KVM: MMU: move audit to a separate file
[linux-3.10.git] / arch / x86 / kvm / mmu_audit.c
1 /*
2  * mmu_audit.c:
3  *
4  * Audit code for KVM MMU
5  *
6  * Copyright (C) 2006 Qumranet, Inc.
7  * Copyright 2010 Red Hat, Inc. and/or its affilates.
8  *
9  * Authors:
10  *   Yaniv Kamay  <yaniv@qumranet.com>
11  *   Avi Kivity   <avi@qumranet.com>
12  *   Marcelo Tosatti <mtosatti@redhat.com>
13  *   Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
14  *
15  * This work is licensed under the terms of the GNU GPL, version 2.  See
16  * the COPYING file in the top-level directory.
17  *
18  */
19
20 static const char *audit_msg;
21
22 typedef void (*inspect_spte_fn) (struct kvm *kvm, u64 *sptep);
23
24 static void __mmu_spte_walk(struct kvm *kvm, struct kvm_mmu_page *sp,
25                             inspect_spte_fn fn)
26 {
27         int i;
28
29         for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
30                 u64 ent = sp->spt[i];
31
32                 if (is_shadow_present_pte(ent)) {
33                         if (!is_last_spte(ent, sp->role.level)) {
34                                 struct kvm_mmu_page *child;
35                                 child = page_header(ent & PT64_BASE_ADDR_MASK);
36                                 __mmu_spte_walk(kvm, child, fn);
37                         } else
38                                 fn(kvm, &sp->spt[i]);
39                 }
40         }
41 }
42
43 static void mmu_spte_walk(struct kvm_vcpu *vcpu, inspect_spte_fn fn)
44 {
45         int i;
46         struct kvm_mmu_page *sp;
47
48         if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
49                 return;
50         if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
51                 hpa_t root = vcpu->arch.mmu.root_hpa;
52                 sp = page_header(root);
53                 __mmu_spte_walk(vcpu->kvm, sp, fn);
54                 return;
55         }
56         for (i = 0; i < 4; ++i) {
57                 hpa_t root = vcpu->arch.mmu.pae_root[i];
58
59                 if (root && VALID_PAGE(root)) {
60                         root &= PT64_BASE_ADDR_MASK;
61                         sp = page_header(root);
62                         __mmu_spte_walk(vcpu->kvm, sp, fn);
63                 }
64         }
65         return;
66 }
67
68 static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
69                                 gva_t va, int level)
70 {
71         u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK);
72         int i;
73         gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1));
74
75         for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) {
76                 u64 *sptep = pt + i;
77                 struct kvm_mmu_page *sp;
78                 gfn_t gfn;
79                 pfn_t pfn;
80                 hpa_t hpa;
81
82                 sp = page_header(__pa(sptep));
83
84                 if (sp->unsync) {
85                         if (level != PT_PAGE_TABLE_LEVEL) {
86                                 printk(KERN_ERR "audit: (%s) error: unsync sp: %p level = %d\n",
87                                                 audit_msg, sp, level);
88                                 return;
89                         }
90
91                         if (*sptep == shadow_notrap_nonpresent_pte) {
92                                 printk(KERN_ERR "audit: (%s) error: notrap spte in unsync sp: %p\n",
93                                                 audit_msg, sp);
94                                 return;
95                         }
96                 }
97
98                 if (sp->role.direct && *sptep == shadow_notrap_nonpresent_pte) {
99                         printk(KERN_ERR "audit: (%s) error: notrap spte in direct sp: %p\n",
100                                         audit_msg, sp);
101                         return;
102                 }
103
104                 if (!is_shadow_present_pte(*sptep) ||
105                       !is_last_spte(*sptep, level))
106                         return;
107
108                 gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt);
109                 pfn = gfn_to_pfn_atomic(vcpu->kvm, gfn);
110
111                 if (is_error_pfn(pfn)) {
112                         kvm_release_pfn_clean(pfn);
113                         return;
114                 }
115
116                 hpa =  pfn << PAGE_SHIFT;
117
118                 if ((*sptep & PT64_BASE_ADDR_MASK) != hpa)
119                         printk(KERN_ERR "xx audit error: (%s) levels %d"
120                                            " gva %lx pfn %llx hpa %llx ent %llxn",
121                                            audit_msg, vcpu->arch.mmu.root_level,
122                                            va, pfn, hpa, *sptep);
123         }
124 }
125
126 static void audit_mappings(struct kvm_vcpu *vcpu)
127 {
128         unsigned i;
129
130         if (vcpu->arch.mmu.root_level == 4)
131                 audit_mappings_page(vcpu, vcpu->arch.mmu.root_hpa, 0, 4);
132         else
133                 for (i = 0; i < 4; ++i)
134                         if (vcpu->arch.mmu.pae_root[i] & PT_PRESENT_MASK)
135                                 audit_mappings_page(vcpu,
136                                                     vcpu->arch.mmu.pae_root[i],
137                                                     i << 30,
138                                                     2);
139 }
140
141 void inspect_spte_has_rmap(struct kvm *kvm, u64 *sptep)
142 {
143         unsigned long *rmapp;
144         struct kvm_mmu_page *rev_sp;
145         gfn_t gfn;
146
147
148         rev_sp = page_header(__pa(sptep));
149         gfn = kvm_mmu_page_get_gfn(rev_sp, sptep - rev_sp->spt);
150
151         if (!gfn_to_memslot(kvm, gfn)) {
152                 if (!printk_ratelimit())
153                         return;
154                 printk(KERN_ERR "%s: no memslot for gfn %llx\n",
155                                  audit_msg, gfn);
156                 printk(KERN_ERR "%s: index %ld of sp (gfn=%llx)\n",
157                        audit_msg, (long int)(sptep - rev_sp->spt),
158                                 rev_sp->gfn);
159                 dump_stack();
160                 return;
161         }
162
163         rmapp = gfn_to_rmap(kvm, gfn, rev_sp->role.level);
164         if (!*rmapp) {
165                 if (!printk_ratelimit())
166                         return;
167                 printk(KERN_ERR "%s: no rmap for writable spte %llx\n",
168                                  audit_msg, *sptep);
169                 dump_stack();
170         }
171 }
172
173 void audit_sptes_have_rmaps(struct kvm_vcpu *vcpu)
174 {
175         mmu_spte_walk(vcpu, inspect_spte_has_rmap);
176 }
177
178 static void check_mappings_rmap(struct kvm_vcpu *vcpu)
179 {
180         struct kvm_mmu_page *sp;
181         int i;
182
183         list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
184                 u64 *pt = sp->spt;
185
186                 if (sp->role.level != PT_PAGE_TABLE_LEVEL)
187                         continue;
188
189                 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
190                         if (!is_rmap_spte(pt[i]))
191                                 continue;
192
193                         inspect_spte_has_rmap(vcpu->kvm, &pt[i]);
194                 }
195         }
196         return;
197 }
198
199 static void audit_rmap(struct kvm_vcpu *vcpu)
200 {
201         check_mappings_rmap(vcpu);
202 }
203
204 static void audit_write_protection(struct kvm_vcpu *vcpu)
205 {
206         struct kvm_mmu_page *sp;
207         struct kvm_memory_slot *slot;
208         unsigned long *rmapp;
209         u64 *spte;
210
211         list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
212                 if (sp->role.direct)
213                         continue;
214                 if (sp->unsync)
215                         continue;
216                 if (sp->role.invalid)
217                         continue;
218
219                 slot = gfn_to_memslot(vcpu->kvm, sp->gfn);
220                 rmapp = &slot->rmap[sp->gfn - slot->base_gfn];
221
222                 spte = rmap_next(vcpu->kvm, rmapp, NULL);
223                 while (spte) {
224                         if (is_writable_pte(*spte))
225                                 printk(KERN_ERR "%s: (%s) shadow page has "
226                                 "writable mappings: gfn %llx role %x\n",
227                                __func__, audit_msg, sp->gfn,
228                                sp->role.word);
229                         spte = rmap_next(vcpu->kvm, rmapp, spte);
230                 }
231         }
232 }
233
234 static void kvm_mmu_audit(void *ignore, struct kvm_vcpu *vcpu, int audit_point)
235 {
236         audit_msg = audit_point_name[audit_point];
237         audit_rmap(vcpu);
238         audit_write_protection(vcpu);
239         if (strcmp("pre pte write", audit_msg) != 0)
240                 audit_mappings(vcpu);
241         audit_sptes_have_rmaps(vcpu);
242 }
243
244 static bool mmu_audit;
245
246 static void mmu_audit_enable(void)
247 {
248         int ret;
249
250         if (mmu_audit)
251                 return;
252
253         ret = register_trace_kvm_mmu_audit(kvm_mmu_audit, NULL);
254         WARN_ON(ret);
255
256         mmu_audit = true;
257 }
258
259 static void mmu_audit_disable(void)
260 {
261         if (!mmu_audit)
262                 return;
263
264         unregister_trace_kvm_mmu_audit(kvm_mmu_audit, NULL);
265         tracepoint_synchronize_unregister();
266         mmu_audit = false;
267 }
268
269 static int mmu_audit_set(const char *val, const struct kernel_param *kp)
270 {
271         int ret;
272         unsigned long enable;
273
274         ret = strict_strtoul(val, 10, &enable);
275         if (ret < 0)
276                 return -EINVAL;
277
278         switch (enable) {
279         case 0:
280                 mmu_audit_disable();
281                 break;
282         case 1:
283                 mmu_audit_enable();
284                 break;
285         default:
286                 return -EINVAL;
287         }
288
289         return 0;
290 }
291
292 static struct kernel_param_ops audit_param_ops = {
293         .set = mmu_audit_set,
294         .get = param_get_bool,
295 };
296
297 module_param_cb(mmu_audit, &audit_param_ops, &mmu_audit, 0644);