1 /*
2  * access.h -  access guest memory
3  *
4  * Copyright IBM Corp. 2008,2009
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 <asm/uaccess.h>
19 #include "kvm-s390.h"
20 
__guestaddr_to_user(struct kvm_vcpu * vcpu,unsigned long guestaddr)21 static inline void __user *__guestaddr_to_user(struct kvm_vcpu *vcpu,
22 					       unsigned long guestaddr)
23 {
24 	unsigned long prefix  = vcpu->arch.sie_block->prefix;
25 
26 	if (guestaddr < 2 * PAGE_SIZE)
27 		guestaddr += prefix;
28 	else if ((guestaddr >= prefix) && (guestaddr < prefix + 2 * PAGE_SIZE))
29 		guestaddr -= prefix;
30 
31 	return (void __user *) gmap_fault(guestaddr, vcpu->arch.gmap);
32 }
33 
get_guest_u64(struct kvm_vcpu * vcpu,unsigned long guestaddr,u64 * result)34 static inline int get_guest_u64(struct kvm_vcpu *vcpu, unsigned long guestaddr,
35 				u64 *result)
36 {
37 	void __user *uptr = __guestaddr_to_user(vcpu, guestaddr);
38 
39 	BUG_ON(guestaddr & 7);
40 
41 	if (IS_ERR((void __force *) uptr))
42 		return PTR_ERR((void __force *) uptr);
43 
44 	return get_user(*result, (unsigned long __user *) uptr);
45 }
46 
get_guest_u32(struct kvm_vcpu * vcpu,unsigned long guestaddr,u32 * result)47 static inline int get_guest_u32(struct kvm_vcpu *vcpu, unsigned long guestaddr,
48 				u32 *result)
49 {
50 	void __user *uptr = __guestaddr_to_user(vcpu, guestaddr);
51 
52 	BUG_ON(guestaddr & 3);
53 
54 	if (IS_ERR((void __force *) uptr))
55 		return PTR_ERR((void __force *) uptr);
56 
57 	return get_user(*result, (u32 __user *) uptr);
58 }
59 
get_guest_u16(struct kvm_vcpu * vcpu,unsigned long guestaddr,u16 * result)60 static inline int get_guest_u16(struct kvm_vcpu *vcpu, unsigned long guestaddr,
61 				u16 *result)
62 {
63 	void __user *uptr = __guestaddr_to_user(vcpu, guestaddr);
64 
65 	BUG_ON(guestaddr & 1);
66 
67 	if (IS_ERR(uptr))
68 		return PTR_ERR(uptr);
69 
70 	return get_user(*result, (u16 __user *) uptr);
71 }
72 
get_guest_u8(struct kvm_vcpu * vcpu,unsigned long guestaddr,u8 * result)73 static inline int get_guest_u8(struct kvm_vcpu *vcpu, unsigned long guestaddr,
74 			       u8 *result)
75 {
76 	void __user *uptr = __guestaddr_to_user(vcpu, guestaddr);
77 
78 	if (IS_ERR((void __force *) uptr))
79 		return PTR_ERR((void __force *) uptr);
80 
81 	return get_user(*result, (u8 __user *) uptr);
82 }
83 
put_guest_u64(struct kvm_vcpu * vcpu,unsigned long guestaddr,u64 value)84 static inline int put_guest_u64(struct kvm_vcpu *vcpu, unsigned long guestaddr,
85 				u64 value)
86 {
87 	void __user *uptr = __guestaddr_to_user(vcpu, guestaddr);
88 
89 	BUG_ON(guestaddr & 7);
90 
91 	if (IS_ERR((void __force *) uptr))
92 		return PTR_ERR((void __force *) uptr);
93 
94 	return put_user(value, (u64 __user *) uptr);
95 }
96 
put_guest_u32(struct kvm_vcpu * vcpu,unsigned long guestaddr,u32 value)97 static inline int put_guest_u32(struct kvm_vcpu *vcpu, unsigned long guestaddr,
98 				u32 value)
99 {
100 	void __user *uptr = __guestaddr_to_user(vcpu, guestaddr);
101 
102 	BUG_ON(guestaddr & 3);
103 
104 	if (IS_ERR((void __force *) uptr))
105 		return PTR_ERR((void __force *) uptr);
106 
107 	return put_user(value, (u32 __user *) uptr);
108 }
109 
put_guest_u16(struct kvm_vcpu * vcpu,unsigned long guestaddr,u16 value)110 static inline int put_guest_u16(struct kvm_vcpu *vcpu, unsigned long guestaddr,
111 				u16 value)
112 {
113 	void __user *uptr = __guestaddr_to_user(vcpu, guestaddr);
114 
115 	BUG_ON(guestaddr & 1);
116 
117 	if (IS_ERR((void __force *) uptr))
118 		return PTR_ERR((void __force *) uptr);
119 
120 	return put_user(value, (u16 __user *) uptr);
121 }
122 
put_guest_u8(struct kvm_vcpu * vcpu,unsigned long guestaddr,u8 value)123 static inline int put_guest_u8(struct kvm_vcpu *vcpu, unsigned long guestaddr,
124 			       u8 value)
125 {
126 	void __user *uptr = __guestaddr_to_user(vcpu, guestaddr);
127 
128 	if (IS_ERR((void __force *) uptr))
129 		return PTR_ERR((void __force *) uptr);
130 
131 	return put_user(value, (u8 __user *) uptr);
132 }
133 
134 
__copy_to_guest_slow(struct kvm_vcpu * vcpu,unsigned long guestdest,void * from,unsigned long n)135 static inline int __copy_to_guest_slow(struct kvm_vcpu *vcpu,
136 				       unsigned long guestdest,
137 				       void *from, unsigned long n)
138 {
139 	int rc;
140 	unsigned long i;
141 	u8 *data = from;
142 
143 	for (i = 0; i < n; i++) {
144 		rc = put_guest_u8(vcpu, guestdest++, *(data++));
145 		if (rc < 0)
146 			return rc;
147 	}
148 	return 0;
149 }
150 
__copy_to_guest_fast(struct kvm_vcpu * vcpu,unsigned long guestdest,void * from,unsigned long n)151 static inline int __copy_to_guest_fast(struct kvm_vcpu *vcpu,
152 				       unsigned long guestdest,
153 				       void *from, unsigned long n)
154 {
155 	int r;
156 	void __user *uptr;
157 	unsigned long size;
158 
159 	if (guestdest + n < guestdest)
160 		return -EFAULT;
161 
162 	/* simple case: all within one segment table entry? */
163 	if ((guestdest & PMD_MASK) == ((guestdest+n) & PMD_MASK)) {
164 		uptr = (void __user *) gmap_fault(guestdest, vcpu->arch.gmap);
165 
166 		if (IS_ERR((void __force *) uptr))
167 			return PTR_ERR((void __force *) uptr);
168 
169 		r = copy_to_user(uptr, from, n);
170 
171 		if (r)
172 			r = -EFAULT;
173 
174 		goto out;
175 	}
176 
177 	/* copy first segment */
178 	uptr = (void __user *)gmap_fault(guestdest, vcpu->arch.gmap);
179 
180 	if (IS_ERR((void __force *) uptr))
181 		return PTR_ERR((void __force *) uptr);
182 
183 	size = PMD_SIZE - (guestdest & ~PMD_MASK);
184 
185 	r = copy_to_user(uptr, from, size);
186 
187 	if (r) {
188 		r = -EFAULT;
189 		goto out;
190 	}
191 	from += size;
192 	n -= size;
193 	guestdest += size;
194 
195 	/* copy full segments */
196 	while (n >= PMD_SIZE) {
197 		uptr = (void __user *)gmap_fault(guestdest, vcpu->arch.gmap);
198 
199 		if (IS_ERR((void __force *) uptr))
200 			return PTR_ERR((void __force *) uptr);
201 
202 		r = copy_to_user(uptr, from, PMD_SIZE);
203 
204 		if (r) {
205 			r = -EFAULT;
206 			goto out;
207 		}
208 		from += PMD_SIZE;
209 		n -= PMD_SIZE;
210 		guestdest += PMD_SIZE;
211 	}
212 
213 	/* copy the tail segment */
214 	if (n) {
215 		uptr = (void __user *)gmap_fault(guestdest, vcpu->arch.gmap);
216 
217 		if (IS_ERR((void __force *) uptr))
218 			return PTR_ERR((void __force *) uptr);
219 
220 		r = copy_to_user(uptr, from, n);
221 
222 		if (r)
223 			r = -EFAULT;
224 	}
225 out:
226 	return r;
227 }
228 
copy_to_guest_absolute(struct kvm_vcpu * vcpu,unsigned long guestdest,void * from,unsigned long n)229 static inline int copy_to_guest_absolute(struct kvm_vcpu *vcpu,
230 					 unsigned long guestdest,
231 					 void *from, unsigned long n)
232 {
233 	return __copy_to_guest_fast(vcpu, guestdest, from, n);
234 }
235 
copy_to_guest(struct kvm_vcpu * vcpu,unsigned long guestdest,void * from,unsigned long n)236 static inline int copy_to_guest(struct kvm_vcpu *vcpu, unsigned long guestdest,
237 				void *from, unsigned long n)
238 {
239 	unsigned long prefix  = vcpu->arch.sie_block->prefix;
240 
241 	if ((guestdest < 2 * PAGE_SIZE) && (guestdest + n > 2 * PAGE_SIZE))
242 		goto slowpath;
243 
244 	if ((guestdest < prefix) && (guestdest + n > prefix))
245 		goto slowpath;
246 
247 	if ((guestdest < prefix + 2 * PAGE_SIZE)
248 	    && (guestdest + n > prefix + 2 * PAGE_SIZE))
249 		goto slowpath;
250 
251 	if (guestdest < 2 * PAGE_SIZE)
252 		guestdest += prefix;
253 	else if ((guestdest >= prefix) && (guestdest < prefix + 2 * PAGE_SIZE))
254 		guestdest -= prefix;
255 
256 	return __copy_to_guest_fast(vcpu, guestdest, from, n);
257 slowpath:
258 	return __copy_to_guest_slow(vcpu, guestdest, from, n);
259 }
260 
__copy_from_guest_slow(struct kvm_vcpu * vcpu,void * to,unsigned long guestsrc,unsigned long n)261 static inline int __copy_from_guest_slow(struct kvm_vcpu *vcpu, void *to,
262 					 unsigned long guestsrc,
263 					 unsigned long n)
264 {
265 	int rc;
266 	unsigned long i;
267 	u8 *data = to;
268 
269 	for (i = 0; i < n; i++) {
270 		rc = get_guest_u8(vcpu, guestsrc++, data++);
271 		if (rc < 0)
272 			return rc;
273 	}
274 	return 0;
275 }
276 
__copy_from_guest_fast(struct kvm_vcpu * vcpu,void * to,unsigned long guestsrc,unsigned long n)277 static inline int __copy_from_guest_fast(struct kvm_vcpu *vcpu, void *to,
278 					 unsigned long guestsrc,
279 					 unsigned long n)
280 {
281 	int r;
282 	void __user *uptr;
283 	unsigned long size;
284 
285 	if (guestsrc + n < guestsrc)
286 		return -EFAULT;
287 
288 	/* simple case: all within one segment table entry? */
289 	if ((guestsrc & PMD_MASK) == ((guestsrc+n) & PMD_MASK)) {
290 		uptr = (void __user *) gmap_fault(guestsrc, vcpu->arch.gmap);
291 
292 		if (IS_ERR((void __force *) uptr))
293 			return PTR_ERR((void __force *) uptr);
294 
295 		r = copy_from_user(to, uptr, n);
296 
297 		if (r)
298 			r = -EFAULT;
299 
300 		goto out;
301 	}
302 
303 	/* copy first segment */
304 	uptr = (void __user *)gmap_fault(guestsrc, vcpu->arch.gmap);
305 
306 	if (IS_ERR((void __force *) uptr))
307 		return PTR_ERR((void __force *) uptr);
308 
309 	size = PMD_SIZE - (guestsrc & ~PMD_MASK);
310 
311 	r = copy_from_user(to, uptr, size);
312 
313 	if (r) {
314 		r = -EFAULT;
315 		goto out;
316 	}
317 	to += size;
318 	n -= size;
319 	guestsrc += size;
320 
321 	/* copy full segments */
322 	while (n >= PMD_SIZE) {
323 		uptr = (void __user *)gmap_fault(guestsrc, vcpu->arch.gmap);
324 
325 		if (IS_ERR((void __force *) uptr))
326 			return PTR_ERR((void __force *) uptr);
327 
328 		r = copy_from_user(to, uptr, PMD_SIZE);
329 
330 		if (r) {
331 			r = -EFAULT;
332 			goto out;
333 		}
334 		to += PMD_SIZE;
335 		n -= PMD_SIZE;
336 		guestsrc += PMD_SIZE;
337 	}
338 
339 	/* copy the tail segment */
340 	if (n) {
341 		uptr = (void __user *)gmap_fault(guestsrc, vcpu->arch.gmap);
342 
343 		if (IS_ERR((void __force *) uptr))
344 			return PTR_ERR((void __force *) uptr);
345 
346 		r = copy_from_user(to, uptr, n);
347 
348 		if (r)
349 			r = -EFAULT;
350 	}
351 out:
352 	return r;
353 }
354 
copy_from_guest_absolute(struct kvm_vcpu * vcpu,void * to,unsigned long guestsrc,unsigned long n)355 static inline int copy_from_guest_absolute(struct kvm_vcpu *vcpu, void *to,
356 					   unsigned long guestsrc,
357 					   unsigned long n)
358 {
359 	return __copy_from_guest_fast(vcpu, to, guestsrc, n);
360 }
361 
copy_from_guest(struct kvm_vcpu * vcpu,void * to,unsigned long guestsrc,unsigned long n)362 static inline int copy_from_guest(struct kvm_vcpu *vcpu, void *to,
363 				  unsigned long guestsrc, unsigned long n)
364 {
365 	unsigned long prefix  = vcpu->arch.sie_block->prefix;
366 
367 	if ((guestsrc < 2 * PAGE_SIZE) && (guestsrc + n > 2 * PAGE_SIZE))
368 		goto slowpath;
369 
370 	if ((guestsrc < prefix) && (guestsrc + n > prefix))
371 		goto slowpath;
372 
373 	if ((guestsrc < prefix + 2 * PAGE_SIZE)
374 	    && (guestsrc + n > prefix + 2 * PAGE_SIZE))
375 		goto slowpath;
376 
377 	if (guestsrc < 2 * PAGE_SIZE)
378 		guestsrc += prefix;
379 	else if ((guestsrc >= prefix) && (guestsrc < prefix + 2 * PAGE_SIZE))
380 		guestsrc -= prefix;
381 
382 	return __copy_from_guest_fast(vcpu, to, guestsrc, n);
383 slowpath:
384 	return __copy_from_guest_slow(vcpu, to, guestsrc, n);
385 }
386 #endif
387