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![David Vrabel](/assets/img/avatar_default.png)
arch_gnttab_map_frames() and arch_gnttab_unmap_frames() are called in atomic context but were calling alloc_vm_area() which might sleep. Also, if a driver attempts to allocate a grant ref from an interrupt and the table needs expanding, then the CPU may already by in lazy MMU mode and apply_to_page_range() will BUG when it tries to re-enable lazy MMU mode. These two functions are only used in PV guests. Introduce arch_gnttab_init() to allocates the virtual address space in advance. Avoid the use of apply_to_page_range() by using saving and using the array of PTE addresses from the alloc_vm_area() call (which ensures that the required page tables are pre-allocated). Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
1271 lines
34 KiB
C
1271 lines
34 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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#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
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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/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/uaccess.h>
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#include <linux/io.h>
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#include <linux/delay.h>
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#include <linux/hardirq.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 <xen/interface/memory.h>
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#include <xen/hvc-console.h>
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#include <xen/swiotlb-xen.h>
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#include <asm/xen/hypercall.h>
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#include <asm/xen/interface.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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static grant_ref_t **gnttab_list;
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static unsigned int 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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struct grant_frames xen_auto_xlat_grant_frames;
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static union {
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struct grant_entry_v1 *v1;
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union grant_entry_v2 *v2;
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void *addr;
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} gnttab_shared;
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/*This is a structure of function pointers for grant table*/
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struct gnttab_ops {
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/*
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* Mapping a list of frames for storing grant entries. Frames parameter
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* is used to store grant table address when grant table being setup,
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* nr_gframes is the number of frames to map grant table. Returning
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* GNTST_okay means success and negative value means failure.
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*/
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int (*map_frames)(xen_pfn_t *frames, unsigned int nr_gframes);
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/*
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* Release a list of frames which are mapped in map_frames for grant
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* entry status.
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*/
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void (*unmap_frames)(void);
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/*
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* Introducing a valid entry into the grant table, granting the frame of
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* this grant entry to domain for accessing or transfering. Ref
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* parameter is reference of this introduced grant entry, domid is id of
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* granted domain, frame is the page frame to be granted, and flags is
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* status of the grant entry to be updated.
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*/
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void (*update_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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* Stop granting a grant entry to domain for accessing. Ref parameter is
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* reference of a grant entry whose grant access will be stopped,
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* readonly is not in use in this function. If the grant entry is
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* currently mapped for reading or writing, just return failure(==0)
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* directly and don't tear down the grant access. Otherwise, stop grant
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* access for this entry and return success(==1).
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*/
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int (*end_foreign_access_ref)(grant_ref_t ref, int readonly);
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/*
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* Stop granting a grant entry to domain for transfer. Ref parameter is
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* reference of a grant entry whose grant transfer will be stopped. If
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* tranfer has not started, just reclaim the grant entry and return
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* failure(==0). Otherwise, wait for the transfer to complete and then
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* return the frame.
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*/
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unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
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/*
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* Query the status of a grant entry. Ref parameter is reference of
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* queried grant entry, return value is the status of queried entry.
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* Detailed status(writing/reading) can be gotten from the return value
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* by bit operations.
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*/
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int (*query_foreign_access)(grant_ref_t ref);
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/*
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* Grant a domain to access a range of bytes within the page referred by
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* an available grant entry. Ref parameter is reference of a grant entry
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* which will be sub-page accessed, domid is id of grantee domain, frame
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* is frame address of subpage grant, flags is grant type and flag
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* information, page_off is offset of the range of bytes, and length is
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* length of bytes to be accessed.
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*/
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void (*update_subpage_entry)(grant_ref_t ref, domid_t domid,
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unsigned long frame, int flags,
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unsigned page_off, unsigned length);
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/*
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* Redirect an available grant entry on domain A to another grant
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* reference of domain B, then allow domain C to use grant reference
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* of domain B transitively. Ref parameter is an available grant entry
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* reference on domain A, domid is id of domain C which accesses grant
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* entry transitively, flags is grant type and flag information,
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* trans_domid is id of domain B whose grant entry is finally accessed
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* transitively, trans_gref is grant entry transitive reference of
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* domain B.
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*/
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void (*update_trans_entry)(grant_ref_t ref, domid_t domid, int flags,
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domid_t trans_domid, grant_ref_t trans_gref);
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};
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static struct gnttab_ops *gnttab_interface;
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/*This reflects status of grant entries, so act as a global value*/
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static grant_status_t *grstatus;
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static int grant_table_version;
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static int grefs_per_grant_frame;
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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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#define SPP (PAGE_SIZE / sizeof(grant_status_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 = 0;
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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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/*
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* Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2.
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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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static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
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unsigned long frame, unsigned flags)
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{
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gnttab_shared.v1[ref].domid = domid;
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gnttab_shared.v1[ref].frame = frame;
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wmb();
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gnttab_shared.v1[ref].flags = flags;
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}
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static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid,
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unsigned long frame, unsigned flags)
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{
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gnttab_shared.v2[ref].hdr.domid = domid;
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gnttab_shared.v2[ref].full_page.frame = frame;
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wmb();
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gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | 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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gnttab_interface->update_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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static void gnttab_update_subpage_entry_v2(grant_ref_t ref, domid_t domid,
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unsigned long frame, int flags,
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unsigned page_off, unsigned length)
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{
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gnttab_shared.v2[ref].sub_page.frame = frame;
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gnttab_shared.v2[ref].sub_page.page_off = page_off;
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gnttab_shared.v2[ref].sub_page.length = length;
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gnttab_shared.v2[ref].hdr.domid = domid;
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wmb();
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gnttab_shared.v2[ref].hdr.flags =
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GTF_permit_access | GTF_sub_page | flags;
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}
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int gnttab_grant_foreign_access_subpage_ref(grant_ref_t ref, domid_t domid,
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unsigned long frame, int flags,
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unsigned page_off,
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unsigned length)
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{
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if (flags & (GTF_accept_transfer | GTF_reading |
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GTF_writing | GTF_transitive))
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return -EPERM;
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if (gnttab_interface->update_subpage_entry == NULL)
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return -ENOSYS;
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gnttab_interface->update_subpage_entry(ref, domid, frame, flags,
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page_off, length);
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return 0;
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}
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EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_subpage_ref);
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int gnttab_grant_foreign_access_subpage(domid_t domid, unsigned long frame,
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int flags, unsigned page_off,
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unsigned length)
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{
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int ref, rc;
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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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rc = gnttab_grant_foreign_access_subpage_ref(ref, domid, frame, flags,
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page_off, length);
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if (rc < 0) {
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put_free_entry(ref);
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return rc;
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}
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return ref;
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}
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EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_subpage);
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bool gnttab_subpage_grants_available(void)
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{
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return gnttab_interface->update_subpage_entry != NULL;
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}
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EXPORT_SYMBOL_GPL(gnttab_subpage_grants_available);
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static void gnttab_update_trans_entry_v2(grant_ref_t ref, domid_t domid,
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int flags, domid_t trans_domid,
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grant_ref_t trans_gref)
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{
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gnttab_shared.v2[ref].transitive.trans_domid = trans_domid;
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gnttab_shared.v2[ref].transitive.gref = trans_gref;
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gnttab_shared.v2[ref].hdr.domid = domid;
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wmb();
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gnttab_shared.v2[ref].hdr.flags =
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GTF_permit_access | GTF_transitive | flags;
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}
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int gnttab_grant_foreign_access_trans_ref(grant_ref_t ref, domid_t domid,
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int flags, domid_t trans_domid,
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grant_ref_t trans_gref)
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{
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if (flags & (GTF_accept_transfer | GTF_reading |
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GTF_writing | GTF_sub_page))
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return -EPERM;
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if (gnttab_interface->update_trans_entry == NULL)
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return -ENOSYS;
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gnttab_interface->update_trans_entry(ref, domid, flags, trans_domid,
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trans_gref);
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return 0;
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}
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EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_trans_ref);
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int gnttab_grant_foreign_access_trans(domid_t domid, int flags,
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domid_t trans_domid,
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grant_ref_t trans_gref)
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{
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int ref, rc;
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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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rc = gnttab_grant_foreign_access_trans_ref(ref, domid, flags,
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trans_domid, trans_gref);
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if (rc < 0) {
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put_free_entry(ref);
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return rc;
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}
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return ref;
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}
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EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_trans);
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bool gnttab_trans_grants_available(void)
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{
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return gnttab_interface->update_trans_entry != NULL;
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}
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EXPORT_SYMBOL_GPL(gnttab_trans_grants_available);
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static int gnttab_query_foreign_access_v1(grant_ref_t ref)
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{
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return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
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}
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static int gnttab_query_foreign_access_v2(grant_ref_t ref)
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{
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return grstatus[ref] & (GTF_reading|GTF_writing);
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}
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int gnttab_query_foreign_access(grant_ref_t ref)
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{
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return gnttab_interface->query_foreign_access(ref);
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}
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EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
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static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
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{
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u16 flags, nflags;
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u16 *pflags;
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pflags = &gnttab_shared.v1[ref].flags;
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nflags = *pflags;
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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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return 0;
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} while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
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return 1;
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}
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static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref, int readonly)
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{
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gnttab_shared.v2[ref].hdr.flags = 0;
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mb();
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if (grstatus[ref] & (GTF_reading|GTF_writing)) {
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return 0;
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} else {
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/* The read of grstatus needs to have acquire
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semantics. On x86, reads already have
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that, and we just need to protect against
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compiler reorderings. On other
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architectures we may need a full
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barrier. */
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#ifdef CONFIG_X86
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barrier();
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#else
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mb();
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#endif
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}
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return 1;
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}
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static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
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{
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return gnttab_interface->end_foreign_access_ref(ref, readonly);
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}
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int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
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{
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if (_gnttab_end_foreign_access_ref(ref, readonly))
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return 1;
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pr_warn("WARNING: g.e. %#x still in use!\n", ref);
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return 0;
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}
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EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
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|
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struct deferred_entry {
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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;
|
|
}
|
|
|
|
static unsigned long gnttab_end_foreign_transfer_ref_v2(grant_ref_t ref)
|
|
{
|
|
unsigned long frame;
|
|
u16 flags;
|
|
u16 *pflags;
|
|
|
|
pflags = &gnttab_shared.v2[ref].hdr.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.v2[ref].full_page.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:
|
|
for ( ; i >= nr_glist_frames; i--)
|
|
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);
|
|
|
|
/* 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;
|
|
|
|
/* Retry eagain maps */
|
|
for (i = 0; i < count; i++)
|
|
if (map_ops[i].status == GNTST_eagain)
|
|
gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, map_ops + i,
|
|
&map_ops[i].status, __func__);
|
|
|
|
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_map_grant_ref *kmap_ops,
|
|
struct page **pages, unsigned int count)
|
|
{
|
|
int ret;
|
|
|
|
ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
|
|
if (ret)
|
|
return ret;
|
|
|
|
return clear_foreign_p2m_mapping(unmap_ops, kmap_ops, pages, count);
|
|
}
|
|
EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
|
|
|
|
static unsigned nr_status_frames(unsigned nr_grant_frames)
|
|
{
|
|
BUG_ON(grefs_per_grant_frame == 0);
|
|
return (nr_grant_frames * grefs_per_grant_frame + SPP - 1) / SPP;
|
|
}
|
|
|
|
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_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
|
|
{
|
|
uint64_t *sframes;
|
|
unsigned int nr_sframes;
|
|
struct gnttab_get_status_frames getframes;
|
|
int rc;
|
|
|
|
nr_sframes = nr_status_frames(nr_gframes);
|
|
|
|
/* No need for kzalloc as it is initialized in following hypercall
|
|
* GNTTABOP_get_status_frames.
|
|
*/
|
|
sframes = kmalloc(nr_sframes * sizeof(uint64_t), GFP_ATOMIC);
|
|
if (!sframes)
|
|
return -ENOMEM;
|
|
|
|
getframes.dom = DOMID_SELF;
|
|
getframes.nr_frames = nr_sframes;
|
|
set_xen_guest_handle(getframes.frame_list, sframes);
|
|
|
|
rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
|
|
&getframes, 1);
|
|
if (rc == -ENOSYS) {
|
|
kfree(sframes);
|
|
return -ENOSYS;
|
|
}
|
|
|
|
BUG_ON(rc || getframes.status);
|
|
|
|
rc = arch_gnttab_map_status(sframes, nr_sframes,
|
|
nr_status_frames(gnttab_max_grant_frames()),
|
|
&grstatus);
|
|
BUG_ON(rc);
|
|
kfree(sframes);
|
|
|
|
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_v2(void)
|
|
{
|
|
arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
|
|
arch_gnttab_unmap(grstatus, nr_status_frames(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 struct gnttab_ops gnttab_v2_ops = {
|
|
.map_frames = gnttab_map_frames_v2,
|
|
.unmap_frames = gnttab_unmap_frames_v2,
|
|
.update_entry = gnttab_update_entry_v2,
|
|
.end_foreign_access_ref = gnttab_end_foreign_access_ref_v2,
|
|
.end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v2,
|
|
.query_foreign_access = gnttab_query_foreign_access_v2,
|
|
.update_subpage_entry = gnttab_update_subpage_entry_v2,
|
|
.update_trans_entry = gnttab_update_trans_entry_v2,
|
|
};
|
|
|
|
static void gnttab_request_version(void)
|
|
{
|
|
int rc;
|
|
struct gnttab_set_version gsv;
|
|
|
|
gsv.version = 1;
|
|
|
|
rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
|
|
if (rc == 0 && gsv.version == 2) {
|
|
grant_table_version = 2;
|
|
grefs_per_grant_frame = PAGE_SIZE / sizeof(union grant_entry_v2);
|
|
gnttab_interface = &gnttab_v2_ops;
|
|
} else if (grant_table_version == 2) {
|
|
/*
|
|
* If we've already used version 2 features,
|
|
* but then suddenly discover that they're not
|
|
* available (e.g. migrating to an older
|
|
* version of Xen), almost unbounded badness
|
|
* can happen.
|
|
*/
|
|
panic("we need grant tables version 2, but only version 1 is available");
|
|
} else {
|
|
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,
|
|
nr_status_frames(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);
|