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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> | |
0930bba6 | 164 | #include <xen/grant_table.h> |
b5eafe92 | 165 | |
0930bba6 | 166 | #include "multicalls.h" |
b5eafe92 JF |
167 | #include "xen-ops.h" |
168 | ||
448f2831 JF |
169 | static void __init m2p_override_init(void); |
170 | ||
b5eafe92 JF |
171 | unsigned long xen_max_p2m_pfn __read_mostly; |
172 | ||
173 | #define P2M_PER_PAGE (PAGE_SIZE / sizeof(unsigned long)) | |
174 | #define P2M_MID_PER_PAGE (PAGE_SIZE / sizeof(unsigned long *)) | |
175 | #define P2M_TOP_PER_PAGE (PAGE_SIZE / sizeof(unsigned long **)) | |
176 | ||
177 | #define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE) | |
178 | ||
179 | /* Placeholders for holes in the address space */ | |
180 | static RESERVE_BRK_ARRAY(unsigned long, p2m_missing, P2M_PER_PAGE); | |
181 | static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_missing, P2M_MID_PER_PAGE); | |
182 | static RESERVE_BRK_ARRAY(unsigned long, p2m_mid_missing_mfn, P2M_MID_PER_PAGE); | |
183 | ||
184 | static RESERVE_BRK_ARRAY(unsigned long **, p2m_top, P2M_TOP_PER_PAGE); | |
185 | static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn, P2M_TOP_PER_PAGE); | |
186 | static RESERVE_BRK_ARRAY(unsigned long *, p2m_top_mfn_p, P2M_TOP_PER_PAGE); | |
187 | ||
f4cec35b KRW |
188 | static RESERVE_BRK_ARRAY(unsigned long, p2m_identity, P2M_PER_PAGE); |
189 | ||
b5eafe92 JF |
190 | RESERVE_BRK(p2m_mid, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE))); |
191 | RESERVE_BRK(p2m_mid_mfn, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE))); | |
192 | ||
f4cec35b KRW |
193 | /* We might hit two boundary violations at the start and end, at max each |
194 | * boundary violation will require three middle nodes. */ | |
195 | RESERVE_BRK(p2m_mid_identity, PAGE_SIZE * 2 * 3); | |
196 | ||
5bc6f988 KRW |
197 | /* When we populate back during bootup, the amount of pages can vary. The |
198 | * max we have is seen is 395979, but that does not mean it can't be more. | |
250a41e0 KRW |
199 | * Some machines can have 3GB I/O holes even. With early_can_reuse_p2m_middle |
200 | * it can re-use Xen provided mfn_list array, so we only need to allocate at | |
201 | * most three P2M top nodes. */ | |
202 | RESERVE_BRK(p2m_populated, PAGE_SIZE * 3); | |
203 | ||
b5eafe92 JF |
204 | static inline unsigned p2m_top_index(unsigned long pfn) |
205 | { | |
206 | BUG_ON(pfn >= MAX_P2M_PFN); | |
207 | return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE); | |
208 | } | |
209 | ||
210 | static inline unsigned p2m_mid_index(unsigned long pfn) | |
211 | { | |
212 | return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE; | |
213 | } | |
214 | ||
215 | static inline unsigned p2m_index(unsigned long pfn) | |
216 | { | |
217 | return pfn % P2M_PER_PAGE; | |
218 | } | |
219 | ||
220 | static void p2m_top_init(unsigned long ***top) | |
221 | { | |
222 | unsigned i; | |
223 | ||
224 | for (i = 0; i < P2M_TOP_PER_PAGE; i++) | |
225 | top[i] = p2m_mid_missing; | |
226 | } | |
227 | ||
228 | static void p2m_top_mfn_init(unsigned long *top) | |
229 | { | |
230 | unsigned i; | |
231 | ||
232 | for (i = 0; i < P2M_TOP_PER_PAGE; i++) | |
233 | top[i] = virt_to_mfn(p2m_mid_missing_mfn); | |
234 | } | |
235 | ||
236 | static void p2m_top_mfn_p_init(unsigned long **top) | |
237 | { | |
238 | unsigned i; | |
239 | ||
240 | for (i = 0; i < P2M_TOP_PER_PAGE; i++) | |
241 | top[i] = p2m_mid_missing_mfn; | |
242 | } | |
243 | ||
244 | static void p2m_mid_init(unsigned long **mid) | |
245 | { | |
246 | unsigned i; | |
247 | ||
248 | for (i = 0; i < P2M_MID_PER_PAGE; i++) | |
249 | mid[i] = p2m_missing; | |
250 | } | |
251 | ||
252 | static void p2m_mid_mfn_init(unsigned long *mid) | |
253 | { | |
254 | unsigned i; | |
255 | ||
256 | for (i = 0; i < P2M_MID_PER_PAGE; i++) | |
257 | mid[i] = virt_to_mfn(p2m_missing); | |
258 | } | |
259 | ||
260 | static void p2m_init(unsigned long *p2m) | |
261 | { | |
262 | unsigned i; | |
263 | ||
264 | for (i = 0; i < P2M_MID_PER_PAGE; i++) | |
265 | p2m[i] = INVALID_P2M_ENTRY; | |
266 | } | |
267 | ||
268 | /* | |
269 | * Build the parallel p2m_top_mfn and p2m_mid_mfn structures | |
270 | * | |
271 | * This is called both at boot time, and after resuming from suspend: | |
272 | * - At boot time we're called very early, and must use extend_brk() | |
273 | * to allocate memory. | |
274 | * | |
275 | * - After resume we're called from within stop_machine, but the mfn | |
276 | * tree should alreay be completely allocated. | |
277 | */ | |
44b46c3e | 278 | void __ref xen_build_mfn_list_list(void) |
b5eafe92 JF |
279 | { |
280 | unsigned long pfn; | |
281 | ||
282 | /* Pre-initialize p2m_top_mfn to be completely missing */ | |
283 | if (p2m_top_mfn == NULL) { | |
284 | p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
285 | p2m_mid_mfn_init(p2m_mid_missing_mfn); | |
286 | ||
287 | p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
288 | p2m_top_mfn_p_init(p2m_top_mfn_p); | |
289 | ||
290 | p2m_top_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
291 | p2m_top_mfn_init(p2m_top_mfn); | |
292 | } else { | |
293 | /* Reinitialise, mfn's all change after migration */ | |
294 | p2m_mid_mfn_init(p2m_mid_missing_mfn); | |
295 | } | |
296 | ||
297 | for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += P2M_PER_PAGE) { | |
298 | unsigned topidx = p2m_top_index(pfn); | |
299 | unsigned mididx = p2m_mid_index(pfn); | |
300 | unsigned long **mid; | |
301 | unsigned long *mid_mfn_p; | |
302 | ||
303 | mid = p2m_top[topidx]; | |
304 | mid_mfn_p = p2m_top_mfn_p[topidx]; | |
305 | ||
306 | /* Don't bother allocating any mfn mid levels if | |
307 | * they're just missing, just update the stored mfn, | |
308 | * since all could have changed over a migrate. | |
309 | */ | |
310 | if (mid == p2m_mid_missing) { | |
311 | BUG_ON(mididx); | |
312 | BUG_ON(mid_mfn_p != p2m_mid_missing_mfn); | |
313 | p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn); | |
314 | pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE; | |
315 | continue; | |
316 | } | |
317 | ||
318 | if (mid_mfn_p == p2m_mid_missing_mfn) { | |
319 | /* | |
320 | * XXX boot-time only! We should never find | |
321 | * missing parts of the mfn tree after | |
322 | * runtime. extend_brk() will BUG if we call | |
323 | * it too late. | |
324 | */ | |
325 | mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
326 | p2m_mid_mfn_init(mid_mfn_p); | |
327 | ||
328 | p2m_top_mfn_p[topidx] = mid_mfn_p; | |
329 | } | |
330 | ||
331 | p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p); | |
332 | mid_mfn_p[mididx] = virt_to_mfn(mid[mididx]); | |
333 | } | |
334 | } | |
335 | ||
336 | void xen_setup_mfn_list_list(void) | |
337 | { | |
338 | BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); | |
339 | ||
340 | HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = | |
341 | virt_to_mfn(p2m_top_mfn); | |
342 | HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn; | |
343 | } | |
344 | ||
345 | /* Set up p2m_top to point to the domain-builder provided p2m pages */ | |
346 | void __init xen_build_dynamic_phys_to_machine(void) | |
347 | { | |
348 | unsigned long *mfn_list = (unsigned long *)xen_start_info->mfn_list; | |
349 | unsigned long max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages); | |
350 | unsigned long pfn; | |
351 | ||
352 | xen_max_p2m_pfn = max_pfn; | |
353 | ||
354 | p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
355 | p2m_init(p2m_missing); | |
356 | ||
357 | p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
358 | p2m_mid_init(p2m_mid_missing); | |
359 | ||
360 | p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
361 | p2m_top_init(p2m_top); | |
362 | ||
f4cec35b KRW |
363 | p2m_identity = extend_brk(PAGE_SIZE, PAGE_SIZE); |
364 | p2m_init(p2m_identity); | |
365 | ||
b5eafe92 JF |
366 | /* |
367 | * The domain builder gives us a pre-constructed p2m array in | |
368 | * mfn_list for all the pages initially given to us, so we just | |
369 | * need to graft that into our tree structure. | |
370 | */ | |
371 | for (pfn = 0; pfn < max_pfn; pfn += P2M_PER_PAGE) { | |
372 | unsigned topidx = p2m_top_index(pfn); | |
373 | unsigned mididx = p2m_mid_index(pfn); | |
374 | ||
375 | if (p2m_top[topidx] == p2m_mid_missing) { | |
376 | unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
377 | p2m_mid_init(mid); | |
378 | ||
379 | p2m_top[topidx] = mid; | |
380 | } | |
381 | ||
8e1b4cf2 SB |
382 | /* |
383 | * As long as the mfn_list has enough entries to completely | |
384 | * fill a p2m page, pointing into the array is ok. But if | |
385 | * not the entries beyond the last pfn will be undefined. | |
8e1b4cf2 SB |
386 | */ |
387 | if (unlikely(pfn + P2M_PER_PAGE > max_pfn)) { | |
388 | unsigned long p2midx; | |
cf04d120 SB |
389 | |
390 | p2midx = max_pfn % P2M_PER_PAGE; | |
391 | for ( ; p2midx < P2M_PER_PAGE; p2midx++) | |
392 | mfn_list[pfn + p2midx] = INVALID_P2M_ENTRY; | |
393 | } | |
394 | p2m_top[topidx][mididx] = &mfn_list[pfn]; | |
b5eafe92 | 395 | } |
448f2831 JF |
396 | |
397 | m2p_override_init(); | |
b5eafe92 JF |
398 | } |
399 | ||
400 | unsigned long get_phys_to_machine(unsigned long pfn) | |
401 | { | |
402 | unsigned topidx, mididx, idx; | |
403 | ||
404 | if (unlikely(pfn >= MAX_P2M_PFN)) | |
405 | return INVALID_P2M_ENTRY; | |
406 | ||
407 | topidx = p2m_top_index(pfn); | |
408 | mididx = p2m_mid_index(pfn); | |
409 | idx = p2m_index(pfn); | |
410 | ||
f4cec35b KRW |
411 | /* |
412 | * The INVALID_P2M_ENTRY is filled in both p2m_*identity | |
413 | * and in p2m_*missing, so returning the INVALID_P2M_ENTRY | |
414 | * would be wrong. | |
415 | */ | |
416 | if (p2m_top[topidx][mididx] == p2m_identity) | |
417 | return IDENTITY_FRAME(pfn); | |
418 | ||
b5eafe92 JF |
419 | return p2m_top[topidx][mididx][idx]; |
420 | } | |
421 | EXPORT_SYMBOL_GPL(get_phys_to_machine); | |
422 | ||
423 | static void *alloc_p2m_page(void) | |
424 | { | |
425 | return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT); | |
426 | } | |
427 | ||
428 | static void free_p2m_page(void *p) | |
429 | { | |
430 | free_page((unsigned long)p); | |
431 | } | |
432 | ||
433 | /* | |
434 | * Fully allocate the p2m structure for a given pfn. We need to check | |
435 | * that both the top and mid levels are allocated, and make sure the | |
436 | * parallel mfn tree is kept in sync. We may race with other cpus, so | |
437 | * the new pages are installed with cmpxchg; if we lose the race then | |
438 | * simply free the page we allocated and use the one that's there. | |
439 | */ | |
440 | static bool alloc_p2m(unsigned long pfn) | |
441 | { | |
442 | unsigned topidx, mididx; | |
443 | unsigned long ***top_p, **mid; | |
444 | unsigned long *top_mfn_p, *mid_mfn; | |
445 | ||
446 | topidx = p2m_top_index(pfn); | |
447 | mididx = p2m_mid_index(pfn); | |
448 | ||
449 | top_p = &p2m_top[topidx]; | |
450 | mid = *top_p; | |
451 | ||
452 | if (mid == p2m_mid_missing) { | |
453 | /* Mid level is missing, allocate a new one */ | |
454 | mid = alloc_p2m_page(); | |
455 | if (!mid) | |
456 | return false; | |
457 | ||
458 | p2m_mid_init(mid); | |
459 | ||
460 | if (cmpxchg(top_p, p2m_mid_missing, mid) != p2m_mid_missing) | |
461 | free_p2m_page(mid); | |
462 | } | |
463 | ||
464 | top_mfn_p = &p2m_top_mfn[topidx]; | |
465 | mid_mfn = p2m_top_mfn_p[topidx]; | |
466 | ||
467 | BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p); | |
468 | ||
469 | if (mid_mfn == p2m_mid_missing_mfn) { | |
470 | /* Separately check the mid mfn level */ | |
471 | unsigned long missing_mfn; | |
472 | unsigned long mid_mfn_mfn; | |
473 | ||
474 | mid_mfn = alloc_p2m_page(); | |
475 | if (!mid_mfn) | |
476 | return false; | |
477 | ||
478 | p2m_mid_mfn_init(mid_mfn); | |
479 | ||
480 | missing_mfn = virt_to_mfn(p2m_mid_missing_mfn); | |
481 | mid_mfn_mfn = virt_to_mfn(mid_mfn); | |
482 | if (cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn) != missing_mfn) | |
483 | free_p2m_page(mid_mfn); | |
484 | else | |
485 | p2m_top_mfn_p[topidx] = mid_mfn; | |
486 | } | |
487 | ||
f4cec35b KRW |
488 | if (p2m_top[topidx][mididx] == p2m_identity || |
489 | p2m_top[topidx][mididx] == p2m_missing) { | |
b5eafe92 JF |
490 | /* p2m leaf page is missing */ |
491 | unsigned long *p2m; | |
f4cec35b | 492 | unsigned long *p2m_orig = p2m_top[topidx][mididx]; |
b5eafe92 JF |
493 | |
494 | p2m = alloc_p2m_page(); | |
495 | if (!p2m) | |
496 | return false; | |
497 | ||
498 | p2m_init(p2m); | |
499 | ||
f4cec35b | 500 | if (cmpxchg(&mid[mididx], p2m_orig, p2m) != p2m_orig) |
b5eafe92 JF |
501 | free_p2m_page(p2m); |
502 | else | |
503 | mid_mfn[mididx] = virt_to_mfn(p2m); | |
504 | } | |
505 | ||
506 | return true; | |
507 | } | |
508 | ||
cef4cca5 | 509 | static bool __init early_alloc_p2m_middle(unsigned long pfn, bool check_boundary) |
f4cec35b KRW |
510 | { |
511 | unsigned topidx, mididx, idx; | |
d5096850 KRW |
512 | unsigned long *p2m; |
513 | unsigned long *mid_mfn_p; | |
f4cec35b KRW |
514 | |
515 | topidx = p2m_top_index(pfn); | |
516 | mididx = p2m_mid_index(pfn); | |
517 | idx = p2m_index(pfn); | |
518 | ||
519 | /* Pfff.. No boundary cross-over, lets get out. */ | |
cef4cca5 | 520 | if (!idx && check_boundary) |
f4cec35b KRW |
521 | return false; |
522 | ||
523 | WARN(p2m_top[topidx][mididx] == p2m_identity, | |
524 | "P2M[%d][%d] == IDENTITY, should be MISSING (or alloced)!\n", | |
525 | topidx, mididx); | |
526 | ||
527 | /* | |
528 | * Could be done by xen_build_dynamic_phys_to_machine.. | |
529 | */ | |
530 | if (p2m_top[topidx][mididx] != p2m_missing) | |
531 | return false; | |
532 | ||
533 | /* Boundary cross-over for the edges: */ | |
d5096850 | 534 | p2m = extend_brk(PAGE_SIZE, PAGE_SIZE); |
f4cec35b | 535 | |
d5096850 | 536 | p2m_init(p2m); |
f4cec35b | 537 | |
d5096850 | 538 | p2m_top[topidx][mididx] = p2m; |
f4cec35b | 539 | |
d5096850 | 540 | /* For save/restore we need to MFN of the P2M saved */ |
cef4cca5 | 541 | |
d5096850 KRW |
542 | mid_mfn_p = p2m_top_mfn_p[topidx]; |
543 | WARN(mid_mfn_p[mididx] != virt_to_mfn(p2m_missing), | |
544 | "P2M_TOP_P[%d][%d] != MFN of p2m_missing!\n", | |
545 | topidx, mididx); | |
546 | mid_mfn_p[mididx] = virt_to_mfn(p2m); | |
8c595088 | 547 | |
d5096850 | 548 | return true; |
f4cec35b | 549 | } |
3f3aaea2 KRW |
550 | |
551 | static bool __init early_alloc_p2m(unsigned long pfn) | |
552 | { | |
553 | unsigned topidx = p2m_top_index(pfn); | |
554 | unsigned long *mid_mfn_p; | |
555 | unsigned long **mid; | |
556 | ||
557 | mid = p2m_top[topidx]; | |
558 | mid_mfn_p = p2m_top_mfn_p[topidx]; | |
559 | if (mid == p2m_mid_missing) { | |
560 | mid = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
561 | ||
562 | p2m_mid_init(mid); | |
563 | ||
564 | p2m_top[topidx] = mid; | |
565 | ||
566 | BUG_ON(mid_mfn_p != p2m_mid_missing_mfn); | |
567 | } | |
568 | /* And the save/restore P2M tables.. */ | |
569 | if (mid_mfn_p == p2m_mid_missing_mfn) { | |
570 | mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
571 | p2m_mid_mfn_init(mid_mfn_p); | |
572 | ||
573 | p2m_top_mfn_p[topidx] = mid_mfn_p; | |
574 | p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p); | |
575 | /* Note: we don't set mid_mfn_p[midix] here, | |
576 | * look in early_alloc_p2m_middle */ | |
577 | } | |
578 | return true; | |
579 | } | |
250a41e0 KRW |
580 | |
581 | /* | |
582 | * Skim over the P2M tree looking at pages that are either filled with | |
583 | * INVALID_P2M_ENTRY or with 1:1 PFNs. If found, re-use that page and | |
584 | * replace the P2M leaf with a p2m_missing or p2m_identity. | |
585 | * Stick the old page in the new P2M tree location. | |
586 | */ | |
587 | bool __init early_can_reuse_p2m_middle(unsigned long set_pfn, unsigned long set_mfn) | |
588 | { | |
589 | unsigned topidx; | |
590 | unsigned mididx; | |
591 | unsigned ident_pfns; | |
592 | unsigned inv_pfns; | |
593 | unsigned long *p2m; | |
594 | unsigned long *mid_mfn_p; | |
595 | unsigned idx; | |
596 | unsigned long pfn; | |
597 | ||
598 | /* We only look when this entails a P2M middle layer */ | |
599 | if (p2m_index(set_pfn)) | |
600 | return false; | |
601 | ||
50e90041 | 602 | for (pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn += P2M_PER_PAGE) { |
250a41e0 KRW |
603 | topidx = p2m_top_index(pfn); |
604 | ||
605 | if (!p2m_top[topidx]) | |
606 | continue; | |
607 | ||
608 | if (p2m_top[topidx] == p2m_mid_missing) | |
609 | continue; | |
610 | ||
611 | mididx = p2m_mid_index(pfn); | |
612 | p2m = p2m_top[topidx][mididx]; | |
613 | if (!p2m) | |
614 | continue; | |
615 | ||
616 | if ((p2m == p2m_missing) || (p2m == p2m_identity)) | |
617 | continue; | |
618 | ||
619 | if ((unsigned long)p2m == INVALID_P2M_ENTRY) | |
620 | continue; | |
621 | ||
622 | ident_pfns = 0; | |
623 | inv_pfns = 0; | |
624 | for (idx = 0; idx < P2M_PER_PAGE; idx++) { | |
625 | /* IDENTITY_PFNs are 1:1 */ | |
626 | if (p2m[idx] == IDENTITY_FRAME(pfn + idx)) | |
627 | ident_pfns++; | |
628 | else if (p2m[idx] == INVALID_P2M_ENTRY) | |
629 | inv_pfns++; | |
630 | else | |
631 | break; | |
632 | } | |
633 | if ((ident_pfns == P2M_PER_PAGE) || (inv_pfns == P2M_PER_PAGE)) | |
634 | goto found; | |
635 | } | |
636 | return false; | |
637 | found: | |
638 | /* Found one, replace old with p2m_identity or p2m_missing */ | |
639 | p2m_top[topidx][mididx] = (ident_pfns ? p2m_identity : p2m_missing); | |
640 | /* And the other for save/restore.. */ | |
641 | mid_mfn_p = p2m_top_mfn_p[topidx]; | |
642 | /* NOTE: Even if it is a p2m_identity it should still be point to | |
643 | * a page filled with INVALID_P2M_ENTRY entries. */ | |
644 | mid_mfn_p[mididx] = virt_to_mfn(p2m_missing); | |
645 | ||
646 | /* Reset where we want to stick the old page in. */ | |
647 | topidx = p2m_top_index(set_pfn); | |
648 | mididx = p2m_mid_index(set_pfn); | |
649 | ||
650 | /* This shouldn't happen */ | |
651 | if (WARN_ON(p2m_top[topidx] == p2m_mid_missing)) | |
652 | early_alloc_p2m(set_pfn); | |
653 | ||
654 | if (WARN_ON(p2m_top[topidx][mididx] != p2m_missing)) | |
655 | return false; | |
656 | ||
657 | p2m_init(p2m); | |
658 | p2m_top[topidx][mididx] = p2m; | |
659 | mid_mfn_p = p2m_top_mfn_p[topidx]; | |
660 | mid_mfn_p[mididx] = virt_to_mfn(p2m); | |
661 | ||
662 | return true; | |
663 | } | |
940713bb KRW |
664 | bool __init early_set_phys_to_machine(unsigned long pfn, unsigned long mfn) |
665 | { | |
666 | if (unlikely(!__set_phys_to_machine(pfn, mfn))) { | |
667 | if (!early_alloc_p2m(pfn)) | |
668 | return false; | |
669 | ||
250a41e0 KRW |
670 | if (early_can_reuse_p2m_middle(pfn, mfn)) |
671 | return __set_phys_to_machine(pfn, mfn); | |
672 | ||
940713bb KRW |
673 | if (!early_alloc_p2m_middle(pfn, false /* boundary crossover OK!*/)) |
674 | return false; | |
675 | ||
676 | if (!__set_phys_to_machine(pfn, mfn)) | |
677 | return false; | |
678 | } | |
679 | ||
680 | return true; | |
681 | } | |
b83c6e55 | 682 | unsigned long __init set_phys_range_identity(unsigned long pfn_s, |
f4cec35b KRW |
683 | unsigned long pfn_e) |
684 | { | |
685 | unsigned long pfn; | |
686 | ||
687 | if (unlikely(pfn_s >= MAX_P2M_PFN || pfn_e >= MAX_P2M_PFN)) | |
688 | return 0; | |
689 | ||
690 | if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) | |
691 | return pfn_e - pfn_s; | |
692 | ||
693 | if (pfn_s > pfn_e) | |
694 | return 0; | |
695 | ||
696 | for (pfn = (pfn_s & ~(P2M_MID_PER_PAGE * P2M_PER_PAGE - 1)); | |
697 | pfn < ALIGN(pfn_e, (P2M_MID_PER_PAGE * P2M_PER_PAGE)); | |
698 | pfn += P2M_MID_PER_PAGE * P2M_PER_PAGE) | |
699 | { | |
3f3aaea2 | 700 | WARN_ON(!early_alloc_p2m(pfn)); |
f4cec35b KRW |
701 | } |
702 | ||
cef4cca5 KRW |
703 | early_alloc_p2m_middle(pfn_s, true); |
704 | early_alloc_p2m_middle(pfn_e, true); | |
f4cec35b KRW |
705 | |
706 | for (pfn = pfn_s; pfn < pfn_e; pfn++) | |
707 | if (!__set_phys_to_machine(pfn, IDENTITY_FRAME(pfn))) | |
708 | break; | |
709 | ||
710 | if (!WARN((pfn - pfn_s) != (pfn_e - pfn_s), | |
711 | "Identity mapping failed. We are %ld short of 1-1 mappings!\n", | |
712 | (pfn_e - pfn_s) - (pfn - pfn_s))) | |
713 | printk(KERN_DEBUG "1-1 mapping on %lx->%lx\n", pfn_s, pfn); | |
714 | ||
715 | return pfn - pfn_s; | |
716 | } | |
717 | ||
b5eafe92 JF |
718 | /* Try to install p2m mapping; fail if intermediate bits missing */ |
719 | bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) | |
720 | { | |
721 | unsigned topidx, mididx, idx; | |
722 | ||
6eaa412f KRW |
723 | if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) { |
724 | BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY); | |
725 | return true; | |
726 | } | |
b5eafe92 JF |
727 | if (unlikely(pfn >= MAX_P2M_PFN)) { |
728 | BUG_ON(mfn != INVALID_P2M_ENTRY); | |
729 | return true; | |
730 | } | |
731 | ||
732 | topidx = p2m_top_index(pfn); | |
733 | mididx = p2m_mid_index(pfn); | |
734 | idx = p2m_index(pfn); | |
735 | ||
f4cec35b KRW |
736 | /* For sparse holes were the p2m leaf has real PFN along with |
737 | * PCI holes, stick in the PFN as the MFN value. | |
738 | */ | |
739 | if (mfn != INVALID_P2M_ENTRY && (mfn & IDENTITY_FRAME_BIT)) { | |
740 | if (p2m_top[topidx][mididx] == p2m_identity) | |
741 | return true; | |
742 | ||
743 | /* Swap over from MISSING to IDENTITY if needed. */ | |
744 | if (p2m_top[topidx][mididx] == p2m_missing) { | |
c7617798 KRW |
745 | WARN_ON(cmpxchg(&p2m_top[topidx][mididx], p2m_missing, |
746 | p2m_identity) != p2m_missing); | |
f4cec35b KRW |
747 | return true; |
748 | } | |
749 | } | |
750 | ||
b5eafe92 JF |
751 | if (p2m_top[topidx][mididx] == p2m_missing) |
752 | return mfn == INVALID_P2M_ENTRY; | |
753 | ||
754 | p2m_top[topidx][mididx][idx] = mfn; | |
755 | ||
756 | return true; | |
757 | } | |
758 | ||
759 | bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) | |
760 | { | |
b5eafe92 JF |
761 | if (unlikely(!__set_phys_to_machine(pfn, mfn))) { |
762 | if (!alloc_p2m(pfn)) | |
763 | return false; | |
764 | ||
765 | if (!__set_phys_to_machine(pfn, mfn)) | |
766 | return false; | |
767 | } | |
768 | ||
769 | return true; | |
770 | } | |
448f2831 JF |
771 | |
772 | #define M2P_OVERRIDE_HASH_SHIFT 10 | |
773 | #define M2P_OVERRIDE_HASH (1 << M2P_OVERRIDE_HASH_SHIFT) | |
774 | ||
775 | static RESERVE_BRK_ARRAY(struct list_head, m2p_overrides, M2P_OVERRIDE_HASH); | |
776 | static DEFINE_SPINLOCK(m2p_override_lock); | |
777 | ||
778 | static void __init m2p_override_init(void) | |
779 | { | |
780 | unsigned i; | |
781 | ||
782 | m2p_overrides = extend_brk(sizeof(*m2p_overrides) * M2P_OVERRIDE_HASH, | |
783 | sizeof(unsigned long)); | |
784 | ||
785 | for (i = 0; i < M2P_OVERRIDE_HASH; i++) | |
786 | INIT_LIST_HEAD(&m2p_overrides[i]); | |
787 | } | |
788 | ||
789 | static unsigned long mfn_hash(unsigned long mfn) | |
790 | { | |
791 | return hash_long(mfn, M2P_OVERRIDE_HASH_SHIFT); | |
792 | } | |
793 | ||
794 | /* Add an MFN override for a particular page */ | |
0930bba6 SS |
795 | int m2p_add_override(unsigned long mfn, struct page *page, |
796 | struct gnttab_map_grant_ref *kmap_op) | |
448f2831 JF |
797 | { |
798 | unsigned long flags; | |
87f1d40a | 799 | unsigned long pfn; |
6b08cfeb | 800 | unsigned long uninitialized_var(address); |
87f1d40a JF |
801 | unsigned level; |
802 | pte_t *ptep = NULL; | |
b9e0d95c | 803 | int ret = 0; |
87f1d40a JF |
804 | |
805 | pfn = page_to_pfn(page); | |
806 | if (!PageHighMem(page)) { | |
807 | address = (unsigned long)__va(pfn << PAGE_SHIFT); | |
808 | ptep = lookup_address(address, &level); | |
87f1d40a JF |
809 | if (WARN(ptep == NULL || level != PG_LEVEL_4K, |
810 | "m2p_add_override: pfn %lx not mapped", pfn)) | |
811 | return -EINVAL; | |
812 | } | |
0f4b49ea KRW |
813 | WARN_ON(PagePrivate(page)); |
814 | SetPagePrivate(page); | |
815 | set_page_private(page, mfn); | |
9b705f0e | 816 | page->index = pfn_to_mfn(pfn); |
448f2831 | 817 | |
b254244d DDG |
818 | if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) |
819 | return -ENOMEM; | |
820 | ||
0930bba6 SS |
821 | if (kmap_op != NULL) { |
822 | if (!PageHighMem(page)) { | |
823 | struct multicall_space mcs = | |
824 | xen_mc_entry(sizeof(*kmap_op)); | |
825 | ||
826 | MULTI_grant_table_op(mcs.mc, | |
827 | GNTTABOP_map_grant_ref, kmap_op, 1); | |
828 | ||
829 | xen_mc_issue(PARAVIRT_LAZY_MMU); | |
830 | } | |
831 | /* let's use dev_bus_addr to record the old mfn instead */ | |
832 | kmap_op->dev_bus_addr = page->index; | |
833 | page->index = (unsigned long) kmap_op; | |
834 | } | |
448f2831 JF |
835 | spin_lock_irqsave(&m2p_override_lock, flags); |
836 | list_add(&page->lru, &m2p_overrides[mfn_hash(mfn)]); | |
837 | spin_unlock_irqrestore(&m2p_override_lock, flags); | |
87f1d40a | 838 | |
b9e0d95c SS |
839 | /* p2m(m2p(mfn)) == mfn: the mfn is already present somewhere in |
840 | * this domain. Set the FOREIGN_FRAME_BIT in the p2m for the other | |
841 | * pfn so that the following mfn_to_pfn(mfn) calls will return the | |
842 | * pfn from the m2p_override (the backend pfn) instead. | |
843 | * We need to do this because the pages shared by the frontend | |
844 | * (xen-blkfront) can be already locked (lock_page, called by | |
845 | * do_read_cache_page); when the userspace backend tries to use them | |
846 | * with direct_IO, mfn_to_pfn returns the pfn of the frontend, so | |
847 | * do_blockdev_direct_IO is going to try to lock the same pages | |
848 | * again resulting in a deadlock. | |
849 | * As a side effect get_user_pages_fast might not be safe on the | |
850 | * frontend pages while they are being shared with the backend, | |
851 | * because mfn_to_pfn (that ends up being called by GUPF) will | |
852 | * return the backend pfn rather than the frontend pfn. */ | |
853 | ret = __get_user(pfn, &machine_to_phys_mapping[mfn]); | |
854 | if (ret == 0 && get_phys_to_machine(pfn) == mfn) | |
855 | set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)); | |
856 | ||
87f1d40a | 857 | return 0; |
448f2831 | 858 | } |
8a91707d | 859 | EXPORT_SYMBOL_GPL(m2p_add_override); |
cf8d9163 | 860 | int m2p_remove_override(struct page *page, bool clear_pte) |
448f2831 JF |
861 | { |
862 | unsigned long flags; | |
9b705f0e SS |
863 | unsigned long mfn; |
864 | unsigned long pfn; | |
6b08cfeb | 865 | unsigned long uninitialized_var(address); |
87f1d40a JF |
866 | unsigned level; |
867 | pte_t *ptep = NULL; | |
b9e0d95c | 868 | int ret = 0; |
9b705f0e SS |
869 | |
870 | pfn = page_to_pfn(page); | |
871 | mfn = get_phys_to_machine(pfn); | |
872 | if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) | |
87f1d40a JF |
873 | return -EINVAL; |
874 | ||
875 | if (!PageHighMem(page)) { | |
876 | address = (unsigned long)__va(pfn << PAGE_SHIFT); | |
877 | ptep = lookup_address(address, &level); | |
878 | ||
879 | if (WARN(ptep == NULL || level != PG_LEVEL_4K, | |
880 | "m2p_remove_override: pfn %lx not mapped", pfn)) | |
881 | return -EINVAL; | |
882 | } | |
9b705f0e | 883 | |
448f2831 JF |
884 | spin_lock_irqsave(&m2p_override_lock, flags); |
885 | list_del(&page->lru); | |
886 | spin_unlock_irqrestore(&m2p_override_lock, flags); | |
0f4b49ea KRW |
887 | WARN_ON(!PagePrivate(page)); |
888 | ClearPagePrivate(page); | |
87f1d40a | 889 | |
0930bba6 SS |
890 | if (clear_pte) { |
891 | struct gnttab_map_grant_ref *map_op = | |
892 | (struct gnttab_map_grant_ref *) page->index; | |
893 | set_phys_to_machine(pfn, map_op->dev_bus_addr); | |
894 | if (!PageHighMem(page)) { | |
895 | struct multicall_space mcs; | |
896 | struct gnttab_unmap_grant_ref *unmap_op; | |
897 | ||
898 | /* | |
899 | * It might be that we queued all the m2p grant table | |
900 | * hypercalls in a multicall, then m2p_remove_override | |
901 | * get called before the multicall has actually been | |
902 | * issued. In this case handle is going to -1 because | |
903 | * it hasn't been modified yet. | |
904 | */ | |
905 | if (map_op->handle == -1) | |
906 | xen_mc_flush(); | |
907 | /* | |
908 | * Now if map_op->handle is negative it means that the | |
909 | * hypercall actually returned an error. | |
910 | */ | |
911 | if (map_op->handle == GNTST_general_error) { | |
912 | printk(KERN_WARNING "m2p_remove_override: " | |
913 | "pfn %lx mfn %lx, failed to modify kernel mappings", | |
914 | pfn, mfn); | |
915 | return -1; | |
916 | } | |
917 | ||
918 | mcs = xen_mc_entry( | |
919 | sizeof(struct gnttab_unmap_grant_ref)); | |
920 | unmap_op = mcs.args; | |
921 | unmap_op->host_addr = map_op->host_addr; | |
922 | unmap_op->handle = map_op->handle; | |
923 | unmap_op->dev_bus_addr = 0; | |
924 | ||
925 | MULTI_grant_table_op(mcs.mc, | |
926 | GNTTABOP_unmap_grant_ref, unmap_op, 1); | |
927 | ||
928 | xen_mc_issue(PARAVIRT_LAZY_MMU); | |
929 | ||
930 | set_pte_at(&init_mm, address, ptep, | |
931 | pfn_pte(pfn, PAGE_KERNEL)); | |
932 | __flush_tlb_single(address); | |
933 | map_op->host_addr = 0; | |
934 | } | |
935 | } else | |
936 | set_phys_to_machine(pfn, page->index); | |
87f1d40a | 937 | |
b9e0d95c SS |
938 | /* p2m(m2p(mfn)) == FOREIGN_FRAME(mfn): the mfn is already present |
939 | * somewhere in this domain, even before being added to the | |
940 | * m2p_override (see comment above in m2p_add_override). | |
941 | * If there are no other entries in the m2p_override corresponding | |
942 | * to this mfn, then remove the FOREIGN_FRAME_BIT from the p2m for | |
943 | * the original pfn (the one shared by the frontend): the backend | |
944 | * cannot do any IO on this page anymore because it has been | |
945 | * unshared. Removing the FOREIGN_FRAME_BIT from the p2m entry of | |
946 | * the original pfn causes mfn_to_pfn(mfn) to return the frontend | |
947 | * pfn again. */ | |
948 | mfn &= ~FOREIGN_FRAME_BIT; | |
949 | ret = __get_user(pfn, &machine_to_phys_mapping[mfn]); | |
950 | if (ret == 0 && get_phys_to_machine(pfn) == FOREIGN_FRAME(mfn) && | |
951 | m2p_find_override(mfn) == NULL) | |
952 | set_phys_to_machine(pfn, mfn); | |
953 | ||
87f1d40a | 954 | return 0; |
448f2831 | 955 | } |
8a91707d | 956 | EXPORT_SYMBOL_GPL(m2p_remove_override); |
448f2831 JF |
957 | |
958 | struct page *m2p_find_override(unsigned long mfn) | |
959 | { | |
960 | unsigned long flags; | |
961 | struct list_head *bucket = &m2p_overrides[mfn_hash(mfn)]; | |
962 | struct page *p, *ret; | |
963 | ||
964 | ret = NULL; | |
965 | ||
966 | spin_lock_irqsave(&m2p_override_lock, flags); | |
967 | ||
968 | list_for_each_entry(p, bucket, lru) { | |
0f4b49ea | 969 | if (page_private(p) == mfn) { |
448f2831 JF |
970 | ret = p; |
971 | break; | |
972 | } | |
973 | } | |
974 | ||
975 | spin_unlock_irqrestore(&m2p_override_lock, flags); | |
976 | ||
977 | return ret; | |
978 | } | |
979 | ||
980 | unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn) | |
981 | { | |
982 | struct page *p = m2p_find_override(mfn); | |
983 | unsigned long ret = pfn; | |
984 | ||
985 | if (p) | |
986 | ret = page_to_pfn(p); | |
987 | ||
988 | return ret; | |
989 | } | |
e1b478e4 | 990 | EXPORT_SYMBOL_GPL(m2p_find_override_pfn); |
2222e71b KRW |
991 | |
992 | #ifdef CONFIG_XEN_DEBUG_FS | |
a867db10 KRW |
993 | #include <linux/debugfs.h> |
994 | #include "debugfs.h" | |
995 | static int p2m_dump_show(struct seq_file *m, void *v) | |
2222e71b KRW |
996 | { |
997 | static const char * const level_name[] = { "top", "middle", | |
8404877e | 998 | "entry", "abnormal", "error"}; |
2222e71b KRW |
999 | #define TYPE_IDENTITY 0 |
1000 | #define TYPE_MISSING 1 | |
1001 | #define TYPE_PFN 2 | |
1002 | #define TYPE_UNKNOWN 3 | |
a491dbef KRW |
1003 | static const char * const type_name[] = { |
1004 | [TYPE_IDENTITY] = "identity", | |
1005 | [TYPE_MISSING] = "missing", | |
1006 | [TYPE_PFN] = "pfn", | |
1007 | [TYPE_UNKNOWN] = "abnormal"}; | |
2222e71b KRW |
1008 | unsigned long pfn, prev_pfn_type = 0, prev_pfn_level = 0; |
1009 | unsigned int uninitialized_var(prev_level); | |
1010 | unsigned int uninitialized_var(prev_type); | |
1011 | ||
1012 | if (!p2m_top) | |
1013 | return 0; | |
1014 | ||
1015 | for (pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn++) { | |
1016 | unsigned topidx = p2m_top_index(pfn); | |
1017 | unsigned mididx = p2m_mid_index(pfn); | |
1018 | unsigned idx = p2m_index(pfn); | |
1019 | unsigned lvl, type; | |
1020 | ||
1021 | lvl = 4; | |
1022 | type = TYPE_UNKNOWN; | |
1023 | if (p2m_top[topidx] == p2m_mid_missing) { | |
1024 | lvl = 0; type = TYPE_MISSING; | |
1025 | } else if (p2m_top[topidx] == NULL) { | |
1026 | lvl = 0; type = TYPE_UNKNOWN; | |
1027 | } else if (p2m_top[topidx][mididx] == NULL) { | |
1028 | lvl = 1; type = TYPE_UNKNOWN; | |
1029 | } else if (p2m_top[topidx][mididx] == p2m_identity) { | |
1030 | lvl = 1; type = TYPE_IDENTITY; | |
1031 | } else if (p2m_top[topidx][mididx] == p2m_missing) { | |
1032 | lvl = 1; type = TYPE_MISSING; | |
1033 | } else if (p2m_top[topidx][mididx][idx] == 0) { | |
1034 | lvl = 2; type = TYPE_UNKNOWN; | |
1035 | } else if (p2m_top[topidx][mididx][idx] == IDENTITY_FRAME(pfn)) { | |
1036 | lvl = 2; type = TYPE_IDENTITY; | |
1037 | } else if (p2m_top[topidx][mididx][idx] == INVALID_P2M_ENTRY) { | |
1038 | lvl = 2; type = TYPE_MISSING; | |
1039 | } else if (p2m_top[topidx][mididx][idx] == pfn) { | |
1040 | lvl = 2; type = TYPE_PFN; | |
1041 | } else if (p2m_top[topidx][mididx][idx] != pfn) { | |
1042 | lvl = 2; type = TYPE_PFN; | |
1043 | } | |
1044 | if (pfn == 0) { | |
1045 | prev_level = lvl; | |
1046 | prev_type = type; | |
1047 | } | |
1048 | if (pfn == MAX_DOMAIN_PAGES-1) { | |
1049 | lvl = 3; | |
1050 | type = TYPE_UNKNOWN; | |
1051 | } | |
1052 | if (prev_type != type) { | |
1053 | seq_printf(m, " [0x%lx->0x%lx] %s\n", | |
1054 | prev_pfn_type, pfn, type_name[prev_type]); | |
1055 | prev_pfn_type = pfn; | |
1056 | prev_type = type; | |
1057 | } | |
1058 | if (prev_level != lvl) { | |
1059 | seq_printf(m, " [0x%lx->0x%lx] level %s\n", | |
1060 | prev_pfn_level, pfn, level_name[prev_level]); | |
1061 | prev_pfn_level = pfn; | |
1062 | prev_level = lvl; | |
1063 | } | |
1064 | } | |
1065 | return 0; | |
1066 | #undef TYPE_IDENTITY | |
1067 | #undef TYPE_MISSING | |
1068 | #undef TYPE_PFN | |
1069 | #undef TYPE_UNKNOWN | |
1070 | } | |
a867db10 KRW |
1071 | |
1072 | static int p2m_dump_open(struct inode *inode, struct file *filp) | |
1073 | { | |
1074 | return single_open(filp, p2m_dump_show, NULL); | |
1075 | } | |
1076 | ||
1077 | static const struct file_operations p2m_dump_fops = { | |
1078 | .open = p2m_dump_open, | |
1079 | .read = seq_read, | |
1080 | .llseek = seq_lseek, | |
1081 | .release = single_release, | |
1082 | }; | |
1083 | ||
1084 | static struct dentry *d_mmu_debug; | |
1085 | ||
1086 | static int __init xen_p2m_debugfs(void) | |
1087 | { | |
1088 | struct dentry *d_xen = xen_init_debugfs(); | |
1089 | ||
1090 | if (d_xen == NULL) | |
1091 | return -ENOMEM; | |
1092 | ||
1093 | d_mmu_debug = debugfs_create_dir("mmu", d_xen); | |
1094 | ||
1095 | debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops); | |
1096 | return 0; | |
1097 | } | |
1098 | fs_initcall(xen_p2m_debugfs); | |
1099 | #endif /* CONFIG_XEN_DEBUG_FS */ |