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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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