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![Juergen Gross](/assets/img/avatar_default.png)
For support of virtio via grant mappings in rare cases larger mappings using consecutive grants are needed. Support those by adding a bitmap of free grants. As consecutive grants will be needed only in very rare cases (e.g. when configuring a virtio device with a multi-page ring), optimize for the normal case of non-consecutive allocations. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/1654197833-25362-3-git-send-email-olekstysh@gmail.com Signed-off-by: Juergen Gross <jgross@suse.com>
342 lines
11 KiB
C
342 lines
11 KiB
C
/******************************************************************************
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* grant_table.h
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*
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* Two sets of functionality:
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* 1. Granting foreign access to our memory reservation.
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* 2. Accessing others' memory reservations via grant references.
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* (i.e., mechanisms for both sender and recipient of grant references)
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*
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* Copyright (c) 2004-2005, K A Fraser
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* Copyright (c) 2005, Christopher Clark
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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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#ifndef __ASM_GNTTAB_H__
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#define __ASM_GNTTAB_H__
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#include <asm/page.h>
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#include <xen/interface/xen.h>
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#include <xen/interface/grant_table.h>
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#include <asm/xen/hypervisor.h>
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#include <xen/features.h>
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#include <xen/page.h>
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#include <linux/mm_types.h>
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#include <linux/page-flags.h>
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#include <linux/kernel.h>
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/*
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* Technically there's no reliably invalid grant reference or grant handle,
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* so pick the value that is the most unlikely one to be observed valid.
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*/
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#define INVALID_GRANT_REF ((grant_ref_t)-1)
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#define INVALID_GRANT_HANDLE ((grant_handle_t)-1)
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/* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */
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#define NR_GRANT_FRAMES 4
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struct gnttab_free_callback {
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struct gnttab_free_callback *next;
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void (*fn)(void *);
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void *arg;
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u16 count;
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};
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struct gntab_unmap_queue_data;
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typedef void (*gnttab_unmap_refs_done)(int result, struct gntab_unmap_queue_data *data);
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struct gntab_unmap_queue_data
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{
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struct delayed_work gnttab_work;
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void *data;
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gnttab_unmap_refs_done done;
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struct gnttab_unmap_grant_ref *unmap_ops;
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struct gnttab_unmap_grant_ref *kunmap_ops;
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struct page **pages;
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unsigned int count;
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unsigned int age;
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};
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int gnttab_init(void);
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int gnttab_suspend(void);
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int gnttab_resume(void);
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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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* End access through the given grant reference, iff the grant entry is no
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* longer in use. Return 1 if the grant entry was freed, 0 if it is still in
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* use.
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*/
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int gnttab_end_foreign_access_ref(grant_ref_t ref);
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/*
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* Eventually end access through the given grant reference, and once that
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* access has been ended, free the given page too. Access will be ended
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* immediately iff the grant entry is not in use, otherwise it will happen
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* some time later. page may be NULL, in which case no freeing will occur.
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* Note that the granted page might still be accessed (read or write) by the
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* other side after gnttab_end_foreign_access() returns, so even if page was
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* specified as NULL it is not allowed to just reuse the page for other
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* purposes immediately. gnttab_end_foreign_access() will take an additional
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* reference to the granted page in this case, which is dropped only after
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* the grant is no longer in use.
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* This requires that multi page allocations for areas subject to
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* gnttab_end_foreign_access() are done via alloc_pages_exact() (and freeing
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* via free_pages_exact()) in order to avoid high order pages.
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*/
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void gnttab_end_foreign_access(grant_ref_t ref, struct page *page);
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/*
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* End access through the given grant reference, iff the grant entry is
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* no longer in use. In case of success ending foreign access, the
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* grant reference is deallocated.
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* Return 1 if the grant entry was freed, 0 if it is still in use.
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*/
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int gnttab_try_end_foreign_access(grant_ref_t ref);
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/*
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* operations on reserved batches of grant references
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*/
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int gnttab_alloc_grant_references(u16 count, grant_ref_t *pprivate_head);
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int gnttab_alloc_grant_reference_seq(unsigned int count, grant_ref_t *first);
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void gnttab_free_grant_reference(grant_ref_t ref);
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void gnttab_free_grant_references(grant_ref_t head);
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void gnttab_free_grant_reference_seq(grant_ref_t head, unsigned int count);
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int gnttab_empty_grant_references(const grant_ref_t *pprivate_head);
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int gnttab_claim_grant_reference(grant_ref_t *pprivate_head);
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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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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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void gnttab_cancel_free_callback(struct gnttab_free_callback *callback);
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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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/* Give access to the first 4K of the page */
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static inline void gnttab_page_grant_foreign_access_ref_one(
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grant_ref_t ref, domid_t domid,
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struct page *page, int readonly)
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{
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gnttab_grant_foreign_access_ref(ref, domid, xen_page_to_gfn(page),
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readonly);
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}
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static inline void
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gnttab_set_map_op(struct gnttab_map_grant_ref *map, phys_addr_t addr,
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uint32_t flags, grant_ref_t ref, domid_t domid)
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{
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if (flags & GNTMAP_contains_pte)
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map->host_addr = addr;
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else if (xen_feature(XENFEAT_auto_translated_physmap))
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map->host_addr = __pa(addr);
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else
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map->host_addr = addr;
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map->flags = flags;
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map->ref = ref;
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map->dom = domid;
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map->status = 1; /* arbitrary positive value */
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}
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static inline void
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gnttab_set_unmap_op(struct gnttab_unmap_grant_ref *unmap, phys_addr_t addr,
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uint32_t flags, grant_handle_t handle)
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{
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if (flags & GNTMAP_contains_pte)
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unmap->host_addr = addr;
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else if (xen_feature(XENFEAT_auto_translated_physmap))
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unmap->host_addr = __pa(addr);
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else
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unmap->host_addr = addr;
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unmap->handle = handle;
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unmap->dev_bus_addr = 0;
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}
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int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status);
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int arch_gnttab_map_shared(xen_pfn_t *frames, unsigned long nr_gframes,
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unsigned long max_nr_gframes,
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void **__shared);
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int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
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unsigned long max_nr_gframes,
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grant_status_t **__shared);
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void arch_gnttab_unmap(void *shared, unsigned long nr_gframes);
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struct grant_frames {
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xen_pfn_t *pfn;
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unsigned int count;
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void *vaddr;
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};
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extern struct grant_frames xen_auto_xlat_grant_frames;
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unsigned int gnttab_max_grant_frames(void);
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int gnttab_setup_auto_xlat_frames(phys_addr_t addr);
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void gnttab_free_auto_xlat_frames(void);
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#define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
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int gnttab_alloc_pages(int nr_pages, struct page **pages);
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void gnttab_free_pages(int nr_pages, struct page **pages);
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struct gnttab_page_cache {
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spinlock_t lock;
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#ifdef CONFIG_XEN_UNPOPULATED_ALLOC
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struct page *pages;
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#else
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struct list_head pages;
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#endif
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unsigned int num_pages;
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};
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void gnttab_page_cache_init(struct gnttab_page_cache *cache);
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int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page);
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void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page,
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unsigned int num);
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void gnttab_page_cache_shrink(struct gnttab_page_cache *cache,
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unsigned int num);
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#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
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struct gnttab_dma_alloc_args {
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/* Device for which DMA memory will be/was allocated. */
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struct device *dev;
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/* If set then DMA buffer is coherent and write-combine otherwise. */
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bool coherent;
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int nr_pages;
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struct page **pages;
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xen_pfn_t *frames;
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void *vaddr;
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dma_addr_t dev_bus_addr;
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};
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int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args);
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int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args);
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#endif
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int gnttab_pages_set_private(int nr_pages, struct page **pages);
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void gnttab_pages_clear_private(int nr_pages, struct page **pages);
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int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
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struct gnttab_map_grant_ref *kmap_ops,
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struct page **pages, unsigned int count);
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int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
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struct gnttab_unmap_grant_ref *kunmap_ops,
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struct page **pages, unsigned int count);
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void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
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int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item);
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/* Perform a batch of grant map/copy operations. Retry every batch slot
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* for which the hypervisor returns GNTST_eagain. This is typically due
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* to paged out target frames.
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*
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* Will retry for 1, 2, ... 255 ms, i.e. 256 times during 32 seconds.
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*
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* Return value in each iand every status field of the batch guaranteed
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* to not be GNTST_eagain.
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*/
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void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count);
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void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count);
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struct xen_page_foreign {
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domid_t domid;
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grant_ref_t gref;
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};
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static inline struct xen_page_foreign *xen_page_foreign(struct page *page)
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{
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if (!PageForeign(page))
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return NULL;
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#if BITS_PER_LONG < 64
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return (struct xen_page_foreign *)page->private;
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#else
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BUILD_BUG_ON(sizeof(struct xen_page_foreign) > BITS_PER_LONG);
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return (struct xen_page_foreign *)&page->private;
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#endif
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}
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/* Split Linux page in chunk of the size of the grant and call fn
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*
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* Parameters of fn:
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* gfn: guest frame number
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* offset: offset in the grant
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* len: length of the data in the grant.
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* data: internal information
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*/
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typedef void (*xen_grant_fn_t)(unsigned long gfn, unsigned int offset,
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unsigned int len, void *data);
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void gnttab_foreach_grant_in_range(struct page *page,
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unsigned int offset,
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unsigned int len,
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xen_grant_fn_t fn,
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void *data);
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/* Helper to get to call fn only on the first "grant chunk" */
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static inline void gnttab_for_one_grant(struct page *page, unsigned int offset,
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unsigned len, xen_grant_fn_t fn,
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void *data)
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{
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/* The first request is limited to the size of one grant */
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len = min_t(unsigned int, XEN_PAGE_SIZE - (offset & ~XEN_PAGE_MASK),
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len);
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gnttab_foreach_grant_in_range(page, offset, len, fn, data);
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}
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/* Get @nr_grefs grants from an array of page and call fn for each grant */
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void gnttab_foreach_grant(struct page **pages,
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unsigned int nr_grefs,
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xen_grant_fn_t fn,
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void *data);
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/* Get the number of grant in a specified region
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*
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* start: Offset from the beginning of the first page
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* len: total length of data (can cross multiple page)
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*/
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static inline unsigned int gnttab_count_grant(unsigned int start,
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unsigned int len)
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{
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return XEN_PFN_UP(xen_offset_in_page(start) + len);
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}
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#endif /* __ASM_GNTTAB_H__ */
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