1 /*
2 * Xen implementation for transcendent memory (tmem)
3 *
4 * Copyright (C) 2009-2011 Oracle Corp. All rights reserved.
5 * Author: Dan Magenheimer
6 */
7
8 #include <linux/kernel.h>
9 #include <linux/types.h>
10 #include <linux/init.h>
11 #include <linux/pagemap.h>
12 #include <linux/cleancache.h>
13
14 /* temporary ifdef until include/linux/frontswap.h is upstream */
15 #ifdef CONFIG_FRONTSWAP
16 #include <linux/frontswap.h>
17 #endif
18
19 #include <xen/xen.h>
20 #include <xen/interface/xen.h>
21 #include <asm/xen/hypercall.h>
22 #include <asm/xen/page.h>
23 #include <asm/xen/hypervisor.h>
24
25 #define TMEM_CONTROL 0
26 #define TMEM_NEW_POOL 1
27 #define TMEM_DESTROY_POOL 2
28 #define TMEM_NEW_PAGE 3
29 #define TMEM_PUT_PAGE 4
30 #define TMEM_GET_PAGE 5
31 #define TMEM_FLUSH_PAGE 6
32 #define TMEM_FLUSH_OBJECT 7
33 #define TMEM_READ 8
34 #define TMEM_WRITE 9
35 #define TMEM_XCHG 10
36
37 /* Bits for HYPERVISOR_tmem_op(TMEM_NEW_POOL) */
38 #define TMEM_POOL_PERSIST 1
39 #define TMEM_POOL_SHARED 2
40 #define TMEM_POOL_PAGESIZE_SHIFT 4
41 #define TMEM_VERSION_SHIFT 24
42
43
44 struct tmem_pool_uuid {
45 u64 uuid_lo;
46 u64 uuid_hi;
47 };
48
49 struct tmem_oid {
50 u64 oid[3];
51 };
52
53 #define TMEM_POOL_PRIVATE_UUID { 0, 0 }
54
55 /* flags for tmem_ops.new_pool */
56 #define TMEM_POOL_PERSIST 1
57 #define TMEM_POOL_SHARED 2
58
59 /* xen tmem foundation ops/hypercalls */
60
xen_tmem_op(u32 tmem_cmd,u32 tmem_pool,struct tmem_oid oid,u32 index,unsigned long gmfn,u32 tmem_offset,u32 pfn_offset,u32 len)61 static inline int xen_tmem_op(u32 tmem_cmd, u32 tmem_pool, struct tmem_oid oid,
62 u32 index, unsigned long gmfn, u32 tmem_offset, u32 pfn_offset, u32 len)
63 {
64 struct tmem_op op;
65 int rc = 0;
66
67 op.cmd = tmem_cmd;
68 op.pool_id = tmem_pool;
69 op.u.gen.oid[0] = oid.oid[0];
70 op.u.gen.oid[1] = oid.oid[1];
71 op.u.gen.oid[2] = oid.oid[2];
72 op.u.gen.index = index;
73 op.u.gen.tmem_offset = tmem_offset;
74 op.u.gen.pfn_offset = pfn_offset;
75 op.u.gen.len = len;
76 set_xen_guest_handle(op.u.gen.gmfn, (void *)gmfn);
77 rc = HYPERVISOR_tmem_op(&op);
78 return rc;
79 }
80
xen_tmem_new_pool(struct tmem_pool_uuid uuid,u32 flags,unsigned long pagesize)81 static int xen_tmem_new_pool(struct tmem_pool_uuid uuid,
82 u32 flags, unsigned long pagesize)
83 {
84 struct tmem_op op;
85 int rc = 0, pageshift;
86
87 for (pageshift = 0; pagesize != 1; pageshift++)
88 pagesize >>= 1;
89 flags |= (pageshift - 12) << TMEM_POOL_PAGESIZE_SHIFT;
90 flags |= TMEM_SPEC_VERSION << TMEM_VERSION_SHIFT;
91 op.cmd = TMEM_NEW_POOL;
92 op.u.new.uuid[0] = uuid.uuid_lo;
93 op.u.new.uuid[1] = uuid.uuid_hi;
94 op.u.new.flags = flags;
95 rc = HYPERVISOR_tmem_op(&op);
96 return rc;
97 }
98
99 /* xen generic tmem ops */
100
xen_tmem_put_page(u32 pool_id,struct tmem_oid oid,u32 index,unsigned long pfn)101 static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid,
102 u32 index, unsigned long pfn)
103 {
104 unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
105
106 return xen_tmem_op(TMEM_PUT_PAGE, pool_id, oid, index,
107 gmfn, 0, 0, 0);
108 }
109
xen_tmem_get_page(u32 pool_id,struct tmem_oid oid,u32 index,unsigned long pfn)110 static int xen_tmem_get_page(u32 pool_id, struct tmem_oid oid,
111 u32 index, unsigned long pfn)
112 {
113 unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
114
115 return xen_tmem_op(TMEM_GET_PAGE, pool_id, oid, index,
116 gmfn, 0, 0, 0);
117 }
118
xen_tmem_flush_page(u32 pool_id,struct tmem_oid oid,u32 index)119 static int xen_tmem_flush_page(u32 pool_id, struct tmem_oid oid, u32 index)
120 {
121 return xen_tmem_op(TMEM_FLUSH_PAGE, pool_id, oid, index,
122 0, 0, 0, 0);
123 }
124
xen_tmem_flush_object(u32 pool_id,struct tmem_oid oid)125 static int xen_tmem_flush_object(u32 pool_id, struct tmem_oid oid)
126 {
127 return xen_tmem_op(TMEM_FLUSH_OBJECT, pool_id, oid, 0, 0, 0, 0, 0);
128 }
129
130 bool __read_mostly tmem_enabled = false;
131
enable_tmem(char * s)132 static int __init enable_tmem(char *s)
133 {
134 tmem_enabled = true;
135 return 1;
136 }
137 __setup("tmem", enable_tmem);
138
139 #ifdef CONFIG_CLEANCACHE
xen_tmem_destroy_pool(u32 pool_id)140 static int xen_tmem_destroy_pool(u32 pool_id)
141 {
142 struct tmem_oid oid = { { 0 } };
143
144 return xen_tmem_op(TMEM_DESTROY_POOL, pool_id, oid, 0, 0, 0, 0, 0);
145 }
146
147 /* cleancache ops */
148
tmem_cleancache_put_page(int pool,struct cleancache_filekey key,pgoff_t index,struct page * page)149 static void tmem_cleancache_put_page(int pool, struct cleancache_filekey key,
150 pgoff_t index, struct page *page)
151 {
152 u32 ind = (u32) index;
153 struct tmem_oid oid = *(struct tmem_oid *)&key;
154 unsigned long pfn = page_to_pfn(page);
155
156 if (pool < 0)
157 return;
158 if (ind != index)
159 return;
160 mb(); /* ensure page is quiescent; tmem may address it with an alias */
161 (void)xen_tmem_put_page((u32)pool, oid, ind, pfn);
162 }
163
tmem_cleancache_get_page(int pool,struct cleancache_filekey key,pgoff_t index,struct page * page)164 static int tmem_cleancache_get_page(int pool, struct cleancache_filekey key,
165 pgoff_t index, struct page *page)
166 {
167 u32 ind = (u32) index;
168 struct tmem_oid oid = *(struct tmem_oid *)&key;
169 unsigned long pfn = page_to_pfn(page);
170 int ret;
171
172 /* translate return values to linux semantics */
173 if (pool < 0)
174 return -1;
175 if (ind != index)
176 return -1;
177 ret = xen_tmem_get_page((u32)pool, oid, ind, pfn);
178 if (ret == 1)
179 return 0;
180 else
181 return -1;
182 }
183
tmem_cleancache_flush_page(int pool,struct cleancache_filekey key,pgoff_t index)184 static void tmem_cleancache_flush_page(int pool, struct cleancache_filekey key,
185 pgoff_t index)
186 {
187 u32 ind = (u32) index;
188 struct tmem_oid oid = *(struct tmem_oid *)&key;
189
190 if (pool < 0)
191 return;
192 if (ind != index)
193 return;
194 (void)xen_tmem_flush_page((u32)pool, oid, ind);
195 }
196
tmem_cleancache_flush_inode(int pool,struct cleancache_filekey key)197 static void tmem_cleancache_flush_inode(int pool, struct cleancache_filekey key)
198 {
199 struct tmem_oid oid = *(struct tmem_oid *)&key;
200
201 if (pool < 0)
202 return;
203 (void)xen_tmem_flush_object((u32)pool, oid);
204 }
205
tmem_cleancache_flush_fs(int pool)206 static void tmem_cleancache_flush_fs(int pool)
207 {
208 if (pool < 0)
209 return;
210 (void)xen_tmem_destroy_pool((u32)pool);
211 }
212
tmem_cleancache_init_fs(size_t pagesize)213 static int tmem_cleancache_init_fs(size_t pagesize)
214 {
215 struct tmem_pool_uuid uuid_private = TMEM_POOL_PRIVATE_UUID;
216
217 return xen_tmem_new_pool(uuid_private, 0, pagesize);
218 }
219
tmem_cleancache_init_shared_fs(char * uuid,size_t pagesize)220 static int tmem_cleancache_init_shared_fs(char *uuid, size_t pagesize)
221 {
222 struct tmem_pool_uuid shared_uuid;
223
224 shared_uuid.uuid_lo = *(u64 *)uuid;
225 shared_uuid.uuid_hi = *(u64 *)(&uuid[8]);
226 return xen_tmem_new_pool(shared_uuid, TMEM_POOL_SHARED, pagesize);
227 }
228
229 static bool __initdata use_cleancache = true;
230
no_cleancache(char * s)231 static int __init no_cleancache(char *s)
232 {
233 use_cleancache = false;
234 return 1;
235 }
236 __setup("nocleancache", no_cleancache);
237
238 static struct cleancache_ops __initdata tmem_cleancache_ops = {
239 .put_page = tmem_cleancache_put_page,
240 .get_page = tmem_cleancache_get_page,
241 .invalidate_page = tmem_cleancache_flush_page,
242 .invalidate_inode = tmem_cleancache_flush_inode,
243 .invalidate_fs = tmem_cleancache_flush_fs,
244 .init_shared_fs = tmem_cleancache_init_shared_fs,
245 .init_fs = tmem_cleancache_init_fs
246 };
247 #endif
248
249 #ifdef CONFIG_FRONTSWAP
250 /* frontswap tmem operations */
251
252 /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
253 static int tmem_frontswap_poolid;
254
255 /*
256 * Swizzling increases objects per swaptype, increasing tmem concurrency
257 * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
258 */
259 #define SWIZ_BITS 4
260 #define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
261 #define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
262 #define iswiz(_ind) (_ind >> SWIZ_BITS)
263
oswiz(unsigned type,u32 ind)264 static inline struct tmem_oid oswiz(unsigned type, u32 ind)
265 {
266 struct tmem_oid oid = { .oid = { 0 } };
267 oid.oid[0] = _oswiz(type, ind);
268 return oid;
269 }
270
271 /* returns 0 if the page was successfully put into frontswap, -1 if not */
tmem_frontswap_put_page(unsigned type,pgoff_t offset,struct page * page)272 static int tmem_frontswap_put_page(unsigned type, pgoff_t offset,
273 struct page *page)
274 {
275 u64 ind64 = (u64)offset;
276 u32 ind = (u32)offset;
277 unsigned long pfn = page_to_pfn(page);
278 int pool = tmem_frontswap_poolid;
279 int ret;
280
281 if (pool < 0)
282 return -1;
283 if (ind64 != ind)
284 return -1;
285 mb(); /* ensure page is quiescent; tmem may address it with an alias */
286 ret = xen_tmem_put_page(pool, oswiz(type, ind), iswiz(ind), pfn);
287 /* translate Xen tmem return values to linux semantics */
288 if (ret == 1)
289 return 0;
290 else
291 return -1;
292 }
293
294 /*
295 * returns 0 if the page was successfully gotten from frontswap, -1 if
296 * was not present (should never happen!)
297 */
tmem_frontswap_get_page(unsigned type,pgoff_t offset,struct page * page)298 static int tmem_frontswap_get_page(unsigned type, pgoff_t offset,
299 struct page *page)
300 {
301 u64 ind64 = (u64)offset;
302 u32 ind = (u32)offset;
303 unsigned long pfn = page_to_pfn(page);
304 int pool = tmem_frontswap_poolid;
305 int ret;
306
307 if (pool < 0)
308 return -1;
309 if (ind64 != ind)
310 return -1;
311 ret = xen_tmem_get_page(pool, oswiz(type, ind), iswiz(ind), pfn);
312 /* translate Xen tmem return values to linux semantics */
313 if (ret == 1)
314 return 0;
315 else
316 return -1;
317 }
318
319 /* flush a single page from frontswap */
tmem_frontswap_flush_page(unsigned type,pgoff_t offset)320 static void tmem_frontswap_flush_page(unsigned type, pgoff_t offset)
321 {
322 u64 ind64 = (u64)offset;
323 u32 ind = (u32)offset;
324 int pool = tmem_frontswap_poolid;
325
326 if (pool < 0)
327 return;
328 if (ind64 != ind)
329 return;
330 (void) xen_tmem_flush_page(pool, oswiz(type, ind), iswiz(ind));
331 }
332
333 /* flush all pages from the passed swaptype */
tmem_frontswap_flush_area(unsigned type)334 static void tmem_frontswap_flush_area(unsigned type)
335 {
336 int pool = tmem_frontswap_poolid;
337 int ind;
338
339 if (pool < 0)
340 return;
341 for (ind = SWIZ_MASK; ind >= 0; ind--)
342 (void)xen_tmem_flush_object(pool, oswiz(type, ind));
343 }
344
tmem_frontswap_init(unsigned ignored)345 static void tmem_frontswap_init(unsigned ignored)
346 {
347 struct tmem_pool_uuid private = TMEM_POOL_PRIVATE_UUID;
348
349 /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
350 if (tmem_frontswap_poolid < 0)
351 tmem_frontswap_poolid =
352 xen_tmem_new_pool(private, TMEM_POOL_PERSIST, PAGE_SIZE);
353 }
354
355 static bool __initdata use_frontswap = true;
356
no_frontswap(char * s)357 static int __init no_frontswap(char *s)
358 {
359 use_frontswap = false;
360 return 1;
361 }
362 __setup("nofrontswap", no_frontswap);
363
364 static struct frontswap_ops __initdata tmem_frontswap_ops = {
365 .put_page = tmem_frontswap_put_page,
366 .get_page = tmem_frontswap_get_page,
367 .invalidate_page = tmem_frontswap_flush_page,
368 .invalidate_area = tmem_frontswap_flush_area,
369 .init = tmem_frontswap_init
370 };
371 #endif
372
xen_tmem_init(void)373 static int __init xen_tmem_init(void)
374 {
375 if (!xen_domain())
376 return 0;
377 #ifdef CONFIG_FRONTSWAP
378 if (tmem_enabled && use_frontswap) {
379 char *s = "";
380 struct frontswap_ops old_ops =
381 frontswap_register_ops(&tmem_frontswap_ops);
382
383 tmem_frontswap_poolid = -1;
384 if (old_ops.init != NULL)
385 s = " (WARNING: frontswap_ops overridden)";
386 printk(KERN_INFO "frontswap enabled, RAM provided by "
387 "Xen Transcendent Memory\n");
388 }
389 #endif
390 #ifdef CONFIG_CLEANCACHE
391 BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
392 if (tmem_enabled && use_cleancache) {
393 char *s = "";
394 struct cleancache_ops old_ops =
395 cleancache_register_ops(&tmem_cleancache_ops);
396 if (old_ops.init_fs != NULL)
397 s = " (WARNING: cleancache_ops overridden)";
398 printk(KERN_INFO "cleancache enabled, RAM provided by "
399 "Xen Transcendent Memory%s\n", s);
400 }
401 #endif
402 return 0;
403 }
404
405 module_init(xen_tmem_init)
406