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 | |
a3118beb | 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 | |
3cb83e46 | 39 | * PCI BARs, or ACPI spaces), we can create mappings easily because we |
f4cec35b KRW |
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 | * | |
3cb83e46 | 63 | * 1GB 2GB 4GB |
f4cec35b KRW |
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 | |
3cb83e46 DV |
80 | * aligned on 512^2*PAGE_SIZE (1GB) we reserve_brk new middle and leaf pages as |
81 | * required to split any existing p2m_mid_missing middle pages. | |
f4cec35b KRW |
82 | * |
83 | * With the E820 example above, 263424 is not 1GB aligned so we allocate a | |
84 | * reserve_brk page which will cover the PFNs estate from 0x40000 to 0x80000. | |
85 | * Each entry in the allocate page is "missing" (points to p2m_missing). | |
86 | * | |
87 | * Next stage is to determine if we need to do a more granular boundary check | |
88 | * on the 4MB (or 2MB depending on architecture) off the start and end pfn's. | |
89 | * We check if the start pfn and end pfn violate that boundary check, and if | |
3cb83e46 | 90 | * so reserve_brk a (p2m[x][y]) leaf page. This way we have a much finer |
f4cec35b KRW |
91 | * granularity of setting which PFNs are missing and which ones are identity. |
92 | * In our example 263424 and 512256 both fail the check so we reserve_brk two | |
93 | * pages. Populate them with INVALID_P2M_ENTRY (so they both have "missing" | |
94 | * values) and assign them to p2m[1][2] and p2m[1][488] respectively. | |
95 | * | |
96 | * At this point we would at minimum reserve_brk one page, but could be up to | |
97 | * three. Each call to set_phys_range_identity has at maximum a three page | |
98 | * cost. If we were to query the P2M at this stage, all those entries from | |
99 | * start PFN through end PFN (so 1029MB -> 2001MB) would return | |
100 | * INVALID_P2M_ENTRY ("missing"). | |
101 | * | |
102 | * The next step is to walk from the start pfn to the end pfn setting | |
103 | * the IDENTITY_FRAME_BIT on each PFN. This is done in set_phys_range_identity. | |
3cb83e46 DV |
104 | * If we find that the middle entry is pointing to p2m_missing we can swap it |
105 | * over to p2m_identity - this way covering 4MB (or 2MB) PFN space (and | |
106 | * similarly swapping p2m_mid_missing for p2m_mid_identity for larger regions). | |
107 | * At this point we do not need to worry about boundary aligment (so no need to | |
f4cec35b KRW |
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 | * | |
3cb83e46 DV |
121 | * Finally, the region beyond the end of of the E820 (4 GB in this example) |
122 | * is set to be identity (in case there are MMIO regions placed here). | |
123 | * | |
f4cec35b KRW |
124 | * This is what the p2m ends up looking (for the E820 above) with this |
125 | * fabulous drawing: | |
126 | * | |
127 | * p2m /--------------\ | |
128 | * /-----\ | &mfn_list[0],| /-----------------\ | |
129 | * | 0 |------>| &mfn_list[1],| /---------------\ | ~0, ~0, .. | | |
130 | * |-----| | ..., ~0, ~0 | | ~0, ~0, [x]---+----->| IDENTITY [@256] | | |
131 | * | 1 |---\ \--------------/ | [p2m_identity]+\ | IDENTITY [@257] | | |
132 | * |-----| \ | [p2m_identity]+\\ | .... | | |
133 | * | 2 |--\ \-------------------->| ... | \\ \----------------/ | |
134 | * |-----| \ \---------------/ \\ | |
3cb83e46 DV |
135 | * | 3 |-\ \ \\ p2m_identity [1] |
136 | * |-----| \ \-------------------->/---------------\ /-----------------\ | |
137 | * | .. |\ | | [p2m_identity]+-->| ~0, ~0, ~0, ... | | |
138 | * \-----/ | | | [p2m_identity]+-->| ..., ~0 | | |
139 | * | | | .... | \-----------------/ | |
140 | * | | +-[x], ~0, ~0.. +\ | |
141 | * | | \---------------/ \ | |
142 | * | | \-> /---------------\ | |
143 | * | V p2m_mid_missing p2m_missing | IDENTITY[@0] | | |
144 | * | /-----------------\ /------------\ | IDENTITY[@256]| | |
145 | * | | [p2m_missing] +---->| ~0, ~0, ...| | ~0, ~0, .... | | |
146 | * | | [p2m_missing] +---->| ..., ~0 | \---------------/ | |
147 | * | | ... | \------------/ | |
148 | * | \-----------------/ | |
149 | * | | |
150 | * | p2m_mid_identity | |
151 | * | /-----------------\ | |
152 | * \-->| [p2m_identity] +---->[1] | |
153 | * | [p2m_identity] +---->[1] | |
154 | * | ... | | |
155 | * \-----------------/ | |
f4cec35b KRW |
156 | * |
157 | * where ~0 is INVALID_P2M_ENTRY. IDENTITY is (PFN | IDENTITY_BIT) | |
b5eafe92 JF |
158 | */ |
159 | ||
160 | #include <linux/init.h> | |
161 | #include <linux/module.h> | |
448f2831 JF |
162 | #include <linux/list.h> |
163 | #include <linux/hash.h> | |
87f1d40a | 164 | #include <linux/sched.h> |
2222e71b | 165 | #include <linux/seq_file.h> |
b5eafe92 JF |
166 | |
167 | #include <asm/cache.h> | |
168 | #include <asm/setup.h> | |
169 | ||
170 | #include <asm/xen/page.h> | |
171 | #include <asm/xen/hypercall.h> | |
172 | #include <asm/xen/hypervisor.h> | |
ee072640 | 173 | #include <xen/balloon.h> |
0930bba6 | 174 | #include <xen/grant_table.h> |
b5eafe92 | 175 | |
0930bba6 | 176 | #include "multicalls.h" |
b5eafe92 JF |
177 | #include "xen-ops.h" |
178 | ||
448f2831 JF |
179 | static void __init m2p_override_init(void); |
180 | ||
b5eafe92 JF |
181 | unsigned long xen_max_p2m_pfn __read_mostly; |
182 | ||
183 | #define P2M_PER_PAGE (PAGE_SIZE / sizeof(unsigned long)) | |
184 | #define P2M_MID_PER_PAGE (PAGE_SIZE / sizeof(unsigned long *)) | |
185 | #define P2M_TOP_PER_PAGE (PAGE_SIZE / sizeof(unsigned long **)) | |
186 | ||
187 | #define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE) | |
188 | ||
189 | /* Placeholders for holes in the address space */ | |
190 | static RESERVE_BRK_ARRAY(unsigned long, p2m_missing, P2M_PER_PAGE); | |
191 | static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_missing, P2M_MID_PER_PAGE); | |
192 | static RESERVE_BRK_ARRAY(unsigned long, p2m_mid_missing_mfn, P2M_MID_PER_PAGE); | |
193 | ||
194 | static RESERVE_BRK_ARRAY(unsigned long **, p2m_top, P2M_TOP_PER_PAGE); | |
195 | static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn, P2M_TOP_PER_PAGE); | |
196 | static RESERVE_BRK_ARRAY(unsigned long *, p2m_top_mfn_p, P2M_TOP_PER_PAGE); | |
197 | ||
f4cec35b | 198 | static RESERVE_BRK_ARRAY(unsigned long, p2m_identity, P2M_PER_PAGE); |
3cb83e46 DV |
199 | static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_identity, P2M_MID_PER_PAGE); |
200 | static RESERVE_BRK_ARRAY(unsigned long, p2m_mid_identity_mfn, P2M_MID_PER_PAGE); | |
f4cec35b | 201 | |
b5eafe92 JF |
202 | RESERVE_BRK(p2m_mid, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE))); |
203 | RESERVE_BRK(p2m_mid_mfn, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE))); | |
204 | ||
f4cec35b KRW |
205 | /* We might hit two boundary violations at the start and end, at max each |
206 | * boundary violation will require three middle nodes. */ | |
3cb83e46 | 207 | RESERVE_BRK(p2m_mid_extra, PAGE_SIZE * 2 * 3); |
f4cec35b | 208 | |
5bc6f988 KRW |
209 | /* When we populate back during bootup, the amount of pages can vary. The |
210 | * max we have is seen is 395979, but that does not mean it can't be more. | |
250a41e0 KRW |
211 | * Some machines can have 3GB I/O holes even. With early_can_reuse_p2m_middle |
212 | * it can re-use Xen provided mfn_list array, so we only need to allocate at | |
213 | * most three P2M top nodes. */ | |
214 | RESERVE_BRK(p2m_populated, PAGE_SIZE * 3); | |
215 | ||
b5eafe92 JF |
216 | static inline unsigned p2m_top_index(unsigned long pfn) |
217 | { | |
218 | BUG_ON(pfn >= MAX_P2M_PFN); | |
219 | return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE); | |
220 | } | |
221 | ||
222 | static inline unsigned p2m_mid_index(unsigned long pfn) | |
223 | { | |
224 | return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE; | |
225 | } | |
226 | ||
227 | static inline unsigned p2m_index(unsigned long pfn) | |
228 | { | |
229 | return pfn % P2M_PER_PAGE; | |
230 | } | |
231 | ||
232 | static void p2m_top_init(unsigned long ***top) | |
233 | { | |
234 | unsigned i; | |
235 | ||
236 | for (i = 0; i < P2M_TOP_PER_PAGE; i++) | |
237 | top[i] = p2m_mid_missing; | |
238 | } | |
239 | ||
240 | static void p2m_top_mfn_init(unsigned long *top) | |
241 | { | |
242 | unsigned i; | |
243 | ||
244 | for (i = 0; i < P2M_TOP_PER_PAGE; i++) | |
245 | top[i] = virt_to_mfn(p2m_mid_missing_mfn); | |
246 | } | |
247 | ||
248 | static void p2m_top_mfn_p_init(unsigned long **top) | |
249 | { | |
250 | unsigned i; | |
251 | ||
252 | for (i = 0; i < P2M_TOP_PER_PAGE; i++) | |
253 | top[i] = p2m_mid_missing_mfn; | |
254 | } | |
255 | ||
3cb83e46 | 256 | static void p2m_mid_init(unsigned long **mid, unsigned long *leaf) |
b5eafe92 JF |
257 | { |
258 | unsigned i; | |
259 | ||
260 | for (i = 0; i < P2M_MID_PER_PAGE; i++) | |
3cb83e46 | 261 | mid[i] = leaf; |
b5eafe92 JF |
262 | } |
263 | ||
3cb83e46 | 264 | static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf) |
b5eafe92 JF |
265 | { |
266 | unsigned i; | |
267 | ||
268 | for (i = 0; i < P2M_MID_PER_PAGE; i++) | |
3cb83e46 | 269 | mid[i] = virt_to_mfn(leaf); |
b5eafe92 JF |
270 | } |
271 | ||
272 | static void p2m_init(unsigned long *p2m) | |
273 | { | |
274 | unsigned i; | |
275 | ||
276 | for (i = 0; i < P2M_MID_PER_PAGE; i++) | |
277 | p2m[i] = INVALID_P2M_ENTRY; | |
278 | } | |
279 | ||
280 | /* | |
281 | * Build the parallel p2m_top_mfn and p2m_mid_mfn structures | |
282 | * | |
283 | * This is called both at boot time, and after resuming from suspend: | |
284 | * - At boot time we're called very early, and must use extend_brk() | |
285 | * to allocate memory. | |
286 | * | |
287 | * - After resume we're called from within stop_machine, but the mfn | |
288 | * tree should alreay be completely allocated. | |
289 | */ | |
44b46c3e | 290 | void __ref xen_build_mfn_list_list(void) |
b5eafe92 JF |
291 | { |
292 | unsigned long pfn; | |
293 | ||
696fd7c5 KRW |
294 | if (xen_feature(XENFEAT_auto_translated_physmap)) |
295 | return; | |
296 | ||
b5eafe92 JF |
297 | /* Pre-initialize p2m_top_mfn to be completely missing */ |
298 | if (p2m_top_mfn == NULL) { | |
299 | p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
3cb83e46 DV |
300 | p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); |
301 | p2m_mid_identity_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
302 | p2m_mid_mfn_init(p2m_mid_identity_mfn, p2m_identity); | |
b5eafe92 JF |
303 | |
304 | p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
305 | p2m_top_mfn_p_init(p2m_top_mfn_p); | |
306 | ||
307 | p2m_top_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
308 | p2m_top_mfn_init(p2m_top_mfn); | |
309 | } else { | |
310 | /* Reinitialise, mfn's all change after migration */ | |
3cb83e46 DV |
311 | p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); |
312 | p2m_mid_mfn_init(p2m_mid_identity_mfn, p2m_identity); | |
b5eafe92 JF |
313 | } |
314 | ||
315 | for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += P2M_PER_PAGE) { | |
316 | unsigned topidx = p2m_top_index(pfn); | |
317 | unsigned mididx = p2m_mid_index(pfn); | |
318 | unsigned long **mid; | |
319 | unsigned long *mid_mfn_p; | |
320 | ||
321 | mid = p2m_top[topidx]; | |
322 | mid_mfn_p = p2m_top_mfn_p[topidx]; | |
323 | ||
324 | /* Don't bother allocating any mfn mid levels if | |
325 | * they're just missing, just update the stored mfn, | |
326 | * since all could have changed over a migrate. | |
327 | */ | |
328 | if (mid == p2m_mid_missing) { | |
329 | BUG_ON(mididx); | |
330 | BUG_ON(mid_mfn_p != p2m_mid_missing_mfn); | |
331 | p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn); | |
332 | pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE; | |
333 | continue; | |
334 | } | |
335 | ||
336 | if (mid_mfn_p == p2m_mid_missing_mfn) { | |
337 | /* | |
338 | * XXX boot-time only! We should never find | |
339 | * missing parts of the mfn tree after | |
340 | * runtime. extend_brk() will BUG if we call | |
341 | * it too late. | |
342 | */ | |
343 | mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
3cb83e46 | 344 | p2m_mid_mfn_init(mid_mfn_p, p2m_missing); |
b5eafe92 JF |
345 | |
346 | p2m_top_mfn_p[topidx] = mid_mfn_p; | |
347 | } | |
348 | ||
349 | p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p); | |
350 | mid_mfn_p[mididx] = virt_to_mfn(mid[mididx]); | |
351 | } | |
352 | } | |
353 | ||
354 | void xen_setup_mfn_list_list(void) | |
355 | { | |
4dd322bc MR |
356 | if (xen_feature(XENFEAT_auto_translated_physmap)) |
357 | return; | |
358 | ||
b5eafe92 JF |
359 | BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); |
360 | ||
361 | HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = | |
362 | virt_to_mfn(p2m_top_mfn); | |
363 | HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn; | |
364 | } | |
365 | ||
366 | /* Set up p2m_top to point to the domain-builder provided p2m pages */ | |
367 | void __init xen_build_dynamic_phys_to_machine(void) | |
368 | { | |
696fd7c5 KRW |
369 | unsigned long *mfn_list; |
370 | unsigned long max_pfn; | |
b5eafe92 JF |
371 | unsigned long pfn; |
372 | ||
696fd7c5 KRW |
373 | if (xen_feature(XENFEAT_auto_translated_physmap)) |
374 | return; | |
375 | ||
376 | mfn_list = (unsigned long *)xen_start_info->mfn_list; | |
377 | max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages); | |
b5eafe92 JF |
378 | xen_max_p2m_pfn = max_pfn; |
379 | ||
380 | p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
381 | p2m_init(p2m_missing); | |
3cb83e46 DV |
382 | p2m_identity = extend_brk(PAGE_SIZE, PAGE_SIZE); |
383 | p2m_init(p2m_identity); | |
b5eafe92 JF |
384 | |
385 | p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
3cb83e46 DV |
386 | p2m_mid_init(p2m_mid_missing, p2m_missing); |
387 | p2m_mid_identity = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
388 | p2m_mid_init(p2m_mid_identity, p2m_identity); | |
b5eafe92 JF |
389 | |
390 | p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
391 | p2m_top_init(p2m_top); | |
392 | ||
393 | /* | |
394 | * The domain builder gives us a pre-constructed p2m array in | |
395 | * mfn_list for all the pages initially given to us, so we just | |
396 | * need to graft that into our tree structure. | |
397 | */ | |
398 | for (pfn = 0; pfn < max_pfn; pfn += P2M_PER_PAGE) { | |
399 | unsigned topidx = p2m_top_index(pfn); | |
400 | unsigned mididx = p2m_mid_index(pfn); | |
401 | ||
402 | if (p2m_top[topidx] == p2m_mid_missing) { | |
403 | unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
3cb83e46 | 404 | p2m_mid_init(mid, p2m_missing); |
b5eafe92 JF |
405 | |
406 | p2m_top[topidx] = mid; | |
407 | } | |
408 | ||
8e1b4cf2 SB |
409 | /* |
410 | * As long as the mfn_list has enough entries to completely | |
411 | * fill a p2m page, pointing into the array is ok. But if | |
412 | * not the entries beyond the last pfn will be undefined. | |
8e1b4cf2 SB |
413 | */ |
414 | if (unlikely(pfn + P2M_PER_PAGE > max_pfn)) { | |
415 | unsigned long p2midx; | |
cf04d120 SB |
416 | |
417 | p2midx = max_pfn % P2M_PER_PAGE; | |
418 | for ( ; p2midx < P2M_PER_PAGE; p2midx++) | |
419 | mfn_list[pfn + p2midx] = INVALID_P2M_ENTRY; | |
420 | } | |
421 | p2m_top[topidx][mididx] = &mfn_list[pfn]; | |
b5eafe92 | 422 | } |
448f2831 JF |
423 | |
424 | m2p_override_init(); | |
b5eafe92 | 425 | } |
357a3cfb KRW |
426 | #ifdef CONFIG_X86_64 |
427 | #include <linux/bootmem.h> | |
428 | unsigned long __init xen_revector_p2m_tree(void) | |
429 | { | |
430 | unsigned long va_start; | |
431 | unsigned long va_end; | |
432 | unsigned long pfn; | |
3fc509fc | 433 | unsigned long pfn_free = 0; |
357a3cfb KRW |
434 | unsigned long *mfn_list = NULL; |
435 | unsigned long size; | |
436 | ||
437 | va_start = xen_start_info->mfn_list; | |
438 | /*We copy in increments of P2M_PER_PAGE * sizeof(unsigned long), | |
439 | * so make sure it is rounded up to that */ | |
440 | size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long)); | |
441 | va_end = va_start + size; | |
442 | ||
443 | /* If we were revectored already, don't do it again. */ | |
444 | if (va_start <= __START_KERNEL_map && va_start >= __PAGE_OFFSET) | |
445 | return 0; | |
446 | ||
447 | mfn_list = alloc_bootmem_align(size, PAGE_SIZE); | |
448 | if (!mfn_list) { | |
449 | pr_warn("Could not allocate space for a new P2M tree!\n"); | |
450 | return xen_start_info->mfn_list; | |
451 | } | |
452 | /* Fill it out with INVALID_P2M_ENTRY value */ | |
453 | memset(mfn_list, 0xFF, size); | |
454 | ||
455 | for (pfn = 0; pfn < ALIGN(MAX_DOMAIN_PAGES, P2M_PER_PAGE); pfn += P2M_PER_PAGE) { | |
456 | unsigned topidx = p2m_top_index(pfn); | |
457 | unsigned mididx; | |
458 | unsigned long *mid_p; | |
459 | ||
460 | if (!p2m_top[topidx]) | |
461 | continue; | |
b5eafe92 | 462 | |
357a3cfb KRW |
463 | if (p2m_top[topidx] == p2m_mid_missing) |
464 | continue; | |
465 | ||
466 | mididx = p2m_mid_index(pfn); | |
467 | mid_p = p2m_top[topidx][mididx]; | |
468 | if (!mid_p) | |
469 | continue; | |
470 | if ((mid_p == p2m_missing) || (mid_p == p2m_identity)) | |
471 | continue; | |
b5eafe92 | 472 | |
357a3cfb KRW |
473 | if ((unsigned long)mid_p == INVALID_P2M_ENTRY) |
474 | continue; | |
475 | ||
476 | /* The old va. Rebase it on mfn_list */ | |
477 | if (mid_p >= (unsigned long *)va_start && mid_p <= (unsigned long *)va_end) { | |
478 | unsigned long *new; | |
479 | ||
3fc509fc KRW |
480 | if (pfn_free > (size / sizeof(unsigned long))) { |
481 | WARN(1, "Only allocated for %ld pages, but we want %ld!\n", | |
482 | size / sizeof(unsigned long), pfn_free); | |
483 | return 0; | |
484 | } | |
485 | new = &mfn_list[pfn_free]; | |
357a3cfb KRW |
486 | |
487 | copy_page(new, mid_p); | |
3fc509fc KRW |
488 | p2m_top[topidx][mididx] = &mfn_list[pfn_free]; |
489 | p2m_top_mfn_p[topidx][mididx] = virt_to_mfn(&mfn_list[pfn_free]); | |
490 | ||
491 | pfn_free += P2M_PER_PAGE; | |
357a3cfb KRW |
492 | |
493 | } | |
494 | /* This should be the leafs allocated for identity from _brk. */ | |
495 | } | |
496 | return (unsigned long)mfn_list; | |
497 | ||
498 | } | |
499 | #else | |
500 | unsigned long __init xen_revector_p2m_tree(void) | |
501 | { | |
502 | return 0; | |
503 | } | |
504 | #endif | |
b5eafe92 JF |
505 | unsigned long get_phys_to_machine(unsigned long pfn) |
506 | { | |
507 | unsigned topidx, mididx, idx; | |
508 | ||
509 | if (unlikely(pfn >= MAX_P2M_PFN)) | |
25b884a8 | 510 | return IDENTITY_FRAME(pfn); |
b5eafe92 JF |
511 | |
512 | topidx = p2m_top_index(pfn); | |
513 | mididx = p2m_mid_index(pfn); | |
514 | idx = p2m_index(pfn); | |
515 | ||
f4cec35b KRW |
516 | /* |
517 | * The INVALID_P2M_ENTRY is filled in both p2m_*identity | |
518 | * and in p2m_*missing, so returning the INVALID_P2M_ENTRY | |
519 | * would be wrong. | |
520 | */ | |
521 | if (p2m_top[topidx][mididx] == p2m_identity) | |
522 | return IDENTITY_FRAME(pfn); | |
523 | ||
b5eafe92 JF |
524 | return p2m_top[topidx][mididx][idx]; |
525 | } | |
526 | EXPORT_SYMBOL_GPL(get_phys_to_machine); | |
527 | ||
528 | static void *alloc_p2m_page(void) | |
529 | { | |
530 | return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT); | |
531 | } | |
532 | ||
533 | static void free_p2m_page(void *p) | |
534 | { | |
535 | free_page((unsigned long)p); | |
536 | } | |
537 | ||
a3118beb | 538 | /* |
b5eafe92 JF |
539 | * Fully allocate the p2m structure for a given pfn. We need to check |
540 | * that both the top and mid levels are allocated, and make sure the | |
541 | * parallel mfn tree is kept in sync. We may race with other cpus, so | |
542 | * the new pages are installed with cmpxchg; if we lose the race then | |
543 | * simply free the page we allocated and use the one that's there. | |
544 | */ | |
545 | static bool alloc_p2m(unsigned long pfn) | |
546 | { | |
547 | unsigned topidx, mididx; | |
548 | unsigned long ***top_p, **mid; | |
549 | unsigned long *top_mfn_p, *mid_mfn; | |
550 | ||
551 | topidx = p2m_top_index(pfn); | |
552 | mididx = p2m_mid_index(pfn); | |
553 | ||
554 | top_p = &p2m_top[topidx]; | |
555 | mid = *top_p; | |
556 | ||
557 | if (mid == p2m_mid_missing) { | |
558 | /* Mid level is missing, allocate a new one */ | |
559 | mid = alloc_p2m_page(); | |
560 | if (!mid) | |
561 | return false; | |
562 | ||
3cb83e46 | 563 | p2m_mid_init(mid, p2m_missing); |
b5eafe92 JF |
564 | |
565 | if (cmpxchg(top_p, p2m_mid_missing, mid) != p2m_mid_missing) | |
566 | free_p2m_page(mid); | |
567 | } | |
568 | ||
569 | top_mfn_p = &p2m_top_mfn[topidx]; | |
570 | mid_mfn = p2m_top_mfn_p[topidx]; | |
571 | ||
572 | BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p); | |
573 | ||
574 | if (mid_mfn == p2m_mid_missing_mfn) { | |
575 | /* Separately check the mid mfn level */ | |
576 | unsigned long missing_mfn; | |
577 | unsigned long mid_mfn_mfn; | |
578 | ||
579 | mid_mfn = alloc_p2m_page(); | |
580 | if (!mid_mfn) | |
581 | return false; | |
582 | ||
3cb83e46 | 583 | p2m_mid_mfn_init(mid_mfn, p2m_missing); |
b5eafe92 JF |
584 | |
585 | missing_mfn = virt_to_mfn(p2m_mid_missing_mfn); | |
586 | mid_mfn_mfn = virt_to_mfn(mid_mfn); | |
587 | if (cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn) != missing_mfn) | |
588 | free_p2m_page(mid_mfn); | |
589 | else | |
590 | p2m_top_mfn_p[topidx] = mid_mfn; | |
591 | } | |
592 | ||
f4cec35b KRW |
593 | if (p2m_top[topidx][mididx] == p2m_identity || |
594 | p2m_top[topidx][mididx] == p2m_missing) { | |
b5eafe92 JF |
595 | /* p2m leaf page is missing */ |
596 | unsigned long *p2m; | |
f4cec35b | 597 | unsigned long *p2m_orig = p2m_top[topidx][mididx]; |
b5eafe92 JF |
598 | |
599 | p2m = alloc_p2m_page(); | |
600 | if (!p2m) | |
601 | return false; | |
602 | ||
603 | p2m_init(p2m); | |
604 | ||
f4cec35b | 605 | if (cmpxchg(&mid[mididx], p2m_orig, p2m) != p2m_orig) |
b5eafe92 JF |
606 | free_p2m_page(p2m); |
607 | else | |
608 | mid_mfn[mididx] = virt_to_mfn(p2m); | |
609 | } | |
610 | ||
611 | return true; | |
612 | } | |
613 | ||
fcca2e31 | 614 | static bool __init early_alloc_p2m(unsigned long pfn, bool check_boundary) |
f4cec35b KRW |
615 | { |
616 | unsigned topidx, mididx, idx; | |
d5096850 KRW |
617 | unsigned long *p2m; |
618 | unsigned long *mid_mfn_p; | |
f4cec35b KRW |
619 | |
620 | topidx = p2m_top_index(pfn); | |
621 | mididx = p2m_mid_index(pfn); | |
622 | idx = p2m_index(pfn); | |
623 | ||
624 | /* Pfff.. No boundary cross-over, lets get out. */ | |
cef4cca5 | 625 | if (!idx && check_boundary) |
f4cec35b KRW |
626 | return false; |
627 | ||
628 | WARN(p2m_top[topidx][mididx] == p2m_identity, | |
629 | "P2M[%d][%d] == IDENTITY, should be MISSING (or alloced)!\n", | |
630 | topidx, mididx); | |
631 | ||
632 | /* | |
633 | * Could be done by xen_build_dynamic_phys_to_machine.. | |
634 | */ | |
635 | if (p2m_top[topidx][mididx] != p2m_missing) | |
636 | return false; | |
637 | ||
638 | /* Boundary cross-over for the edges: */ | |
d5096850 | 639 | p2m = extend_brk(PAGE_SIZE, PAGE_SIZE); |
f4cec35b | 640 | |
d5096850 | 641 | p2m_init(p2m); |
f4cec35b | 642 | |
d5096850 | 643 | p2m_top[topidx][mididx] = p2m; |
f4cec35b | 644 | |
d5096850 | 645 | /* For save/restore we need to MFN of the P2M saved */ |
cef4cca5 | 646 | |
d5096850 KRW |
647 | mid_mfn_p = p2m_top_mfn_p[topidx]; |
648 | WARN(mid_mfn_p[mididx] != virt_to_mfn(p2m_missing), | |
649 | "P2M_TOP_P[%d][%d] != MFN of p2m_missing!\n", | |
650 | topidx, mididx); | |
651 | mid_mfn_p[mididx] = virt_to_mfn(p2m); | |
8c595088 | 652 | |
d5096850 | 653 | return true; |
f4cec35b | 654 | } |
3f3aaea2 | 655 | |
fcca2e31 | 656 | static bool __init early_alloc_p2m_middle(unsigned long pfn) |
3f3aaea2 KRW |
657 | { |
658 | unsigned topidx = p2m_top_index(pfn); | |
659 | unsigned long *mid_mfn_p; | |
660 | unsigned long **mid; | |
661 | ||
662 | mid = p2m_top[topidx]; | |
663 | mid_mfn_p = p2m_top_mfn_p[topidx]; | |
664 | if (mid == p2m_mid_missing) { | |
665 | mid = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
666 | ||
3cb83e46 | 667 | p2m_mid_init(mid, p2m_missing); |
3f3aaea2 KRW |
668 | |
669 | p2m_top[topidx] = mid; | |
670 | ||
671 | BUG_ON(mid_mfn_p != p2m_mid_missing_mfn); | |
672 | } | |
673 | /* And the save/restore P2M tables.. */ | |
674 | if (mid_mfn_p == p2m_mid_missing_mfn) { | |
675 | mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); | |
3cb83e46 | 676 | p2m_mid_mfn_init(mid_mfn_p, p2m_missing); |
3f3aaea2 KRW |
677 | |
678 | p2m_top_mfn_p[topidx] = mid_mfn_p; | |
679 | p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p); | |
680 | /* Note: we don't set mid_mfn_p[midix] here, | |
fcca2e31 | 681 | * look in early_alloc_p2m() */ |
3f3aaea2 KRW |
682 | } |
683 | return true; | |
684 | } | |
250a41e0 KRW |
685 | |
686 | /* | |
687 | * Skim over the P2M tree looking at pages that are either filled with | |
688 | * INVALID_P2M_ENTRY or with 1:1 PFNs. If found, re-use that page and | |
689 | * replace the P2M leaf with a p2m_missing or p2m_identity. | |
690 | * Stick the old page in the new P2M tree location. | |
691 | */ | |
692 | bool __init early_can_reuse_p2m_middle(unsigned long set_pfn, unsigned long set_mfn) | |
693 | { | |
694 | unsigned topidx; | |
695 | unsigned mididx; | |
696 | unsigned ident_pfns; | |
697 | unsigned inv_pfns; | |
698 | unsigned long *p2m; | |
699 | unsigned long *mid_mfn_p; | |
700 | unsigned idx; | |
701 | unsigned long pfn; | |
702 | ||
703 | /* We only look when this entails a P2M middle layer */ | |
704 | if (p2m_index(set_pfn)) | |
705 | return false; | |
706 | ||
50e90041 | 707 | for (pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn += P2M_PER_PAGE) { |
250a41e0 KRW |
708 | topidx = p2m_top_index(pfn); |
709 | ||
710 | if (!p2m_top[topidx]) | |
711 | continue; | |
712 | ||
713 | if (p2m_top[topidx] == p2m_mid_missing) | |
714 | continue; | |
715 | ||
716 | mididx = p2m_mid_index(pfn); | |
717 | p2m = p2m_top[topidx][mididx]; | |
718 | if (!p2m) | |
719 | continue; | |
720 | ||
721 | if ((p2m == p2m_missing) || (p2m == p2m_identity)) | |
722 | continue; | |
723 | ||
724 | if ((unsigned long)p2m == INVALID_P2M_ENTRY) | |
725 | continue; | |
726 | ||
727 | ident_pfns = 0; | |
728 | inv_pfns = 0; | |
729 | for (idx = 0; idx < P2M_PER_PAGE; idx++) { | |
730 | /* IDENTITY_PFNs are 1:1 */ | |
731 | if (p2m[idx] == IDENTITY_FRAME(pfn + idx)) | |
732 | ident_pfns++; | |
733 | else if (p2m[idx] == INVALID_P2M_ENTRY) | |
734 | inv_pfns++; | |
735 | else | |
736 | break; | |
737 | } | |
738 | if ((ident_pfns == P2M_PER_PAGE) || (inv_pfns == P2M_PER_PAGE)) | |
739 | goto found; | |
740 | } | |
741 | return false; | |
742 | found: | |
743 | /* Found one, replace old with p2m_identity or p2m_missing */ | |
744 | p2m_top[topidx][mididx] = (ident_pfns ? p2m_identity : p2m_missing); | |
745 | /* And the other for save/restore.. */ | |
746 | mid_mfn_p = p2m_top_mfn_p[topidx]; | |
747 | /* NOTE: Even if it is a p2m_identity it should still be point to | |
748 | * a page filled with INVALID_P2M_ENTRY entries. */ | |
749 | mid_mfn_p[mididx] = virt_to_mfn(p2m_missing); | |
750 | ||
751 | /* Reset where we want to stick the old page in. */ | |
752 | topidx = p2m_top_index(set_pfn); | |
753 | mididx = p2m_mid_index(set_pfn); | |
754 | ||
755 | /* This shouldn't happen */ | |
756 | if (WARN_ON(p2m_top[topidx] == p2m_mid_missing)) | |
fcca2e31 | 757 | early_alloc_p2m_middle(set_pfn); |
250a41e0 KRW |
758 | |
759 | if (WARN_ON(p2m_top[topidx][mididx] != p2m_missing)) | |
760 | return false; | |
761 | ||
762 | p2m_init(p2m); | |
763 | p2m_top[topidx][mididx] = p2m; | |
764 | mid_mfn_p = p2m_top_mfn_p[topidx]; | |
765 | mid_mfn_p[mididx] = virt_to_mfn(p2m); | |
766 | ||
767 | return true; | |
768 | } | |
940713bb KRW |
769 | bool __init early_set_phys_to_machine(unsigned long pfn, unsigned long mfn) |
770 | { | |
771 | if (unlikely(!__set_phys_to_machine(pfn, mfn))) { | |
fcca2e31 | 772 | if (!early_alloc_p2m_middle(pfn)) |
940713bb KRW |
773 | return false; |
774 | ||
250a41e0 KRW |
775 | if (early_can_reuse_p2m_middle(pfn, mfn)) |
776 | return __set_phys_to_machine(pfn, mfn); | |
777 | ||
fcca2e31 | 778 | if (!early_alloc_p2m(pfn, false /* boundary crossover OK!*/)) |
940713bb KRW |
779 | return false; |
780 | ||
781 | if (!__set_phys_to_machine(pfn, mfn)) | |
782 | return false; | |
783 | } | |
784 | ||
785 | return true; | |
786 | } | |
3cb83e46 DV |
787 | |
788 | static void __init early_split_p2m(unsigned long pfn) | |
789 | { | |
790 | unsigned long mididx, idx; | |
791 | ||
792 | mididx = p2m_mid_index(pfn); | |
793 | idx = p2m_index(pfn); | |
794 | ||
795 | /* | |
796 | * Allocate new middle and leaf pages if this pfn lies in the | |
797 | * middle of one. | |
798 | */ | |
799 | if (mididx || idx) | |
800 | early_alloc_p2m_middle(pfn); | |
801 | if (idx) | |
802 | early_alloc_p2m(pfn, false); | |
803 | } | |
804 | ||
b83c6e55 | 805 | unsigned long __init set_phys_range_identity(unsigned long pfn_s, |
f4cec35b KRW |
806 | unsigned long pfn_e) |
807 | { | |
808 | unsigned long pfn; | |
809 | ||
a9b5bff6 | 810 | if (unlikely(pfn_s >= MAX_P2M_PFN)) |
f4cec35b KRW |
811 | return 0; |
812 | ||
813 | if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) | |
814 | return pfn_e - pfn_s; | |
815 | ||
816 | if (pfn_s > pfn_e) | |
817 | return 0; | |
818 | ||
a9b5bff6 DV |
819 | if (pfn_e > MAX_P2M_PFN) |
820 | pfn_e = MAX_P2M_PFN; | |
821 | ||
3cb83e46 DV |
822 | early_split_p2m(pfn_s); |
823 | early_split_p2m(pfn_e); | |
f4cec35b | 824 | |
3cb83e46 DV |
825 | for (pfn = pfn_s; pfn < pfn_e;) { |
826 | unsigned topidx = p2m_top_index(pfn); | |
827 | unsigned mididx = p2m_mid_index(pfn); | |
f4cec35b | 828 | |
f4cec35b KRW |
829 | if (!__set_phys_to_machine(pfn, IDENTITY_FRAME(pfn))) |
830 | break; | |
3cb83e46 DV |
831 | pfn++; |
832 | ||
833 | /* | |
834 | * If the PFN was set to a middle or leaf identity | |
835 | * page the remainder must also be identity, so skip | |
836 | * ahead to the next middle or leaf entry. | |
837 | */ | |
838 | if (p2m_top[topidx] == p2m_mid_identity) | |
839 | pfn = ALIGN(pfn, P2M_MID_PER_PAGE * P2M_PER_PAGE); | |
840 | else if (p2m_top[topidx][mididx] == p2m_identity) | |
841 | pfn = ALIGN(pfn, P2M_PER_PAGE); | |
842 | } | |
f4cec35b | 843 | |
3fbdf631 | 844 | WARN((pfn - pfn_s) != (pfn_e - pfn_s), |
f4cec35b | 845 | "Identity mapping failed. We are %ld short of 1-1 mappings!\n", |
3fbdf631 | 846 | (pfn_e - pfn_s) - (pfn - pfn_s)); |
f4cec35b KRW |
847 | |
848 | return pfn - pfn_s; | |
849 | } | |
850 | ||
b5eafe92 JF |
851 | /* Try to install p2m mapping; fail if intermediate bits missing */ |
852 | bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) | |
853 | { | |
854 | unsigned topidx, mididx, idx; | |
855 | ||
2f558d40 SS |
856 | /* don't track P2M changes in autotranslate guests */ |
857 | if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) | |
6eaa412f | 858 | return true; |
2f558d40 | 859 | |
b5eafe92 JF |
860 | if (unlikely(pfn >= MAX_P2M_PFN)) { |
861 | BUG_ON(mfn != INVALID_P2M_ENTRY); | |
862 | return true; | |
863 | } | |
864 | ||
865 | topidx = p2m_top_index(pfn); | |
866 | mididx = p2m_mid_index(pfn); | |
867 | idx = p2m_index(pfn); | |
868 | ||
f4cec35b KRW |
869 | /* For sparse holes were the p2m leaf has real PFN along with |
870 | * PCI holes, stick in the PFN as the MFN value. | |
3cb83e46 DV |
871 | * |
872 | * set_phys_range_identity() will have allocated new middle | |
873 | * and leaf pages as required so an existing p2m_mid_missing | |
874 | * or p2m_missing mean that whole range will be identity so | |
875 | * these can be switched to p2m_mid_identity or p2m_identity. | |
f4cec35b KRW |
876 | */ |
877 | if (mfn != INVALID_P2M_ENTRY && (mfn & IDENTITY_FRAME_BIT)) { | |
3cb83e46 DV |
878 | if (p2m_top[topidx] == p2m_mid_identity) |
879 | return true; | |
880 | ||
881 | if (p2m_top[topidx] == p2m_mid_missing) { | |
882 | WARN_ON(cmpxchg(&p2m_top[topidx], p2m_mid_missing, | |
883 | p2m_mid_identity) != p2m_mid_missing); | |
884 | return true; | |
885 | } | |
886 | ||
f4cec35b KRW |
887 | if (p2m_top[topidx][mididx] == p2m_identity) |
888 | return true; | |
889 | ||
890 | /* Swap over from MISSING to IDENTITY if needed. */ | |
891 | if (p2m_top[topidx][mididx] == p2m_missing) { | |
c7617798 KRW |
892 | WARN_ON(cmpxchg(&p2m_top[topidx][mididx], p2m_missing, |
893 | p2m_identity) != p2m_missing); | |
f4cec35b KRW |
894 | return true; |
895 | } | |
896 | } | |
897 | ||
b5eafe92 JF |
898 | if (p2m_top[topidx][mididx] == p2m_missing) |
899 | return mfn == INVALID_P2M_ENTRY; | |
900 | ||
901 | p2m_top[topidx][mididx][idx] = mfn; | |
902 | ||
903 | return true; | |
904 | } | |
905 | ||
906 | bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) | |
907 | { | |
b5eafe92 JF |
908 | if (unlikely(!__set_phys_to_machine(pfn, mfn))) { |
909 | if (!alloc_p2m(pfn)) | |
910 | return false; | |
911 | ||
912 | if (!__set_phys_to_machine(pfn, mfn)) | |
913 | return false; | |
914 | } | |
915 | ||
916 | return true; | |
917 | } | |
448f2831 JF |
918 | |
919 | #define M2P_OVERRIDE_HASH_SHIFT 10 | |
920 | #define M2P_OVERRIDE_HASH (1 << M2P_OVERRIDE_HASH_SHIFT) | |
921 | ||
922 | static RESERVE_BRK_ARRAY(struct list_head, m2p_overrides, M2P_OVERRIDE_HASH); | |
923 | static DEFINE_SPINLOCK(m2p_override_lock); | |
924 | ||
925 | static void __init m2p_override_init(void) | |
926 | { | |
927 | unsigned i; | |
928 | ||
929 | m2p_overrides = extend_brk(sizeof(*m2p_overrides) * M2P_OVERRIDE_HASH, | |
930 | sizeof(unsigned long)); | |
931 | ||
932 | for (i = 0; i < M2P_OVERRIDE_HASH; i++) | |
933 | INIT_LIST_HEAD(&m2p_overrides[i]); | |
934 | } | |
935 | ||
936 | static unsigned long mfn_hash(unsigned long mfn) | |
937 | { | |
938 | return hash_long(mfn, M2P_OVERRIDE_HASH_SHIFT); | |
939 | } | |
940 | ||
1429d46d ZK |
941 | int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, |
942 | struct gnttab_map_grant_ref *kmap_ops, | |
943 | struct page **pages, unsigned int count) | |
944 | { | |
945 | int i, ret = 0; | |
946 | bool lazy = false; | |
947 | pte_t *pte; | |
948 | ||
949 | if (xen_feature(XENFEAT_auto_translated_physmap)) | |
950 | return 0; | |
951 | ||
952 | if (kmap_ops && | |
953 | !in_interrupt() && | |
954 | paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) { | |
955 | arch_enter_lazy_mmu_mode(); | |
956 | lazy = true; | |
957 | } | |
958 | ||
959 | for (i = 0; i < count; i++) { | |
960 | unsigned long mfn, pfn; | |
961 | ||
962 | /* Do not add to override if the map failed. */ | |
963 | if (map_ops[i].status) | |
964 | continue; | |
965 | ||
966 | if (map_ops[i].flags & GNTMAP_contains_pte) { | |
967 | pte = (pte_t *) (mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) + | |
968 | (map_ops[i].host_addr & ~PAGE_MASK)); | |
969 | mfn = pte_mfn(*pte); | |
970 | } else { | |
971 | mfn = PFN_DOWN(map_ops[i].dev_bus_addr); | |
972 | } | |
973 | pfn = page_to_pfn(pages[i]); | |
974 | ||
975 | WARN_ON(PagePrivate(pages[i])); | |
976 | SetPagePrivate(pages[i]); | |
977 | set_page_private(pages[i], mfn); | |
978 | pages[i]->index = pfn_to_mfn(pfn); | |
979 | ||
980 | if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) { | |
981 | ret = -ENOMEM; | |
982 | goto out; | |
983 | } | |
984 | ||
985 | if (kmap_ops) { | |
986 | ret = m2p_add_override(mfn, pages[i], &kmap_ops[i]); | |
987 | if (ret) | |
988 | goto out; | |
989 | } | |
990 | } | |
991 | ||
992 | out: | |
993 | if (lazy) | |
994 | arch_leave_lazy_mmu_mode(); | |
995 | ||
996 | return ret; | |
997 | } | |
998 | EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping); | |
999 | ||
448f2831 | 1000 | /* Add an MFN override for a particular page */ |
0930bba6 SS |
1001 | int m2p_add_override(unsigned long mfn, struct page *page, |
1002 | struct gnttab_map_grant_ref *kmap_op) | |
448f2831 JF |
1003 | { |
1004 | unsigned long flags; | |
87f1d40a | 1005 | unsigned long pfn; |
6b08cfeb | 1006 | unsigned long uninitialized_var(address); |
87f1d40a JF |
1007 | unsigned level; |
1008 | pte_t *ptep = NULL; | |
1009 | ||
1010 | pfn = page_to_pfn(page); | |
1011 | if (!PageHighMem(page)) { | |
1012 | address = (unsigned long)__va(pfn << PAGE_SHIFT); | |
1013 | ptep = lookup_address(address, &level); | |
87f1d40a JF |
1014 | if (WARN(ptep == NULL || level != PG_LEVEL_4K, |
1015 | "m2p_add_override: pfn %lx not mapped", pfn)) | |
1016 | return -EINVAL; | |
1017 | } | |
b254244d | 1018 | |
0930bba6 SS |
1019 | if (kmap_op != NULL) { |
1020 | if (!PageHighMem(page)) { | |
1021 | struct multicall_space mcs = | |
1022 | xen_mc_entry(sizeof(*kmap_op)); | |
1023 | ||
1024 | MULTI_grant_table_op(mcs.mc, | |
1025 | GNTTABOP_map_grant_ref, kmap_op, 1); | |
1026 | ||
1027 | xen_mc_issue(PARAVIRT_LAZY_MMU); | |
1028 | } | |
0930bba6 | 1029 | } |
448f2831 JF |
1030 | spin_lock_irqsave(&m2p_override_lock, flags); |
1031 | list_add(&page->lru, &m2p_overrides[mfn_hash(mfn)]); | |
1032 | spin_unlock_irqrestore(&m2p_override_lock, flags); | |
87f1d40a | 1033 | |
b9e0d95c SS |
1034 | /* p2m(m2p(mfn)) == mfn: the mfn is already present somewhere in |
1035 | * this domain. Set the FOREIGN_FRAME_BIT in the p2m for the other | |
1036 | * pfn so that the following mfn_to_pfn(mfn) calls will return the | |
1037 | * pfn from the m2p_override (the backend pfn) instead. | |
1038 | * We need to do this because the pages shared by the frontend | |
1039 | * (xen-blkfront) can be already locked (lock_page, called by | |
1040 | * do_read_cache_page); when the userspace backend tries to use them | |
1041 | * with direct_IO, mfn_to_pfn returns the pfn of the frontend, so | |
1042 | * do_blockdev_direct_IO is going to try to lock the same pages | |
1043 | * again resulting in a deadlock. | |
1044 | * As a side effect get_user_pages_fast might not be safe on the | |
1045 | * frontend pages while they are being shared with the backend, | |
1046 | * because mfn_to_pfn (that ends up being called by GUPF) will | |
1047 | * return the backend pfn rather than the frontend pfn. */ | |
0160676b DV |
1048 | pfn = mfn_to_pfn_no_overrides(mfn); |
1049 | if (get_phys_to_machine(pfn) == mfn) | |
b9e0d95c SS |
1050 | set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)); |
1051 | ||
87f1d40a | 1052 | return 0; |
448f2831 | 1053 | } |
8a91707d | 1054 | EXPORT_SYMBOL_GPL(m2p_add_override); |
1429d46d ZK |
1055 | |
1056 | int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, | |
1057 | struct gnttab_map_grant_ref *kmap_ops, | |
1058 | struct page **pages, unsigned int count) | |
1059 | { | |
1060 | int i, ret = 0; | |
1061 | bool lazy = false; | |
1062 | ||
1063 | if (xen_feature(XENFEAT_auto_translated_physmap)) | |
1064 | return 0; | |
1065 | ||
1066 | if (kmap_ops && | |
1067 | !in_interrupt() && | |
1068 | paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) { | |
1069 | arch_enter_lazy_mmu_mode(); | |
1070 | lazy = true; | |
1071 | } | |
1072 | ||
1073 | for (i = 0; i < count; i++) { | |
1074 | unsigned long mfn = get_phys_to_machine(page_to_pfn(pages[i])); | |
1075 | unsigned long pfn = page_to_pfn(pages[i]); | |
1076 | ||
1077 | if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) { | |
1078 | ret = -EINVAL; | |
1079 | goto out; | |
1080 | } | |
1081 | ||
1082 | set_page_private(pages[i], INVALID_P2M_ENTRY); | |
1083 | WARN_ON(!PagePrivate(pages[i])); | |
1084 | ClearPagePrivate(pages[i]); | |
1085 | set_phys_to_machine(pfn, pages[i]->index); | |
1086 | ||
1087 | if (kmap_ops) | |
1088 | ret = m2p_remove_override(pages[i], &kmap_ops[i], mfn); | |
1089 | if (ret) | |
1090 | goto out; | |
1091 | } | |
1092 | ||
1093 | out: | |
1094 | if (lazy) | |
1095 | arch_leave_lazy_mmu_mode(); | |
1096 | return ret; | |
1097 | } | |
1098 | EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping); | |
1099 | ||
2fc136ee | 1100 | int m2p_remove_override(struct page *page, |
1429d46d ZK |
1101 | struct gnttab_map_grant_ref *kmap_op, |
1102 | unsigned long mfn) | |
448f2831 JF |
1103 | { |
1104 | unsigned long flags; | |
9b705f0e | 1105 | unsigned long pfn; |
6b08cfeb | 1106 | unsigned long uninitialized_var(address); |
87f1d40a JF |
1107 | unsigned level; |
1108 | pte_t *ptep = NULL; | |
9b705f0e SS |
1109 | |
1110 | pfn = page_to_pfn(page); | |
87f1d40a JF |
1111 | |
1112 | if (!PageHighMem(page)) { | |
1113 | address = (unsigned long)__va(pfn << PAGE_SHIFT); | |
1114 | ptep = lookup_address(address, &level); | |
1115 | ||
1116 | if (WARN(ptep == NULL || level != PG_LEVEL_4K, | |
1117 | "m2p_remove_override: pfn %lx not mapped", pfn)) | |
1118 | return -EINVAL; | |
1119 | } | |
9b705f0e | 1120 | |
448f2831 JF |
1121 | spin_lock_irqsave(&m2p_override_lock, flags); |
1122 | list_del(&page->lru); | |
1123 | spin_unlock_irqrestore(&m2p_override_lock, flags); | |
87f1d40a | 1124 | |
2fc136ee | 1125 | if (kmap_op != NULL) { |
0930bba6 SS |
1126 | if (!PageHighMem(page)) { |
1127 | struct multicall_space mcs; | |
ee072640 SS |
1128 | struct gnttab_unmap_and_replace *unmap_op; |
1129 | struct page *scratch_page = get_balloon_scratch_page(); | |
1130 | unsigned long scratch_page_address = (unsigned long) | |
1131 | __va(page_to_pfn(scratch_page) << PAGE_SHIFT); | |
0930bba6 SS |
1132 | |
1133 | /* | |
1134 | * It might be that we queued all the m2p grant table | |
1135 | * hypercalls in a multicall, then m2p_remove_override | |
1136 | * get called before the multicall has actually been | |
1137 | * issued. In this case handle is going to -1 because | |
1138 | * it hasn't been modified yet. | |
1139 | */ | |
2fc136ee | 1140 | if (kmap_op->handle == -1) |
0930bba6 SS |
1141 | xen_mc_flush(); |
1142 | /* | |
2fc136ee | 1143 | * Now if kmap_op->handle is negative it means that the |
0930bba6 SS |
1144 | * hypercall actually returned an error. |
1145 | */ | |
2fc136ee | 1146 | if (kmap_op->handle == GNTST_general_error) { |
0930bba6 SS |
1147 | printk(KERN_WARNING "m2p_remove_override: " |
1148 | "pfn %lx mfn %lx, failed to modify kernel mappings", | |
1149 | pfn, mfn); | |
d7f8f48d | 1150 | put_balloon_scratch_page(); |
0930bba6 SS |
1151 | return -1; |
1152 | } | |
1153 | ||
d7f8f48d BO |
1154 | xen_mc_batch(); |
1155 | ||
1156 | mcs = __xen_mc_entry( | |
ee072640 | 1157 | sizeof(struct gnttab_unmap_and_replace)); |
0930bba6 | 1158 | unmap_op = mcs.args; |
2fc136ee | 1159 | unmap_op->host_addr = kmap_op->host_addr; |
ee072640 | 1160 | unmap_op->new_addr = scratch_page_address; |
2fc136ee | 1161 | unmap_op->handle = kmap_op->handle; |
0930bba6 SS |
1162 | |
1163 | MULTI_grant_table_op(mcs.mc, | |
ee072640 | 1164 | GNTTABOP_unmap_and_replace, unmap_op, 1); |
0930bba6 | 1165 | |
ee072640 SS |
1166 | mcs = __xen_mc_entry(0); |
1167 | MULTI_update_va_mapping(mcs.mc, scratch_page_address, | |
d7f8f48d | 1168 | pfn_pte(page_to_pfn(scratch_page), |
ee072640 | 1169 | PAGE_KERNEL_RO), 0); |
d7f8f48d | 1170 | |
ee072640 SS |
1171 | xen_mc_issue(PARAVIRT_LAZY_MMU); |
1172 | ||
2fc136ee | 1173 | kmap_op->host_addr = 0; |
ee072640 | 1174 | put_balloon_scratch_page(); |
0930bba6 | 1175 | } |
2fc136ee | 1176 | } |
87f1d40a | 1177 | |
b9e0d95c SS |
1178 | /* p2m(m2p(mfn)) == FOREIGN_FRAME(mfn): the mfn is already present |
1179 | * somewhere in this domain, even before being added to the | |
1180 | * m2p_override (see comment above in m2p_add_override). | |
1181 | * If there are no other entries in the m2p_override corresponding | |
1182 | * to this mfn, then remove the FOREIGN_FRAME_BIT from the p2m for | |
1183 | * the original pfn (the one shared by the frontend): the backend | |
1184 | * cannot do any IO on this page anymore because it has been | |
1185 | * unshared. Removing the FOREIGN_FRAME_BIT from the p2m entry of | |
1186 | * the original pfn causes mfn_to_pfn(mfn) to return the frontend | |
1187 | * pfn again. */ | |
1188 | mfn &= ~FOREIGN_FRAME_BIT; | |
0160676b DV |
1189 | pfn = mfn_to_pfn_no_overrides(mfn); |
1190 | if (get_phys_to_machine(pfn) == FOREIGN_FRAME(mfn) && | |
b9e0d95c SS |
1191 | m2p_find_override(mfn) == NULL) |
1192 | set_phys_to_machine(pfn, mfn); | |
1193 | ||
87f1d40a | 1194 | return 0; |
448f2831 | 1195 | } |
8a91707d | 1196 | EXPORT_SYMBOL_GPL(m2p_remove_override); |
448f2831 JF |
1197 | |
1198 | struct page *m2p_find_override(unsigned long mfn) | |
1199 | { | |
1200 | unsigned long flags; | |
1201 | struct list_head *bucket = &m2p_overrides[mfn_hash(mfn)]; | |
1202 | struct page *p, *ret; | |
1203 | ||
1204 | ret = NULL; | |
1205 | ||
1206 | spin_lock_irqsave(&m2p_override_lock, flags); | |
1207 | ||
1208 | list_for_each_entry(p, bucket, lru) { | |
0f4b49ea | 1209 | if (page_private(p) == mfn) { |
448f2831 JF |
1210 | ret = p; |
1211 | break; | |
1212 | } | |
1213 | } | |
1214 | ||
1215 | spin_unlock_irqrestore(&m2p_override_lock, flags); | |
1216 | ||
1217 | return ret; | |
1218 | } | |
1219 | ||
1220 | unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn) | |
1221 | { | |
1222 | struct page *p = m2p_find_override(mfn); | |
1223 | unsigned long ret = pfn; | |
1224 | ||
1225 | if (p) | |
1226 | ret = page_to_pfn(p); | |
1227 | ||
1228 | return ret; | |
1229 | } | |
e1b478e4 | 1230 | EXPORT_SYMBOL_GPL(m2p_find_override_pfn); |
2222e71b KRW |
1231 | |
1232 | #ifdef CONFIG_XEN_DEBUG_FS | |
a867db10 KRW |
1233 | #include <linux/debugfs.h> |
1234 | #include "debugfs.h" | |
1235 | static int p2m_dump_show(struct seq_file *m, void *v) | |
2222e71b KRW |
1236 | { |
1237 | static const char * const level_name[] = { "top", "middle", | |
8404877e | 1238 | "entry", "abnormal", "error"}; |
2222e71b KRW |
1239 | #define TYPE_IDENTITY 0 |
1240 | #define TYPE_MISSING 1 | |
1241 | #define TYPE_PFN 2 | |
1242 | #define TYPE_UNKNOWN 3 | |
a491dbef KRW |
1243 | static const char * const type_name[] = { |
1244 | [TYPE_IDENTITY] = "identity", | |
1245 | [TYPE_MISSING] = "missing", | |
1246 | [TYPE_PFN] = "pfn", | |
1247 | [TYPE_UNKNOWN] = "abnormal"}; | |
2222e71b KRW |
1248 | unsigned long pfn, prev_pfn_type = 0, prev_pfn_level = 0; |
1249 | unsigned int uninitialized_var(prev_level); | |
1250 | unsigned int uninitialized_var(prev_type); | |
1251 | ||
1252 | if (!p2m_top) | |
1253 | return 0; | |
1254 | ||
1255 | for (pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn++) { | |
1256 | unsigned topidx = p2m_top_index(pfn); | |
1257 | unsigned mididx = p2m_mid_index(pfn); | |
1258 | unsigned idx = p2m_index(pfn); | |
1259 | unsigned lvl, type; | |
1260 | ||
1261 | lvl = 4; | |
1262 | type = TYPE_UNKNOWN; | |
1263 | if (p2m_top[topidx] == p2m_mid_missing) { | |
1264 | lvl = 0; type = TYPE_MISSING; | |
1265 | } else if (p2m_top[topidx] == NULL) { | |
1266 | lvl = 0; type = TYPE_UNKNOWN; | |
1267 | } else if (p2m_top[topidx][mididx] == NULL) { | |
1268 | lvl = 1; type = TYPE_UNKNOWN; | |
1269 | } else if (p2m_top[topidx][mididx] == p2m_identity) { | |
1270 | lvl = 1; type = TYPE_IDENTITY; | |
1271 | } else if (p2m_top[topidx][mididx] == p2m_missing) { | |
1272 | lvl = 1; type = TYPE_MISSING; | |
1273 | } else if (p2m_top[topidx][mididx][idx] == 0) { | |
1274 | lvl = 2; type = TYPE_UNKNOWN; | |
1275 | } else if (p2m_top[topidx][mididx][idx] == IDENTITY_FRAME(pfn)) { | |
1276 | lvl = 2; type = TYPE_IDENTITY; | |
1277 | } else if (p2m_top[topidx][mididx][idx] == INVALID_P2M_ENTRY) { | |
1278 | lvl = 2; type = TYPE_MISSING; | |
1279 | } else if (p2m_top[topidx][mididx][idx] == pfn) { | |
1280 | lvl = 2; type = TYPE_PFN; | |
1281 | } else if (p2m_top[topidx][mididx][idx] != pfn) { | |
1282 | lvl = 2; type = TYPE_PFN; | |
1283 | } | |
1284 | if (pfn == 0) { | |
1285 | prev_level = lvl; | |
1286 | prev_type = type; | |
1287 | } | |
1288 | if (pfn == MAX_DOMAIN_PAGES-1) { | |
1289 | lvl = 3; | |
1290 | type = TYPE_UNKNOWN; | |
1291 | } | |
1292 | if (prev_type != type) { | |
1293 | seq_printf(m, " [0x%lx->0x%lx] %s\n", | |
1294 | prev_pfn_type, pfn, type_name[prev_type]); | |
1295 | prev_pfn_type = pfn; | |
1296 | prev_type = type; | |
1297 | } | |
1298 | if (prev_level != lvl) { | |
1299 | seq_printf(m, " [0x%lx->0x%lx] level %s\n", | |
1300 | prev_pfn_level, pfn, level_name[prev_level]); | |
1301 | prev_pfn_level = pfn; | |
1302 | prev_level = lvl; | |
1303 | } | |
1304 | } | |
1305 | return 0; | |
1306 | #undef TYPE_IDENTITY | |
1307 | #undef TYPE_MISSING | |
1308 | #undef TYPE_PFN | |
1309 | #undef TYPE_UNKNOWN | |
1310 | } | |
a867db10 KRW |
1311 | |
1312 | static int p2m_dump_open(struct inode *inode, struct file *filp) | |
1313 | { | |
1314 | return single_open(filp, p2m_dump_show, NULL); | |
1315 | } | |
1316 | ||
1317 | static const struct file_operations p2m_dump_fops = { | |
1318 | .open = p2m_dump_open, | |
1319 | .read = seq_read, | |
1320 | .llseek = seq_lseek, | |
1321 | .release = single_release, | |
1322 | }; | |
1323 | ||
1324 | static struct dentry *d_mmu_debug; | |
1325 | ||
1326 | static int __init xen_p2m_debugfs(void) | |
1327 | { | |
1328 | struct dentry *d_xen = xen_init_debugfs(); | |
1329 | ||
1330 | if (d_xen == NULL) | |
1331 | return -ENOMEM; | |
1332 | ||
1333 | d_mmu_debug = debugfs_create_dir("mmu", d_xen); | |
1334 | ||
1335 | debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops); | |
1336 | return 0; | |
1337 | } | |
1338 | fs_initcall(xen_p2m_debugfs); | |
1339 | #endif /* CONFIG_XEN_DEBUG_FS */ |