diff options
Diffstat (limited to 'drivers/xen/xenbus/xenbus_client.c')
| -rw-r--r-- | drivers/xen/xenbus/xenbus_client.c | 949 |
1 files changed, 949 insertions, 0 deletions
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c new file mode 100644 index 000000000..d4b251925 --- /dev/null +++ b/drivers/xen/xenbus/xenbus_client.c @@ -0,0 +1,949 @@ +/****************************************************************************** + * Client-facing interface for the Xenbus driver. In other words, the + * interface between the Xenbus and the device-specific code, be it the + * frontend or the backend of that driver. + * + * Copyright (C) 2005 XenSource Ltd + * + * 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. + */ + +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/spinlock.h> +#include <linux/vmalloc.h> +#include <linux/export.h> +#include <asm/xen/hypervisor.h> +#include <xen/page.h> +#include <xen/interface/xen.h> +#include <xen/interface/event_channel.h> +#include <xen/balloon.h> +#include <xen/events.h> +#include <xen/grant_table.h> +#include <xen/xenbus.h> +#include <xen/xen.h> +#include <xen/features.h> + +#include "xenbus.h" + +#define XENBUS_PAGES(_grants) (DIV_ROUND_UP(_grants, XEN_PFN_PER_PAGE)) + +#define XENBUS_MAX_RING_PAGES (XENBUS_PAGES(XENBUS_MAX_RING_GRANTS)) + +struct xenbus_map_node { + struct list_head next; + union { + struct { + struct vm_struct *area; + } pv; + struct { + struct page *pages[XENBUS_MAX_RING_PAGES]; + unsigned long addrs[XENBUS_MAX_RING_GRANTS]; + void *addr; + } hvm; + }; + grant_handle_t handles[XENBUS_MAX_RING_GRANTS]; + unsigned int nr_handles; +}; + +struct map_ring_valloc { + struct xenbus_map_node *node; + + /* Why do we need two arrays? See comment of __xenbus_map_ring */ + unsigned long addrs[XENBUS_MAX_RING_GRANTS]; + phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS]; + + struct gnttab_map_grant_ref map[XENBUS_MAX_RING_GRANTS]; + struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS]; + + unsigned int idx; +}; + +static DEFINE_SPINLOCK(xenbus_valloc_lock); +static LIST_HEAD(xenbus_valloc_pages); + +struct xenbus_ring_ops { + int (*map)(struct xenbus_device *dev, struct map_ring_valloc *info, + grant_ref_t *gnt_refs, unsigned int nr_grefs, + void **vaddr); + int (*unmap)(struct xenbus_device *dev, void *vaddr); +}; + +static const struct xenbus_ring_ops *ring_ops __read_mostly; + +const char *xenbus_strstate(enum xenbus_state state) +{ + static const char *const name[] = { + [ XenbusStateUnknown ] = "Unknown", + [ XenbusStateInitialising ] = "Initialising", + [ XenbusStateInitWait ] = "InitWait", + [ XenbusStateInitialised ] = "Initialised", + [ XenbusStateConnected ] = "Connected", + [ XenbusStateClosing ] = "Closing", + [ XenbusStateClosed ] = "Closed", + [XenbusStateReconfiguring] = "Reconfiguring", + [XenbusStateReconfigured] = "Reconfigured", + }; + return (state < ARRAY_SIZE(name)) ? name[state] : "INVALID"; +} +EXPORT_SYMBOL_GPL(xenbus_strstate); + +/** + * xenbus_watch_path - register a watch + * @dev: xenbus device + * @path: path to watch + * @watch: watch to register + * @callback: callback to register + * + * Register a @watch on the given path, using the given xenbus_watch structure + * for storage, and the given @callback function as the callback. Return 0 on + * success, or -errno on error. On success, the given @path will be saved as + * @watch->node, and remains the caller's to free. On error, @watch->node will + * be NULL, the device will switch to %XenbusStateClosing, and the error will + * be saved in the store. + */ +int xenbus_watch_path(struct xenbus_device *dev, const char *path, + struct xenbus_watch *watch, + bool (*will_handle)(struct xenbus_watch *, + const char *, const char *), + void (*callback)(struct xenbus_watch *, + const char *, const char *)) +{ + int err; + + watch->node = path; + watch->will_handle = will_handle; + watch->callback = callback; + + err = register_xenbus_watch(watch); + + if (err) { + watch->node = NULL; + watch->will_handle = NULL; + watch->callback = NULL; + xenbus_dev_fatal(dev, err, "adding watch on %s", path); + } + + return err; +} +EXPORT_SYMBOL_GPL(xenbus_watch_path); + + +/** + * xenbus_watch_pathfmt - register a watch on a sprintf-formatted path + * @dev: xenbus device + * @watch: watch to register + * @callback: callback to register + * @pathfmt: format of path to watch + * + * Register a watch on the given @path, using the given xenbus_watch + * structure for storage, and the given @callback function as the callback. + * Return 0 on success, or -errno on error. On success, the watched path + * (@path/@path2) will be saved as @watch->node, and becomes the caller's to + * kfree(). On error, watch->node will be NULL, so the caller has nothing to + * free, the device will switch to %XenbusStateClosing, and the error will be + * saved in the store. + */ +int xenbus_watch_pathfmt(struct xenbus_device *dev, + struct xenbus_watch *watch, + bool (*will_handle)(struct xenbus_watch *, + const char *, const char *), + void (*callback)(struct xenbus_watch *, + const char *, const char *), + const char *pathfmt, ...) +{ + int err; + va_list ap; + char *path; + + va_start(ap, pathfmt); + path = kvasprintf(GFP_NOIO | __GFP_HIGH, pathfmt, ap); + va_end(ap); + + if (!path) { + xenbus_dev_fatal(dev, -ENOMEM, "allocating path for watch"); + return -ENOMEM; + } + err = xenbus_watch_path(dev, path, watch, will_handle, callback); + + if (err) + kfree(path); + return err; +} +EXPORT_SYMBOL_GPL(xenbus_watch_pathfmt); + +static void xenbus_switch_fatal(struct xenbus_device *, int, int, + const char *, ...); + +static int +__xenbus_switch_state(struct xenbus_device *dev, + enum xenbus_state state, int depth) +{ + /* We check whether the state is currently set to the given value, and + if not, then the state is set. We don't want to unconditionally + write the given state, because we don't want to fire watches + unnecessarily. Furthermore, if the node has gone, we don't write + to it, as the device will be tearing down, and we don't want to + resurrect that directory. + + Note that, because of this cached value of our state, this + function will not take a caller's Xenstore transaction + (something it was trying to in the past) because dev->state + would not get reset if the transaction was aborted. + */ + + struct xenbus_transaction xbt; + int current_state; + int err, abort; + + if (state == dev->state) + return 0; + +again: + abort = 1; + + err = xenbus_transaction_start(&xbt); + if (err) { + xenbus_switch_fatal(dev, depth, err, "starting transaction"); + return 0; + } + + err = xenbus_scanf(xbt, dev->nodename, "state", "%d", ¤t_state); + if (err != 1) + goto abort; + + err = xenbus_printf(xbt, dev->nodename, "state", "%d", state); + if (err) { + xenbus_switch_fatal(dev, depth, err, "writing new state"); + goto abort; + } + + abort = 0; +abort: + err = xenbus_transaction_end(xbt, abort); + if (err) { + if (err == -EAGAIN && !abort) + goto again; + xenbus_switch_fatal(dev, depth, err, "ending transaction"); + } else + dev->state = state; + + return 0; +} + +/** + * xenbus_switch_state + * @dev: xenbus device + * @state: new state + * + * Advertise in the store a change of the given driver to the given new_state. + * Return 0 on success, or -errno on error. On error, the device will switch + * to XenbusStateClosing, and the error will be saved in the store. + */ +int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state) +{ + return __xenbus_switch_state(dev, state, 0); +} + +EXPORT_SYMBOL_GPL(xenbus_switch_state); + +int xenbus_frontend_closed(struct xenbus_device *dev) +{ + xenbus_switch_state(dev, XenbusStateClosed); + complete(&dev->down); + return 0; +} +EXPORT_SYMBOL_GPL(xenbus_frontend_closed); + +static void xenbus_va_dev_error(struct xenbus_device *dev, int err, + const char *fmt, va_list ap) +{ + unsigned int len; + char *printf_buffer; + char *path_buffer; + +#define PRINTF_BUFFER_SIZE 4096 + + printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL); + if (!printf_buffer) + return; + + len = sprintf(printf_buffer, "%i ", -err); + vsnprintf(printf_buffer + len, PRINTF_BUFFER_SIZE - len, fmt, ap); + + dev_err(&dev->dev, "%s\n", printf_buffer); + + path_buffer = kasprintf(GFP_KERNEL, "error/%s", dev->nodename); + if (path_buffer) + xenbus_write(XBT_NIL, path_buffer, "error", printf_buffer); + + kfree(printf_buffer); + kfree(path_buffer); +} + +/** + * xenbus_dev_error + * @dev: xenbus device + * @err: error to report + * @fmt: error message format + * + * Report the given negative errno into the store, along with the given + * formatted message. + */ +void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...) +{ + va_list ap; + + va_start(ap, fmt); + xenbus_va_dev_error(dev, err, fmt, ap); + va_end(ap); +} +EXPORT_SYMBOL_GPL(xenbus_dev_error); + +/** + * xenbus_dev_fatal + * @dev: xenbus device + * @err: error to report + * @fmt: error message format + * + * Equivalent to xenbus_dev_error(dev, err, fmt, args), followed by + * xenbus_switch_state(dev, XenbusStateClosing) to schedule an orderly + * closedown of this driver and its peer. + */ + +void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...) +{ + va_list ap; + + va_start(ap, fmt); + xenbus_va_dev_error(dev, err, fmt, ap); + va_end(ap); + + xenbus_switch_state(dev, XenbusStateClosing); +} +EXPORT_SYMBOL_GPL(xenbus_dev_fatal); + +/** + * Equivalent to xenbus_dev_fatal(dev, err, fmt, args), but helps + * avoiding recursion within xenbus_switch_state. + */ +static void xenbus_switch_fatal(struct xenbus_device *dev, int depth, int err, + const char *fmt, ...) +{ + va_list ap; + + va_start(ap, fmt); + xenbus_va_dev_error(dev, err, fmt, ap); + va_end(ap); + + if (!depth) + __xenbus_switch_state(dev, XenbusStateClosing, 1); +} + +/* + * xenbus_setup_ring + * @dev: xenbus device + * @vaddr: pointer to starting virtual address of the ring + * @nr_pages: number of pages to be granted + * @grefs: grant reference array to be filled in + * + * Allocate physically contiguous pages for a shared ring buffer and grant it + * to the peer of the given device. The ring buffer is initially filled with + * zeroes. The virtual address of the ring is stored at @vaddr and the + * grant references are stored in the @grefs array. In case of error @vaddr + * will be set to NULL and @grefs will be filled with INVALID_GRANT_REF. + */ +int xenbus_setup_ring(struct xenbus_device *dev, gfp_t gfp, void **vaddr, + unsigned int nr_pages, grant_ref_t *grefs) +{ + unsigned long ring_size = nr_pages * XEN_PAGE_SIZE; + grant_ref_t gref_head; + unsigned int i; + void *addr; + int ret; + + addr = *vaddr = alloc_pages_exact(ring_size, gfp | __GFP_ZERO); + if (!*vaddr) { + ret = -ENOMEM; + goto err; + } + + ret = gnttab_alloc_grant_references(nr_pages, &gref_head); + if (ret) { + xenbus_dev_fatal(dev, ret, "granting access to %u ring pages", + nr_pages); + goto err; + } + + for (i = 0; i < nr_pages; i++) { + unsigned long gfn; + + if (is_vmalloc_addr(*vaddr)) + gfn = pfn_to_gfn(vmalloc_to_pfn(addr)); + else + gfn = virt_to_gfn(addr); + + grefs[i] = gnttab_claim_grant_reference(&gref_head); + gnttab_grant_foreign_access_ref(grefs[i], dev->otherend_id, + gfn, 0); + + addr += XEN_PAGE_SIZE; + } + + return 0; + + err: + if (*vaddr) + free_pages_exact(*vaddr, ring_size); + for (i = 0; i < nr_pages; i++) + grefs[i] = INVALID_GRANT_REF; + *vaddr = NULL; + + return ret; +} +EXPORT_SYMBOL_GPL(xenbus_setup_ring); + +/* + * xenbus_teardown_ring + * @vaddr: starting virtual address of the ring + * @nr_pages: number of pages + * @grefs: grant reference array + * + * Remove grants for the shared ring buffer and free the associated memory. + * On return the grant reference array is filled with INVALID_GRANT_REF. + */ +void xenbus_teardown_ring(void **vaddr, unsigned int nr_pages, + grant_ref_t *grefs) +{ + unsigned int i; + + for (i = 0; i < nr_pages; i++) { + if (grefs[i] != INVALID_GRANT_REF) { + gnttab_end_foreign_access(grefs[i], NULL); + grefs[i] = INVALID_GRANT_REF; + } + } + + if (*vaddr) + free_pages_exact(*vaddr, nr_pages * XEN_PAGE_SIZE); + *vaddr = NULL; +} +EXPORT_SYMBOL_GPL(xenbus_teardown_ring); + +/** + * Allocate an event channel for the given xenbus_device, assigning the newly + * created local port to *port. Return 0 on success, or -errno on error. On + * error, the device will switch to XenbusStateClosing, and the error will be + * saved in the store. + */ +int xenbus_alloc_evtchn(struct xenbus_device *dev, evtchn_port_t *port) +{ + struct evtchn_alloc_unbound alloc_unbound; + int err; + + alloc_unbound.dom = DOMID_SELF; + alloc_unbound.remote_dom = dev->otherend_id; + + err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, + &alloc_unbound); + if (err) + xenbus_dev_fatal(dev, err, "allocating event channel"); + else + *port = alloc_unbound.port; + + return err; +} +EXPORT_SYMBOL_GPL(xenbus_alloc_evtchn); + + +/** + * Free an existing event channel. Returns 0 on success or -errno on error. + */ +int xenbus_free_evtchn(struct xenbus_device *dev, evtchn_port_t port) +{ + struct evtchn_close close; + int err; + + close.port = port; + + err = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close); + if (err) + xenbus_dev_error(dev, err, "freeing event channel %u", port); + + return err; +} +EXPORT_SYMBOL_GPL(xenbus_free_evtchn); + + +/** + * xenbus_map_ring_valloc + * @dev: xenbus device + * @gnt_refs: grant reference array + * @nr_grefs: number of grant references + * @vaddr: pointer to address to be filled out by mapping + * + * Map @nr_grefs pages of memory into this domain from another + * domain's grant table. xenbus_map_ring_valloc allocates @nr_grefs + * pages of virtual address space, maps the pages to that address, and + * sets *vaddr to that address. Returns 0 on success, and -errno on + * error. If an error is returned, device will switch to + * XenbusStateClosing and the error message will be saved in XenStore. + */ +int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs, + unsigned int nr_grefs, void **vaddr) +{ + int err; + struct map_ring_valloc *info; + + *vaddr = NULL; + + if (nr_grefs > XENBUS_MAX_RING_GRANTS) + return -EINVAL; + + info = kzalloc(sizeof(*info), GFP_KERNEL); + if (!info) + return -ENOMEM; + + info->node = kzalloc(sizeof(*info->node), GFP_KERNEL); + if (!info->node) + err = -ENOMEM; + else + err = ring_ops->map(dev, info, gnt_refs, nr_grefs, vaddr); + + kfree(info->node); + kfree(info); + return err; +} +EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc); + +/* N.B. sizeof(phys_addr_t) doesn't always equal to sizeof(unsigned + * long), e.g. 32-on-64. Caller is responsible for preparing the + * right array to feed into this function */ +static int __xenbus_map_ring(struct xenbus_device *dev, + grant_ref_t *gnt_refs, + unsigned int nr_grefs, + grant_handle_t *handles, + struct map_ring_valloc *info, + unsigned int flags, + bool *leaked) +{ + int i, j; + + if (nr_grefs > XENBUS_MAX_RING_GRANTS) + return -EINVAL; + + for (i = 0; i < nr_grefs; i++) { + gnttab_set_map_op(&info->map[i], info->phys_addrs[i], flags, + gnt_refs[i], dev->otherend_id); + handles[i] = INVALID_GRANT_HANDLE; + } + + gnttab_batch_map(info->map, i); + + for (i = 0; i < nr_grefs; i++) { + if (info->map[i].status != GNTST_okay) { + xenbus_dev_fatal(dev, info->map[i].status, + "mapping in shared page %d from domain %d", + gnt_refs[i], dev->otherend_id); + goto fail; + } else + handles[i] = info->map[i].handle; + } + + return 0; + + fail: + for (i = j = 0; i < nr_grefs; i++) { + if (handles[i] != INVALID_GRANT_HANDLE) { + gnttab_set_unmap_op(&info->unmap[j], + info->phys_addrs[i], + GNTMAP_host_map, handles[i]); + j++; + } + } + + BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, info->unmap, j)); + + *leaked = false; + for (i = 0; i < j; i++) { + if (info->unmap[i].status != GNTST_okay) { + *leaked = true; + break; + } + } + + return -ENOENT; +} + +/** + * xenbus_unmap_ring + * @dev: xenbus device + * @handles: grant handle array + * @nr_handles: number of handles in the array + * @vaddrs: addresses to unmap + * + * Unmap memory in this domain that was imported from another domain. + * Returns 0 on success and returns GNTST_* on error + * (see xen/include/interface/grant_table.h). + */ +static int xenbus_unmap_ring(struct xenbus_device *dev, grant_handle_t *handles, + unsigned int nr_handles, unsigned long *vaddrs) +{ + struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS]; + int i; + int err; + + if (nr_handles > XENBUS_MAX_RING_GRANTS) + return -EINVAL; + + for (i = 0; i < nr_handles; i++) + gnttab_set_unmap_op(&unmap[i], vaddrs[i], + GNTMAP_host_map, handles[i]); + + BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i)); + + err = GNTST_okay; + for (i = 0; i < nr_handles; i++) { + if (unmap[i].status != GNTST_okay) { + xenbus_dev_error(dev, unmap[i].status, + "unmapping page at handle %d error %d", + handles[i], unmap[i].status); + err = unmap[i].status; + break; + } + } + + return err; +} + +static void xenbus_map_ring_setup_grant_hvm(unsigned long gfn, + unsigned int goffset, + unsigned int len, + void *data) +{ + struct map_ring_valloc *info = data; + unsigned long vaddr = (unsigned long)gfn_to_virt(gfn); + + info->phys_addrs[info->idx] = vaddr; + info->addrs[info->idx] = vaddr; + + info->idx++; +} + +static int xenbus_map_ring_hvm(struct xenbus_device *dev, + struct map_ring_valloc *info, + grant_ref_t *gnt_ref, + unsigned int nr_grefs, + void **vaddr) +{ + struct xenbus_map_node *node = info->node; + int err; + void *addr; + bool leaked = false; + unsigned int nr_pages = XENBUS_PAGES(nr_grefs); + + err = xen_alloc_unpopulated_pages(nr_pages, node->hvm.pages); + if (err) + goto out_err; + + gnttab_foreach_grant(node->hvm.pages, nr_grefs, + xenbus_map_ring_setup_grant_hvm, + info); + + err = __xenbus_map_ring(dev, gnt_ref, nr_grefs, node->handles, + info, GNTMAP_host_map, &leaked); + node->nr_handles = nr_grefs; + + if (err) + goto out_free_ballooned_pages; + + addr = vmap(node->hvm.pages, nr_pages, VM_MAP | VM_IOREMAP, + PAGE_KERNEL); + if (!addr) { + err = -ENOMEM; + goto out_xenbus_unmap_ring; + } + + node->hvm.addr = addr; + + spin_lock(&xenbus_valloc_lock); + list_add(&node->next, &xenbus_valloc_pages); + spin_unlock(&xenbus_valloc_lock); + + *vaddr = addr; + info->node = NULL; + + return 0; + + out_xenbus_unmap_ring: + if (!leaked) + xenbus_unmap_ring(dev, node->handles, nr_grefs, info->addrs); + else + pr_alert("leaking %p size %u page(s)", + addr, nr_pages); + out_free_ballooned_pages: + if (!leaked) + xen_free_unpopulated_pages(nr_pages, node->hvm.pages); + out_err: + return err; +} + +/** + * xenbus_unmap_ring_vfree + * @dev: xenbus device + * @vaddr: addr to unmap + * + * Based on Rusty Russell's skeleton driver's unmap_page. + * Unmap a page of memory in this domain that was imported from another domain. + * Use xenbus_unmap_ring_vfree if you mapped in your memory with + * xenbus_map_ring_valloc (it will free the virtual address space). + * Returns 0 on success and returns GNTST_* on error + * (see xen/include/interface/grant_table.h). + */ +int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr) +{ + return ring_ops->unmap(dev, vaddr); +} +EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree); + +#ifdef CONFIG_XEN_PV +static int map_ring_apply(pte_t *pte, unsigned long addr, void *data) +{ + struct map_ring_valloc *info = data; + + info->phys_addrs[info->idx++] = arbitrary_virt_to_machine(pte).maddr; + return 0; +} + +static int xenbus_map_ring_pv(struct xenbus_device *dev, + struct map_ring_valloc *info, + grant_ref_t *gnt_refs, + unsigned int nr_grefs, + void **vaddr) +{ + struct xenbus_map_node *node = info->node; + struct vm_struct *area; + bool leaked = false; + int err = -ENOMEM; + + area = get_vm_area(XEN_PAGE_SIZE * nr_grefs, VM_IOREMAP); + if (!area) + return -ENOMEM; + if (apply_to_page_range(&init_mm, (unsigned long)area->addr, + XEN_PAGE_SIZE * nr_grefs, map_ring_apply, info)) + goto failed; + err = __xenbus_map_ring(dev, gnt_refs, nr_grefs, node->handles, + info, GNTMAP_host_map | GNTMAP_contains_pte, + &leaked); + if (err) + goto failed; + + node->nr_handles = nr_grefs; + node->pv.area = area; + + spin_lock(&xenbus_valloc_lock); + list_add(&node->next, &xenbus_valloc_pages); + spin_unlock(&xenbus_valloc_lock); + + *vaddr = area->addr; + info->node = NULL; + + return 0; + +failed: + if (!leaked) + free_vm_area(area); + else + pr_alert("leaking VM area %p size %u page(s)", area, nr_grefs); + + return err; +} + +static int xenbus_unmap_ring_pv(struct xenbus_device *dev, void *vaddr) +{ + struct xenbus_map_node *node; + struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS]; + unsigned int level; + int i; + bool leaked = false; + int err; + + spin_lock(&xenbus_valloc_lock); + list_for_each_entry(node, &xenbus_valloc_pages, next) { + if (node->pv.area->addr == vaddr) { + list_del(&node->next); + goto found; + } + } + node = NULL; + found: + spin_unlock(&xenbus_valloc_lock); + + if (!node) { + xenbus_dev_error(dev, -ENOENT, + "can't find mapped virtual address %p", vaddr); + return GNTST_bad_virt_addr; + } + + for (i = 0; i < node->nr_handles; i++) { + unsigned long addr; + + memset(&unmap[i], 0, sizeof(unmap[i])); + addr = (unsigned long)vaddr + (XEN_PAGE_SIZE * i); + unmap[i].host_addr = arbitrary_virt_to_machine( + lookup_address(addr, &level)).maddr; + unmap[i].dev_bus_addr = 0; + unmap[i].handle = node->handles[i]; + } + + BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i)); + + err = GNTST_okay; + leaked = false; + for (i = 0; i < node->nr_handles; i++) { + if (unmap[i].status != GNTST_okay) { + leaked = true; + xenbus_dev_error(dev, unmap[i].status, + "unmapping page at handle %d error %d", + node->handles[i], unmap[i].status); + err = unmap[i].status; + break; + } + } + + if (!leaked) + free_vm_area(node->pv.area); + else + pr_alert("leaking VM area %p size %u page(s)", + node->pv.area, node->nr_handles); + + kfree(node); + return err; +} + +static const struct xenbus_ring_ops ring_ops_pv = { + .map = xenbus_map_ring_pv, + .unmap = xenbus_unmap_ring_pv, +}; +#endif + +struct unmap_ring_hvm +{ + unsigned int idx; + unsigned long addrs[XENBUS_MAX_RING_GRANTS]; +}; + +static void xenbus_unmap_ring_setup_grant_hvm(unsigned long gfn, + unsigned int goffset, + unsigned int len, + void *data) +{ + struct unmap_ring_hvm *info = data; + + info->addrs[info->idx] = (unsigned long)gfn_to_virt(gfn); + + info->idx++; +} + +static int xenbus_unmap_ring_hvm(struct xenbus_device *dev, void *vaddr) +{ + int rv; + struct xenbus_map_node *node; + void *addr; + struct unmap_ring_hvm info = { + .idx = 0, + }; + unsigned int nr_pages; + + spin_lock(&xenbus_valloc_lock); + list_for_each_entry(node, &xenbus_valloc_pages, next) { + addr = node->hvm.addr; + if (addr == vaddr) { + list_del(&node->next); + goto found; + } + } + node = addr = NULL; + found: + spin_unlock(&xenbus_valloc_lock); + + if (!node) { + xenbus_dev_error(dev, -ENOENT, + "can't find mapped virtual address %p", vaddr); + return GNTST_bad_virt_addr; + } + + nr_pages = XENBUS_PAGES(node->nr_handles); + + gnttab_foreach_grant(node->hvm.pages, node->nr_handles, + xenbus_unmap_ring_setup_grant_hvm, + &info); + + rv = xenbus_unmap_ring(dev, node->handles, node->nr_handles, + info.addrs); + if (!rv) { + vunmap(vaddr); + xen_free_unpopulated_pages(nr_pages, node->hvm.pages); + } + else + WARN(1, "Leaking %p, size %u page(s)\n", vaddr, nr_pages); + + kfree(node); + return rv; +} + +/** + * xenbus_read_driver_state + * @path: path for driver + * + * Return the state of the driver rooted at the given store path, or + * XenbusStateUnknown if no state can be read. + */ +enum xenbus_state xenbus_read_driver_state(const char *path) +{ + enum xenbus_state result; + int err = xenbus_gather(XBT_NIL, path, "state", "%d", &result, NULL); + if (err) + result = XenbusStateUnknown; + + return result; +} +EXPORT_SYMBOL_GPL(xenbus_read_driver_state); + +static const struct xenbus_ring_ops ring_ops_hvm = { + .map = xenbus_map_ring_hvm, + .unmap = xenbus_unmap_ring_hvm, +}; + +void __init xenbus_ring_ops_init(void) +{ +#ifdef CONFIG_XEN_PV + if (!xen_feature(XENFEAT_auto_translated_physmap)) + ring_ops = &ring_ops_pv; + else +#endif + ring_ops = &ring_ops_hvm; +} |