KVM: SVM: count all irq windows exit
[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 affiliates.
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 #include <linux/ratelimit.h>
21
22 char const *audit_point_name[] = {
23         "pre page fault",
24         "post page fault",
25         "pre pte write",
26         "post pte write",
27         "pre sync",
28         "post sync"
29 };
30
31 #define audit_printk(kvm, fmt, args...)         \
32         printk(KERN_ERR "audit: (%s) error: "   \
33                 fmt, audit_point_name[kvm->arch.audit_point], ##args)
34
35 typedef void (*inspect_spte_fn) (struct kvm_vcpu *vcpu, u64 *sptep, int level);
36
37 static void __mmu_spte_walk(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
38                             inspect_spte_fn fn, int level)
39 {
40         int i;
41
42         for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
43                 u64 *ent = sp->spt;
44
45                 fn(vcpu, ent + i, level);
46
47                 if (is_shadow_present_pte(ent[i]) &&
48                       !is_last_spte(ent[i], level)) {
49                         struct kvm_mmu_page *child;
50
51                         child = page_header(ent[i] & PT64_BASE_ADDR_MASK);
52                         __mmu_spte_walk(vcpu, child, fn, level - 1);
53                 }
54         }
55 }
56
57 static void mmu_spte_walk(struct kvm_vcpu *vcpu, inspect_spte_fn fn)
58 {
59         int i;
60         struct kvm_mmu_page *sp;
61
62         if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
63                 return;
64
65         if (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL) {
66                 hpa_t root = vcpu->arch.mmu.root_hpa;
67
68                 sp = page_header(root);
69                 __mmu_spte_walk(vcpu, sp, fn, PT64_ROOT_LEVEL);
70                 return;
71         }
72
73         for (i = 0; i < 4; ++i) {
74                 hpa_t root = vcpu->arch.mmu.pae_root[i];
75
76                 if (root && VALID_PAGE(root)) {
77                         root &= PT64_BASE_ADDR_MASK;
78                         sp = page_header(root);
79                         __mmu_spte_walk(vcpu, sp, fn, 2);
80                 }
81         }
82
83         return;
84 }
85
86 typedef void (*sp_handler) (struct kvm *kvm, struct kvm_mmu_page *sp);
87
88 static void walk_all_active_sps(struct kvm *kvm, sp_handler fn)
89 {
90         struct kvm_mmu_page *sp;
91
92         list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link)
93                 fn(kvm, sp);
94 }
95
96 static void audit_mappings(struct kvm_vcpu *vcpu, u64 *sptep, int level)
97 {
98         struct kvm_mmu_page *sp;
99         gfn_t gfn;
100         pfn_t pfn;
101         hpa_t hpa;
102
103         sp = page_header(__pa(sptep));
104
105         if (sp->unsync) {
106                 if (level != PT_PAGE_TABLE_LEVEL) {
107                         audit_printk(vcpu->kvm, "unsync sp: %p "
108                                      "level = %d\n", sp, level);
109                         return;
110                 }
111         }
112
113         if (!is_shadow_present_pte(*sptep) || !is_last_spte(*sptep, level))
114                 return;
115
116         gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt);
117         pfn = gfn_to_pfn_atomic(vcpu->kvm, gfn);
118
119         if (is_error_pfn(pfn)) {
120                 kvm_release_pfn_clean(pfn);
121                 return;
122         }
123
124         hpa =  pfn << PAGE_SHIFT;
125         if ((*sptep & PT64_BASE_ADDR_MASK) != hpa)
126                 audit_printk(vcpu->kvm, "levels %d pfn %llx hpa %llx "
127                              "ent %llxn", vcpu->arch.mmu.root_level, pfn,
128                              hpa, *sptep);
129 }
130
131 static void inspect_spte_has_rmap(struct kvm *kvm, u64 *sptep)
132 {
133         static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
134         unsigned long *rmapp;
135         struct kvm_mmu_page *rev_sp;
136         gfn_t gfn;
137
138         rev_sp = page_header(__pa(sptep));
139         gfn = kvm_mmu_page_get_gfn(rev_sp, sptep - rev_sp->spt);
140
141         if (!gfn_to_memslot(kvm, gfn)) {
142                 if (!__ratelimit(&ratelimit_state))
143                         return;
144                 audit_printk(kvm, "no memslot for gfn %llx\n", gfn);
145                 audit_printk(kvm, "index %ld of sp (gfn=%llx)\n",
146                        (long int)(sptep - rev_sp->spt), rev_sp->gfn);
147                 dump_stack();
148                 return;
149         }
150
151         rmapp = gfn_to_rmap(kvm, gfn, rev_sp->role.level);
152         if (!*rmapp) {
153                 if (!__ratelimit(&ratelimit_state))
154                         return;
155                 audit_printk(kvm, "no rmap for writable spte %llx\n",
156                              *sptep);
157                 dump_stack();
158         }
159 }
160
161 static void audit_sptes_have_rmaps(struct kvm_vcpu *vcpu, u64 *sptep, int level)
162 {
163         if (is_shadow_present_pte(*sptep) && is_last_spte(*sptep, level))
164                 inspect_spte_has_rmap(vcpu->kvm, sptep);
165 }
166
167 static void audit_spte_after_sync(struct kvm_vcpu *vcpu, u64 *sptep, int level)
168 {
169         struct kvm_mmu_page *sp = page_header(__pa(sptep));
170
171         if (vcpu->kvm->arch.audit_point == AUDIT_POST_SYNC && sp->unsync)
172                 audit_printk(vcpu->kvm, "meet unsync sp(%p) after sync "
173                              "root.\n", sp);
174 }
175
176 static void check_mappings_rmap(struct kvm *kvm, struct kvm_mmu_page *sp)
177 {
178         int i;
179
180         if (sp->role.level != PT_PAGE_TABLE_LEVEL)
181                 return;
182
183         for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
184                 if (!is_rmap_spte(sp->spt[i]))
185                         continue;
186
187                 inspect_spte_has_rmap(kvm, sp->spt + i);
188         }
189 }
190
191 static void audit_write_protection(struct kvm *kvm, struct kvm_mmu_page *sp)
192 {
193         struct kvm_memory_slot *slot;
194         unsigned long *rmapp;
195         u64 *spte;
196
197         if (sp->role.direct || sp->unsync || sp->role.invalid)
198                 return;
199
200         slot = gfn_to_memslot(kvm, sp->gfn);
201         rmapp = &slot->rmap[sp->gfn - slot->base_gfn];
202
203         spte = rmap_next(rmapp, NULL);
204         while (spte) {
205                 if (is_writable_pte(*spte))
206                         audit_printk(kvm, "shadow page has writable "
207                                      "mappings: gfn %llx role %x\n",
208                                      sp->gfn, sp->role.word);
209                 spte = rmap_next(rmapp, spte);
210         }
211 }
212
213 static void audit_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
214 {
215         check_mappings_rmap(kvm, sp);
216         audit_write_protection(kvm, sp);
217 }
218
219 static void audit_all_active_sps(struct kvm *kvm)
220 {
221         walk_all_active_sps(kvm, audit_sp);
222 }
223
224 static void audit_spte(struct kvm_vcpu *vcpu, u64 *sptep, int level)
225 {
226         audit_sptes_have_rmaps(vcpu, sptep, level);
227         audit_mappings(vcpu, sptep, level);
228         audit_spte_after_sync(vcpu, sptep, level);
229 }
230
231 static void audit_vcpu_spte(struct kvm_vcpu *vcpu)
232 {
233         mmu_spte_walk(vcpu, audit_spte);
234 }
235
236 static bool mmu_audit;
237 static struct static_key mmu_audit_key;
238
239 static void __kvm_mmu_audit(struct kvm_vcpu *vcpu, int point)
240 {
241         static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
242
243         if (!__ratelimit(&ratelimit_state))
244                 return;
245
246         vcpu->kvm->arch.audit_point = point;
247         audit_all_active_sps(vcpu->kvm);
248         audit_vcpu_spte(vcpu);
249 }
250
251 static inline void kvm_mmu_audit(struct kvm_vcpu *vcpu, int point)
252 {
253         if (static_key_false((&mmu_audit_key)))
254                 __kvm_mmu_audit(vcpu, point);
255 }
256
257 static void mmu_audit_enable(void)
258 {
259         if (mmu_audit)
260                 return;
261
262         static_key_slow_inc(&mmu_audit_key);
263         mmu_audit = true;
264 }
265
266 static void mmu_audit_disable(void)
267 {
268         if (!mmu_audit)
269                 return;
270
271         static_key_slow_dec(&mmu_audit_key);
272         mmu_audit = false;
273 }
274
275 static int mmu_audit_set(const char *val, const struct kernel_param *kp)
276 {
277         int ret;
278         unsigned long enable;
279
280         ret = strict_strtoul(val, 10, &enable);
281         if (ret < 0)
282                 return -EINVAL;
283
284         switch (enable) {
285         case 0:
286                 mmu_audit_disable();
287                 break;
288         case 1:
289                 mmu_audit_enable();
290                 break;
291         default:
292                 return -EINVAL;
293         }
294
295         return 0;
296 }
297
298 static struct kernel_param_ops audit_param_ops = {
299         .set = mmu_audit_set,
300         .get = param_get_bool,
301 };
302
303 module_param_cb(mmu_audit, &audit_param_ops, &mmu_audit, 0644);