1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * access guest memory
4 *
5 * Copyright IBM Corp. 2008, 2014
6 *
7 * Author(s): Carsten Otte <cotte@de.ibm.com>
8 */
9
10 #ifndef __KVM_S390_GACCESS_H
11 #define __KVM_S390_GACCESS_H
12
13 #include <linux/compiler.h>
14 #include <linux/kvm_host.h>
15 #include <linux/uaccess.h>
16 #include <linux/ptrace.h>
17 #include "kvm-s390.h"
18
19 /**
20 * kvm_s390_real_to_abs - convert guest real address to guest absolute address
21 * @vcpu - guest virtual cpu
22 * @gra - guest real address
23 *
24 * Returns the guest absolute address that corresponds to the passed guest real
25 * address @gra of a virtual guest cpu by applying its prefix.
26 */
27 static inline unsigned long kvm_s390_real_to_abs(struct kvm_vcpu *vcpu,
28 unsigned long gra)
29 {
30 unsigned long prefix = kvm_s390_get_prefix(vcpu);
31
32 if (gra < 2 * PAGE_SIZE)
33 gra += prefix;
34 else if (gra >= prefix && gra < prefix + 2 * PAGE_SIZE)
35 gra -= prefix;
36 return gra;
37 }
38
39 /**
40 * kvm_s390_logical_to_effective - convert guest logical to effective address
41 * @vcpu: guest virtual cpu
42 * @ga: guest logical address
43 *
44 * Convert a guest vcpu logical address to a guest vcpu effective address by
45 * applying the rules of the vcpu's addressing mode defined by PSW bits 31
46 * and 32 (extendended/basic addressing mode).
47 *
48 * Depending on the vcpu's addressing mode the upper 40 bits (24 bit addressing
49 * mode), 33 bits (31 bit addressing mode) or no bits (64 bit addressing mode)
50 * of @ga will be zeroed and the remaining bits will be returned.
51 */
52 static inline unsigned long kvm_s390_logical_to_effective(struct kvm_vcpu *vcpu,
53 unsigned long ga)
54 {
55 psw_t *psw = &vcpu->arch.sie_block->gpsw;
56
57 if (psw_bits(*psw).eaba == PSW_BITS_AMODE_64BIT)
58 return ga;
59 if (psw_bits(*psw).eaba == PSW_BITS_AMODE_31BIT)
60 return ga & ((1UL << 31) - 1);
61 return ga & ((1UL << 24) - 1);
62 }
63
64 /*
65 * put_guest_lc, read_guest_lc and write_guest_lc are guest access functions
66 * which shall only be used to access the lowcore of a vcpu.
67 * These functions should be used for e.g. interrupt handlers where no
68 * guest memory access protection facilities, like key or low address
69 * protection, are applicable.
70 * At a later point guest vcpu lowcore access should happen via pinned
71 * prefix pages, so that these pages can be accessed directly via the
72 * kernel mapping. All of these *_lc functions can be removed then.
73 */
74
75 /**
76 * put_guest_lc - write a simple variable to a guest vcpu's lowcore
77 * @vcpu: virtual cpu
78 * @x: value to copy to guest
79 * @gra: vcpu's destination guest real address
80 *
81 * Copies a simple value from kernel space to a guest vcpu's lowcore.
82 * The size of the variable may be 1, 2, 4 or 8 bytes. The destination
83 * must be located in the vcpu's lowcore. Otherwise the result is undefined.
84 *
85 * Returns zero on success or -EFAULT on error.
86 *
87 * Note: an error indicates that either the kernel is out of memory or
88 * the guest memory mapping is broken. In any case the best solution
89 * would be to terminate the guest.
90 * It is wrong to inject a guest exception.
91 */
92 #define put_guest_lc(vcpu, x, gra) \
93 ({ \
94 struct kvm_vcpu *__vcpu = (vcpu); \
95 __typeof__(*(gra)) __x = (x); \
96 unsigned long __gpa; \
97 \
98 __gpa = (unsigned long)(gra); \
99 __gpa += kvm_s390_get_prefix(__vcpu); \
100 kvm_write_guest(__vcpu->kvm, __gpa, &__x, sizeof(__x)); \
101 })
102
103 /**
104 * write_guest_lc - copy data from kernel space to guest vcpu's lowcore
105 * @vcpu: virtual cpu
106 * @gra: vcpu's source guest real address
107 * @data: source address in kernel space
108 * @len: number of bytes to copy
109 *
110 * Copy data from kernel space to guest vcpu's lowcore. The entire range must
111 * be located within the vcpu's lowcore, otherwise the result is undefined.
112 *
113 * Returns zero on success or -EFAULT on error.
114 *
115 * Note: an error indicates that either the kernel is out of memory or
116 * the guest memory mapping is broken. In any case the best solution
117 * would be to terminate the guest.
118 * It is wrong to inject a guest exception.
119 */
120 static inline __must_check
121 int write_guest_lc(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
122 unsigned long len)
123 {
124 unsigned long gpa = gra + kvm_s390_get_prefix(vcpu);
125
126 return kvm_write_guest(vcpu->kvm, gpa, data, len);
127 }
128
129 /**
130 * read_guest_lc - copy data from guest vcpu's lowcore to kernel space
131 * @vcpu: virtual cpu
132 * @gra: vcpu's source guest real address
133 * @data: destination address in kernel space
134 * @len: number of bytes to copy
135 *
136 * Copy data from guest vcpu's lowcore to kernel space. The entire range must
137 * be located within the vcpu's lowcore, otherwise the result is undefined.
138 *
139 * Returns zero on success or -EFAULT on error.
140 *
141 * Note: an error indicates that either the kernel is out of memory or
142 * the guest memory mapping is broken. In any case the best solution
143 * would be to terminate the guest.
144 * It is wrong to inject a guest exception.
145 */
146 static inline __must_check
147 int read_guest_lc(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
148 unsigned long len)
149 {
150 unsigned long gpa = gra + kvm_s390_get_prefix(vcpu);
151
152 return kvm_read_guest(vcpu->kvm, gpa, data, len);
153 }
154
155 enum gacc_mode {
156 GACC_FETCH,
157 GACC_STORE,
158 GACC_IFETCH,
159 };
160
161 int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva,
162 u8 ar, unsigned long *gpa, enum gacc_mode mode);
163 int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,
164 unsigned long length, enum gacc_mode mode);
165
166 int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data,
167 unsigned long len, enum gacc_mode mode);
168
169 int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra,
170 void *data, unsigned long len, enum gacc_mode mode);
171
172 /**
173 * write_guest - copy data from kernel space to guest space
174 * @vcpu: virtual cpu
175 * @ga: guest address
176 * @ar: access register
177 * @data: source address in kernel space
178 * @len: number of bytes to copy
179 *
180 * Copy @len bytes from @data (kernel space) to @ga (guest address).
181 * In order to copy data to guest space the PSW of the vcpu is inspected:
182 * If DAT is off data will be copied to guest real or absolute memory.
183 * If DAT is on data will be copied to the address space as specified by
184 * the address space bits of the PSW:
185 * Primary, secondary, home space or access register mode.
186 * The addressing mode of the PSW is also inspected, so that address wrap
187 * around is taken into account for 24-, 31- and 64-bit addressing mode,
188 * if the to be copied data crosses page boundaries in guest address space.
189 * In addition also low address and DAT protection are inspected before
190 * copying any data (key protection is currently not implemented).
191 *
192 * This function modifies the 'struct kvm_s390_pgm_info pgm' member of @vcpu.
193 * In case of an access exception (e.g. protection exception) pgm will contain
194 * all data necessary so that a subsequent call to 'kvm_s390_inject_prog_vcpu()'
195 * will inject a correct exception into the guest.
196 * If no access exception happened, the contents of pgm are undefined when
197 * this function returns.
198 *
199 * Returns: - zero on success
200 * - a negative value if e.g. the guest mapping is broken or in
201 * case of out-of-memory. In this case the contents of pgm are
202 * undefined. Also parts of @data may have been copied to guest
203 * space.
204 * - a positive value if an access exception happened. In this case
205 * the returned value is the program interruption code and the
206 * contents of pgm may be used to inject an exception into the
207 * guest. No data has been copied to guest space.
208 *
209 * Note: in case an access exception is recognized no data has been copied to
210 * guest space (this is also true, if the to be copied data would cross
211 * one or more page boundaries in guest space).
212 * Therefore this function may be used for nullifying and suppressing
213 * instruction emulation.
214 * It may also be used for terminating instructions, if it is undefined
215 * if data has been changed in guest space in case of an exception.
216 */
217 static inline __must_check
218 int write_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data,
219 unsigned long len)
220 {
221 return access_guest(vcpu, ga, ar, data, len, GACC_STORE);
222 }
223
224 /**
225 * read_guest - copy data from guest space to kernel space
226 * @vcpu: virtual cpu
227 * @ga: guest address
228 * @ar: access register
229 * @data: destination address in kernel space
230 * @len: number of bytes to copy
231 *
232 * Copy @len bytes from @ga (guest address) to @data (kernel space).
233 *
234 * The behaviour of read_guest is identical to write_guest, except that
235 * data will be copied from guest space to kernel space.
236 */
237 static inline __must_check
238 int read_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data,
239 unsigned long len)
240 {
241 return access_guest(vcpu, ga, ar, data, len, GACC_FETCH);
242 }
243
244 /**
245 * read_guest_instr - copy instruction data from guest space to kernel space
246 * @vcpu: virtual cpu
247 * @ga: guest address
248 * @data: destination address in kernel space
249 * @len: number of bytes to copy
250 *
251 * Copy @len bytes from the given address (guest space) to @data (kernel
252 * space).
253 *
254 * The behaviour of read_guest_instr is identical to read_guest, except that
255 * instruction data will be read from primary space when in home-space or
256 * address-space mode.
257 */
258 static inline __must_check
259 int read_guest_instr(struct kvm_vcpu *vcpu, unsigned long ga, void *data,
260 unsigned long len)
261 {
262 return access_guest(vcpu, ga, 0, data, len, GACC_IFETCH);
263 }
264
265 /**
266 * write_guest_abs - copy data from kernel space to guest space absolute
267 * @vcpu: virtual cpu
268 * @gpa: guest physical (absolute) address
269 * @data: source address in kernel space
270 * @len: number of bytes to copy
271 *
272 * Copy @len bytes from @data (kernel space) to @gpa (guest absolute address).
273 * It is up to the caller to ensure that the entire guest memory range is
274 * valid memory before calling this function.
275 * Guest low address and key protection are not checked.
276 *
277 * Returns zero on success or -EFAULT on error.
278 *
279 * If an error occurs data may have been copied partially to guest memory.
280 */
281 static inline __must_check
282 int write_guest_abs(struct kvm_vcpu *vcpu, unsigned long gpa, void *data,
283 unsigned long len)
284 {
285 return kvm_write_guest(vcpu->kvm, gpa, data, len);
286 }
287
288 /**
289 * read_guest_abs - copy data from guest space absolute to kernel space
290 * @vcpu: virtual cpu
291 * @gpa: guest physical (absolute) address
292 * @data: destination address in kernel space
293 * @len: number of bytes to copy
294 *
295 * Copy @len bytes from @gpa (guest absolute address) to @data (kernel space).
296 * It is up to the caller to ensure that the entire guest memory range is
297 * valid memory before calling this function.
298 * Guest key protection is not checked.
299 *
300 * Returns zero on success or -EFAULT on error.
301 *
302 * If an error occurs data may have been copied partially to kernel space.
303 */
304 static inline __must_check
305 int read_guest_abs(struct kvm_vcpu *vcpu, unsigned long gpa, void *data,
306 unsigned long len)
307 {
308 return kvm_read_guest(vcpu->kvm, gpa, data, len);
309 }
310
311 /**
312 * write_guest_real - copy data from kernel space to guest space real
313 * @vcpu: virtual cpu
314 * @gra: guest real address
315 * @data: source address in kernel space
316 * @len: number of bytes to copy
317 *
318 * Copy @len bytes from @data (kernel space) to @gra (guest real address).
319 * It is up to the caller to ensure that the entire guest memory range is
320 * valid memory before calling this function.
321 * Guest low address and key protection are not checked.
322 *
323 * Returns zero on success or -EFAULT on error.
324 *
325 * If an error occurs data may have been copied partially to guest memory.
326 */
327 static inline __must_check
328 int write_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
329 unsigned long len)
330 {
331 return access_guest_real(vcpu, gra, data, len, 1);
332 }
333
334 /**
335 * read_guest_real - copy data from guest space real to kernel space
336 * @vcpu: virtual cpu
337 * @gra: guest real address
338 * @data: destination address in kernel space
339 * @len: number of bytes to copy
340 *
341 * Copy @len bytes from @gra (guest real address) to @data (kernel space).
342 * It is up to the caller to ensure that the entire guest memory range is
343 * valid memory before calling this function.
344 * Guest key protection is not checked.
345 *
346 * Returns zero on success or -EFAULT on error.
347 *
348 * If an error occurs data may have been copied partially to kernel space.
349 */
350 static inline __must_check
351 int read_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
352 unsigned long len)
353 {
354 return access_guest_real(vcpu, gra, data, len, 0);
355 }
356
357 void ipte_lock(struct kvm_vcpu *vcpu);
358 void ipte_unlock(struct kvm_vcpu *vcpu);
359 int ipte_lock_held(struct kvm_vcpu *vcpu);
360 int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra);
361
362 int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *shadow,
363 unsigned long saddr);
364
365 #endif /* __KVM_S390_GACCESS_H */