LXR linux/drivers/xen/xlate

   1/*
   2 * MMU operations common to all auto-translated physmap guests.
   3 *
   4 * Copyright (C) 2015 Citrix Systems R&D Ltd.
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License version 2
   8 * as published by the Free Software Foundation; or, when distributed
   9 * separately from the Linux kernel or incorporated into other
  10 * software packages, subject to the following license:
  11 *
  12 * Permission is hereby granted, free of charge, to any person obtaining a copy
  13 * of this source file (the "Software"), to deal in the Software without
  14 * restriction, including without limitation the rights to use, copy, modify,
  15 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  16 * and to permit persons to whom the Software is furnished to do so, subject to
  17 * the following conditions:
  18 *
  19 * The above copyright notice and this permission notice shall be included in
  20 * all copies or substantial portions of the Software.
  21 *
  22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  23 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  24 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  25 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  26 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  27 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  28 * IN THE SOFTWARE.
  29 */
  30#include <linux/kernel.h>
  31#include <linux/mm.h>
  32
  33#include <asm/xen/hypercall.h>
  34#include <asm/xen/hypervisor.h>
  35
  36#include <xen/xen.h>
  37#include <xen/page.h>
  38#include <xen/interface/xen.h>
  39#include <xen/interface/memory.h>
  40
  41typedef void (*xen_gfn_fn_t)(unsigned long gfn, void *data);
  42
  43/* Break down the pages in 4KB chunk and call fn for each gfn */
  44static void xen_for_each_gfn(struct page **pages, unsigned nr_gfn,
  45                             xen_gfn_fn_t fn, void *data)
  46{
  47        unsigned long xen_pfn = 0;
  48        struct page *page;
  49        int i;
  50
  51        for (i = 0; i < nr_gfn; i++) {
  52                if ((i % XEN_PFN_PER_PAGE) == 0) {
  53                        page = pages[i / XEN_PFN_PER_PAGE];
  54                        xen_pfn = page_to_xen_pfn(page);
  55                }
  56                fn(pfn_to_gfn(xen_pfn++), data);
  57        }
  58}
  59
  60struct remap_data {
  61        xen_pfn_t *fgfn; /* foreign domain's gfn */
  62        int nr_fgfn; /* Number of foreign gfn left to map */
  63        pgprot_t prot;
  64        domid_t  domid;
  65        struct vm_area_struct *vma;
  66        int index;
  67        struct page **pages;
  68        struct xen_remap_gfn_info *info;
  69        int *err_ptr;
  70        int mapped;
  71
  72        /* Hypercall parameters */
  73        int h_errs[XEN_PFN_PER_PAGE];
  74        xen_ulong_t h_idxs[XEN_PFN_PER_PAGE];
  75        xen_pfn_t h_gpfns[XEN_PFN_PER_PAGE];
  76
  77        int h_iter;     /* Iterator */
  78};
  79
  80static void setup_hparams(unsigned long gfn, void *data)
  81{
  82        struct remap_data *info = data;
  83
  84        info->h_idxs[info->h_iter] = *info->fgfn;
  85        info->h_gpfns[info->h_iter] = gfn;
  86        info->h_errs[info->h_iter] = 0;
  87
  88        info->h_iter++;
  89        info->fgfn++;
  90}
  91
  92static int remap_pte_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
  93                        void *data)
  94{
  95        struct remap_data *info = data;
  96        struct page *page = info->pages[info->index++];
  97        pte_t pte = pte_mkspecial(pfn_pte(page_to_pfn(page), info->prot));
  98        int rc, nr_gfn;
  99        uint32_t i;
 100        struct xen_add_to_physmap_range xatp = {
 101                .domid = DOMID_SELF,
 102                .foreign_domid = info->domid,
 103                .space = XENMAPSPACE_gmfn_foreign,
 104        };
 105
 106        nr_gfn = min_t(typeof(info->nr_fgfn), XEN_PFN_PER_PAGE, info->nr_fgfn);
 107        info->nr_fgfn -= nr_gfn;
 108
 109        info->h_iter = 0;
 110        xen_for_each_gfn(&page, nr_gfn, setup_hparams, info);
 111        BUG_ON(info->h_iter != nr_gfn);
 112
 113        set_xen_guest_handle(xatp.idxs, info->h_idxs);
 114        set_xen_guest_handle(xatp.gpfns, info->h_gpfns);
 115        set_xen_guest_handle(xatp.errs, info->h_errs);
 116        xatp.size = nr_gfn;
 117
 118        rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);
 119
 120        /* info->err_ptr expect to have one error status per Xen PFN */
 121        for (i = 0; i < nr_gfn; i++) {
 122                int err = (rc < 0) ? rc : info->h_errs[i];
 123
 124                *(info->err_ptr++) = err;
 125                if (!err)
 126                        info->mapped++;
 127        }
 128
 129        /*
 130         * Note: The hypercall will return 0 in most of the case if even if
 131         * all the fgmfn are not mapped. We still have to update the pte
 132         * as the userspace may decide to continue.
 133         */
 134        if (!rc)
 135                set_pte_at(info->vma->vm_mm, addr, ptep, pte);
 136
 137        return 0;
 138}
 139
 140int xen_xlate_remap_gfn_array(struct vm_area_struct *vma,
 141                              unsigned long addr,
 142                              xen_pfn_t *gfn, int nr,
 143                              int *err_ptr, pgprot_t prot,
 144                              unsigned domid,
 145                              struct page **pages)
 146{
 147        int err;
 148        struct remap_data data;
 149        unsigned long range = DIV_ROUND_UP(nr, XEN_PFN_PER_PAGE) << PAGE_SHIFT;
 150
 151        /* Kept here for the purpose of making sure code doesn't break
 152           x86 PVOPS */
 153        BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_IO)) == (VM_PFNMAP | VM_IO)));
 154
 155        data.fgfn = gfn;
 156        data.nr_fgfn = nr;
 157        data.prot  = prot;
 158        data.domid = domid;
 159        data.vma   = vma;
 160        data.pages = pages;
 161        data.index = 0;
 162        data.err_ptr = err_ptr;
 163        data.mapped = 0;
 164
 165        err = apply_to_page_range(vma->vm_mm, addr, range,
 166                                  remap_pte_fn, &data);
 167        return err < 0 ? err : data.mapped;
 168}
 169EXPORT_SYMBOL_GPL(xen_xlate_remap_gfn_array);
 170
 171static void unmap_gfn(unsigned long gfn, void *data)
 172{
 173        struct xen_remove_from_physmap xrp;
 174
 175        xrp.domid = DOMID_SELF;
 176        xrp.gpfn = gfn;
 177        (void)HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &xrp);
 178}
 179
 180int xen_xlate_unmap_gfn_range(struct vm_area_struct *vma,
 181                              int nr, struct page **pages)
 182{
 183        xen_for_each_gfn(pages, nr, unmap_gfn, NULL);
 184
 185        return 0;
 186}
 187EXPORT_SYMBOL_GPL(xen_xlate_unmap_gfn_range);
 188