1 /*
2 * access guest memory
3 *
4 * Copyright IBM Corp. 2008, 2014
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License (version 2 only)
8 * as published by the Free Software Foundation.
9 *
10 * Author(s): Carsten Otte <cotte@de.ibm.com>
11 */
12
13 #ifndef __KVM_S390_GACCESS_H
14 #define __KVM_S390_GACCESS_H
15
16 #include <linux/compiler.h>
17 #include <linux/kvm_host.h>
18 #include <linux/uaccess.h>
19 #include <linux/ptrace.h>
20 #include "kvm-s390.h"
21
22 /**
23 * kvm_s390_real_to_abs - convert guest real address to guest absolute address
24 * @prefix - guest prefix
25 * @gra - guest real address
26 *
27 * Returns the guest absolute address that corresponds to the passed guest real
28 * address @gra of by applying the given prefix.
29 */
_kvm_s390_real_to_abs(u32 prefix,unsigned long gra)30 static inline unsigned long _kvm_s390_real_to_abs(u32 prefix, unsigned long gra)
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_real_to_abs - convert guest real address to guest absolute address
41 * @vcpu - guest virtual cpu
42 * @gra - guest real address
43 *
44 * Returns the guest absolute address that corresponds to the passed guest real
45 * address @gra of a virtual guest cpu by applying its prefix.
46 */
kvm_s390_real_to_abs(struct kvm_vcpu * vcpu,unsigned long gra)47 static inline unsigned long kvm_s390_real_to_abs(struct kvm_vcpu *vcpu,
48 unsigned long gra)
49 {
50 return _kvm_s390_real_to_abs(kvm_s390_get_prefix(vcpu), gra);
51 }
52
53 /**
54 * kvm_s390_logical_to_effective - convert guest logical to effective address
55 * @vcpu: guest virtual cpu
56 * @ga: guest logical address
57 *
58 * Convert a guest vcpu logical address to a guest vcpu effective address by
59 * applying the rules of the vcpu's addressing mode defined by PSW bits 31
60 * and 32 (extendended/basic addressing mode).
61 *
62 * Depending on the vcpu's addressing mode the upper 40 bits (24 bit addressing
63 * mode), 33 bits (31 bit addressing mode) or no bits (64 bit addressing mode)
64 * of @ga will be zeroed and the remaining bits will be returned.
65 */
kvm_s390_logical_to_effective(struct kvm_vcpu * vcpu,unsigned long ga)66 static inline unsigned long kvm_s390_logical_to_effective(struct kvm_vcpu *vcpu,
67 unsigned long ga)
68 {
69 psw_t *psw = &vcpu->arch.sie_block->gpsw;
70
71 if (psw_bits(*psw).eaba == PSW_AMODE_64BIT)
72 return ga;
73 if (psw_bits(*psw).eaba == PSW_AMODE_31BIT)
74 return ga & ((1UL << 31) - 1);
75 return ga & ((1UL << 24) - 1);
76 }
77
78 /*
79 * put_guest_lc, read_guest_lc and write_guest_lc are guest access functions
80 * which shall only be used to access the lowcore of a vcpu.
81 * These functions should be used for e.g. interrupt handlers where no
82 * guest memory access protection facilities, like key or low address
83 * protection, are applicable.
84 * At a later point guest vcpu lowcore access should happen via pinned
85 * prefix pages, so that these pages can be accessed directly via the
86 * kernel mapping. All of these *_lc functions can be removed then.
87 */
88
89 /**
90 * put_guest_lc - write a simple variable to a guest vcpu's lowcore
91 * @vcpu: virtual cpu
92 * @x: value to copy to guest
93 * @gra: vcpu's destination guest real address
94 *
95 * Copies a simple value from kernel space to a guest vcpu's lowcore.
96 * The size of the variable may be 1, 2, 4 or 8 bytes. The destination
97 * must be located in the vcpu's lowcore. Otherwise the result is undefined.
98 *
99 * Returns zero on success or -EFAULT on error.
100 *
101 * Note: an error indicates that either the kernel is out of memory or
102 * the guest memory mapping is broken. In any case the best solution
103 * would be to terminate the guest.
104 * It is wrong to inject a guest exception.
105 */
106 #define put_guest_lc(vcpu, x, gra) \
107 ({ \
108 struct kvm_vcpu *__vcpu = (vcpu); \
109 __typeof__(*(gra)) __x = (x); \
110 unsigned long __gpa; \
111 \
112 __gpa = (unsigned long)(gra); \
113 __gpa += kvm_s390_get_prefix(__vcpu); \
114 kvm_write_guest(__vcpu->kvm, __gpa, &__x, sizeof(__x)); \
115 })
116
117 /**
118 * write_guest_lc - copy data from kernel space to guest vcpu's lowcore
119 * @vcpu: virtual cpu
120 * @gra: vcpu's source guest real address
121 * @data: source address in kernel space
122 * @len: number of bytes to copy
123 *
124 * Copy data from kernel space to guest vcpu's lowcore. The entire range must
125 * be located within the vcpu's lowcore, otherwise the result is undefined.
126 *
127 * Returns zero on success or -EFAULT on error.
128 *
129 * Note: an error indicates that either the kernel is out of memory or
130 * the guest memory mapping is broken. In any case the best solution
131 * would be to terminate the guest.
132 * It is wrong to inject a guest exception.
133 */
134 static inline __must_check
write_guest_lc(struct kvm_vcpu * vcpu,unsigned long gra,void * data,unsigned long len)135 int write_guest_lc(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
136 unsigned long len)
137 {
138 unsigned long gpa = gra + kvm_s390_get_prefix(vcpu);
139
140 return kvm_write_guest(vcpu->kvm, gpa, data, len);
141 }
142
143 /**
144 * read_guest_lc - copy data from guest vcpu's lowcore to kernel space
145 * @vcpu: virtual cpu
146 * @gra: vcpu's source guest real address
147 * @data: destination address in kernel space
148 * @len: number of bytes to copy
149 *
150 * Copy data from guest vcpu's lowcore to kernel space. The entire range must
151 * be located within the vcpu's lowcore, otherwise the result is undefined.
152 *
153 * Returns zero on success or -EFAULT on error.
154 *
155 * Note: an error indicates that either the kernel is out of memory or
156 * the guest memory mapping is broken. In any case the best solution
157 * would be to terminate the guest.
158 * It is wrong to inject a guest exception.
159 */
160 static inline __must_check
read_guest_lc(struct kvm_vcpu * vcpu,unsigned long gra,void * data,unsigned long len)161 int read_guest_lc(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
162 unsigned long len)
163 {
164 unsigned long gpa = gra + kvm_s390_get_prefix(vcpu);
165
166 return kvm_read_guest(vcpu->kvm, gpa, data, len);
167 }
168
169 int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva,
170 ar_t ar, unsigned long *gpa, int write);
171 int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, ar_t ar,
172 unsigned long length, int is_write);
173
174 int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, ar_t ar, void *data,
175 unsigned long len, int write);
176
177 int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra,
178 void *data, unsigned long len, int write);
179
180 /**
181 * write_guest - copy data from kernel space to guest space
182 * @vcpu: virtual cpu
183 * @ga: guest address
184 * @ar: access register
185 * @data: source address in kernel space
186 * @len: number of bytes to copy
187 *
188 * Copy @len bytes from @data (kernel space) to @ga (guest address).
189 * In order to copy data to guest space the PSW of the vcpu is inspected:
190 * If DAT is off data will be copied to guest real or absolute memory.
191 * If DAT is on data will be copied to the address space as specified by
192 * the address space bits of the PSW:
193 * Primary, secondary, home space or access register mode.
194 * The addressing mode of the PSW is also inspected, so that address wrap
195 * around is taken into account for 24-, 31- and 64-bit addressing mode,
196 * if the to be copied data crosses page boundaries in guest address space.
197 * In addition also low address and DAT protection are inspected before
198 * copying any data (key protection is currently not implemented).
199 *
200 * This function modifies the 'struct kvm_s390_pgm_info pgm' member of @vcpu.
201 * In case of an access exception (e.g. protection exception) pgm will contain
202 * all data necessary so that a subsequent call to 'kvm_s390_inject_prog_vcpu()'
203 * will inject a correct exception into the guest.
204 * If no access exception happened, the contents of pgm are undefined when
205 * this function returns.
206 *
207 * Returns: - zero on success
208 * - a negative value if e.g. the guest mapping is broken or in
209 * case of out-of-memory. In this case the contents of pgm are
210 * undefined. Also parts of @data may have been copied to guest
211 * space.
212 * - a positive value if an access exception happened. In this case
213 * the returned value is the program interruption code and the
214 * contents of pgm may be used to inject an exception into the
215 * guest. No data has been copied to guest space.
216 *
217 * Note: in case an access exception is recognized no data has been copied to
218 * guest space (this is also true, if the to be copied data would cross
219 * one or more page boundaries in guest space).
220 * Therefore this function may be used for nullifying and suppressing
221 * instruction emulation.
222 * It may also be used for terminating instructions, if it is undefined
223 * if data has been changed in guest space in case of an exception.
224 */
225 static inline __must_check
write_guest(struct kvm_vcpu * vcpu,unsigned long ga,ar_t ar,void * data,unsigned long len)226 int write_guest(struct kvm_vcpu *vcpu, unsigned long ga, ar_t ar, void *data,
227 unsigned long len)
228 {
229 return access_guest(vcpu, ga, ar, data, len, 1);
230 }
231
232 /**
233 * read_guest - copy data from guest space to kernel space
234 * @vcpu: virtual cpu
235 * @ga: guest address
236 * @ar: access register
237 * @data: destination address in kernel space
238 * @len: number of bytes to copy
239 *
240 * Copy @len bytes from @ga (guest address) to @data (kernel space).
241 *
242 * The behaviour of read_guest is identical to write_guest, except that
243 * data will be copied from guest space to kernel space.
244 */
245 static inline __must_check
read_guest(struct kvm_vcpu * vcpu,unsigned long ga,ar_t ar,void * data,unsigned long len)246 int read_guest(struct kvm_vcpu *vcpu, unsigned long ga, ar_t ar, void *data,
247 unsigned long len)
248 {
249 return access_guest(vcpu, ga, ar, data, len, 0);
250 }
251
252 /**
253 * write_guest_abs - copy data from kernel space to guest space absolute
254 * @vcpu: virtual cpu
255 * @gpa: guest physical (absolute) address
256 * @data: source address in kernel space
257 * @len: number of bytes to copy
258 *
259 * Copy @len bytes from @data (kernel space) to @gpa (guest absolute address).
260 * It is up to the caller to ensure that the entire guest memory range is
261 * valid memory before calling this function.
262 * Guest low address and key protection are not checked.
263 *
264 * Returns zero on success or -EFAULT on error.
265 *
266 * If an error occurs data may have been copied partially to guest memory.
267 */
268 static inline __must_check
write_guest_abs(struct kvm_vcpu * vcpu,unsigned long gpa,void * data,unsigned long len)269 int write_guest_abs(struct kvm_vcpu *vcpu, unsigned long gpa, void *data,
270 unsigned long len)
271 {
272 return kvm_write_guest(vcpu->kvm, gpa, data, len);
273 }
274
275 /**
276 * read_guest_abs - copy data from guest space absolute to kernel space
277 * @vcpu: virtual cpu
278 * @gpa: guest physical (absolute) address
279 * @data: destination address in kernel space
280 * @len: number of bytes to copy
281 *
282 * Copy @len bytes from @gpa (guest absolute address) to @data (kernel space).
283 * It is up to the caller to ensure that the entire guest memory range is
284 * valid memory before calling this function.
285 * Guest key protection is not checked.
286 *
287 * Returns zero on success or -EFAULT on error.
288 *
289 * If an error occurs data may have been copied partially to kernel space.
290 */
291 static inline __must_check
read_guest_abs(struct kvm_vcpu * vcpu,unsigned long gpa,void * data,unsigned long len)292 int read_guest_abs(struct kvm_vcpu *vcpu, unsigned long gpa, void *data,
293 unsigned long len)
294 {
295 return kvm_read_guest(vcpu->kvm, gpa, data, len);
296 }
297
298 /**
299 * write_guest_real - copy data from kernel space to guest space real
300 * @vcpu: virtual cpu
301 * @gra: guest real address
302 * @data: source address in kernel space
303 * @len: number of bytes to copy
304 *
305 * Copy @len bytes from @data (kernel space) to @gra (guest real address).
306 * It is up to the caller to ensure that the entire guest memory range is
307 * valid memory before calling this function.
308 * Guest low address and key protection are not checked.
309 *
310 * Returns zero on success or -EFAULT on error.
311 *
312 * If an error occurs data may have been copied partially to guest memory.
313 */
314 static inline __must_check
write_guest_real(struct kvm_vcpu * vcpu,unsigned long gra,void * data,unsigned long len)315 int write_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
316 unsigned long len)
317 {
318 return access_guest_real(vcpu, gra, data, len, 1);
319 }
320
321 /**
322 * read_guest_real - copy data from guest space real to kernel space
323 * @vcpu: virtual cpu
324 * @gra: guest real address
325 * @data: destination address in kernel space
326 * @len: number of bytes to copy
327 *
328 * Copy @len bytes from @gra (guest real address) to @data (kernel space).
329 * It is up to the caller to ensure that the entire guest memory range is
330 * valid memory before calling this function.
331 * Guest key protection is not checked.
332 *
333 * Returns zero on success or -EFAULT on error.
334 *
335 * If an error occurs data may have been copied partially to kernel space.
336 */
337 static inline __must_check
read_guest_real(struct kvm_vcpu * vcpu,unsigned long gra,void * data,unsigned long len)338 int read_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
339 unsigned long len)
340 {
341 return access_guest_real(vcpu, gra, data, len, 0);
342 }
343
344 void ipte_lock(struct kvm_vcpu *vcpu);
345 void ipte_unlock(struct kvm_vcpu *vcpu);
346 int ipte_lock_held(struct kvm_vcpu *vcpu);
347 int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra);
348
349 #endif /* __KVM_S390_GACCESS_H */
350