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