grant-table.c
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/******************************************************************************
* grant_table.c
* x86 specific part
*
* Granting foreign access to our memory reservation.
*
* Copyright (c) 2005-2006, Christopher Clark
* Copyright (c) 2004-2005, K A Fraser
* Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
* VA Linux Systems Japan. Split out x86 specific part.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation; or, when distributed
* separately from the Linux kernel or incorporated into other
* software packages, subject to the following license:
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this source file (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy, modify,
* merge, publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <xen/interface/xen.h>
#include <xen/page.h>
#include <xen/grant_table.h>
#include <asm/pgtable.h>
static int map_pte_fn(pte_t *pte, struct page *pmd_page,
unsigned long addr, void *data)
{
unsigned long **frames = (unsigned long **)data;
set_pte_at(&init_mm, addr, pte, mfn_pte((*frames)[0], PAGE_KERNEL));
(*frames)++;
return 0;
}
/*
* This function is used to map shared frames to store grant status. It is
* different from map_pte_fn above, the frames type here is uint64_t.
*/
static int map_pte_fn_status(pte_t *pte, struct page *pmd_page,
unsigned long addr, void *data)
{
uint64_t **frames = (uint64_t **)data;
set_pte_at(&init_mm, addr, pte, mfn_pte((*frames)[0], PAGE_KERNEL));
(*frames)++;
return 0;
}
static int unmap_pte_fn(pte_t *pte, struct page *pmd_page,
unsigned long addr, void *data)
{
set_pte_at(&init_mm, addr, pte, __pte(0));
return 0;
}
int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
unsigned long max_nr_gframes,
void **__shared)
{
int rc;
void *shared = *__shared;
if (shared == NULL) {
struct vm_struct *area =
alloc_vm_area(PAGE_SIZE * max_nr_gframes, NULL);
BUG_ON(area == NULL);
shared = area->addr;
*__shared = shared;
}
rc = apply_to_page_range(&init_mm, (unsigned long)shared,
PAGE_SIZE * nr_gframes,
map_pte_fn, &frames);
return rc;
}
int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
unsigned long max_nr_gframes,
grant_status_t **__shared)
{
int rc;
grant_status_t *shared = *__shared;
if (shared == NULL) {
/* No need to pass in PTE as we are going to do it
* in apply_to_page_range anyhow. */
struct vm_struct *area =
alloc_vm_area(PAGE_SIZE * max_nr_gframes, NULL);
BUG_ON(area == NULL);
shared = area->addr;
*__shared = shared;
}
rc = apply_to_page_range(&init_mm, (unsigned long)shared,
PAGE_SIZE * nr_gframes,
map_pte_fn_status, &frames);
return rc;
}
void arch_gnttab_unmap(void *shared, unsigned long nr_gframes)
{
apply_to_page_range(&init_mm, (unsigned long)shared,
PAGE_SIZE * nr_gframes, unmap_pte_fn, NULL);
}
#ifdef CONFIG_XEN_PVH
#include <xen/balloon.h>
#include <xen/events.h>
#include <xen/xen.h>
#include <linux/slab.h>
static int __init xlated_setup_gnttab_pages(void)
{
struct page **pages;
xen_pfn_t *pfns;
void *vaddr;
int rc;
unsigned int i;
unsigned long nr_grant_frames = gnttab_max_grant_frames();
BUG_ON(nr_grant_frames == 0);
pages = kcalloc(nr_grant_frames, sizeof(pages[0]), GFP_KERNEL);
if (!pages)
return -ENOMEM;
pfns = kcalloc(nr_grant_frames, sizeof(pfns[0]), GFP_KERNEL);
if (!pfns) {
kfree(pages);
return -ENOMEM;
}
rc = alloc_xenballooned_pages(nr_grant_frames, pages, 0 /* lowmem */);
if (rc) {
pr_warn("%s Couldn't balloon alloc %ld pfns rc:%d\n", __func__,
nr_grant_frames, rc);
kfree(pages);
kfree(pfns);
return rc;
}
for (i = 0; i < nr_grant_frames; i++)
pfns[i] = page_to_pfn(pages[i]);
vaddr = vmap(pages, nr_grant_frames, 0, PAGE_KERNEL);
if (!vaddr) {
pr_warn("%s Couldn't map %ld pfns rc:%d\n", __func__,
nr_grant_frames, rc);
free_xenballooned_pages(nr_grant_frames, pages);
kfree(pages);
kfree(pfns);
return -ENOMEM;
}
kfree(pages);
xen_auto_xlat_grant_frames.pfn = pfns;
xen_auto_xlat_grant_frames.count = nr_grant_frames;
xen_auto_xlat_grant_frames.vaddr = vaddr;
return 0;
}
static int __init xen_pvh_gnttab_setup(void)
{
if (!xen_pvh_domain())
return -ENODEV;
return xlated_setup_gnttab_pages();
}
/* Call it _before_ __gnttab_init as we need to initialize the
* xen_auto_xlat_grant_frames first. */
core_initcall(xen_pvh_gnttab_setup);
#endif