1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __KVM_X86_MMU_INTERNAL_H
3 #define __KVM_X86_MMU_INTERNAL_H
4
5 #include <linux/types.h>
6 #include <linux/kvm_host.h>
7 #include <asm/kvm_host.h>
8
9 #undef MMU_DEBUG
10
11 #ifdef MMU_DEBUG
12 extern bool dbg;
13
14 #define pgprintk(x...) do { if (dbg) printk(x); } while (0)
15 #define rmap_printk(fmt, args...) do { if (dbg) printk("%s: " fmt, __func__, ## args); } while (0)
16 #define MMU_WARN_ON(x) WARN_ON(x)
17 #else
18 #define pgprintk(x...) do { } while (0)
19 #define rmap_printk(x...) do { } while (0)
20 #define MMU_WARN_ON(x) do { } while (0)
21 #endif
22
23 /*
24 * Unlike regular MMU roots, PAE "roots", a.k.a. PDPTEs/PDPTRs, have a PRESENT
25 * bit, and thus are guaranteed to be non-zero when valid. And, when a guest
26 * PDPTR is !PRESENT, its corresponding PAE root cannot be set to INVALID_PAGE,
27 * as the CPU would treat that as PRESENT PDPTR with reserved bits set. Use
28 * '0' instead of INVALID_PAGE to indicate an invalid PAE root.
29 */
30 #define INVALID_PAE_ROOT 0
31 #define IS_VALID_PAE_ROOT(x) (!!(x))
32
33 typedef u64 __rcu *tdp_ptep_t;
34
35 struct kvm_mmu_page {
36 /*
37 * Note, "link" through "spt" fit in a single 64 byte cache line on
38 * 64-bit kernels, keep it that way unless there's a reason not to.
39 */
40 struct list_head link;
41 struct hlist_node hash_link;
42
43 bool tdp_mmu_page;
44 bool unsync;
45 u8 mmu_valid_gen;
46 bool lpage_disallowed; /* Can't be replaced by an equiv large page */
47
48 /*
49 * The following two entries are used to key the shadow page in the
50 * hash table.
51 */
52 union kvm_mmu_page_role role;
53 gfn_t gfn;
54
55 u64 *spt;
56 /* hold the gfn of each spte inside spt */
57 gfn_t *gfns;
58 /* Currently serving as active root */
59 union {
60 int root_count;
61 refcount_t tdp_mmu_root_count;
62 };
63 unsigned int unsync_children;
64 union {
65 struct kvm_rmap_head parent_ptes; /* rmap pointers to parent sptes */
66 tdp_ptep_t ptep;
67 };
68 union {
69 DECLARE_BITMAP(unsync_child_bitmap, 512);
70 struct {
71 struct work_struct tdp_mmu_async_work;
72 void *tdp_mmu_async_data;
73 };
74 };
75
76 struct list_head lpage_disallowed_link;
77 #ifdef CONFIG_X86_32
78 /*
79 * Used out of the mmu-lock to avoid reading spte values while an
80 * update is in progress; see the comments in __get_spte_lockless().
81 */
82 int clear_spte_count;
83 #endif
84
85 /* Number of writes since the last time traversal visited this page. */
86 atomic_t write_flooding_count;
87
88 #ifdef CONFIG_X86_64
89 /* Used for freeing the page asynchronously if it is a TDP MMU page. */
90 struct rcu_head rcu_head;
91 #endif
92 };
93
94 extern struct kmem_cache *mmu_page_header_cache;
95
to_shadow_page(hpa_t shadow_page)96 static inline struct kvm_mmu_page *to_shadow_page(hpa_t shadow_page)
97 {
98 struct page *page = pfn_to_page(shadow_page >> PAGE_SHIFT);
99
100 return (struct kvm_mmu_page *)page_private(page);
101 }
102
sptep_to_sp(u64 * sptep)103 static inline struct kvm_mmu_page *sptep_to_sp(u64 *sptep)
104 {
105 return to_shadow_page(__pa(sptep));
106 }
107
kvm_mmu_role_as_id(union kvm_mmu_page_role role)108 static inline int kvm_mmu_role_as_id(union kvm_mmu_page_role role)
109 {
110 return role.smm ? 1 : 0;
111 }
112
kvm_mmu_page_as_id(struct kvm_mmu_page * sp)113 static inline int kvm_mmu_page_as_id(struct kvm_mmu_page *sp)
114 {
115 return kvm_mmu_role_as_id(sp->role);
116 }
117
kvm_mmu_page_ad_need_write_protect(struct kvm_mmu_page * sp)118 static inline bool kvm_mmu_page_ad_need_write_protect(struct kvm_mmu_page *sp)
119 {
120 /*
121 * When using the EPT page-modification log, the GPAs in the CPU dirty
122 * log would come from L2 rather than L1. Therefore, we need to rely
123 * on write protection to record dirty pages, which bypasses PML, since
124 * writes now result in a vmexit. Note, the check on CPU dirty logging
125 * being enabled is mandatory as the bits used to denote WP-only SPTEs
126 * are reserved for PAE paging (32-bit KVM).
127 */
128 return kvm_x86_ops.cpu_dirty_log_size && sp->role.guest_mode;
129 }
130
131 int mmu_try_to_unsync_pages(struct kvm *kvm, const struct kvm_memory_slot *slot,
132 gfn_t gfn, bool can_unsync, bool prefetch);
133
134 void kvm_mmu_gfn_disallow_lpage(const struct kvm_memory_slot *slot, gfn_t gfn);
135 void kvm_mmu_gfn_allow_lpage(const struct kvm_memory_slot *slot, gfn_t gfn);
136 bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
137 struct kvm_memory_slot *slot, u64 gfn,
138 int min_level);
139 void kvm_flush_remote_tlbs_with_address(struct kvm *kvm,
140 u64 start_gfn, u64 pages);
141 unsigned int pte_list_count(struct kvm_rmap_head *rmap_head);
142
143 extern int nx_huge_pages;
is_nx_huge_page_enabled(void)144 static inline bool is_nx_huge_page_enabled(void)
145 {
146 return READ_ONCE(nx_huge_pages);
147 }
148
149 struct kvm_page_fault {
150 /* arguments to kvm_mmu_do_page_fault. */
151 const gpa_t addr;
152 const u32 error_code;
153 const bool prefetch;
154
155 /* Derived from error_code. */
156 const bool exec;
157 const bool write;
158 const bool present;
159 const bool rsvd;
160 const bool user;
161
162 /* Derived from mmu and global state. */
163 const bool is_tdp;
164 const bool nx_huge_page_workaround_enabled;
165
166 /*
167 * Whether a >4KB mapping can be created or is forbidden due to NX
168 * hugepages.
169 */
170 bool huge_page_disallowed;
171
172 /*
173 * Maximum page size that can be created for this fault; input to
174 * FNAME(fetch), __direct_map and kvm_tdp_mmu_map.
175 */
176 u8 max_level;
177
178 /*
179 * Page size that can be created based on the max_level and the
180 * page size used by the host mapping.
181 */
182 u8 req_level;
183
184 /*
185 * Page size that will be created based on the req_level and
186 * huge_page_disallowed.
187 */
188 u8 goal_level;
189
190 /* Shifted addr, or result of guest page table walk if addr is a gva. */
191 gfn_t gfn;
192
193 /* The memslot containing gfn. May be NULL. */
194 struct kvm_memory_slot *slot;
195
196 /* Outputs of kvm_faultin_pfn. */
197 kvm_pfn_t pfn;
198 hva_t hva;
199 bool map_writable;
200 };
201
202 int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault);
203
204 /*
205 * Return values of handle_mmio_page_fault(), mmu.page_fault(), fast_page_fault(),
206 * and of course kvm_mmu_do_page_fault().
207 *
208 * RET_PF_CONTINUE: So far, so good, keep handling the page fault.
209 * RET_PF_RETRY: let CPU fault again on the address.
210 * RET_PF_EMULATE: mmio page fault, emulate the instruction directly.
211 * RET_PF_INVALID: the spte is invalid, let the real page fault path update it.
212 * RET_PF_FIXED: The faulting entry has been fixed.
213 * RET_PF_SPURIOUS: The faulting entry was already fixed, e.g. by another vCPU.
214 *
215 * Any names added to this enum should be exported to userspace for use in
216 * tracepoints via TRACE_DEFINE_ENUM() in mmutrace.h
217 *
218 * Note, all values must be greater than or equal to zero so as not to encroach
219 * on -errno return values. Somewhat arbitrarily use '0' for CONTINUE, which
220 * will allow for efficient machine code when checking for CONTINUE, e.g.
221 * "TEST %rax, %rax, JNZ", as all "stop!" values are non-zero.
222 */
223 enum {
224 RET_PF_CONTINUE = 0,
225 RET_PF_RETRY,
226 RET_PF_EMULATE,
227 RET_PF_INVALID,
228 RET_PF_FIXED,
229 RET_PF_SPURIOUS,
230 };
231
kvm_mmu_do_page_fault(struct kvm_vcpu * vcpu,gpa_t cr2_or_gpa,u32 err,bool prefetch)232 static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
233 u32 err, bool prefetch)
234 {
235 struct kvm_page_fault fault = {
236 .addr = cr2_or_gpa,
237 .error_code = err,
238 .exec = err & PFERR_FETCH_MASK,
239 .write = err & PFERR_WRITE_MASK,
240 .present = err & PFERR_PRESENT_MASK,
241 .rsvd = err & PFERR_RSVD_MASK,
242 .user = err & PFERR_USER_MASK,
243 .prefetch = prefetch,
244 .is_tdp = likely(vcpu->arch.mmu->page_fault == kvm_tdp_page_fault),
245 .nx_huge_page_workaround_enabled = is_nx_huge_page_enabled(),
246
247 .max_level = KVM_MAX_HUGEPAGE_LEVEL,
248 .req_level = PG_LEVEL_4K,
249 .goal_level = PG_LEVEL_4K,
250 };
251 int r;
252
253 /*
254 * Async #PF "faults", a.k.a. prefetch faults, are not faults from the
255 * guest perspective and have already been counted at the time of the
256 * original fault.
257 */
258 if (!prefetch)
259 vcpu->stat.pf_taken++;
260
261 if (IS_ENABLED(CONFIG_RETPOLINE) && fault.is_tdp)
262 r = kvm_tdp_page_fault(vcpu, &fault);
263 else
264 r = vcpu->arch.mmu->page_fault(vcpu, &fault);
265
266 /*
267 * Similar to above, prefetch faults aren't truly spurious, and the
268 * async #PF path doesn't do emulation. Do count faults that are fixed
269 * by the async #PF handler though, otherwise they'll never be counted.
270 */
271 if (r == RET_PF_FIXED)
272 vcpu->stat.pf_fixed++;
273 else if (prefetch)
274 ;
275 else if (r == RET_PF_EMULATE)
276 vcpu->stat.pf_emulate++;
277 else if (r == RET_PF_SPURIOUS)
278 vcpu->stat.pf_spurious++;
279 return r;
280 }
281
282 int kvm_mmu_max_mapping_level(struct kvm *kvm,
283 const struct kvm_memory_slot *slot, gfn_t gfn,
284 kvm_pfn_t pfn, int max_level);
285 void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault);
286 void disallowed_hugepage_adjust(struct kvm_page_fault *fault, u64 spte, int cur_level);
287
288 void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc);
289
290 void account_huge_nx_page(struct kvm *kvm, struct kvm_mmu_page *sp);
291 void unaccount_huge_nx_page(struct kvm *kvm, struct kvm_mmu_page *sp);
292
293 #endif /* __KVM_X86_MMU_INTERNAL_H */
294