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
  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
  41 typedef 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 */
  44 static 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
  60 struct 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
  80 static 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
  92 static 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
 140 int 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 }
 169 EXPORT_SYMBOL_GPL(xen_xlate_remap_gfn_array);
 170
 171 static 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
 180 int 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 }
 187 EXPORT_SYMBOL_GPL(xen_xlate_unmap_gfn_range);