--- /dev/null
+/******************************************************************************
+ * grant_table.c
+ *
+ * Granting foreign access to our memory reservation.
+ *
+ * Copyright (c) 2005-2006, Christopher Clark
+ * Copyright (c) 2004-2005, K A Fraser
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/hardirq.h>
+#include <linux/workqueue.h>
+
+#include <xen/xen.h>
+#include <xen/interface/xen.h>
+#include <xen/page.h>
+#include <xen/grant_table.h>
+#include <xen/interface/memory.h>
+#include <xen/hvc-console.h>
+#include <xen/swiotlb-xen.h>
+#include <xen/balloon.h>
+#include <asm/xen/hypercall.h>
+#include <asm/xen/interface.h>
+
+#include <asm/pgtable.h>
+#include <asm/sync_bitops.h>
+
+/* External tools reserve first few grant table entries. */
+#define NR_RESERVED_ENTRIES 8
+#define GNTTAB_LIST_END 0xffffffff
+
+static grant_ref_t **gnttab_list;
+static unsigned int nr_grant_frames;
+static int gnttab_free_count;
+static grant_ref_t gnttab_free_head;
+static DEFINE_SPINLOCK(gnttab_list_lock);
+struct grant_frames xen_auto_xlat_grant_frames;
+
+static union {
+ struct grant_entry_v1 *v1;
+ void *addr;
+} gnttab_shared;
+
+/*This is a structure of function pointers for grant table*/
+struct gnttab_ops {
+ /*
+ * Mapping a list of frames for storing grant entries. Frames parameter
+ * is used to store grant table address when grant table being setup,
+ * nr_gframes is the number of frames to map grant table. Returning
+ * GNTST_okay means success and negative value means failure.
+ */
+ int (*map_frames)(xen_pfn_t *frames, unsigned int nr_gframes);
+ /*
+ * Release a list of frames which are mapped in map_frames for grant
+ * entry status.
+ */
+ void (*unmap_frames)(void);
+ /*
+ * Introducing a valid entry into the grant table, granting the frame of
+ * this grant entry to domain for accessing or transfering. Ref
+ * parameter is reference of this introduced grant entry, domid is id of
+ * granted domain, frame is the page frame to be granted, and flags is
+ * status of the grant entry to be updated.
+ */
+ void (*update_entry)(grant_ref_t ref, domid_t domid,
+ unsigned long frame, unsigned flags);
+ /*
+ * Stop granting a grant entry to domain for accessing. Ref parameter is
+ * reference of a grant entry whose grant access will be stopped,
+ * readonly is not in use in this function. If the grant entry is
+ * currently mapped for reading or writing, just return failure(==0)
+ * directly and don't tear down the grant access. Otherwise, stop grant
+ * access for this entry and return success(==1).
+ */
+ int (*end_foreign_access_ref)(grant_ref_t ref, int readonly);
+ /*
+ * Stop granting a grant entry to domain for transfer. Ref parameter is
+ * reference of a grant entry whose grant transfer will be stopped. If
+ * tranfer has not started, just reclaim the grant entry and return
+ * failure(==0). Otherwise, wait for the transfer to complete and then
+ * return the frame.
+ */
+ unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
+ /*
+ * Query the status of a grant entry. Ref parameter is reference of
+ * queried grant entry, return value is the status of queried entry.
+ * Detailed status(writing/reading) can be gotten from the return value
+ * by bit operations.
+ */
+ int (*query_foreign_access)(grant_ref_t ref);
+};
+
+struct unmap_refs_callback_data {
+ struct completion completion;
+ int result;
+};
+
+static struct gnttab_ops *gnttab_interface;
+
+static int grant_table_version;
+static int grefs_per_grant_frame;
+
+static struct gnttab_free_callback *gnttab_free_callback_list;
+
+static int gnttab_expand(unsigned int req_entries);
+
+#define RPP (PAGE_SIZE / sizeof(grant_ref_t))
+#define SPP (PAGE_SIZE / sizeof(grant_status_t))
+
+static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
+{
+ return &gnttab_list[(entry) / RPP][(entry) % RPP];
+}
+/* This can be used as an l-value */
+#define gnttab_entry(entry) (*__gnttab_entry(entry))
+
+static int get_free_entries(unsigned count)
+{
+ unsigned long flags;
+ int ref, rc = 0;
+ grant_ref_t head;
+
+ spin_lock_irqsave(&gnttab_list_lock, flags);
+
+ if ((gnttab_free_count < count) &&
+ ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
+ spin_unlock_irqrestore(&gnttab_list_lock, flags);
+ return rc;
+ }
+
+ ref = head = gnttab_free_head;
+ gnttab_free_count -= count;
+ while (count-- > 1)
+ head = gnttab_entry(head);
+ gnttab_free_head = gnttab_entry(head);
+ gnttab_entry(head) = GNTTAB_LIST_END;
+
+ spin_unlock_irqrestore(&gnttab_list_lock, flags);
+
+ return ref;
+}
+
+static void do_free_callbacks(void)
+{
+ struct gnttab_free_callback *callback, *next;
+
+ callback = gnttab_free_callback_list;
+ gnttab_free_callback_list = NULL;
+
+ while (callback != NULL) {
+ next = callback->next;
+ if (gnttab_free_count >= callback->count) {
+ callback->next = NULL;
+ callback->fn(callback->arg);
+ } else {
+ callback->next = gnttab_free_callback_list;
+ gnttab_free_callback_list = callback;
+ }
+ callback = next;
+ }
+}
+
+static inline void check_free_callbacks(void)
+{
+ if (unlikely(gnttab_free_callback_list))
+ do_free_callbacks();
+}
+
+static void put_free_entry(grant_ref_t ref)
+{
+ unsigned long flags;
+ spin_lock_irqsave(&gnttab_list_lock, flags);
+ gnttab_entry(ref) = gnttab_free_head;
+ gnttab_free_head = ref;
+ gnttab_free_count++;
+ check_free_callbacks();
+ spin_unlock_irqrestore(&gnttab_list_lock, flags);
+}
+
+/*
+ * Following applies to gnttab_update_entry_v1.
+ * Introducing a valid entry into the grant table:
+ * 1. Write ent->domid.
+ * 2. Write ent->frame:
+ * GTF_permit_access: Frame to which access is permitted.
+ * GTF_accept_transfer: Pseudo-phys frame slot being filled by new
+ * frame, or zero if none.
+ * 3. Write memory barrier (WMB).
+ * 4. Write ent->flags, inc. valid type.
+ */
+static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
+ unsigned long frame, unsigned flags)
+{
+ gnttab_shared.v1[ref].domid = domid;
+ gnttab_shared.v1[ref].frame = frame;
+ wmb();
+ gnttab_shared.v1[ref].flags = flags;
+}
+
+/*
+ * Public grant-issuing interface functions
+ */
+void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
+ unsigned long frame, int readonly)
+{
+ gnttab_interface->update_entry(ref, domid, frame,
+ GTF_permit_access | (readonly ? GTF_readonly : 0));
+}
+EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
+
+int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
+ int readonly)
+{
+ int ref;
+
+ ref = get_free_entries(1);
+ if (unlikely(ref < 0))
+ return -ENOSPC;
+
+ gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
+
+ return ref;
+}
+EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
+
+static int gnttab_query_foreign_access_v1(grant_ref_t ref)
+{
+ return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
+}
+
+int gnttab_query_foreign_access(grant_ref_t ref)
+{
+ return gnttab_interface->query_foreign_access(ref);
+}
+EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
+
+static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
+{
+ u16 flags, nflags;
+ u16 *pflags;
+
+ pflags = &gnttab_shared.v1[ref].flags;
+ nflags = *pflags;
+ do {
+ flags = nflags;
+ if (flags & (GTF_reading|GTF_writing))
+ return 0;
+ } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
+
+ return 1;
+}
+
+static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
+{
+ return gnttab_interface->end_foreign_access_ref(ref, readonly);
+}
+
+int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
+{
+ if (_gnttab_end_foreign_access_ref(ref, readonly))
+ return 1;
+ pr_warn("WARNING: g.e. %#x still in use!\n", ref);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
+
+struct deferred_entry {
+ struct list_head list;
+ grant_ref_t ref;
+ bool ro;
+ uint16_t warn_delay;
+ struct page *page;
+};
+static LIST_HEAD(deferred_list);
+static void gnttab_handle_deferred(unsigned long);
+static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred, 0, 0);
+
+static void gnttab_handle_deferred(unsigned long unused)
+{
+ unsigned int nr = 10;
+ struct deferred_entry *first = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&gnttab_list_lock, flags);
+ while (nr--) {
+ struct deferred_entry *entry
+ = list_first_entry(&deferred_list,
+ struct deferred_entry, list);
+
+ if (entry == first)
+ break;
+ list_del(&entry->list);
+ spin_unlock_irqrestore(&gnttab_list_lock, flags);
+ if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
+ put_free_entry(entry->ref);
+ if (entry->page) {
+ pr_debug("freeing g.e. %#x (pfn %#lx)\n",
+ entry->ref, page_to_pfn(entry->page));
+ __free_page(entry->page);
+ } else
+ pr_info("freeing g.e. %#x\n", entry->ref);
+ kfree(entry);
+ entry = NULL;
+ } else {
+ if (!--entry->warn_delay)
+ pr_info("g.e. %#x still pending\n", entry->ref);
+ if (!first)
+ first = entry;
+ }
+ spin_lock_irqsave(&gnttab_list_lock, flags);
+ if (entry)
+ list_add_tail(&entry->list, &deferred_list);
+ else if (list_empty(&deferred_list))
+ break;
+ }
+ if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {
+ deferred_timer.expires = jiffies + HZ;
+ add_timer(&deferred_timer);
+ }
+ spin_unlock_irqrestore(&gnttab_list_lock, flags);
+}
+
+static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
+ struct page *page)
+{
+ struct deferred_entry *entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
+ const char *what = KERN_WARNING "leaking";
+
+ if (entry) {
+ unsigned long flags;
+
+ entry->ref = ref;
+ entry->ro = readonly;
+ entry->page = page;
+ entry->warn_delay = 60;
+ spin_lock_irqsave(&gnttab_list_lock, flags);
+ list_add_tail(&entry->list, &deferred_list);
+ if (!timer_pending(&deferred_timer)) {
+ deferred_timer.expires = jiffies + HZ;
+ add_timer(&deferred_timer);
+ }
+ spin_unlock_irqrestore(&gnttab_list_lock, flags);
+ what = KERN_DEBUG "deferring";
+ }
+ printk("%s g.e. %#x (pfn %#lx)\n",
+ what, ref, page ? page_to_pfn(page) : -1);
+}
+
+void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
+ unsigned long page)
+{
+ if (gnttab_end_foreign_access_ref(ref, readonly)) {
+ put_free_entry(ref);
+ if (page != 0)
+ free_page(page);
+ } else
+ gnttab_add_deferred(ref, readonly,
+ page ? virt_to_page(page) : NULL);
+}
+EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
+
+int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
+{
+ int ref;
+
+ ref = get_free_entries(1);
+ if (unlikely(ref < 0))
+ return -ENOSPC;
+ gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
+
+ return ref;
+}
+EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
+
+void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
+ unsigned long pfn)
+{
+ gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer);
+}
+EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
+
+static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
+{
+ unsigned long frame;
+ u16 flags;
+ u16 *pflags;
+
+ pflags = &gnttab_shared.v1[ref].flags;
+
+ /*
+ * If a transfer is not even yet started, try to reclaim the grant
+ * reference and return failure (== 0).
+ */
+ while (!((flags = *pflags) & GTF_transfer_committed)) {
+ if (sync_cmpxchg(pflags, flags, 0) == flags)
+ return 0;
+ cpu_relax();
+ }
+
+ /* If a transfer is in progress then wait until it is completed. */
+ while (!(flags & GTF_transfer_completed)) {
+ flags = *pflags;
+ cpu_relax();
+ }
+
+ rmb(); /* Read the frame number /after/ reading completion status. */
+ frame = gnttab_shared.v1[ref].frame;
+ BUG_ON(frame == 0);
+
+ return frame;
+}
+
+unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
+{
+ return gnttab_interface->end_foreign_transfer_ref(ref);
+}
+EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
+
+unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
+{
+ unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
+ put_free_entry(ref);
+ return frame;
+}
+EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
+
+void gnttab_free_grant_reference(grant_ref_t ref)
+{
+ put_free_entry(ref);
+}
+EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
+
+void gnttab_free_grant_references(grant_ref_t head)
+{
+ grant_ref_t ref;
+ unsigned long flags;
+ int count = 1;
+ if (head == GNTTAB_LIST_END)
+ return;
+ spin_lock_irqsave(&gnttab_list_lock, flags);
+ ref = head;
+ while (gnttab_entry(ref) != GNTTAB_LIST_END) {
+ ref = gnttab_entry(ref);
+ count++;
+ }
+ gnttab_entry(ref) = gnttab_free_head;
+ gnttab_free_head = head;
+ gnttab_free_count += count;
+ check_free_callbacks();
+ spin_unlock_irqrestore(&gnttab_list_lock, flags);
+}
+EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
+
+int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
+{
+ int h = get_free_entries(count);
+
+ if (h < 0)
+ return -ENOSPC;
+
+ *head = h;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
+
+int gnttab_empty_grant_references(const grant_ref_t *private_head)
+{
+ return (*private_head == GNTTAB_LIST_END);
+}
+EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
+
+int gnttab_claim_grant_reference(grant_ref_t *private_head)
+{
+ grant_ref_t g = *private_head;
+ if (unlikely(g == GNTTAB_LIST_END))
+ return -ENOSPC;
+ *private_head = gnttab_entry(g);
+ return g;
+}
+EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
+
+void gnttab_release_grant_reference(grant_ref_t *private_head,
+ grant_ref_t release)
+{
+ gnttab_entry(release) = *private_head;
+ *private_head = release;
+}
+EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
+
+void gnttab_request_free_callback(struct gnttab_free_callback *callback,
+ void (*fn)(void *), void *arg, u16 count)
+{
+ unsigned long flags;
+ struct gnttab_free_callback *cb;
+
+ spin_lock_irqsave(&gnttab_list_lock, flags);
+
+ /* Check if the callback is already on the list */
+ cb = gnttab_free_callback_list;
+ while (cb) {
+ if (cb == callback)
+ goto out;
+ cb = cb->next;
+ }
+
+ callback->fn = fn;
+ callback->arg = arg;
+ callback->count = count;
+ callback->next = gnttab_free_callback_list;
+ gnttab_free_callback_list = callback;
+ check_free_callbacks();
+out:
+ spin_unlock_irqrestore(&gnttab_list_lock, flags);
+}
+EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
+
+void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
+{
+ struct gnttab_free_callback **pcb;
+ unsigned long flags;
+
+ spin_lock_irqsave(&gnttab_list_lock, flags);
+ for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
+ if (*pcb == callback) {
+ *pcb = callback->next;
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&gnttab_list_lock, flags);
+}
+EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
+
+static int grow_gnttab_list(unsigned int more_frames)
+{
+ unsigned int new_nr_grant_frames, extra_entries, i;
+ unsigned int nr_glist_frames, new_nr_glist_frames;
+
+ BUG_ON(grefs_per_grant_frame == 0);
+
+ new_nr_grant_frames = nr_grant_frames + more_frames;
+ extra_entries = more_frames * grefs_per_grant_frame;
+
+ nr_glist_frames = (nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
+ new_nr_glist_frames =
+ (new_nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
+ for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
+ gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
+ if (!gnttab_list[i])
+ goto grow_nomem;
+ }
+
+
+ for (i = grefs_per_grant_frame * nr_grant_frames;
+ i < grefs_per_grant_frame * new_nr_grant_frames - 1; i++)
+ gnttab_entry(i) = i + 1;
+
+ gnttab_entry(i) = gnttab_free_head;
+ gnttab_free_head = grefs_per_grant_frame * nr_grant_frames;
+ gnttab_free_count += extra_entries;
+
+ nr_grant_frames = new_nr_grant_frames;
+
+ check_free_callbacks();
+
+ return 0;
+
+grow_nomem:
+ while (i-- > nr_glist_frames)
+ free_page((unsigned long) gnttab_list[i]);
+ return -ENOMEM;
+}
+
+static unsigned int __max_nr_grant_frames(void)
+{
+ struct gnttab_query_size query;
+ int rc;
+
+ query.dom = DOMID_SELF;
+
+ rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
+ if ((rc < 0) || (query.status != GNTST_okay))
+ return 4; /* Legacy max supported number of frames */
+
+ return query.max_nr_frames;
+}
+
+unsigned int gnttab_max_grant_frames(void)
+{
+ unsigned int xen_max = __max_nr_grant_frames();
+ static unsigned int boot_max_nr_grant_frames;
+
+ /* First time, initialize it properly. */
+ if (!boot_max_nr_grant_frames)
+ boot_max_nr_grant_frames = __max_nr_grant_frames();
+
+ if (xen_max > boot_max_nr_grant_frames)
+ return boot_max_nr_grant_frames;
+ return xen_max;
+}
+EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
+
+int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
+{
+ xen_pfn_t *pfn;
+ unsigned int max_nr_gframes = __max_nr_grant_frames();
+ unsigned int i;
+ void *vaddr;
+
+ if (xen_auto_xlat_grant_frames.count)
+ return -EINVAL;
+
+ vaddr = xen_remap(addr, PAGE_SIZE * max_nr_gframes);
+ if (vaddr == NULL) {
+ pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
+ &addr);
+ return -ENOMEM;
+ }
+ pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
+ if (!pfn) {
+ xen_unmap(vaddr);
+ return -ENOMEM;
+ }
+ for (i = 0; i < max_nr_gframes; i++)
+ pfn[i] = PFN_DOWN(addr) + i;
+
+ xen_auto_xlat_grant_frames.vaddr = vaddr;
+ xen_auto_xlat_grant_frames.pfn = pfn;
+ xen_auto_xlat_grant_frames.count = max_nr_gframes;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
+
+void gnttab_free_auto_xlat_frames(void)
+{
+ if (!xen_auto_xlat_grant_frames.count)
+ return;
+ kfree(xen_auto_xlat_grant_frames.pfn);
+ xen_unmap(xen_auto_xlat_grant_frames.vaddr);
+
+ xen_auto_xlat_grant_frames.pfn = NULL;
+ xen_auto_xlat_grant_frames.count = 0;
+ xen_auto_xlat_grant_frames.vaddr = NULL;
+}
+EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
+
+/**
+ * gnttab_alloc_pages - alloc pages suitable for grant mapping into
+ * @nr_pages: number of pages to alloc
+ * @pages: returns the pages
+ */
+int gnttab_alloc_pages(int nr_pages, struct page **pages)
+{
+ int i;
+ int ret;
+
+ ret = alloc_xenballooned_pages(nr_pages, pages, false);
+ if (ret < 0)
+ return ret;
+
+ for (i = 0; i < nr_pages; i++) {
+#if BITS_PER_LONG < 64
+ struct xen_page_foreign *foreign;
+
+ foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
+ if (!foreign) {
+ gnttab_free_pages(nr_pages, pages);
+ return -ENOMEM;
+ }
+ set_page_private(pages[i], (unsigned long)foreign);
+#endif
+ SetPagePrivate(pages[i]);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(gnttab_alloc_pages);
+
+/**
+ * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
+ * @nr_pages; number of pages to free
+ * @pages: the pages
+ */
+void gnttab_free_pages(int nr_pages, struct page **pages)
+{
+ int i;
+
+ for (i = 0; i < nr_pages; i++) {
+ if (PagePrivate(pages[i])) {
+#if BITS_PER_LONG < 64
+ kfree((void *)page_private(pages[i]));
+#endif
+ ClearPagePrivate(pages[i]);
+ }
+ }
+ free_xenballooned_pages(nr_pages, pages);
+}
+EXPORT_SYMBOL(gnttab_free_pages);
+
+/* Handling of paged out grant targets (GNTST_eagain) */
+#define MAX_DELAY 256
+static inline void
+gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
+ const char *func)
+{
+ unsigned delay = 1;
+
+ do {
+ BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
+ if (*status == GNTST_eagain)
+ msleep(delay++);
+ } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
+
+ if (delay >= MAX_DELAY) {
+ pr_err("%s: %s eagain grant\n", func, current->comm);
+ *status = GNTST_bad_page;
+ }
+}
+
+void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
+{
+ struct gnttab_map_grant_ref *op;
+
+ if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
+ BUG();
+ for (op = batch; op < batch + count; op++)
+ if (op->status == GNTST_eagain)
+ gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
+ &op->status, __func__);
+}
+EXPORT_SYMBOL_GPL(gnttab_batch_map);
+
+void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
+{
+ struct gnttab_copy *op;
+
+ if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
+ BUG();
+ for (op = batch; op < batch + count; op++)
+ if (op->status == GNTST_eagain)
+ gnttab_retry_eagain_gop(GNTTABOP_copy, op,
+ &op->status, __func__);
+}
+EXPORT_SYMBOL_GPL(gnttab_batch_copy);
+
+int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
+ struct gnttab_map_grant_ref *kmap_ops,
+ struct page **pages, unsigned int count)
+{
+ int i, ret;
+
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < count; i++) {
+ /* Retry eagain maps */
+ if (map_ops[i].status == GNTST_eagain)
+ gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, map_ops + i,
+ &map_ops[i].status, __func__);
+
+ if (map_ops[i].status == GNTST_okay) {
+ struct xen_page_foreign *foreign;
+
+ SetPageForeign(pages[i]);
+ foreign = xen_page_foreign(pages[i]);
+ foreign->domid = map_ops[i].dom;
+ foreign->gref = map_ops[i].ref;
+ }
+ }
+
+ return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
+}
+EXPORT_SYMBOL_GPL(gnttab_map_refs);
+
+int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
+ struct gnttab_unmap_grant_ref *kunmap_ops,
+ struct page **pages, unsigned int count)
+{
+ unsigned int i;
+ int ret;
+
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < count; i++)
+ ClearPageForeign(pages[i]);
+
+ return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
+}
+EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
+
+#define GNTTAB_UNMAP_REFS_DELAY 5
+
+static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
+
+static void gnttab_unmap_work(struct work_struct *work)
+{
+ struct gntab_unmap_queue_data
+ *unmap_data = container_of(work,
+ struct gntab_unmap_queue_data,
+ gnttab_work.work);
+ if (unmap_data->age != UINT_MAX)
+ unmap_data->age++;
+ __gnttab_unmap_refs_async(unmap_data);
+}
+
+static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
+{
+ int ret;
+ int pc;
+
+ for (pc = 0; pc < item->count; pc++) {
+ if (page_count(item->pages[pc]) > 1) {
+ unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
+ schedule_delayed_work(&item->gnttab_work,
+ msecs_to_jiffies(delay));
+ return;
+ }
+ }
+
+ ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
+ item->pages, item->count);
+ item->done(ret, item);
+}
+
+void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
+{
+ INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
+ item->age = 0;
+
+ __gnttab_unmap_refs_async(item);
+}
+EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
+
+static void unmap_refs_callback(int result,
+ struct gntab_unmap_queue_data *data)
+{
+ struct unmap_refs_callback_data *d = data->data;
+
+ d->result = result;
+ complete(&d->completion);
+}
+
+int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
+{
+ struct unmap_refs_callback_data data;
+
+ init_completion(&data.completion);
+ item->data = &data;
+ item->done = &unmap_refs_callback;
+ gnttab_unmap_refs_async(item);
+ wait_for_completion(&data.completion);
+
+ return data.result;
+}
+EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
+
+static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
+{
+ int rc;
+
+ rc = arch_gnttab_map_shared(frames, nr_gframes,
+ gnttab_max_grant_frames(),
+ &gnttab_shared.addr);
+ BUG_ON(rc);
+
+ return 0;
+}
+
+static void gnttab_unmap_frames_v1(void)
+{
+ arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
+}
+
+static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
+{
+ struct gnttab_setup_table setup;
+ xen_pfn_t *frames;
+ unsigned int nr_gframes = end_idx + 1;
+ int rc;
+
+ if (xen_feature(XENFEAT_auto_translated_physmap)) {
+ struct xen_add_to_physmap xatp;
+ unsigned int i = end_idx;
+ rc = 0;
+ BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
+ /*
+ * Loop backwards, so that the first hypercall has the largest
+ * index, ensuring that the table will grow only once.
+ */
+ do {
+ xatp.domid = DOMID_SELF;
+ xatp.idx = i;
+ xatp.space = XENMAPSPACE_grant_table;
+ xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
+ rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
+ if (rc != 0) {
+ pr_warn("grant table add_to_physmap failed, err=%d\n",
+ rc);
+ break;
+ }
+ } while (i-- > start_idx);
+
+ return rc;
+ }
+
+ /* No need for kzalloc as it is initialized in following hypercall
+ * GNTTABOP_setup_table.
+ */
+ frames = kmalloc(nr_gframes * sizeof(unsigned long), GFP_ATOMIC);
+ if (!frames)
+ return -ENOMEM;
+
+ setup.dom = DOMID_SELF;
+ setup.nr_frames = nr_gframes;
+ set_xen_guest_handle(setup.frame_list, frames);
+
+ rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
+ if (rc == -ENOSYS) {
+ kfree(frames);
+ return -ENOSYS;
+ }
+
+ BUG_ON(rc || setup.status);
+
+ rc = gnttab_interface->map_frames(frames, nr_gframes);
+
+ kfree(frames);
+
+ return rc;
+}
+
+static struct gnttab_ops gnttab_v1_ops = {
+ .map_frames = gnttab_map_frames_v1,
+ .unmap_frames = gnttab_unmap_frames_v1,
+ .update_entry = gnttab_update_entry_v1,
+ .end_foreign_access_ref = gnttab_end_foreign_access_ref_v1,
+ .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v1,
+ .query_foreign_access = gnttab_query_foreign_access_v1,
+};
+
+static void gnttab_request_version(void)
+{
+ /* Only version 1 is used, which will always be available. */
+ grant_table_version = 1;
+ grefs_per_grant_frame = PAGE_SIZE / sizeof(struct grant_entry_v1);
+ gnttab_interface = &gnttab_v1_ops;
+
+ pr_info("Grant tables using version %d layout\n", grant_table_version);
+}
+
+static int gnttab_setup(void)
+{
+ unsigned int max_nr_gframes;
+
+ max_nr_gframes = gnttab_max_grant_frames();
+ if (max_nr_gframes < nr_grant_frames)
+ return -ENOSYS;
+
+ if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
+ gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
+ if (gnttab_shared.addr == NULL) {
+ pr_warn("gnttab share frames (addr=0x%08lx) is not mapped!\n",
+ (unsigned long)xen_auto_xlat_grant_frames.vaddr);
+ return -ENOMEM;
+ }
+ }
+ return gnttab_map(0, nr_grant_frames - 1);
+}
+
+int gnttab_resume(void)
+{
+ gnttab_request_version();
+ return gnttab_setup();
+}
+
+int gnttab_suspend(void)
+{
+ if (!xen_feature(XENFEAT_auto_translated_physmap))
+ gnttab_interface->unmap_frames();
+ return 0;
+}
+
+static int gnttab_expand(unsigned int req_entries)
+{
+ int rc;
+ unsigned int cur, extra;
+
+ BUG_ON(grefs_per_grant_frame == 0);
+ cur = nr_grant_frames;
+ extra = ((req_entries + (grefs_per_grant_frame-1)) /
+ grefs_per_grant_frame);
+ if (cur + extra > gnttab_max_grant_frames())
+ return -ENOSPC;
+
+ rc = gnttab_map(cur, cur + extra - 1);
+ if (rc == 0)
+ rc = grow_gnttab_list(extra);
+
+ return rc;
+}
+
+int gnttab_init(void)
+{
+ int i;
+ unsigned long max_nr_grant_frames;
+ unsigned int max_nr_glist_frames, nr_glist_frames;
+ unsigned int nr_init_grefs;
+ int ret;
+
+ gnttab_request_version();
+ max_nr_grant_frames = gnttab_max_grant_frames();
+ nr_grant_frames = 1;
+
+ /* Determine the maximum number of frames required for the
+ * grant reference free list on the current hypervisor.
+ */
+ BUG_ON(grefs_per_grant_frame == 0);
+ max_nr_glist_frames = (max_nr_grant_frames *
+ grefs_per_grant_frame / RPP);
+
+ gnttab_list = kmalloc(max_nr_glist_frames * sizeof(grant_ref_t *),
+ GFP_KERNEL);
+ if (gnttab_list == NULL)
+ return -ENOMEM;
+
+ nr_glist_frames = (nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
+ for (i = 0; i < nr_glist_frames; i++) {
+ gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
+ if (gnttab_list[i] == NULL) {
+ ret = -ENOMEM;
+ goto ini_nomem;
+ }
+ }
+
+ ret = arch_gnttab_init(max_nr_grant_frames);
+ if (ret < 0)
+ goto ini_nomem;
+
+ if (gnttab_setup() < 0) {
+ ret = -ENODEV;
+ goto ini_nomem;
+ }
+
+ nr_init_grefs = nr_grant_frames * grefs_per_grant_frame;
+
+ for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
+ gnttab_entry(i) = i + 1;
+
+ gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
+ gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
+ gnttab_free_head = NR_RESERVED_ENTRIES;
+
+ printk("Grant table initialized\n");
+ return 0;
+
+ ini_nomem:
+ for (i--; i >= 0; i--)
+ free_page((unsigned long)gnttab_list[i]);
+ kfree(gnttab_list);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(gnttab_init);
+
+static int __gnttab_init(void)
+{
+ /* Delay grant-table initialization in the PV on HVM case */
+ if (xen_hvm_domain())
+ return 0;
+
+ if (!xen_pv_domain())
+ return -ENODEV;
+
+ return gnttab_init();
+}
+/* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
+ * beforehand to initialize xen_auto_xlat_grant_frames. */
+core_initcall_sync(__gnttab_init);
Code Review / kvmfornfv.git / blobdiff