->list, &hvt_list); + spin_unlock(&hvt_list_lock); + + hvt->on_msg = on_msg; + hvt->on_reset = on_reset; + + if (misc_register(&hvt->mdev)) + goto err_free_hvt; + + /* Use cn_id.idx/cn_id.val to determine if we need to setup netlink */ + if (hvt->cn_id.idx > 0 && hvt->cn_id.val > 0 && + cn_add_callback(&hvt->cn_id, name, hvt_cn_callback)) + goto err_free_hvt; + + return hvt; + +err_free_hvt: + kfree(hvt); + return NULL; +} + +void hvutil_transport_destroy(struct hvutil_transport *hvt) +{ + spin_lock(&hvt_list_lock); + list_del(&hvt->list); + spin_unlock(&hvt_list_lock); + if (hvt->cn_id.idx > 0 && hvt->cn_id.val > 0) + cn_del_callback(&hvt->cn_id); + misc_deregister(&hvt->mdev); + kfree(hvt->outmsg); + kfree(hvt); +} diff --git a/drivers/hv/hv_utils_transport.h b/drivers/hv/hv_utils_transport.h new file mode 100644 index 0000000..314c76c --- /dev/null +++ b/drivers/hv/hv_utils_transport.h @@ -0,0 +1,51 @@ +/* + * Kernel/userspace transport abstraction for Hyper-V util driver. + * + * Copyright (C) 2015, Vitaly Kuznetsov <vkuznets@redhat.com> + * + * 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, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for more + * details. + * + */ + +#ifndef _HV_UTILS_TRANSPORT_H +#define _HV_UTILS_TRANSPORT_H + +#include <linux/connector.h> +#include <linux/miscdevice.h> + +enum hvutil_transport_mode { + HVUTIL_TRANSPORT_INIT = 0, + HVUTIL_TRANSPORT_NETLINK, + HVUTIL_TRANSPORT_CHARDEV, +}; + +struct hvutil_transport { + int mode; /* hvutil_transport_mode */ + struct file_operations fops; /* file operations */ + struct miscdevice mdev; /* misc device */ + struct cb_id cn_id; /* CN_*_IDX/CN_*_VAL */ + struct list_head list; /* hvt_list */ + int (*on_msg)(void *, int); /* callback on new user message */ + void (*on_reset)(void); /* callback when userspace drops */ + u8 *outmsg; /* message to the userspace */ + int outmsg_len; /* its length */ + wait_queue_head_t outmsg_q; /* poll/read wait queue */ + struct mutex outmsg_lock; /* protects outmsg */ +}; + +struct hvutil_transport *hvutil_transport_init(const char *name, + u32 cn_idx, u32 cn_val, + int (*on_msg)(void *, int), + void (*on_reset)(void)); +int hvutil_transport_send(struct hvutil_transport *hvt, void *msg, int len); +void hvutil_transport_destroy(struct hvutil_transport *hvt); + +#endif /* _HV_UTILS_TRANSPORT_H */ |