v4.19.13 snapshot.
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
new file mode 100644
index 0000000..a1c1700
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -0,0 +1,939 @@
+/******************************************************************************
+ * 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;
+};
+
+static DEFINE_SPINLOCK(xenbus_valloc_lock);
+static LIST_HEAD(xenbus_valloc_pages);
+
+struct xenbus_ring_ops {
+ int (*map)(struct xenbus_device *dev,
+ 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,
+ void (*callback)(struct xenbus_watch *,
+ const char *, const char *))
+{
+ int err;
+
+ watch->node = path;
+ watch->callback = callback;
+
+ err = register_xenbus_watch(watch);
+
+ if (err) {
+ watch->node = 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,
+ 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, 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))
+ dev_err(&dev->dev, "failed to write error node for %s (%s)\n",
+ dev->nodename, 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_grant_ring
+ * @dev: xenbus device
+ * @vaddr: starting virtual address of the ring
+ * @nr_pages: number of pages to be granted
+ * @grefs: grant reference array to be filled in
+ *
+ * Grant access to the given @vaddr to the peer of the given device.
+ * Then fill in @grefs with grant references. 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_grant_ring(struct xenbus_device *dev, void *vaddr,
+ unsigned int nr_pages, grant_ref_t *grefs)
+{
+ int err;
+ int i, j;
+
+ for (i = 0; i < nr_pages; i++) {
+ err = gnttab_grant_foreign_access(dev->otherend_id,
+ virt_to_gfn(vaddr), 0);
+ if (err < 0) {
+ xenbus_dev_fatal(dev, err,
+ "granting access to ring page");
+ goto fail;
+ }
+ grefs[i] = err;
+
+ vaddr = vaddr + XEN_PAGE_SIZE;
+ }
+
+ return 0;
+
+fail:
+ for (j = 0; j < i; j++)
+ gnttab_end_foreign_access_ref(grefs[j], 0);
+ return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_grant_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, int *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, int 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 %d", 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 GNTST_*
+ * (see xen/include/interface/grant_table.h) or -ENOMEM / -EINVAL 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)
+{
+ return ring_ops->map(dev, gnt_refs, nr_grefs, vaddr);
+}
+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,
+ phys_addr_t *addrs,
+ unsigned int flags,
+ bool *leaked)
+{
+ struct gnttab_map_grant_ref map[XENBUS_MAX_RING_GRANTS];
+ struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS];
+ int i, j;
+ int err = GNTST_okay;
+
+ if (nr_grefs > XENBUS_MAX_RING_GRANTS)
+ return -EINVAL;
+
+ for (i = 0; i < nr_grefs; i++) {
+ memset(&map[i], 0, sizeof(map[i]));
+ gnttab_set_map_op(&map[i], addrs[i], flags, gnt_refs[i],
+ dev->otherend_id);
+ handles[i] = INVALID_GRANT_HANDLE;
+ }
+
+ gnttab_batch_map(map, i);
+
+ for (i = 0; i < nr_grefs; i++) {
+ if (map[i].status != GNTST_okay) {
+ err = map[i].status;
+ xenbus_dev_fatal(dev, map[i].status,
+ "mapping in shared page %d from domain %d",
+ gnt_refs[i], dev->otherend_id);
+ goto fail;
+ } else
+ handles[i] = map[i].handle;
+ }
+
+ return GNTST_okay;
+
+ fail:
+ for (i = j = 0; i < nr_grefs; i++) {
+ if (handles[i] != INVALID_GRANT_HANDLE) {
+ memset(&unmap[j], 0, sizeof(unmap[j]));
+ gnttab_set_unmap_op(&unmap[j], (phys_addr_t)addrs[i],
+ GNTMAP_host_map, handles[i]);
+ j++;
+ }
+ }
+
+ if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, j))
+ BUG();
+
+ *leaked = false;
+ for (i = 0; i < j; i++) {
+ if (unmap[i].status != GNTST_okay) {
+ *leaked = true;
+ break;
+ }
+ }
+
+ return err;
+}
+
+struct map_ring_valloc_hvm
+{
+ unsigned int idx;
+
+ /* Why do we need two arrays? See comment of __xenbus_map_ring */
+ phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS];
+ unsigned long addrs[XENBUS_MAX_RING_GRANTS];
+};
+
+static void xenbus_map_ring_setup_grant_hvm(unsigned long gfn,
+ unsigned int goffset,
+ unsigned int len,
+ void *data)
+{
+ struct map_ring_valloc_hvm *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_valloc_hvm(struct xenbus_device *dev,
+ grant_ref_t *gnt_ref,
+ unsigned int nr_grefs,
+ void **vaddr)
+{
+ struct xenbus_map_node *node;
+ int err;
+ void *addr;
+ bool leaked = false;
+ struct map_ring_valloc_hvm info = {
+ .idx = 0,
+ };
+ unsigned int nr_pages = XENBUS_PAGES(nr_grefs);
+
+ if (nr_grefs > XENBUS_MAX_RING_GRANTS)
+ return -EINVAL;
+
+ *vaddr = NULL;
+
+ node = kzalloc(sizeof(*node), GFP_KERNEL);
+ if (!node)
+ return -ENOMEM;
+
+ err = alloc_xenballooned_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.phys_addrs, 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;
+ 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)
+ free_xenballooned_pages(nr_pages, node->hvm.pages);
+ out_err:
+ kfree(node);
+ return err;
+}
+
+
+/**
+ * xenbus_map_ring
+ * @dev: xenbus device
+ * @gnt_refs: grant reference array
+ * @nr_grefs: number of grant reference
+ * @handles: pointer to grant handle to be filled
+ * @vaddrs: addresses to be mapped to
+ * @leaked: fail to clean up a failed map, caller should not free vaddr
+ *
+ * Map pages of memory into this domain from another domain's grant table.
+ * xenbus_map_ring does not allocate the virtual address space (you must do
+ * this yourself!). It only maps in the pages to the specified address.
+ * Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h)
+ * or -ENOMEM / -EINVAL on error. If an error is returned, device will switch to
+ * XenbusStateClosing and the first error message will be saved in XenStore.
+ * Further more if we fail to map the ring, caller should check @leaked.
+ * If @leaked is not zero it means xenbus_map_ring fails to clean up, caller
+ * should not free the address space of @vaddr.
+ */
+int xenbus_map_ring(struct xenbus_device *dev, grant_ref_t *gnt_refs,
+ unsigned int nr_grefs, grant_handle_t *handles,
+ unsigned long *vaddrs, bool *leaked)
+{
+ phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS];
+ int i;
+
+ if (nr_grefs > XENBUS_MAX_RING_GRANTS)
+ return -EINVAL;
+
+ for (i = 0; i < nr_grefs; i++)
+ phys_addrs[i] = (unsigned long)vaddrs[i];
+
+ return __xenbus_map_ring(dev, gnt_refs, nr_grefs, handles,
+ phys_addrs, GNTMAP_host_map, leaked);
+}
+EXPORT_SYMBOL_GPL(xenbus_map_ring);
+
+
+/**
+ * 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 xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
+ grant_ref_t *gnt_refs,
+ unsigned int nr_grefs,
+ void **vaddr)
+{
+ struct xenbus_map_node *node;
+ struct vm_struct *area;
+ pte_t *ptes[XENBUS_MAX_RING_GRANTS];
+ phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS];
+ int err = GNTST_okay;
+ int i;
+ bool leaked;
+
+ *vaddr = NULL;
+
+ if (nr_grefs > XENBUS_MAX_RING_GRANTS)
+ return -EINVAL;
+
+ node = kzalloc(sizeof(*node), GFP_KERNEL);
+ if (!node)
+ return -ENOMEM;
+
+ area = alloc_vm_area(XEN_PAGE_SIZE * nr_grefs, ptes);
+ if (!area) {
+ kfree(node);
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < nr_grefs; i++)
+ phys_addrs[i] = arbitrary_virt_to_machine(ptes[i]).maddr;
+
+ err = __xenbus_map_ring(dev, gnt_refs, nr_grefs, node->handles,
+ phys_addrs,
+ 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;
+ return 0;
+
+failed:
+ if (!leaked)
+ free_vm_area(area);
+ else
+ pr_alert("leaking VM area %p size %u page(s)", area, nr_grefs);
+
+ kfree(node);
+ return err;
+}
+
+static int xenbus_unmap_ring_vfree_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];
+ }
+
+ if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i))
+ BUG();
+
+ 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_valloc_pv,
+ .unmap = xenbus_unmap_ring_vfree_pv,
+};
+#endif
+
+struct unmap_ring_vfree_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_vfree_hvm *info = data;
+
+ info->addrs[info->idx] = (unsigned long)gfn_to_virt(gfn);
+
+ info->idx++;
+}
+
+static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
+{
+ int rv;
+ struct xenbus_map_node *node;
+ void *addr;
+ struct unmap_ring_vfree_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);
+ free_xenballooned_pages(nr_pages, node->hvm.pages);
+ }
+ else
+ WARN(1, "Leaking %p, size %u page(s)\n", vaddr, nr_pages);
+
+ kfree(node);
+ return rv;
+}
+
+/**
+ * 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).
+ */
+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]);
+
+ if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i))
+ BUG();
+
+ 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;
+}
+EXPORT_SYMBOL_GPL(xenbus_unmap_ring);
+
+
+/**
+ * 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_valloc_hvm,
+ .unmap = xenbus_unmap_ring_vfree_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;
+}