![Jeremy Fitzhardinge](/assets/img/avatar_default.png)
Move xen_domain and related tests out of asm-x86 to xen/xen.h so they can be included whenever they are necessary. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
560 lines
14 KiB
C
560 lines
14 KiB
C
/******************************************************************************
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* grant_table.c
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*
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* Granting foreign access to our memory reservation.
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*
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* Copyright (c) 2005-2006, Christopher Clark
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* Copyright (c) 2004-2005, K A Fraser
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation; or, when distributed
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* separately from the Linux kernel or incorporated into other
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* software packages, subject to the following license:
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this source file (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy, modify,
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* merge, publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/vmalloc.h>
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#include <linux/uaccess.h>
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#include <xen/xen.h>
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#include <xen/interface/xen.h>
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#include <xen/page.h>
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#include <xen/grant_table.h>
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#include <asm/xen/hypercall.h>
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#include <asm/pgtable.h>
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#include <asm/sync_bitops.h>
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/* External tools reserve first few grant table entries. */
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#define NR_RESERVED_ENTRIES 8
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#define GNTTAB_LIST_END 0xffffffff
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#define GREFS_PER_GRANT_FRAME (PAGE_SIZE / sizeof(struct grant_entry))
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static grant_ref_t **gnttab_list;
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static unsigned int nr_grant_frames;
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static unsigned int boot_max_nr_grant_frames;
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static int gnttab_free_count;
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static grant_ref_t gnttab_free_head;
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static DEFINE_SPINLOCK(gnttab_list_lock);
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static struct grant_entry *shared;
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static struct gnttab_free_callback *gnttab_free_callback_list;
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static int gnttab_expand(unsigned int req_entries);
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#define RPP (PAGE_SIZE / sizeof(grant_ref_t))
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static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
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{
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return &gnttab_list[(entry) / RPP][(entry) % RPP];
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}
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/* This can be used as an l-value */
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#define gnttab_entry(entry) (*__gnttab_entry(entry))
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static int get_free_entries(unsigned count)
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{
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unsigned long flags;
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int ref, rc;
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grant_ref_t head;
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spin_lock_irqsave(&gnttab_list_lock, flags);
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if ((gnttab_free_count < count) &&
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((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
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spin_unlock_irqrestore(&gnttab_list_lock, flags);
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return rc;
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}
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ref = head = gnttab_free_head;
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gnttab_free_count -= count;
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while (count-- > 1)
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head = gnttab_entry(head);
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gnttab_free_head = gnttab_entry(head);
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gnttab_entry(head) = GNTTAB_LIST_END;
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spin_unlock_irqrestore(&gnttab_list_lock, flags);
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return ref;
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}
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static void do_free_callbacks(void)
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{
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struct gnttab_free_callback *callback, *next;
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callback = gnttab_free_callback_list;
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gnttab_free_callback_list = NULL;
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while (callback != NULL) {
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next = callback->next;
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if (gnttab_free_count >= callback->count) {
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callback->next = NULL;
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callback->fn(callback->arg);
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} else {
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callback->next = gnttab_free_callback_list;
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gnttab_free_callback_list = callback;
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}
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callback = next;
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}
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}
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static inline void check_free_callbacks(void)
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{
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if (unlikely(gnttab_free_callback_list))
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do_free_callbacks();
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}
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static void put_free_entry(grant_ref_t ref)
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{
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unsigned long flags;
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spin_lock_irqsave(&gnttab_list_lock, flags);
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gnttab_entry(ref) = gnttab_free_head;
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gnttab_free_head = ref;
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gnttab_free_count++;
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check_free_callbacks();
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spin_unlock_irqrestore(&gnttab_list_lock, flags);
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}
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static void update_grant_entry(grant_ref_t ref, domid_t domid,
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unsigned long frame, unsigned flags)
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{
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/*
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* Introducing a valid entry into the grant table:
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* 1. Write ent->domid.
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* 2. Write ent->frame:
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* GTF_permit_access: Frame to which access is permitted.
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* GTF_accept_transfer: Pseudo-phys frame slot being filled by new
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* frame, or zero if none.
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* 3. Write memory barrier (WMB).
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* 4. Write ent->flags, inc. valid type.
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*/
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shared[ref].frame = frame;
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shared[ref].domid = domid;
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wmb();
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shared[ref].flags = flags;
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}
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/*
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* Public grant-issuing interface functions
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*/
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void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
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unsigned long frame, int readonly)
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{
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update_grant_entry(ref, domid, frame,
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GTF_permit_access | (readonly ? GTF_readonly : 0));
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}
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EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
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int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
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int readonly)
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{
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int ref;
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ref = get_free_entries(1);
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if (unlikely(ref < 0))
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return -ENOSPC;
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gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
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return ref;
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}
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EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
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int gnttab_query_foreign_access(grant_ref_t ref)
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{
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u16 nflags;
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nflags = shared[ref].flags;
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return (nflags & (GTF_reading|GTF_writing));
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}
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EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
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int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
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{
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u16 flags, nflags;
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nflags = shared[ref].flags;
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do {
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flags = nflags;
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if (flags & (GTF_reading|GTF_writing)) {
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printk(KERN_ALERT "WARNING: g.e. still in use!\n");
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return 0;
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}
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} while ((nflags = sync_cmpxchg(&shared[ref].flags, flags, 0)) != flags);
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return 1;
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}
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EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
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void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
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unsigned long page)
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{
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if (gnttab_end_foreign_access_ref(ref, readonly)) {
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put_free_entry(ref);
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if (page != 0)
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free_page(page);
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} else {
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/* XXX This needs to be fixed so that the ref and page are
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placed on a list to be freed up later. */
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printk(KERN_WARNING
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"WARNING: leaking g.e. and page still in use!\n");
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}
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}
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EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
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int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
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{
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int ref;
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ref = get_free_entries(1);
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if (unlikely(ref < 0))
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return -ENOSPC;
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gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
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return ref;
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}
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EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
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void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
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unsigned long pfn)
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{
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update_grant_entry(ref, domid, pfn, GTF_accept_transfer);
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}
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EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
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unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
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{
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unsigned long frame;
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u16 flags;
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/*
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* If a transfer is not even yet started, try to reclaim the grant
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* reference and return failure (== 0).
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*/
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while (!((flags = shared[ref].flags) & GTF_transfer_committed)) {
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if (sync_cmpxchg(&shared[ref].flags, flags, 0) == flags)
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return 0;
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cpu_relax();
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}
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/* If a transfer is in progress then wait until it is completed. */
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while (!(flags & GTF_transfer_completed)) {
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flags = shared[ref].flags;
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cpu_relax();
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}
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rmb(); /* Read the frame number /after/ reading completion status. */
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frame = shared[ref].frame;
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BUG_ON(frame == 0);
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return frame;
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}
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EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
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unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
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{
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unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
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put_free_entry(ref);
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return frame;
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}
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EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
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void gnttab_free_grant_reference(grant_ref_t ref)
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{
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put_free_entry(ref);
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}
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EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
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void gnttab_free_grant_references(grant_ref_t head)
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{
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grant_ref_t ref;
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unsigned long flags;
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int count = 1;
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if (head == GNTTAB_LIST_END)
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return;
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spin_lock_irqsave(&gnttab_list_lock, flags);
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ref = head;
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while (gnttab_entry(ref) != GNTTAB_LIST_END) {
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ref = gnttab_entry(ref);
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count++;
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}
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gnttab_entry(ref) = gnttab_free_head;
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gnttab_free_head = head;
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gnttab_free_count += count;
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check_free_callbacks();
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spin_unlock_irqrestore(&gnttab_list_lock, flags);
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}
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EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
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int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
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{
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int h = get_free_entries(count);
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if (h < 0)
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return -ENOSPC;
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*head = h;
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return 0;
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}
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EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
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int gnttab_empty_grant_references(const grant_ref_t *private_head)
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{
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return (*private_head == GNTTAB_LIST_END);
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}
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EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
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int gnttab_claim_grant_reference(grant_ref_t *private_head)
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{
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grant_ref_t g = *private_head;
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if (unlikely(g == GNTTAB_LIST_END))
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return -ENOSPC;
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*private_head = gnttab_entry(g);
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return g;
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}
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EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
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void gnttab_release_grant_reference(grant_ref_t *private_head,
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grant_ref_t release)
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{
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gnttab_entry(release) = *private_head;
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*private_head = release;
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}
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EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
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void gnttab_request_free_callback(struct gnttab_free_callback *callback,
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void (*fn)(void *), void *arg, u16 count)
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{
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unsigned long flags;
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spin_lock_irqsave(&gnttab_list_lock, flags);
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if (callback->next)
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goto out;
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callback->fn = fn;
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callback->arg = arg;
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callback->count = count;
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callback->next = gnttab_free_callback_list;
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gnttab_free_callback_list = callback;
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check_free_callbacks();
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out:
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spin_unlock_irqrestore(&gnttab_list_lock, flags);
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}
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EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
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void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
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{
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struct gnttab_free_callback **pcb;
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unsigned long flags;
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spin_lock_irqsave(&gnttab_list_lock, flags);
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for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
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if (*pcb == callback) {
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*pcb = callback->next;
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break;
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}
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}
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spin_unlock_irqrestore(&gnttab_list_lock, flags);
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}
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EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
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static int grow_gnttab_list(unsigned int more_frames)
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{
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unsigned int new_nr_grant_frames, extra_entries, i;
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unsigned int nr_glist_frames, new_nr_glist_frames;
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new_nr_grant_frames = nr_grant_frames + more_frames;
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extra_entries = more_frames * GREFS_PER_GRANT_FRAME;
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nr_glist_frames = (nr_grant_frames * GREFS_PER_GRANT_FRAME + RPP - 1) / RPP;
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new_nr_glist_frames =
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(new_nr_grant_frames * GREFS_PER_GRANT_FRAME + RPP - 1) / RPP;
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for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
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gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
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if (!gnttab_list[i])
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goto grow_nomem;
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}
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for (i = GREFS_PER_GRANT_FRAME * nr_grant_frames;
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i < GREFS_PER_GRANT_FRAME * new_nr_grant_frames - 1; i++)
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gnttab_entry(i) = i + 1;
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gnttab_entry(i) = gnttab_free_head;
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gnttab_free_head = GREFS_PER_GRANT_FRAME * nr_grant_frames;
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gnttab_free_count += extra_entries;
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nr_grant_frames = new_nr_grant_frames;
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check_free_callbacks();
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return 0;
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grow_nomem:
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for ( ; i >= nr_glist_frames; i--)
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free_page((unsigned long) gnttab_list[i]);
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return -ENOMEM;
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}
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static unsigned int __max_nr_grant_frames(void)
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{
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struct gnttab_query_size query;
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int rc;
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query.dom = DOMID_SELF;
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rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
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if ((rc < 0) || (query.status != GNTST_okay))
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return 4; /* Legacy max supported number of frames */
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return query.max_nr_frames;
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}
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static inline unsigned int max_nr_grant_frames(void)
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{
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unsigned int xen_max = __max_nr_grant_frames();
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if (xen_max > boot_max_nr_grant_frames)
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return boot_max_nr_grant_frames;
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return xen_max;
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}
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static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
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{
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struct gnttab_setup_table setup;
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unsigned long *frames;
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unsigned int nr_gframes = end_idx + 1;
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int rc;
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frames = kmalloc(nr_gframes * sizeof(unsigned long), GFP_ATOMIC);
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if (!frames)
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return -ENOMEM;
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setup.dom = DOMID_SELF;
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setup.nr_frames = nr_gframes;
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set_xen_guest_handle(setup.frame_list, frames);
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rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
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if (rc == -ENOSYS) {
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kfree(frames);
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return -ENOSYS;
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}
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BUG_ON(rc || setup.status);
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rc = arch_gnttab_map_shared(frames, nr_gframes, max_nr_grant_frames(),
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&shared);
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BUG_ON(rc);
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kfree(frames);
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return 0;
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}
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int gnttab_resume(void)
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{
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if (max_nr_grant_frames() < nr_grant_frames)
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return -ENOSYS;
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return gnttab_map(0, nr_grant_frames - 1);
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}
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int gnttab_suspend(void)
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{
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arch_gnttab_unmap_shared(shared, nr_grant_frames);
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return 0;
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}
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static int gnttab_expand(unsigned int req_entries)
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{
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int rc;
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unsigned int cur, extra;
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cur = nr_grant_frames;
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extra = ((req_entries + (GREFS_PER_GRANT_FRAME-1)) /
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GREFS_PER_GRANT_FRAME);
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if (cur + extra > max_nr_grant_frames())
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return -ENOSPC;
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rc = gnttab_map(cur, cur + extra - 1);
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if (rc == 0)
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rc = grow_gnttab_list(extra);
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return rc;
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}
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static int __devinit gnttab_init(void)
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{
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int i;
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unsigned int max_nr_glist_frames, nr_glist_frames;
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unsigned int nr_init_grefs;
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if (!xen_domain())
|
|
return -ENODEV;
|
|
|
|
nr_grant_frames = 1;
|
|
boot_max_nr_grant_frames = __max_nr_grant_frames();
|
|
|
|
/* Determine the maximum number of frames required for the
|
|
* grant reference free list on the current hypervisor.
|
|
*/
|
|
max_nr_glist_frames = (boot_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)
|
|
goto ini_nomem;
|
|
}
|
|
|
|
if (gnttab_resume() < 0)
|
|
return -ENODEV;
|
|
|
|
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 -ENOMEM;
|
|
}
|
|
|
|
core_initcall(gnttab_init);
|