diff options
author | root <root@artemis.panaceas.org> | 2015-12-25 04:40:36 +0000 |
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committer | root <root@artemis.panaceas.org> | 2015-12-25 04:40:36 +0000 |
commit | 849369d6c66d3054688672f97d31fceb8e8230fb (patch) | |
tree | 6135abc790ca67dedbe07c39806591e70eda81ce /drivers/xen/xenfs | |
download | linux-3.0.35-kobo-849369d6c66d3054688672f97d31fceb8e8230fb.tar.gz linux-3.0.35-kobo-849369d6c66d3054688672f97d31fceb8e8230fb.tar.bz2 linux-3.0.35-kobo-849369d6c66d3054688672f97d31fceb8e8230fb.zip |
initial_commit
Diffstat (limited to 'drivers/xen/xenfs')
-rw-r--r-- | drivers/xen/xenfs/Makefile | 4 | ||||
-rw-r--r-- | drivers/xen/xenfs/privcmd.c | 400 | ||||
-rw-r--r-- | drivers/xen/xenfs/super.c | 137 | ||||
-rw-r--r-- | drivers/xen/xenfs/xenbus.c | 593 | ||||
-rw-r--r-- | drivers/xen/xenfs/xenfs.h | 9 | ||||
-rw-r--r-- | drivers/xen/xenfs/xenstored.c | 68 |
6 files changed, 1211 insertions, 0 deletions
diff --git a/drivers/xen/xenfs/Makefile b/drivers/xen/xenfs/Makefile new file mode 100644 index 00000000..4fde9440 --- /dev/null +++ b/drivers/xen/xenfs/Makefile @@ -0,0 +1,4 @@ +obj-$(CONFIG_XENFS) += xenfs.o + +xenfs-y = super.o xenbus.o privcmd.o +xenfs-$(CONFIG_XEN_DOM0) += xenstored.o diff --git a/drivers/xen/xenfs/privcmd.c b/drivers/xen/xenfs/privcmd.c new file mode 100644 index 00000000..dbd3b16f --- /dev/null +++ b/drivers/xen/xenfs/privcmd.c @@ -0,0 +1,400 @@ +/****************************************************************************** + * privcmd.c + * + * Interface to privileged domain-0 commands. + * + * Copyright (c) 2002-2004, K A Fraser, B Dragovic + */ + +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/errno.h> +#include <linux/mm.h> +#include <linux/mman.h> +#include <linux/uaccess.h> +#include <linux/swap.h> +#include <linux/highmem.h> +#include <linux/pagemap.h> +#include <linux/seq_file.h> + +#include <asm/pgalloc.h> +#include <asm/pgtable.h> +#include <asm/tlb.h> +#include <asm/xen/hypervisor.h> +#include <asm/xen/hypercall.h> + +#include <xen/xen.h> +#include <xen/privcmd.h> +#include <xen/interface/xen.h> +#include <xen/features.h> +#include <xen/page.h> +#include <xen/xen-ops.h> + +#ifndef HAVE_ARCH_PRIVCMD_MMAP +static int privcmd_enforce_singleshot_mapping(struct vm_area_struct *vma); +#endif + +static long privcmd_ioctl_hypercall(void __user *udata) +{ + struct privcmd_hypercall hypercall; + long ret; + + if (copy_from_user(&hypercall, udata, sizeof(hypercall))) + return -EFAULT; + + ret = privcmd_call(hypercall.op, + hypercall.arg[0], hypercall.arg[1], + hypercall.arg[2], hypercall.arg[3], + hypercall.arg[4]); + + return ret; +} + +static void free_page_list(struct list_head *pages) +{ + struct page *p, *n; + + list_for_each_entry_safe(p, n, pages, lru) + __free_page(p); + + INIT_LIST_HEAD(pages); +} + +/* + * Given an array of items in userspace, return a list of pages + * containing the data. If copying fails, either because of memory + * allocation failure or a problem reading user memory, return an + * error code; its up to the caller to dispose of any partial list. + */ +static int gather_array(struct list_head *pagelist, + unsigned nelem, size_t size, + void __user *data) +{ + unsigned pageidx; + void *pagedata; + int ret; + + if (size > PAGE_SIZE) + return 0; + + pageidx = PAGE_SIZE; + pagedata = NULL; /* quiet, gcc */ + while (nelem--) { + if (pageidx > PAGE_SIZE-size) { + struct page *page = alloc_page(GFP_KERNEL); + + ret = -ENOMEM; + if (page == NULL) + goto fail; + + pagedata = page_address(page); + + list_add_tail(&page->lru, pagelist); + pageidx = 0; + } + + ret = -EFAULT; + if (copy_from_user(pagedata + pageidx, data, size)) + goto fail; + + data += size; + pageidx += size; + } + + ret = 0; + +fail: + return ret; +} + +/* + * Call function "fn" on each element of the array fragmented + * over a list of pages. + */ +static int traverse_pages(unsigned nelem, size_t size, + struct list_head *pos, + int (*fn)(void *data, void *state), + void *state) +{ + void *pagedata; + unsigned pageidx; + int ret = 0; + + BUG_ON(size > PAGE_SIZE); + + pageidx = PAGE_SIZE; + pagedata = NULL; /* hush, gcc */ + + while (nelem--) { + if (pageidx > PAGE_SIZE-size) { + struct page *page; + pos = pos->next; + page = list_entry(pos, struct page, lru); + pagedata = page_address(page); + pageidx = 0; + } + + ret = (*fn)(pagedata + pageidx, state); + if (ret) + break; + pageidx += size; + } + + return ret; +} + +struct mmap_mfn_state { + unsigned long va; + struct vm_area_struct *vma; + domid_t domain; +}; + +static int mmap_mfn_range(void *data, void *state) +{ + struct privcmd_mmap_entry *msg = data; + struct mmap_mfn_state *st = state; + struct vm_area_struct *vma = st->vma; + int rc; + + /* Do not allow range to wrap the address space. */ + if ((msg->npages > (LONG_MAX >> PAGE_SHIFT)) || + ((unsigned long)(msg->npages << PAGE_SHIFT) >= -st->va)) + return -EINVAL; + + /* Range chunks must be contiguous in va space. */ + if ((msg->va != st->va) || + ((msg->va+(msg->npages<<PAGE_SHIFT)) > vma->vm_end)) + return -EINVAL; + + rc = xen_remap_domain_mfn_range(vma, + msg->va & PAGE_MASK, + msg->mfn, msg->npages, + vma->vm_page_prot, + st->domain); + if (rc < 0) + return rc; + + st->va += msg->npages << PAGE_SHIFT; + + return 0; +} + +static long privcmd_ioctl_mmap(void __user *udata) +{ + struct privcmd_mmap mmapcmd; + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + int rc; + LIST_HEAD(pagelist); + struct mmap_mfn_state state; + + if (!xen_initial_domain()) + return -EPERM; + + if (copy_from_user(&mmapcmd, udata, sizeof(mmapcmd))) + return -EFAULT; + + rc = gather_array(&pagelist, + mmapcmd.num, sizeof(struct privcmd_mmap_entry), + mmapcmd.entry); + + if (rc || list_empty(&pagelist)) + goto out; + + down_write(&mm->mmap_sem); + + { + struct page *page = list_first_entry(&pagelist, + struct page, lru); + struct privcmd_mmap_entry *msg = page_address(page); + + vma = find_vma(mm, msg->va); + rc = -EINVAL; + + if (!vma || (msg->va != vma->vm_start) || + !privcmd_enforce_singleshot_mapping(vma)) + goto out_up; + } + + state.va = vma->vm_start; + state.vma = vma; + state.domain = mmapcmd.dom; + + rc = traverse_pages(mmapcmd.num, sizeof(struct privcmd_mmap_entry), + &pagelist, + mmap_mfn_range, &state); + + +out_up: + up_write(&mm->mmap_sem); + +out: + free_page_list(&pagelist); + + return rc; +} + +struct mmap_batch_state { + domid_t domain; + unsigned long va; + struct vm_area_struct *vma; + int err; + + xen_pfn_t __user *user; +}; + +static int mmap_batch_fn(void *data, void *state) +{ + xen_pfn_t *mfnp = data; + struct mmap_batch_state *st = state; + + if (xen_remap_domain_mfn_range(st->vma, st->va & PAGE_MASK, *mfnp, 1, + st->vma->vm_page_prot, st->domain) < 0) { + *mfnp |= 0xf0000000U; + st->err++; + } + st->va += PAGE_SIZE; + + return 0; +} + +static int mmap_return_errors(void *data, void *state) +{ + xen_pfn_t *mfnp = data; + struct mmap_batch_state *st = state; + + return put_user(*mfnp, st->user++); +} + +static struct vm_operations_struct privcmd_vm_ops; + +static long privcmd_ioctl_mmap_batch(void __user *udata) +{ + int ret; + struct privcmd_mmapbatch m; + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + unsigned long nr_pages; + LIST_HEAD(pagelist); + struct mmap_batch_state state; + + if (!xen_initial_domain()) + return -EPERM; + + if (copy_from_user(&m, udata, sizeof(m))) + return -EFAULT; + + nr_pages = m.num; + if ((m.num <= 0) || (nr_pages > (LONG_MAX >> PAGE_SHIFT))) + return -EINVAL; + + ret = gather_array(&pagelist, m.num, sizeof(xen_pfn_t), + m.arr); + + if (ret || list_empty(&pagelist)) + goto out; + + down_write(&mm->mmap_sem); + + vma = find_vma(mm, m.addr); + ret = -EINVAL; + if (!vma || + vma->vm_ops != &privcmd_vm_ops || + (m.addr != vma->vm_start) || + ((m.addr + (nr_pages << PAGE_SHIFT)) != vma->vm_end) || + !privcmd_enforce_singleshot_mapping(vma)) { + up_write(&mm->mmap_sem); + goto out; + } + + state.domain = m.dom; + state.vma = vma; + state.va = m.addr; + state.err = 0; + + ret = traverse_pages(m.num, sizeof(xen_pfn_t), + &pagelist, mmap_batch_fn, &state); + + up_write(&mm->mmap_sem); + + if (state.err > 0) { + state.user = m.arr; + ret = traverse_pages(m.num, sizeof(xen_pfn_t), + &pagelist, + mmap_return_errors, &state); + } + +out: + free_page_list(&pagelist); + + return ret; +} + +static long privcmd_ioctl(struct file *file, + unsigned int cmd, unsigned long data) +{ + int ret = -ENOSYS; + void __user *udata = (void __user *) data; + + switch (cmd) { + case IOCTL_PRIVCMD_HYPERCALL: + ret = privcmd_ioctl_hypercall(udata); + break; + + case IOCTL_PRIVCMD_MMAP: + ret = privcmd_ioctl_mmap(udata); + break; + + case IOCTL_PRIVCMD_MMAPBATCH: + ret = privcmd_ioctl_mmap_batch(udata); + break; + + default: + ret = -EINVAL; + break; + } + + return ret; +} + +#ifndef HAVE_ARCH_PRIVCMD_MMAP +static int privcmd_fault(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + printk(KERN_DEBUG "privcmd_fault: vma=%p %lx-%lx, pgoff=%lx, uv=%p\n", + vma, vma->vm_start, vma->vm_end, + vmf->pgoff, vmf->virtual_address); + + return VM_FAULT_SIGBUS; +} + +static struct vm_operations_struct privcmd_vm_ops = { + .fault = privcmd_fault +}; + +static int privcmd_mmap(struct file *file, struct vm_area_struct *vma) +{ + /* Unsupported for auto-translate guests. */ + if (xen_feature(XENFEAT_auto_translated_physmap)) + return -ENOSYS; + + /* DONTCOPY is essential for Xen because copy_page_range doesn't know + * how to recreate these mappings */ + vma->vm_flags |= VM_RESERVED | VM_IO | VM_DONTCOPY | VM_PFNMAP; + vma->vm_ops = &privcmd_vm_ops; + vma->vm_private_data = NULL; + + return 0; +} + +static int privcmd_enforce_singleshot_mapping(struct vm_area_struct *vma) +{ + return (xchg(&vma->vm_private_data, (void *)1) == NULL); +} +#endif + +const struct file_operations privcmd_file_ops = { + .unlocked_ioctl = privcmd_ioctl, + .mmap = privcmd_mmap, +}; diff --git a/drivers/xen/xenfs/super.c b/drivers/xen/xenfs/super.c new file mode 100644 index 00000000..1aa38971 --- /dev/null +++ b/drivers/xen/xenfs/super.c @@ -0,0 +1,137 @@ +/* + * xenfs.c - a filesystem for passing info between the a domain and + * the hypervisor. + * + * 2008-10-07 Alex Zeffertt Replaced /proc/xen/xenbus with xenfs filesystem + * and /proc/xen compatibility mount point. + * Turned xenfs into a loadable module. + */ + +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/module.h> +#include <linux/fs.h> +#include <linux/magic.h> + +#include <xen/xen.h> + +#include "xenfs.h" + +#include <asm/xen/hypervisor.h> + +MODULE_DESCRIPTION("Xen filesystem"); +MODULE_LICENSE("GPL"); + +static struct inode *xenfs_make_inode(struct super_block *sb, int mode) +{ + struct inode *ret = new_inode(sb); + + if (ret) { + ret->i_mode = mode; + ret->i_uid = ret->i_gid = 0; + ret->i_blocks = 0; + ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME; + } + return ret; +} + +static struct dentry *xenfs_create_file(struct super_block *sb, + struct dentry *parent, + const char *name, + const struct file_operations *fops, + void *data, + int mode) +{ + struct dentry *dentry; + struct inode *inode; + + dentry = d_alloc_name(parent, name); + if (!dentry) + return NULL; + + inode = xenfs_make_inode(sb, S_IFREG | mode); + if (!inode) { + dput(dentry); + return NULL; + } + + inode->i_fop = fops; + inode->i_private = data; + + d_add(dentry, inode); + return dentry; +} + +static ssize_t capabilities_read(struct file *file, char __user *buf, + size_t size, loff_t *off) +{ + char *tmp = ""; + + if (xen_initial_domain()) + tmp = "control_d\n"; + + return simple_read_from_buffer(buf, size, off, tmp, strlen(tmp)); +} + +static const struct file_operations capabilities_file_ops = { + .read = capabilities_read, + .llseek = default_llseek, +}; + +static int xenfs_fill_super(struct super_block *sb, void *data, int silent) +{ + static struct tree_descr xenfs_files[] = { + [1] = {}, + { "xenbus", &xenbus_file_ops, S_IRUSR|S_IWUSR }, + { "capabilities", &capabilities_file_ops, S_IRUGO }, + { "privcmd", &privcmd_file_ops, S_IRUSR|S_IWUSR }, + {""}, + }; + int rc; + + rc = simple_fill_super(sb, XENFS_SUPER_MAGIC, xenfs_files); + if (rc < 0) + return rc; + + if (xen_initial_domain()) { + xenfs_create_file(sb, sb->s_root, "xsd_kva", + &xsd_kva_file_ops, NULL, S_IRUSR|S_IWUSR); + xenfs_create_file(sb, sb->s_root, "xsd_port", + &xsd_port_file_ops, NULL, S_IRUSR|S_IWUSR); + } + + return rc; +} + +static struct dentry *xenfs_mount(struct file_system_type *fs_type, + int flags, const char *dev_name, + void *data) +{ + return mount_single(fs_type, flags, data, xenfs_fill_super); +} + +static struct file_system_type xenfs_type = { + .owner = THIS_MODULE, + .name = "xenfs", + .mount = xenfs_mount, + .kill_sb = kill_litter_super, +}; + +static int __init xenfs_init(void) +{ + if (xen_domain()) + return register_filesystem(&xenfs_type); + + printk(KERN_INFO "XENFS: not registering filesystem on non-xen platform\n"); + return 0; +} + +static void __exit xenfs_exit(void) +{ + if (xen_domain()) + unregister_filesystem(&xenfs_type); +} + +module_init(xenfs_init); +module_exit(xenfs_exit); + diff --git a/drivers/xen/xenfs/xenbus.c b/drivers/xen/xenfs/xenbus.c new file mode 100644 index 00000000..bbd000f8 --- /dev/null +++ b/drivers/xen/xenfs/xenbus.c @@ -0,0 +1,593 @@ +/* + * Driver giving user-space access to the kernel's xenbus connection + * to xenstore. + * + * Copyright (c) 2005, Christian Limpach + * Copyright (c) 2005, Rusty Russell, IBM 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; or, when distributed + * separately from the Linux kernel or incorporated into other + * software packages, subject to the following license: + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this source file (the "Software"), to deal in the Software without + * restriction, including without limitation the rights to use, copy, modify, + * merge, publish, distribute, sublicense, and/or sell copies of the Software, + * and to permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS + * IN THE SOFTWARE. + * + * Changes: + * 2008-10-07 Alex Zeffertt Replaced /proc/xen/xenbus with xenfs filesystem + * and /proc/xen compatibility mount point. + * Turned xenfs into a loadable module. + */ + +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/uio.h> +#include <linux/notifier.h> +#include <linux/wait.h> +#include <linux/fs.h> +#include <linux/poll.h> +#include <linux/mutex.h> +#include <linux/sched.h> +#include <linux/spinlock.h> +#include <linux/mount.h> +#include <linux/pagemap.h> +#include <linux/uaccess.h> +#include <linux/init.h> +#include <linux/namei.h> +#include <linux/string.h> +#include <linux/slab.h> + +#include "xenfs.h" +#include "../xenbus/xenbus_comms.h" + +#include <xen/xenbus.h> +#include <asm/xen/hypervisor.h> + +/* + * An element of a list of outstanding transactions, for which we're + * still waiting a reply. + */ +struct xenbus_transaction_holder { + struct list_head list; + struct xenbus_transaction handle; +}; + +/* + * A buffer of data on the queue. + */ +struct read_buffer { + struct list_head list; + unsigned int cons; + unsigned int len; + char msg[]; +}; + +struct xenbus_file_priv { + /* + * msgbuffer_mutex is held while partial requests are built up + * and complete requests are acted on. It therefore protects + * the "transactions" and "watches" lists, and the partial + * request length and buffer. + * + * reply_mutex protects the reply being built up to return to + * usermode. It nests inside msgbuffer_mutex but may be held + * alone during a watch callback. + */ + struct mutex msgbuffer_mutex; + + /* In-progress transactions */ + struct list_head transactions; + + /* Active watches. */ + struct list_head watches; + + /* Partial request. */ + unsigned int len; + union { + struct xsd_sockmsg msg; + char buffer[PAGE_SIZE]; + } u; + + /* Response queue. */ + struct mutex reply_mutex; + struct list_head read_buffers; + wait_queue_head_t read_waitq; + +}; + +/* Read out any raw xenbus messages queued up. */ +static ssize_t xenbus_file_read(struct file *filp, + char __user *ubuf, + size_t len, loff_t *ppos) +{ + struct xenbus_file_priv *u = filp->private_data; + struct read_buffer *rb; + unsigned i; + int ret; + + mutex_lock(&u->reply_mutex); +again: + while (list_empty(&u->read_buffers)) { + mutex_unlock(&u->reply_mutex); + if (filp->f_flags & O_NONBLOCK) + return -EAGAIN; + + ret = wait_event_interruptible(u->read_waitq, + !list_empty(&u->read_buffers)); + if (ret) + return ret; + mutex_lock(&u->reply_mutex); + } + + rb = list_entry(u->read_buffers.next, struct read_buffer, list); + i = 0; + while (i < len) { + unsigned sz = min((unsigned)len - i, rb->len - rb->cons); + + ret = copy_to_user(ubuf + i, &rb->msg[rb->cons], sz); + + i += sz - ret; + rb->cons += sz - ret; + + if (ret != 0) { + if (i == 0) + i = -EFAULT; + goto out; + } + + /* Clear out buffer if it has been consumed */ + if (rb->cons == rb->len) { + list_del(&rb->list); + kfree(rb); + if (list_empty(&u->read_buffers)) + break; + rb = list_entry(u->read_buffers.next, + struct read_buffer, list); + } + } + if (i == 0) + goto again; + +out: + mutex_unlock(&u->reply_mutex); + return i; +} + +/* + * Add a buffer to the queue. Caller must hold the appropriate lock + * if the queue is not local. (Commonly the caller will build up + * multiple queued buffers on a temporary local list, and then add it + * to the appropriate list under lock once all the buffers have een + * successfully allocated.) + */ +static int queue_reply(struct list_head *queue, const void *data, size_t len) +{ + struct read_buffer *rb; + + if (len == 0) + return 0; + + rb = kmalloc(sizeof(*rb) + len, GFP_KERNEL); + if (rb == NULL) + return -ENOMEM; + + rb->cons = 0; + rb->len = len; + + memcpy(rb->msg, data, len); + + list_add_tail(&rb->list, queue); + return 0; +} + +/* + * Free all the read_buffer s on a list. + * Caller must have sole reference to list. + */ +static void queue_cleanup(struct list_head *list) +{ + struct read_buffer *rb; + + while (!list_empty(list)) { + rb = list_entry(list->next, struct read_buffer, list); + list_del(list->next); + kfree(rb); + } +} + +struct watch_adapter { + struct list_head list; + struct xenbus_watch watch; + struct xenbus_file_priv *dev_data; + char *token; +}; + +static void free_watch_adapter(struct watch_adapter *watch) +{ + kfree(watch->watch.node); + kfree(watch->token); + kfree(watch); +} + +static struct watch_adapter *alloc_watch_adapter(const char *path, + const char *token) +{ + struct watch_adapter *watch; + + watch = kzalloc(sizeof(*watch), GFP_KERNEL); + if (watch == NULL) + goto out_fail; + + watch->watch.node = kstrdup(path, GFP_KERNEL); + if (watch->watch.node == NULL) + goto out_free; + + watch->token = kstrdup(token, GFP_KERNEL); + if (watch->token == NULL) + goto out_free; + + return watch; + +out_free: + free_watch_adapter(watch); + +out_fail: + return NULL; +} + +static void watch_fired(struct xenbus_watch *watch, + const char **vec, + unsigned int len) +{ + struct watch_adapter *adap; + struct xsd_sockmsg hdr; + const char *path, *token; + int path_len, tok_len, body_len, data_len = 0; + int ret; + LIST_HEAD(staging_q); + + adap = container_of(watch, struct watch_adapter, watch); + + path = vec[XS_WATCH_PATH]; + token = adap->token; + + path_len = strlen(path) + 1; + tok_len = strlen(token) + 1; + if (len > 2) + data_len = vec[len] - vec[2] + 1; + body_len = path_len + tok_len + data_len; + + hdr.type = XS_WATCH_EVENT; + hdr.len = body_len; + + mutex_lock(&adap->dev_data->reply_mutex); + + ret = queue_reply(&staging_q, &hdr, sizeof(hdr)); + if (!ret) + ret = queue_reply(&staging_q, path, path_len); + if (!ret) + ret = queue_reply(&staging_q, token, tok_len); + if (!ret && len > 2) + ret = queue_reply(&staging_q, vec[2], data_len); + + if (!ret) { + /* success: pass reply list onto watcher */ + list_splice_tail(&staging_q, &adap->dev_data->read_buffers); + wake_up(&adap->dev_data->read_waitq); + } else + queue_cleanup(&staging_q); + + mutex_unlock(&adap->dev_data->reply_mutex); +} + +static int xenbus_write_transaction(unsigned msg_type, + struct xenbus_file_priv *u) +{ + int rc; + void *reply; + struct xenbus_transaction_holder *trans = NULL; + LIST_HEAD(staging_q); + + if (msg_type == XS_TRANSACTION_START) { + trans = kmalloc(sizeof(*trans), GFP_KERNEL); + if (!trans) { + rc = -ENOMEM; + goto out; + } + } + + reply = xenbus_dev_request_and_reply(&u->u.msg); + if (IS_ERR(reply)) { + kfree(trans); + rc = PTR_ERR(reply); + goto out; + } + + if (msg_type == XS_TRANSACTION_START) { + trans->handle.id = simple_strtoul(reply, NULL, 0); + + list_add(&trans->list, &u->transactions); + } else if (msg_type == XS_TRANSACTION_END) { + list_for_each_entry(trans, &u->transactions, list) + if (trans->handle.id == u->u.msg.tx_id) + break; + BUG_ON(&trans->list == &u->transactions); + list_del(&trans->list); + + kfree(trans); + } + + mutex_lock(&u->reply_mutex); + rc = queue_reply(&staging_q, &u->u.msg, sizeof(u->u.msg)); + if (!rc) + rc = queue_reply(&staging_q, reply, u->u.msg.len); + if (!rc) { + list_splice_tail(&staging_q, &u->read_buffers); + wake_up(&u->read_waitq); + } else { + queue_cleanup(&staging_q); + } + mutex_unlock(&u->reply_mutex); + + kfree(reply); + +out: + return rc; +} + +static int xenbus_write_watch(unsigned msg_type, struct xenbus_file_priv *u) +{ + struct watch_adapter *watch, *tmp_watch; + char *path, *token; + int err, rc; + LIST_HEAD(staging_q); + + path = u->u.buffer + sizeof(u->u.msg); + token = memchr(path, 0, u->u.msg.len); + if (token == NULL) { + rc = -EILSEQ; + goto out; + } + token++; + + if (msg_type == XS_WATCH) { + watch = alloc_watch_adapter(path, token); + if (watch == NULL) { + rc = -ENOMEM; + goto out; + } + + watch->watch.callback = watch_fired; + watch->dev_data = u; + + err = register_xenbus_watch(&watch->watch); + if (err) { + free_watch_adapter(watch); + rc = err; + goto out; + } + list_add(&watch->list, &u->watches); + } else { + list_for_each_entry_safe(watch, tmp_watch, &u->watches, list) { + if (!strcmp(watch->token, token) && + !strcmp(watch->watch.node, path)) { + unregister_xenbus_watch(&watch->watch); + list_del(&watch->list); + free_watch_adapter(watch); + break; + } + } + } + + /* Success. Synthesize a reply to say all is OK. */ + { + struct { + struct xsd_sockmsg hdr; + char body[3]; + } __packed reply = { + { + .type = msg_type, + .len = sizeof(reply.body) + }, + "OK" + }; + + mutex_lock(&u->reply_mutex); + rc = queue_reply(&u->read_buffers, &reply, sizeof(reply)); + wake_up(&u->read_waitq); + mutex_unlock(&u->reply_mutex); + } + +out: + return rc; +} + +static ssize_t xenbus_file_write(struct file *filp, + const char __user *ubuf, + size_t len, loff_t *ppos) +{ + struct xenbus_file_priv *u = filp->private_data; + uint32_t msg_type; + int rc = len; + int ret; + LIST_HEAD(staging_q); + + /* + * We're expecting usermode to be writing properly formed + * xenbus messages. If they write an incomplete message we + * buffer it up. Once it is complete, we act on it. + */ + + /* + * Make sure concurrent writers can't stomp all over each + * other's messages and make a mess of our partial message + * buffer. We don't make any attemppt to stop multiple + * writers from making a mess of each other's incomplete + * messages; we're just trying to guarantee our own internal + * consistency and make sure that single writes are handled + * atomically. + */ + mutex_lock(&u->msgbuffer_mutex); + + /* Get this out of the way early to avoid confusion */ + if (len == 0) + goto out; + + /* Can't write a xenbus message larger we can buffer */ + if ((len + u->len) > sizeof(u->u.buffer)) { + /* On error, dump existing buffer */ + u->len = 0; + rc = -EINVAL; + goto out; + } + + ret = copy_from_user(u->u.buffer + u->len, ubuf, len); + + if (ret != 0) { + rc = -EFAULT; + goto out; + } + + /* Deal with a partial copy. */ + len -= ret; + rc = len; + + u->len += len; + + /* Return if we haven't got a full message yet */ + if (u->len < sizeof(u->u.msg)) + goto out; /* not even the header yet */ + + /* If we're expecting a message that's larger than we can + possibly send, dump what we have and return an error. */ + if ((sizeof(u->u.msg) + u->u.msg.len) > sizeof(u->u.buffer)) { + rc = -E2BIG; + u->len = 0; + goto out; + } + + if (u->len < (sizeof(u->u.msg) + u->u.msg.len)) + goto out; /* incomplete data portion */ + + /* + * OK, now we have a complete message. Do something with it. + */ + + msg_type = u->u.msg.type; + + switch (msg_type) { + case XS_WATCH: + case XS_UNWATCH: + /* (Un)Ask for some path to be watched for changes */ + ret = xenbus_write_watch(msg_type, u); + break; + + default: + /* Send out a transaction */ + ret = xenbus_write_transaction(msg_type, u); + break; + } + if (ret != 0) + rc = ret; + + /* Buffered message consumed */ + u->len = 0; + + out: + mutex_unlock(&u->msgbuffer_mutex); + return rc; +} + +static int xenbus_file_open(struct inode *inode, struct file *filp) +{ + struct xenbus_file_priv *u; + + if (xen_store_evtchn == 0) + return -ENOENT; + + nonseekable_open(inode, filp); + + u = kzalloc(sizeof(*u), GFP_KERNEL); + if (u == NULL) + return -ENOMEM; + + INIT_LIST_HEAD(&u->transactions); + INIT_LIST_HEAD(&u->watches); + INIT_LIST_HEAD(&u->read_buffers); + init_waitqueue_head(&u->read_waitq); + + mutex_init(&u->reply_mutex); + mutex_init(&u->msgbuffer_mutex); + + filp->private_data = u; + + return 0; +} + +static int xenbus_file_release(struct inode *inode, struct file *filp) +{ + struct xenbus_file_priv *u = filp->private_data; + struct xenbus_transaction_holder *trans, *tmp; + struct watch_adapter *watch, *tmp_watch; + struct read_buffer *rb, *tmp_rb; + + /* + * No need for locking here because there are no other users, + * by definition. + */ + + list_for_each_entry_safe(trans, tmp, &u->transactions, list) { + xenbus_transaction_end(trans->handle, 1); + list_del(&trans->list); + kfree(trans); + } + + list_for_each_entry_safe(watch, tmp_watch, &u->watches, list) { + unregister_xenbus_watch(&watch->watch); + list_del(&watch->list); + free_watch_adapter(watch); + } + + list_for_each_entry_safe(rb, tmp_rb, &u->read_buffers, list) { + list_del(&rb->list); + kfree(rb); + } + kfree(u); + + return 0; +} + +static unsigned int xenbus_file_poll(struct file *file, poll_table *wait) +{ + struct xenbus_file_priv *u = file->private_data; + + poll_wait(file, &u->read_waitq, wait); + if (!list_empty(&u->read_buffers)) + return POLLIN | POLLRDNORM; + return 0; +} + +const struct file_operations xenbus_file_ops = { + .read = xenbus_file_read, + .write = xenbus_file_write, + .open = xenbus_file_open, + .release = xenbus_file_release, + .poll = xenbus_file_poll, + .llseek = no_llseek, +}; diff --git a/drivers/xen/xenfs/xenfs.h b/drivers/xen/xenfs/xenfs.h new file mode 100644 index 00000000..b68aa620 --- /dev/null +++ b/drivers/xen/xenfs/xenfs.h @@ -0,0 +1,9 @@ +#ifndef _XENFS_XENBUS_H +#define _XENFS_XENBUS_H + +extern const struct file_operations xenbus_file_ops; +extern const struct file_operations privcmd_file_ops; +extern const struct file_operations xsd_kva_file_ops; +extern const struct file_operations xsd_port_file_ops; + +#endif /* _XENFS_XENBUS_H */ diff --git a/drivers/xen/xenfs/xenstored.c b/drivers/xen/xenfs/xenstored.c new file mode 100644 index 00000000..fef20dbc --- /dev/null +++ b/drivers/xen/xenfs/xenstored.c @@ -0,0 +1,68 @@ +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/mm.h> +#include <linux/fs.h> + +#include <xen/page.h> + +#include "xenfs.h" +#include "../xenbus/xenbus_comms.h" + +static ssize_t xsd_read(struct file *file, char __user *buf, + size_t size, loff_t *off) +{ + const char *str = (const char *)file->private_data; + return simple_read_from_buffer(buf, size, off, str, strlen(str)); +} + +static int xsd_release(struct inode *inode, struct file *file) +{ + kfree(file->private_data); + return 0; +} + +static int xsd_kva_open(struct inode *inode, struct file *file) +{ + file->private_data = (void *)kasprintf(GFP_KERNEL, "0x%p", + xen_store_interface); + if (!file->private_data) + return -ENOMEM; + return 0; +} + +static int xsd_kva_mmap(struct file *file, struct vm_area_struct *vma) +{ + size_t size = vma->vm_end - vma->vm_start; + + if ((size > PAGE_SIZE) || (vma->vm_pgoff != 0)) + return -EINVAL; + + if (remap_pfn_range(vma, vma->vm_start, + virt_to_pfn(xen_store_interface), + size, vma->vm_page_prot)) + return -EAGAIN; + + return 0; +} + +const struct file_operations xsd_kva_file_ops = { + .open = xsd_kva_open, + .mmap = xsd_kva_mmap, + .read = xsd_read, + .release = xsd_release, +}; + +static int xsd_port_open(struct inode *inode, struct file *file) +{ + file->private_data = (void *)kasprintf(GFP_KERNEL, "%d", + xen_store_evtchn); + if (!file->private_data) + return -ENOMEM; + return 0; +} + +const struct file_operations xsd_port_file_ops = { + .open = xsd_port_open, + .read = xsd_read, + .release = xsd_release, +}; |