arch/x86/kvm/page_track.c

   1 /*
   2  * Support KVM gust page tracking
   3  *
   4  * This feature allows us to track page access in guest. Currently, only
   5  * write access is tracked.
   6  *
   7  * Copyright(C) 2015 Intel Corporation.
   8  *
   9  * Author:
  10  *   Xiao Guangrong <guangrong.xiao@linux.intel.com>
  11  *
  12  * This work is licensed under the terms of the GNU GPL, version 2.  See
  13  * the COPYING file in the top-level directory.
  14  */
  15
  16 #include <linux/kvm_host.h>
  17 #include <asm/kvm_host.h>
  18 #include <asm/kvm_page_track.h>
  19
  20 #include "mmu.h"
  21
  22 void kvm_page_track_free_memslot(struct kvm_memory_slot *free,
  23                                  struct kvm_memory_slot *dont)
  24 {
  25         int i;
  26
  27         for (i = 0; i < KVM_PAGE_TRACK_MAX; i++)
  28                 if (!dont || free->arch.gfn_track[i] !=
  29                       dont->arch.gfn_track[i]) {
  30                         kvfree(free->arch.gfn_track[i]);
  31                         free->arch.gfn_track[i] = NULL;
  32                 }
  33 }
  34
  35 int kvm_page_track_create_memslot(struct kvm_memory_slot *slot,
  36                                   unsigned long npages)
  37 {
  38         int  i;
  39
  40         for (i = 0; i < KVM_PAGE_TRACK_MAX; i++) {
  41                 slot->arch.gfn_track[i] = kvm_kvzalloc(npages *
  42                                             sizeof(*slot->arch.gfn_track[i]));
  43                 if (!slot->arch.gfn_track[i])
  44                         goto track_free;
  45         }
  46
  47         return 0;
  48
  49 track_free:
  50         kvm_page_track_free_memslot(slot, NULL);
  51         return -ENOMEM;
  52 }