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// SPDX-License-Identifier: GPL-2.0 OR MIT
/******************************************************************************
* 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.
*/
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <xen/interface/xen.h>
#include <xen/page.h>
#include <xen/grant_table.h>
#include <xen/xen.h>
static struct gnttab_vm_area {
struct vm_struct *area;
pte_t **ptes;
int idx;
} gnttab_shared_vm_area, gnttab_status_vm_area;
int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
unsigned long max_nr_gframes,
void **__shared)
{
void *shared = *__shared;
unsigned long addr;
unsigned long i;
if (shared == NULL)
*__shared = shared = gnttab_shared_vm_area.area->addr;
addr = (unsigned long)shared;
for (i = 0; i < nr_gframes; i++) {
set_pte_at(&init_mm, addr, gnttab_shared_vm_area.ptes[i],
mfn_pte(frames[i], PAGE_KERNEL));
addr += PAGE_SIZE;
}
return 0;
}
int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
unsigned long max_nr_gframes,
grant_status_t **__shared)
{
grant_status_t *shared = *__shared;
unsigned long addr;
unsigned long i;
if (shared == NULL)
*__shared = shared = gnttab_status_vm_area.area->addr;
addr = (unsigned long)shared;
for (i = 0; i < nr_gframes; i++) {
set_pte_at(&init_mm, addr, gnttab_status_vm_area.ptes[i],
mfn_pte(frames[i], PAGE_KERNEL));
addr += PAGE_SIZE;
}
return 0;
}
void arch_gnttab_unmap(void *shared, unsigned long nr_gframes)
{
pte_t **ptes;
unsigned long addr;
unsigned long i;
if (shared == gnttab_status_vm_area.area->addr)
ptes = gnttab_status_vm_area.ptes;
else
ptes = gnttab_shared_vm_area.ptes;
addr = (unsigned long)shared;
for (i = 0; i < nr_gframes; i++) {
set_pte_at(&init_mm, addr, ptes[i], __pte(0));
addr += PAGE_SIZE;
}
}
static int gnttab_apply(pte_t *pte, unsigned long addr, void *data)
{
struct gnttab_vm_area *area = data;
area->ptes[area->idx++] = pte;
return 0;
}
static int arch_gnttab_valloc(struct gnttab_vm_area *area, unsigned nr_frames)
{
area->ptes = kmalloc_array(nr_frames, sizeof(*area->ptes), GFP_KERNEL);
if (area->ptes == NULL)
return -ENOMEM;
area->area = get_vm_area(PAGE_SIZE * nr_frames, VM_IOREMAP);
if (!area->area)
goto out_free_ptes;
if (apply_to_page_range(&init_mm, (unsigned long)area->area->addr,
PAGE_SIZE * nr_frames, gnttab_apply, area))
goto out_free_vm_area;
return 0;
out_free_vm_area:
free_vm_area(area->area);
out_free_ptes:
kfree(area->ptes);
return -ENOMEM;
}
static void arch_gnttab_vfree(struct gnttab_vm_area *area)
{
free_vm_area(area->area);
kfree(area->ptes);
}
int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status)
{
int ret;
if (!xen_pv_domain())
return 0;
ret = arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared);
if (ret < 0)
return ret;
/*
* Always allocate the space for the status frames in case
* we're migrated to a host with V2 support.
*/
ret = arch_gnttab_valloc(&gnttab_status_vm_area, nr_status);
if (ret < 0)
goto err;
return 0;
err:
arch_gnttab_vfree(&gnttab_shared_vm_area);
return -ENOMEM;
}
#ifdef CONFIG_XEN_PVH
#include <xen/events.h>
#include <xen/xen-ops.h>
static int __init xen_pvh_gnttab_setup(void)
{
if (!xen_pvh_domain())
return -ENODEV;
xen_auto_xlat_grant_frames.count = gnttab_max_grant_frames();
return xen_xlate_map_ballooned_pages(&xen_auto_xlat_grant_frames.pfn,
&xen_auto_xlat_grant_frames.vaddr,
xen_auto_xlat_grant_frames.count);
}
/* Call it _before_ __gnttab_init as we need to initialize the
* xen_auto_xlat_grant_frames first. */
core_initcall(xen_pvh_gnttab_setup);
#endif
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