drivers/xen/xlate_mmu.c

   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 #include <linux/slab.h>
  33 #include <linux/vmalloc.h>
  34
  35 #include <asm/xen/hypercall.h>
  36 #include <asm/xen/hypervisor.h>
  37
  38 #include <xen/xen.h>
  39 #include <xen/page.h>
  40 #include <xen/interface/xen.h>
  41 #include <xen/interface/memory.h>
  42 #include <xen/balloon.h>
  43
  44 typedef void (*xen_gfn_fn_t)(unsigned long gfn, void *data);
  45
  46 /* Break down the pages in 4KB chunk and call fn for each gfn */
  47 static void xen_for_each_gfn(struct page **pages, unsigned nr_gfn,
  48                              xen_gfn_fn_t fn, void *data)
  49 {
  50         unsigned long xen_pfn = 0;
  51         struct page *page;
  52         int i;
  53
  54         for (i = 0; i < nr_gfn; i++) {
  55                 if ((i % XEN_PFN_PER_PAGE) == 0) {
  56                         page = pages[i / XEN_PFN_PER_PAGE];
  57                         xen_pfn = page_to_xen_pfn(page);
  58                 }
  59                 fn(pfn_to_gfn(xen_pfn++), data);
  60         }
  61 }
  62
  63 struct remap_data {
  64         xen_pfn_t *fgfn; /* foreign domain's gfn */
  65         int nr_fgfn; /* Number of foreign gfn left to map */
  66         pgprot_t prot;
  67         domid_t  domid;
  68         struct vm_area_struct *vma;
  69         int index;
  70         struct page **pages;
  71         struct xen_remap_gfn_info *info;
  72         int *err_ptr;
  73         int mapped;
  74
  75         /* Hypercall parameters */
  76         int h_errs[XEN_PFN_PER_PAGE];
  77         xen_ulong_t h_idxs[XEN_PFN_PER_PAGE];
  78         xen_pfn_t h_gpfns[XEN_PFN_PER_PAGE];
  79
  80         int h_iter;     /* Iterator */
  81 };
  82
  83 static void setup_hparams(unsigned long gfn, void *data)
  84 {
  85         struct remap_data *info = data;
  86
  87         info->h_idxs[info->h_iter] = *info->fgfn;
  88         info->h_gpfns[info->h_iter] = gfn;
  89         info->h_errs[info->h_iter] = 0;
  90
  91         info->h_iter++;
  92         info->fgfn++;
  93 }
  94
  95 static int remap_pte_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
  96                         void *data)
  97 {
  98         struct remap_data *info = data;
  99         struct page *page = info->pages[info->index++];
 100         pte_t pte = pte_mkspecial(pfn_pte(page_to_pfn(page), info->prot));
 101         int rc, nr_gfn;
 102         uint32_t i;
 103         struct xen_add_to_physmap_range xatp = {
 104                 .domid = DOMID_SELF,
 105                 .foreign_domid = info->domid,
 106                 .space = XENMAPSPACE_gmfn_foreign,
 107         };
 108
 109         nr_gfn = min_t(typeof(info->nr_fgfn), XEN_PFN_PER_PAGE, info->nr_fgfn);
 110         info->nr_fgfn -= nr_gfn;
 111
 112         info->h_iter = 0;
 113         xen_for_each_gfn(&page, nr_gfn, setup_hparams, info);
 114         BUG_ON(info->h_iter != nr_gfn);
 115
 116         set_xen_guest_handle(xatp.idxs, info->h_idxs);
 117         set_xen_guest_handle(xatp.gpfns, info->h_gpfns);
 118         set_xen_guest_handle(xatp.errs, info->h_errs);
 119         xatp.size = nr_gfn;
 120
 121         rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);
 122
 123         /* info->err_ptr expect to have one error status per Xen PFN */
 124         for (i = 0; i < nr_gfn; i++) {
 125                 int err = (rc < 0) ? rc : info->h_errs[i];
 126
 127                 *(info->err_ptr++) = err;
 128                 if (!err)
 129                         info->mapped++;
 130         }
 131
 132         /*
 133          * Note: The hypercall will return 0 in most of the case if even if
 134          * all the fgmfn are not mapped. We still have to update the pte
 135          * as the userspace may decide to continue.
 136          */
 137         if (!rc)
 138                 set_pte_at(info->vma->vm_mm, addr, ptep, pte);
 139
 140         return 0;
 141 }
 142
 143 int xen_xlate_remap_gfn_array(struct vm_area_struct *vma,
 144                               unsigned long addr,
 145                               xen_pfn_t *gfn, int nr,
 146                               int *err_ptr, pgprot_t prot,
 147                               unsigned domid,
 148                               struct page **pages)
 149 {
 150         int err;
 151         struct remap_data data;
 152         unsigned long range = DIV_ROUND_UP(nr, XEN_PFN_PER_PAGE) << PAGE_SHIFT;
 153
 154         /* Kept here for the purpose of making sure code doesn't break
 155            x86 PVOPS */
 156         BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_IO)) == (VM_PFNMAP | VM_IO)));
 157
 158         data.fgfn = gfn;
 159         data.nr_fgfn = nr;
 160         data.prot  = prot;
 161         data.domid = domid;
 162         data.vma   = vma;
 163         data.pages = pages;
 164         data.index = 0;
 165         data.err_ptr = err_ptr;
 166         data.mapped = 0;
 167
 168         err = apply_to_page_range(vma->vm_mm, addr, range,
 169                                   remap_pte_fn, &data);
 170         return err < 0 ? err : data.mapped;
 171 }
 172 EXPORT_SYMBOL_GPL(xen_xlate_remap_gfn_array);
 173
 174 static void unmap_gfn(unsigned long gfn, void *data)
 175 {
 176         struct xen_remove_from_physmap xrp;
 177
 178         xrp.domid = DOMID_SELF;
 179         xrp.gpfn = gfn;
 180         (void)HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &xrp);
 181 }
 182
 183 int xen_xlate_unmap_gfn_range(struct vm_area_struct *vma,
 184                               int nr, struct page **pages)
 185 {
 186         xen_for_each_gfn(pages, nr, unmap_gfn, NULL);
 187
 188         return 0;
 189 }
 190 EXPORT_SYMBOL_GPL(xen_xlate_unmap_gfn_range);
 191
 192 struct map_balloon_pages {
 193         xen_pfn_t *pfns;
 194         unsigned int idx;
 195 };
 196
 197 static void setup_balloon_gfn(unsigned long gfn, void *data)
 198 {
 199         struct map_balloon_pages *info = data;
 200
 201         info->pfns[info->idx++] = gfn;
 202 }
 203
 204 /**
 205  * xen_xlate_map_ballooned_pages - map a new set of ballooned pages
 206  * @gfns: returns the array of corresponding GFNs
 207  * @virt: returns the virtual address of the mapped region
 208  * @nr_grant_frames: number of GFNs
 209  * @return 0 on success, error otherwise
 210  *
 211  * This allocates a set of ballooned pages and maps them into the
 212  * kernel's address space.
 213  */
 214 int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt,
 215                                          unsigned long nr_grant_frames)
 216 {
 217         struct page **pages;
 218         xen_pfn_t *pfns;
 219         void *vaddr;
 220         struct map_balloon_pages data;
 221         int rc;
 222         unsigned long nr_pages;
 223
 224         BUG_ON(nr_grant_frames == 0);
 225         nr_pages = DIV_ROUND_UP(nr_grant_frames, XEN_PFN_PER_PAGE);
 226         pages = kcalloc(nr_pages, sizeof(pages[0]), GFP_KERNEL);
 227         if (!pages)
 228                 return -ENOMEM;
 229
 230         pfns = kcalloc(nr_grant_frames, sizeof(pfns[0]), GFP_KERNEL);
 231         if (!pfns) {
 232                 kfree(pages);
 233                 return -ENOMEM;
 234         }
 235         rc = alloc_xenballooned_pages(nr_pages, pages);
 236         if (rc) {
 237                 pr_warn("%s Couldn't balloon alloc %ld pages rc:%d\n", __func__,
 238                         nr_pages, rc);
 239                 kfree(pages);
 240                 kfree(pfns);
 241                 return rc;
 242         }
 243
 244         data.pfns = pfns;
 245         data.idx = 0;
 246         xen_for_each_gfn(pages, nr_grant_frames, setup_balloon_gfn, &data);
 247
 248         vaddr = vmap(pages, nr_pages, 0, PAGE_KERNEL);
 249         if (!vaddr) {
 250                 pr_warn("%s Couldn't map %ld pages rc:%d\n", __func__,
 251                         nr_pages, rc);
 252                 free_xenballooned_pages(nr_pages, pages);
 253                 kfree(pages);
 254                 kfree(pfns);
 255                 return -ENOMEM;
 256         }
 257         kfree(pages);
 258
 259         *gfns = pfns;
 260         *virt = vaddr;
 261
 262         return 0;
 263 }
 264 EXPORT_SYMBOL_GPL(xen_xlate_map_ballooned_pages);