Commit | Line | Data |
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b5eafe92 JF |
1 | /* |
2 | * Xen leaves the responsibility for maintaining p2m mappings to the | |
3 | * guests themselves, but it must also access and update the p2m array | |
4 | * during suspend/resume when all the pages are reallocated. | |
5 | * | |
6 | * The p2m table is logically a flat array, but we implement it as a | |
7 | * three-level tree to allow the address space to be sparse. | |
8 | * | |
9 | * Xen | |
10 | * | | |
11 | * p2m_top p2m_top_mfn | |
12 | * / \ / \ | |
13 | * p2m_mid p2m_mid p2m_mid_mfn p2m_mid_mfn | |
14 | * / \ / \ / / | |
15 | * p2m p2m p2m p2m p2m p2m p2m ... | |
16 | * | |
17 | * The p2m_mid_mfn pages are mapped by p2m_top_mfn_p. | |
18 | * | |
19 | * The p2m_top and p2m_top_mfn levels are limited to 1 page, so the | |
20 | * maximum representable pseudo-physical address space is: | |
21 | * P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE pages | |
22 | * | |
23 | * P2M_PER_PAGE depends on the architecture, as a mfn is always | |
24 | * unsigned long (8 bytes on 64-bit, 4 bytes on 32), leading to | |
25 | * 512 and 1024 entries respectively. | |
f4cec35b KRW |
26 | * |
27 | * In short, these structures contain the Machine Frame Number (MFN) of the PFN. | |
28 | * | |
29 | * However not all entries are filled with MFNs. Specifically for all other | |
30 | * leaf entries, or for the top root, or middle one, for which there is a void | |
31 | * entry, we assume it is "missing". So (for example) | |
32 | * pfn_to_mfn(0x90909090)=INVALID_P2M_ENTRY. | |
33 | * | |
34 | * We also have the possibility of setting 1-1 mappings on certain regions, so | |
35 | * that: | |
36 | * pfn_to_mfn(0xc0000)=0xc0000 | |
37 | * | |
38 | * The benefit of this is, that we can assume for non-RAM regions (think | |
39 | * PCI BARs, or ACPI spaces), we can create mappings easily b/c we | |
40 | * get the PFN value to match the MFN. | |
41 | * | |
42 | * For this to work efficiently we have one new page p2m_identity and | |
43 | * allocate (via reserved_brk) any other pages we need to cover the sides | |
44 | * (1GB or 4MB boundary violations). All entries in p2m_identity are set to | |
45 | * INVALID_P2M_ENTRY type (Xen toolstack only recognizes that and MFNs, | |
46 | * no other fancy value). | |
47 | * | |
48 | * On lookup we spot that the entry points to p2m_identity and return the | |
49 | * identity value instead of dereferencing and returning INVALID_P2M_ENTRY. | |
50 | * If the entry points to an allocated page, we just proceed as before and | |
51 | * return the PFN. If the PFN has IDENTITY_FRAME_BIT set we unmask that in | |
52 | * appropriate functions (pfn_to_mfn). | |
53 | * | |
54 | * The reason for having the IDENTITY_FRAME_BIT instead of just returning the | |
55 | * PFN is that we could find ourselves where pfn_to_mfn(pfn)==pfn for a | |
56 | * non-identity pfn. To protect ourselves against we elect to set (and get) the | |
57 | * IDENTITY_FRAME_BIT on all identity mapped PFNs. | |
58 | * | |
59 | * This simplistic diagram is used to explain the more subtle piece of code. | |
60 | * There is also a digram of the P2M at the end that can help. | |
61 | * Imagine your E820 looking as so: | |
62 | * | |
63 | * 1GB 2GB | |
64 | * /-------------------+---------\/----\ /----------\ /---+-----\ | |
65 | * | System RAM | Sys RAM ||ACPI| | reserved | | Sys RAM | | |
66 | * \-------------------+---------/\----/ \----------/ \---+-----/ | |
67 | * ^- 1029MB ^- 2001MB | |
68 | * | |
69 | * [1029MB = 263424 (0x40500), 2001MB = 512256 (0x7D100), | |
70 | * 2048MB = 524288 (0x80000)] | |
71 | * | |
72 | * And dom0_mem=max:3GB,1GB is passed in to the guest, meaning memory past 1GB | |
73 | * is actually not present (would have to kick the balloon driver to put it in). | |
74 | * | |
75 | * When we are told to set the PFNs for identity mapping (see patch: "xen/setup: | |
76 | * Set identity mapping for non-RAM E820 and E820 gaps.") we pass in the start | |
77 | * of the PFN and the end PFN (263424 and 512256 respectively). The first step | |
78 | * is to reserve_brk a top leaf page if the p2m[1] is missing. The top leaf page | |
79 | * covers 512^2 of page estate (1GB) and in case the start or end PFN is not | |
80 | * aligned on 512^2*PAGE_SIZE (1GB) we loop on aligned 1GB PFNs from start pfn | |
81 | * to end pfn. We reserve_brk top leaf pages if they are missing (means they | |
82 | * point to p2m_mid_missing). | |
83 | * | |
84 | * With the E820 example above, 263424 is not 1GB aligned so we allocate a | |
85 | * reserve_brk page which will cover the PFNs estate from 0x40000 to 0x80000. | |
86 | * Each entry in the allocate page is "missing" (points to p2m_missing). | |
87 | * | |
88 | * Next stage is to determine if we need to do a more granular boundary check | |
89 | * on the 4MB (or 2MB depending on architecture) off the start and end pfn's. | |
90 | * We check if the start pfn and end pfn violate that boundary check, and if | |
91 | * so reserve_brk a middle (p2m[x][y]) leaf page. This way we have a much finer | |
92 | * granularity of setting which PFNs are missing and which ones are identity. | |
93 | * In our example 263424 and 512256 both fail the check so we reserve_brk two | |
94 | * pages. Populate them with INVALID_P2M_ENTRY (so they both have "missing" | |
95 | * values) and assign them to p2m[1][2] and p2m[1][488] respectively. | |
96 | * | |
97 | * At this point we would at minimum reserve_brk one page, but could be up to | |
98 | * three. Each call to set_phys_range_identity has at maximum a three page | |
99 | * cost. If we were to query the P2M at this stage, all those entries from | |
100 | * start PFN through end PFN (so 1029MB -> 2001MB) would return | |
101 | * INVALID_P2M_ENTRY ("missing"). | |
102 | * | |
103 | * The next step is to walk from the start pfn to the end pfn setting | |
104 | * the IDENTITY_FRAME_BIT on each PFN. This is done in set_phys_range_identity. | |
105 | * If we find that the middle leaf is pointing to p2m_missing we can swap it | |
106 | * over to p2m_identity - this way covering 4MB (or 2MB) PFN space. At this | |
107 | * point we do not need to worry about boundary aligment (so no need to | |
108 | * reserve_brk a middle page, figure out which PFNs are "missing" and which | |
109 | * ones are identity), as that has been done earlier. If we find that the | |
110 | * middle leaf is not occupied by p2m_identity or p2m_missing, we dereference | |
111 | * that page (which covers 512 PFNs) and set the appropriate PFN with | |
112 | * IDENTITY_FRAME_BIT. In our example 263424 and 512256 end up there, and we | |
113 | * set from p2m[1][2][256->511] and p2m[1][488][0->256] with | |
114 | * IDENTITY_FRAME_BIT set. | |
115 | * | |
116 | * All other regions that are void (or not filled) either point to p2m_missing | |
117 | * (considered missing) or have the default value of INVALID_P2M_ENTRY (also | |
118 | * considered missing). In our case, p2m[1][2][0->255] and p2m[1][488][257->511] | |
119 | * contain the INVALID_P2M_ENTRY value and are considered "missing." | |
120 | * | |
121 | * This is what the p2m ends up looking (for the E820 above) with this | |
122 | * fabulous drawing: | |
123 | * | |
124 | * p2m /--------------\ | |
125 | * /-----\ | &mfn_list[0],| /-----------------\ | |
126 | * | 0 |------>| &mfn_list[1],| /---------------\ | ~0, ~0, .. | | |
127 | * |-----| | ..., ~0, ~0 | | ~0, ~0, [x]---+----->| IDENTITY [@256] | | |
128 | * | 1 |---\ \--------------/ | [p2m_identity]+\ | IDENTITY [@257] | | |
129 | * |-----| \ | [p2m_identity]+\\ | .... | | |
130 | * | 2 |--\ \-------------------->| ... | \\ \----------------/ | |
131 | * |-----| \ \---------------/ \\ | |
132 | * | 3 |\ \ \\ p2m_identity | |
133 | * |-----| \ \-------------------->/---------------\ /-----------------\ | |
134 | * | .. +->+ | [p2m_identity]+-->| ~0, ~0, ~0, ... | | |
135 | * \-----/ / | [p2m_identity]+-->| ..., ~0 | | |
136 | * / /---------------\ | .... | \-----------------/ | |
137 | * / | IDENTITY[@0] | /-+-[x], ~0, ~0.. | | |
138 | * / | IDENTITY[@256]|<----/ \---------------/ | |
139 | * / | ~0, ~0, .... | | |
140 | * | \---------------/ | |
141 | * | | |
142 | * p2m_missing p2m_missing | |
143 | * /------------------\ /------------\ | |
144 | * | [p2m_mid_missing]+---->| ~0, ~0, ~0 | | |
145 | * | [p2m_mid_missing]+---->| ..., ~0 | | |
146 | * \------------------/ \------------/ | |
147 | * | |
148 | * where ~0 is INVALID_P2M_ENTRY. IDENTITY is (PFN | IDENTITY_BIT) | |
b5eafe92 JF |
149 | */ |
150 | ||
151 | #include <linux/init.h> | |
152 | #include <linux/module.h> | |
448f2831 JF |
153 | #include <linux/list.h> |
154 | #include <linux/hash.h> | |
87f1d40a | 155 | #include <linux/sched.h> |
2222e71b | 156 | #include <linux/seq_file.h> |
b5eafe92 JF |
157 | |
158 | #include <asm/cache.h> | |
159 | #include <asm/setup.h> | |
160 | ||
161 | #include <asm/xen/page.h> | |
162 | #include <asm/xen/hypercall.h> | |
163 | #include <asm/xen/hypervisor.h> | |
164 | ||
165 | #include "xen-ops.h" | |
166 | ||
448f2831 JF |
167 | static void __init m2p_override_init(void); |
168 | ||
b5eafe92 JF |
169 | unsigned long xen_max_p2m_pfn __read_mostly; |
170 | ||
171 | #define P2M_PER_PAGE (PAGE_SIZE / sizeof(unsigned long)) | |
172 | #define P2M_MID_PER_PAGE (PAGE_SIZE / sizeof(unsigned long *)) | |
173 | #define P2M_TOP_PER_PAGE (PAGE_SIZE / sizeof(unsigned long **)) | |
174 | ||
175 | #define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE) | |
176 | ||
177 | /* Placeholders for holes in the address space */ | |
178 | static RESERVE_BRK_ARRAY(unsigned long, p2m_missing, P2M_PER_PAGE); | |
179 | static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_missing, P2M_MID_PER_PAGE); | |
180 | static RESERVE_BRK_ARRAY(unsigned long, p2m_mid_missing_mfn, P2M_MID_PER_PAGE); | |
181 | ||
182 | static RESERVE_BRK_ARRAY(unsigned long **, p2m_top, P2M_TOP_PER_PAGE); | |
183 | static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn, P2M_TOP_PER_PAGE); | |
184 | static RESERVE_BRK_ARRAY(unsigned long *, p2m_top_mfn_p, P2M_TOP_PER_PAGE); | |
185 | ||
f4cec35b KRW |
186 | static RESERVE_BRK_ARRAY(unsigned long, p2m_identity, P2M_PER_PAGE); |
187 | ||
b5eafe92 JF |
188 | RESERVE_BRK(p2m_mid, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE))); |
189 | RESERVE_BRK(p2m_mid_mfn, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE))); | |
190 | ||
f4cec35b KRW |
191 | /* We might hit two boundary violations at the start and end, at max each |
192 | * boundary violation will require three middle nodes. */ | |
193 | RESERVE_BRK(p2m_mid_identity, PAGE_SIZE * 2 * 3); | |
194 | ||
b5eafe92 JF |
195 | static inline unsigned p2m_top_index(unsigned long pfn) |
196 | { | |
197 | BUG_ON(pfn >= MAX_P2M_PFN); | |
198 | return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE); | |
199 | } | |
200 | ||
201 | static inline unsigned p2m_mid_index(unsigned long pfn) | |
202 | { | |
203 | return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE; | |
204 | } | |
205 | ||
206 | static inline unsigned p2m_index(unsigned long pfn) | |
207 | { | |
208 | return pfn % P2M_PER_PAGE; | |
209 | } | |
210 | ||
211 | static void p2m_top_init(unsigned long ***top) | |
212 | { | |
213 | unsigned i; | |
214 | ||
215 | for (i = 0; i < P2M_TOP_PER_PAGE; i++) | |
216 | top[i] = p2m_mid_missing; | |
217 | } | |
218 | ||
219 | static void p2m_top_mfn_init(unsigned long *top) | |
220 | { | |
221 | unsigned i; | |
222 | ||
223 | for (i = 0; i < P2M_TOP_PER_PAGE; i++) | |
224 | top[i] = virt_to_mfn(p2m_mid_missing_mfn); | |
225 | } | |
226 | ||
227 | static void p2m_top_mfn_p_init(unsigned long **top) | |
228 | { | |
229 | unsigned i; | |
230 | ||
231 | for (i = 0; i < P2M_TOP_PER_PAGE; i++) | |
232 | top[i] = p2m_mid_missing_mfn; | |
233 | } | |
234 | ||
235 | static void p2m_mid_init(unsigned long **mid) | |
236 | { | |
237 | unsigned i; | |
238 | ||
239 | for (i = 0; i < P2M_MID_PER_PAGE; i++) | |
240 | mid[i] = p2m_missing; | |
241 | } | |
242 | ||
243 | static void p2m_mid_mfn_init(unsigned long *mid) | |
244 | { | |
245 | unsigned i; | |
246 | ||
247 | for (i = 0; i < P2M_MID_PER_PAGE; i++) | |
248 | mid[i] = virt_to_mfn(p2m_missing); | |
249 | } | |
250 | ||
251 | static void p2m_init(unsigned long *p2m) | |
252 | { | |
253 | unsigned i; | |
254 | ||
255 | for (i = 0; i < P2M_MID_PER_PAGE; i++) | |
256 | p2m[i] = INVALID_P2M_ENTRY; | |
257 | } | |
258 | ||
259 | /* | |
260 | * Build the parallel p2m_top_mfn and p2m_mid_mfn structures | |
261 | * | |
262 | * This is called both at boot time, and after resuming from suspend: | |
263 | * - At boot time we're called very early, and must use extend_brk() | |
264 | * to allocate memory. | |
265 | * | |
266 | * - After resume we're called from within stop_machine, but the mfn | |
267 | * tree should alreay be completely allocated. | |
268 | */ | |
44b46c3e | 269 | void __ref xen_build_mfn_list_list(void) |
b5eafe92 JF |
270 | { |
271 | unsigned long pfn; | |
272 | ||
273 | /* Pre-initialize p2m_top_mfn to be completely missing */ | |
274 | if (p2m_top_mfn == NULL) { | |
275 | p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
276 | p2m_mid_mfn_init(p2m_mid_missing_mfn); | |
277 | ||
278 | p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
279 | p2m_top_mfn_p_init(p2m_top_mfn_p); | |
280 | ||
281 | p2m_top_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
282 | p2m_top_mfn_init(p2m_top_mfn); | |
283 | } else { | |
284 | /* Reinitialise, mfn's all change after migration */ | |
285 | p2m_mid_mfn_init(p2m_mid_missing_mfn); | |
286 | } | |
287 | ||
288 | for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += P2M_PER_PAGE) { | |
289 | unsigned topidx = p2m_top_index(pfn); | |
290 | unsigned mididx = p2m_mid_index(pfn); | |
291 | unsigned long **mid; | |
292 | unsigned long *mid_mfn_p; | |
293 | ||
294 | mid = p2m_top[topidx]; | |
295 | mid_mfn_p = p2m_top_mfn_p[topidx]; | |
296 | ||
297 | /* Don't bother allocating any mfn mid levels if | |
298 | * they're just missing, just update the stored mfn, | |
299 | * since all could have changed over a migrate. | |
300 | */ | |
301 | if (mid == p2m_mid_missing) { | |
302 | BUG_ON(mididx); | |
303 | BUG_ON(mid_mfn_p != p2m_mid_missing_mfn); | |
304 | p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn); | |
305 | pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE; | |
306 | continue; | |
307 | } | |
308 | ||
309 | if (mid_mfn_p == p2m_mid_missing_mfn) { | |
310 | /* | |
311 | * XXX boot-time only! We should never find | |
312 | * missing parts of the mfn tree after | |
313 | * runtime. extend_brk() will BUG if we call | |
314 | * it too late. | |
315 | */ | |
316 | mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
317 | p2m_mid_mfn_init(mid_mfn_p); | |
318 | ||
319 | p2m_top_mfn_p[topidx] = mid_mfn_p; | |
320 | } | |
321 | ||
322 | p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p); | |
323 | mid_mfn_p[mididx] = virt_to_mfn(mid[mididx]); | |
324 | } | |
325 | } | |
326 | ||
327 | void xen_setup_mfn_list_list(void) | |
328 | { | |
329 | BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); | |
330 | ||
331 | HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = | |
332 | virt_to_mfn(p2m_top_mfn); | |
333 | HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn; | |
334 | } | |
335 | ||
336 | /* Set up p2m_top to point to the domain-builder provided p2m pages */ | |
337 | void __init xen_build_dynamic_phys_to_machine(void) | |
338 | { | |
339 | unsigned long *mfn_list = (unsigned long *)xen_start_info->mfn_list; | |
340 | unsigned long max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages); | |
341 | unsigned long pfn; | |
342 | ||
343 | xen_max_p2m_pfn = max_pfn; | |
344 | ||
345 | p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
346 | p2m_init(p2m_missing); | |
347 | ||
348 | p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
349 | p2m_mid_init(p2m_mid_missing); | |
350 | ||
351 | p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
352 | p2m_top_init(p2m_top); | |
353 | ||
f4cec35b KRW |
354 | p2m_identity = extend_brk(PAGE_SIZE, PAGE_SIZE); |
355 | p2m_init(p2m_identity); | |
356 | ||
b5eafe92 JF |
357 | /* |
358 | * The domain builder gives us a pre-constructed p2m array in | |
359 | * mfn_list for all the pages initially given to us, so we just | |
360 | * need to graft that into our tree structure. | |
361 | */ | |
362 | for (pfn = 0; pfn < max_pfn; pfn += P2M_PER_PAGE) { | |
363 | unsigned topidx = p2m_top_index(pfn); | |
364 | unsigned mididx = p2m_mid_index(pfn); | |
365 | ||
366 | if (p2m_top[topidx] == p2m_mid_missing) { | |
367 | unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
368 | p2m_mid_init(mid); | |
369 | ||
370 | p2m_top[topidx] = mid; | |
371 | } | |
372 | ||
8e1b4cf2 SB |
373 | /* |
374 | * As long as the mfn_list has enough entries to completely | |
375 | * fill a p2m page, pointing into the array is ok. But if | |
376 | * not the entries beyond the last pfn will be undefined. | |
8e1b4cf2 SB |
377 | */ |
378 | if (unlikely(pfn + P2M_PER_PAGE > max_pfn)) { | |
379 | unsigned long p2midx; | |
cf04d120 SB |
380 | |
381 | p2midx = max_pfn % P2M_PER_PAGE; | |
382 | for ( ; p2midx < P2M_PER_PAGE; p2midx++) | |
383 | mfn_list[pfn + p2midx] = INVALID_P2M_ENTRY; | |
384 | } | |
385 | p2m_top[topidx][mididx] = &mfn_list[pfn]; | |
b5eafe92 | 386 | } |
448f2831 JF |
387 | |
388 | m2p_override_init(); | |
b5eafe92 JF |
389 | } |
390 | ||
391 | unsigned long get_phys_to_machine(unsigned long pfn) | |
392 | { | |
393 | unsigned topidx, mididx, idx; | |
394 | ||
395 | if (unlikely(pfn >= MAX_P2M_PFN)) | |
396 | return INVALID_P2M_ENTRY; | |
397 | ||
398 | topidx = p2m_top_index(pfn); | |
399 | mididx = p2m_mid_index(pfn); | |
400 | idx = p2m_index(pfn); | |
401 | ||
f4cec35b KRW |
402 | /* |
403 | * The INVALID_P2M_ENTRY is filled in both p2m_*identity | |
404 | * and in p2m_*missing, so returning the INVALID_P2M_ENTRY | |
405 | * would be wrong. | |
406 | */ | |
407 | if (p2m_top[topidx][mididx] == p2m_identity) | |
408 | return IDENTITY_FRAME(pfn); | |
409 | ||
b5eafe92 JF |
410 | return p2m_top[topidx][mididx][idx]; |
411 | } | |
412 | EXPORT_SYMBOL_GPL(get_phys_to_machine); | |
413 | ||
414 | static void *alloc_p2m_page(void) | |
415 | { | |
416 | return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT); | |
417 | } | |
418 | ||
419 | static void free_p2m_page(void *p) | |
420 | { | |
421 | free_page((unsigned long)p); | |
422 | } | |
423 | ||
424 | /* | |
425 | * Fully allocate the p2m structure for a given pfn. We need to check | |
426 | * that both the top and mid levels are allocated, and make sure the | |
427 | * parallel mfn tree is kept in sync. We may race with other cpus, so | |
428 | * the new pages are installed with cmpxchg; if we lose the race then | |
429 | * simply free the page we allocated and use the one that's there. | |
430 | */ | |
431 | static bool alloc_p2m(unsigned long pfn) | |
432 | { | |
433 | unsigned topidx, mididx; | |
434 | unsigned long ***top_p, **mid; | |
435 | unsigned long *top_mfn_p, *mid_mfn; | |
436 | ||
437 | topidx = p2m_top_index(pfn); | |
438 | mididx = p2m_mid_index(pfn); | |
439 | ||
440 | top_p = &p2m_top[topidx]; | |
441 | mid = *top_p; | |
442 | ||
443 | if (mid == p2m_mid_missing) { | |
444 | /* Mid level is missing, allocate a new one */ | |
445 | mid = alloc_p2m_page(); | |
446 | if (!mid) | |
447 | return false; | |
448 | ||
449 | p2m_mid_init(mid); | |
450 | ||
451 | if (cmpxchg(top_p, p2m_mid_missing, mid) != p2m_mid_missing) | |
452 | free_p2m_page(mid); | |
453 | } | |
454 | ||
455 | top_mfn_p = &p2m_top_mfn[topidx]; | |
456 | mid_mfn = p2m_top_mfn_p[topidx]; | |
457 | ||
458 | BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p); | |
459 | ||
460 | if (mid_mfn == p2m_mid_missing_mfn) { | |
461 | /* Separately check the mid mfn level */ | |
462 | unsigned long missing_mfn; | |
463 | unsigned long mid_mfn_mfn; | |
464 | ||
465 | mid_mfn = alloc_p2m_page(); | |
466 | if (!mid_mfn) | |
467 | return false; | |
468 | ||
469 | p2m_mid_mfn_init(mid_mfn); | |
470 | ||
471 | missing_mfn = virt_to_mfn(p2m_mid_missing_mfn); | |
472 | mid_mfn_mfn = virt_to_mfn(mid_mfn); | |
473 | if (cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn) != missing_mfn) | |
474 | free_p2m_page(mid_mfn); | |
475 | else | |
476 | p2m_top_mfn_p[topidx] = mid_mfn; | |
477 | } | |
478 | ||
f4cec35b KRW |
479 | if (p2m_top[topidx][mididx] == p2m_identity || |
480 | p2m_top[topidx][mididx] == p2m_missing) { | |
b5eafe92 JF |
481 | /* p2m leaf page is missing */ |
482 | unsigned long *p2m; | |
f4cec35b | 483 | unsigned long *p2m_orig = p2m_top[topidx][mididx]; |
b5eafe92 JF |
484 | |
485 | p2m = alloc_p2m_page(); | |
486 | if (!p2m) | |
487 | return false; | |
488 | ||
489 | p2m_init(p2m); | |
490 | ||
f4cec35b | 491 | if (cmpxchg(&mid[mididx], p2m_orig, p2m) != p2m_orig) |
b5eafe92 JF |
492 | free_p2m_page(p2m); |
493 | else | |
494 | mid_mfn[mididx] = virt_to_mfn(p2m); | |
495 | } | |
496 | ||
497 | return true; | |
498 | } | |
499 | ||
b83c6e55 | 500 | static bool __init __early_alloc_p2m(unsigned long pfn) |
f4cec35b KRW |
501 | { |
502 | unsigned topidx, mididx, idx; | |
503 | ||
504 | topidx = p2m_top_index(pfn); | |
505 | mididx = p2m_mid_index(pfn); | |
506 | idx = p2m_index(pfn); | |
507 | ||
508 | /* Pfff.. No boundary cross-over, lets get out. */ | |
509 | if (!idx) | |
510 | return false; | |
511 | ||
512 | WARN(p2m_top[topidx][mididx] == p2m_identity, | |
513 | "P2M[%d][%d] == IDENTITY, should be MISSING (or alloced)!\n", | |
514 | topidx, mididx); | |
515 | ||
516 | /* | |
517 | * Could be done by xen_build_dynamic_phys_to_machine.. | |
518 | */ | |
519 | if (p2m_top[topidx][mididx] != p2m_missing) | |
520 | return false; | |
521 | ||
522 | /* Boundary cross-over for the edges: */ | |
523 | if (idx) { | |
524 | unsigned long *p2m = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
8c595088 | 525 | unsigned long *mid_mfn_p; |
f4cec35b KRW |
526 | |
527 | p2m_init(p2m); | |
528 | ||
529 | p2m_top[topidx][mididx] = p2m; | |
530 | ||
8c595088 KRW |
531 | /* For save/restore we need to MFN of the P2M saved */ |
532 | ||
533 | mid_mfn_p = p2m_top_mfn_p[topidx]; | |
534 | WARN(mid_mfn_p[mididx] != virt_to_mfn(p2m_missing), | |
535 | "P2M_TOP_P[%d][%d] != MFN of p2m_missing!\n", | |
536 | topidx, mididx); | |
537 | mid_mfn_p[mididx] = virt_to_mfn(p2m); | |
538 | ||
f4cec35b KRW |
539 | } |
540 | return idx != 0; | |
541 | } | |
b83c6e55 | 542 | unsigned long __init set_phys_range_identity(unsigned long pfn_s, |
f4cec35b KRW |
543 | unsigned long pfn_e) |
544 | { | |
545 | unsigned long pfn; | |
546 | ||
547 | if (unlikely(pfn_s >= MAX_P2M_PFN || pfn_e >= MAX_P2M_PFN)) | |
548 | return 0; | |
549 | ||
550 | if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) | |
551 | return pfn_e - pfn_s; | |
552 | ||
553 | if (pfn_s > pfn_e) | |
554 | return 0; | |
555 | ||
556 | for (pfn = (pfn_s & ~(P2M_MID_PER_PAGE * P2M_PER_PAGE - 1)); | |
557 | pfn < ALIGN(pfn_e, (P2M_MID_PER_PAGE * P2M_PER_PAGE)); | |
558 | pfn += P2M_MID_PER_PAGE * P2M_PER_PAGE) | |
559 | { | |
560 | unsigned topidx = p2m_top_index(pfn); | |
8c595088 KRW |
561 | unsigned long *mid_mfn_p; |
562 | unsigned long **mid; | |
563 | ||
564 | mid = p2m_top[topidx]; | |
565 | mid_mfn_p = p2m_top_mfn_p[topidx]; | |
566 | if (mid == p2m_mid_missing) { | |
567 | mid = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
f4cec35b KRW |
568 | |
569 | p2m_mid_init(mid); | |
570 | ||
571 | p2m_top[topidx] = mid; | |
8c595088 KRW |
572 | |
573 | BUG_ON(mid_mfn_p != p2m_mid_missing_mfn); | |
574 | } | |
575 | /* And the save/restore P2M tables.. */ | |
576 | if (mid_mfn_p == p2m_mid_missing_mfn) { | |
577 | mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
578 | p2m_mid_mfn_init(mid_mfn_p); | |
579 | ||
580 | p2m_top_mfn_p[topidx] = mid_mfn_p; | |
581 | p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p); | |
582 | /* Note: we don't set mid_mfn_p[midix] here, | |
583 | * look in __early_alloc_p2m */ | |
f4cec35b KRW |
584 | } |
585 | } | |
586 | ||
587 | __early_alloc_p2m(pfn_s); | |
588 | __early_alloc_p2m(pfn_e); | |
589 | ||
590 | for (pfn = pfn_s; pfn < pfn_e; pfn++) | |
591 | if (!__set_phys_to_machine(pfn, IDENTITY_FRAME(pfn))) | |
592 | break; | |
593 | ||
594 | if (!WARN((pfn - pfn_s) != (pfn_e - pfn_s), | |
595 | "Identity mapping failed. We are %ld short of 1-1 mappings!\n", | |
596 | (pfn_e - pfn_s) - (pfn - pfn_s))) | |
597 | printk(KERN_DEBUG "1-1 mapping on %lx->%lx\n", pfn_s, pfn); | |
598 | ||
599 | return pfn - pfn_s; | |
600 | } | |
601 | ||
b5eafe92 JF |
602 | /* Try to install p2m mapping; fail if intermediate bits missing */ |
603 | bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) | |
604 | { | |
605 | unsigned topidx, mididx, idx; | |
606 | ||
6eaa412f KRW |
607 | if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) { |
608 | BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY); | |
609 | return true; | |
610 | } | |
b5eafe92 JF |
611 | if (unlikely(pfn >= MAX_P2M_PFN)) { |
612 | BUG_ON(mfn != INVALID_P2M_ENTRY); | |
613 | return true; | |
614 | } | |
615 | ||
616 | topidx = p2m_top_index(pfn); | |
617 | mididx = p2m_mid_index(pfn); | |
618 | idx = p2m_index(pfn); | |
619 | ||
f4cec35b KRW |
620 | /* For sparse holes were the p2m leaf has real PFN along with |
621 | * PCI holes, stick in the PFN as the MFN value. | |
622 | */ | |
623 | if (mfn != INVALID_P2M_ENTRY && (mfn & IDENTITY_FRAME_BIT)) { | |
624 | if (p2m_top[topidx][mididx] == p2m_identity) | |
625 | return true; | |
626 | ||
627 | /* Swap over from MISSING to IDENTITY if needed. */ | |
628 | if (p2m_top[topidx][mididx] == p2m_missing) { | |
c7617798 KRW |
629 | WARN_ON(cmpxchg(&p2m_top[topidx][mididx], p2m_missing, |
630 | p2m_identity) != p2m_missing); | |
f4cec35b KRW |
631 | return true; |
632 | } | |
633 | } | |
634 | ||
b5eafe92 JF |
635 | if (p2m_top[topidx][mididx] == p2m_missing) |
636 | return mfn == INVALID_P2M_ENTRY; | |
637 | ||
638 | p2m_top[topidx][mididx][idx] = mfn; | |
639 | ||
640 | return true; | |
641 | } | |
642 | ||
643 | bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) | |
644 | { | |
b5eafe92 JF |
645 | if (unlikely(!__set_phys_to_machine(pfn, mfn))) { |
646 | if (!alloc_p2m(pfn)) | |
647 | return false; | |
648 | ||
649 | if (!__set_phys_to_machine(pfn, mfn)) | |
650 | return false; | |
651 | } | |
652 | ||
653 | return true; | |
654 | } | |
448f2831 JF |
655 | |
656 | #define M2P_OVERRIDE_HASH_SHIFT 10 | |
657 | #define M2P_OVERRIDE_HASH (1 << M2P_OVERRIDE_HASH_SHIFT) | |
658 | ||
659 | static RESERVE_BRK_ARRAY(struct list_head, m2p_overrides, M2P_OVERRIDE_HASH); | |
660 | static DEFINE_SPINLOCK(m2p_override_lock); | |
661 | ||
662 | static void __init m2p_override_init(void) | |
663 | { | |
664 | unsigned i; | |
665 | ||
666 | m2p_overrides = extend_brk(sizeof(*m2p_overrides) * M2P_OVERRIDE_HASH, | |
667 | sizeof(unsigned long)); | |
668 | ||
669 | for (i = 0; i < M2P_OVERRIDE_HASH; i++) | |
670 | INIT_LIST_HEAD(&m2p_overrides[i]); | |
671 | } | |
672 | ||
673 | static unsigned long mfn_hash(unsigned long mfn) | |
674 | { | |
675 | return hash_long(mfn, M2P_OVERRIDE_HASH_SHIFT); | |
676 | } | |
677 | ||
678 | /* Add an MFN override for a particular page */ | |
cf8d9163 | 679 | int m2p_add_override(unsigned long mfn, struct page *page, bool clear_pte) |
448f2831 JF |
680 | { |
681 | unsigned long flags; | |
87f1d40a | 682 | unsigned long pfn; |
6b08cfeb | 683 | unsigned long uninitialized_var(address); |
87f1d40a JF |
684 | unsigned level; |
685 | pte_t *ptep = NULL; | |
686 | ||
687 | pfn = page_to_pfn(page); | |
688 | if (!PageHighMem(page)) { | |
689 | address = (unsigned long)__va(pfn << PAGE_SHIFT); | |
690 | ptep = lookup_address(address, &level); | |
87f1d40a JF |
691 | if (WARN(ptep == NULL || level != PG_LEVEL_4K, |
692 | "m2p_add_override: pfn %lx not mapped", pfn)) | |
693 | return -EINVAL; | |
694 | } | |
0f4b49ea KRW |
695 | WARN_ON(PagePrivate(page)); |
696 | SetPagePrivate(page); | |
697 | set_page_private(page, mfn); | |
9b705f0e | 698 | page->index = pfn_to_mfn(pfn); |
448f2831 | 699 | |
b254244d DDG |
700 | if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) |
701 | return -ENOMEM; | |
702 | ||
cf8d9163 | 703 | if (clear_pte && !PageHighMem(page)) |
87f1d40a JF |
704 | /* Just zap old mapping for now */ |
705 | pte_clear(&init_mm, address, ptep); | |
448f2831 JF |
706 | spin_lock_irqsave(&m2p_override_lock, flags); |
707 | list_add(&page->lru, &m2p_overrides[mfn_hash(mfn)]); | |
708 | spin_unlock_irqrestore(&m2p_override_lock, flags); | |
87f1d40a JF |
709 | |
710 | return 0; | |
448f2831 | 711 | } |
8a91707d | 712 | EXPORT_SYMBOL_GPL(m2p_add_override); |
cf8d9163 | 713 | int m2p_remove_override(struct page *page, bool clear_pte) |
448f2831 JF |
714 | { |
715 | unsigned long flags; | |
9b705f0e SS |
716 | unsigned long mfn; |
717 | unsigned long pfn; | |
6b08cfeb | 718 | unsigned long uninitialized_var(address); |
87f1d40a JF |
719 | unsigned level; |
720 | pte_t *ptep = NULL; | |
9b705f0e SS |
721 | |
722 | pfn = page_to_pfn(page); | |
723 | mfn = get_phys_to_machine(pfn); | |
724 | if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) | |
87f1d40a JF |
725 | return -EINVAL; |
726 | ||
727 | if (!PageHighMem(page)) { | |
728 | address = (unsigned long)__va(pfn << PAGE_SHIFT); | |
729 | ptep = lookup_address(address, &level); | |
730 | ||
731 | if (WARN(ptep == NULL || level != PG_LEVEL_4K, | |
732 | "m2p_remove_override: pfn %lx not mapped", pfn)) | |
733 | return -EINVAL; | |
734 | } | |
9b705f0e | 735 | |
448f2831 JF |
736 | spin_lock_irqsave(&m2p_override_lock, flags); |
737 | list_del(&page->lru); | |
738 | spin_unlock_irqrestore(&m2p_override_lock, flags); | |
b254244d | 739 | set_phys_to_machine(pfn, page->index); |
0f4b49ea KRW |
740 | WARN_ON(!PagePrivate(page)); |
741 | ClearPagePrivate(page); | |
cf8d9163 | 742 | if (clear_pte && !PageHighMem(page)) |
87f1d40a JF |
743 | set_pte_at(&init_mm, address, ptep, |
744 | pfn_pte(pfn, PAGE_KERNEL)); | |
745 | /* No tlb flush necessary because the caller already | |
746 | * left the pte unmapped. */ | |
747 | ||
748 | return 0; | |
448f2831 | 749 | } |
8a91707d | 750 | EXPORT_SYMBOL_GPL(m2p_remove_override); |
448f2831 JF |
751 | |
752 | struct page *m2p_find_override(unsigned long mfn) | |
753 | { | |
754 | unsigned long flags; | |
755 | struct list_head *bucket = &m2p_overrides[mfn_hash(mfn)]; | |
756 | struct page *p, *ret; | |
757 | ||
758 | ret = NULL; | |
759 | ||
760 | spin_lock_irqsave(&m2p_override_lock, flags); | |
761 | ||
762 | list_for_each_entry(p, bucket, lru) { | |
0f4b49ea | 763 | if (page_private(p) == mfn) { |
448f2831 JF |
764 | ret = p; |
765 | break; | |
766 | } | |
767 | } | |
768 | ||
769 | spin_unlock_irqrestore(&m2p_override_lock, flags); | |
770 | ||
771 | return ret; | |
772 | } | |
773 | ||
774 | unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn) | |
775 | { | |
776 | struct page *p = m2p_find_override(mfn); | |
777 | unsigned long ret = pfn; | |
778 | ||
779 | if (p) | |
780 | ret = page_to_pfn(p); | |
781 | ||
782 | return ret; | |
783 | } | |
e1b478e4 | 784 | EXPORT_SYMBOL_GPL(m2p_find_override_pfn); |
2222e71b KRW |
785 | |
786 | #ifdef CONFIG_XEN_DEBUG_FS | |
a867db10 KRW |
787 | #include <linux/debugfs.h> |
788 | #include "debugfs.h" | |
789 | static int p2m_dump_show(struct seq_file *m, void *v) | |
2222e71b KRW |
790 | { |
791 | static const char * const level_name[] = { "top", "middle", | |
792 | "entry", "abnormal" }; | |
793 | static const char * const type_name[] = { "identity", "missing", | |
794 | "pfn", "abnormal"}; | |
795 | #define TYPE_IDENTITY 0 | |
796 | #define TYPE_MISSING 1 | |
797 | #define TYPE_PFN 2 | |
798 | #define TYPE_UNKNOWN 3 | |
799 | unsigned long pfn, prev_pfn_type = 0, prev_pfn_level = 0; | |
800 | unsigned int uninitialized_var(prev_level); | |
801 | unsigned int uninitialized_var(prev_type); | |
802 | ||
803 | if (!p2m_top) | |
804 | return 0; | |
805 | ||
806 | for (pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn++) { | |
807 | unsigned topidx = p2m_top_index(pfn); | |
808 | unsigned mididx = p2m_mid_index(pfn); | |
809 | unsigned idx = p2m_index(pfn); | |
810 | unsigned lvl, type; | |
811 | ||
812 | lvl = 4; | |
813 | type = TYPE_UNKNOWN; | |
814 | if (p2m_top[topidx] == p2m_mid_missing) { | |
815 | lvl = 0; type = TYPE_MISSING; | |
816 | } else if (p2m_top[topidx] == NULL) { | |
817 | lvl = 0; type = TYPE_UNKNOWN; | |
818 | } else if (p2m_top[topidx][mididx] == NULL) { | |
819 | lvl = 1; type = TYPE_UNKNOWN; | |
820 | } else if (p2m_top[topidx][mididx] == p2m_identity) { | |
821 | lvl = 1; type = TYPE_IDENTITY; | |
822 | } else if (p2m_top[topidx][mididx] == p2m_missing) { | |
823 | lvl = 1; type = TYPE_MISSING; | |
824 | } else if (p2m_top[topidx][mididx][idx] == 0) { | |
825 | lvl = 2; type = TYPE_UNKNOWN; | |
826 | } else if (p2m_top[topidx][mididx][idx] == IDENTITY_FRAME(pfn)) { | |
827 | lvl = 2; type = TYPE_IDENTITY; | |
828 | } else if (p2m_top[topidx][mididx][idx] == INVALID_P2M_ENTRY) { | |
829 | lvl = 2; type = TYPE_MISSING; | |
830 | } else if (p2m_top[topidx][mididx][idx] == pfn) { | |
831 | lvl = 2; type = TYPE_PFN; | |
832 | } else if (p2m_top[topidx][mididx][idx] != pfn) { | |
833 | lvl = 2; type = TYPE_PFN; | |
834 | } | |
835 | if (pfn == 0) { | |
836 | prev_level = lvl; | |
837 | prev_type = type; | |
838 | } | |
839 | if (pfn == MAX_DOMAIN_PAGES-1) { | |
840 | lvl = 3; | |
841 | type = TYPE_UNKNOWN; | |
842 | } | |
843 | if (prev_type != type) { | |
844 | seq_printf(m, " [0x%lx->0x%lx] %s\n", | |
845 | prev_pfn_type, pfn, type_name[prev_type]); | |
846 | prev_pfn_type = pfn; | |
847 | prev_type = type; | |
848 | } | |
849 | if (prev_level != lvl) { | |
850 | seq_printf(m, " [0x%lx->0x%lx] level %s\n", | |
851 | prev_pfn_level, pfn, level_name[prev_level]); | |
852 | prev_pfn_level = pfn; | |
853 | prev_level = lvl; | |
854 | } | |
855 | } | |
856 | return 0; | |
857 | #undef TYPE_IDENTITY | |
858 | #undef TYPE_MISSING | |
859 | #undef TYPE_PFN | |
860 | #undef TYPE_UNKNOWN | |
861 | } | |
a867db10 KRW |
862 | |
863 | static int p2m_dump_open(struct inode *inode, struct file *filp) | |
864 | { | |
865 | return single_open(filp, p2m_dump_show, NULL); | |
866 | } | |
867 | ||
868 | static const struct file_operations p2m_dump_fops = { | |
869 | .open = p2m_dump_open, | |
870 | .read = seq_read, | |
871 | .llseek = seq_lseek, | |
872 | .release = single_release, | |
873 | }; | |
874 | ||
875 | static struct dentry *d_mmu_debug; | |
876 | ||
877 | static int __init xen_p2m_debugfs(void) | |
878 | { | |
879 | struct dentry *d_xen = xen_init_debugfs(); | |
880 | ||
881 | if (d_xen == NULL) | |
882 | return -ENOMEM; | |
883 | ||
884 | d_mmu_debug = debugfs_create_dir("mmu", d_xen); | |
885 | ||
886 | debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops); | |
887 | return 0; | |
888 | } | |
889 | fs_initcall(xen_p2m_debugfs); | |
890 | #endif /* CONFIG_XEN_DEBUG_FS */ |