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b097186f KRW |
1 | /* |
2 | * Copyright 2010 | |
3 | * by Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | |
4 | * | |
5 | * This code provides a IOMMU for Xen PV guests with PCI passthrough. | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License v2.0 as published by | |
9 | * the Free Software Foundation | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * PV guests under Xen are running in an non-contiguous memory architecture. | |
17 | * | |
18 | * When PCI pass-through is utilized, this necessitates an IOMMU for | |
19 | * translating bus (DMA) to virtual and vice-versa and also providing a | |
20 | * mechanism to have contiguous pages for device drivers operations (say DMA | |
21 | * operations). | |
22 | * | |
23 | * Specifically, under Xen the Linux idea of pages is an illusion. It | |
24 | * assumes that pages start at zero and go up to the available memory. To | |
25 | * help with that, the Linux Xen MMU provides a lookup mechanism to | |
26 | * translate the page frame numbers (PFN) to machine frame numbers (MFN) | |
27 | * and vice-versa. The MFN are the "real" frame numbers. Furthermore | |
28 | * memory is not contiguous. Xen hypervisor stitches memory for guests | |
29 | * from different pools, which means there is no guarantee that PFN==MFN | |
30 | * and PFN+1==MFN+1. Lastly with Xen 4.0, pages (in debug mode) are | |
31 | * allocated in descending order (high to low), meaning the guest might | |
32 | * never get any MFN's under the 4GB mark. | |
33 | * | |
34 | */ | |
35 | ||
36 | #include <linux/bootmem.h> | |
37 | #include <linux/dma-mapping.h> | |
38 | #include <xen/swiotlb-xen.h> | |
39 | #include <xen/page.h> | |
40 | #include <xen/xen-ops.h> | |
f4b2f07b | 41 | #include <xen/hvc-console.h> |
b097186f KRW |
42 | /* |
43 | * Used to do a quick range check in swiotlb_tbl_unmap_single and | |
44 | * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this | |
45 | * API. | |
46 | */ | |
47 | ||
48 | static char *xen_io_tlb_start, *xen_io_tlb_end; | |
49 | static unsigned long xen_io_tlb_nslabs; | |
50 | /* | |
51 | * Quick lookup value of the bus address of the IOTLB. | |
52 | */ | |
53 | ||
54 | u64 start_dma_addr; | |
55 | ||
56 | static dma_addr_t xen_phys_to_bus(phys_addr_t paddr) | |
57 | { | |
6eab04a8 | 58 | return phys_to_machine(XPADDR(paddr)).maddr; |
b097186f KRW |
59 | } |
60 | ||
61 | static phys_addr_t xen_bus_to_phys(dma_addr_t baddr) | |
62 | { | |
63 | return machine_to_phys(XMADDR(baddr)).paddr; | |
64 | } | |
65 | ||
66 | static dma_addr_t xen_virt_to_bus(void *address) | |
67 | { | |
68 | return xen_phys_to_bus(virt_to_phys(address)); | |
69 | } | |
70 | ||
71 | static int check_pages_physically_contiguous(unsigned long pfn, | |
72 | unsigned int offset, | |
73 | size_t length) | |
74 | { | |
75 | unsigned long next_mfn; | |
76 | int i; | |
77 | int nr_pages; | |
78 | ||
79 | next_mfn = pfn_to_mfn(pfn); | |
80 | nr_pages = (offset + length + PAGE_SIZE-1) >> PAGE_SHIFT; | |
81 | ||
82 | for (i = 1; i < nr_pages; i++) { | |
83 | if (pfn_to_mfn(++pfn) != ++next_mfn) | |
84 | return 0; | |
85 | } | |
86 | return 1; | |
87 | } | |
88 | ||
89 | static int range_straddles_page_boundary(phys_addr_t p, size_t size) | |
90 | { | |
91 | unsigned long pfn = PFN_DOWN(p); | |
92 | unsigned int offset = p & ~PAGE_MASK; | |
93 | ||
94 | if (offset + size <= PAGE_SIZE) | |
95 | return 0; | |
96 | if (check_pages_physically_contiguous(pfn, offset, size)) | |
97 | return 0; | |
98 | return 1; | |
99 | } | |
100 | ||
101 | static int is_xen_swiotlb_buffer(dma_addr_t dma_addr) | |
102 | { | |
103 | unsigned long mfn = PFN_DOWN(dma_addr); | |
104 | unsigned long pfn = mfn_to_local_pfn(mfn); | |
105 | phys_addr_t paddr; | |
106 | ||
107 | /* If the address is outside our domain, it CAN | |
108 | * have the same virtual address as another address | |
109 | * in our domain. Therefore _only_ check address within our domain. | |
110 | */ | |
111 | if (pfn_valid(pfn)) { | |
112 | paddr = PFN_PHYS(pfn); | |
113 | return paddr >= virt_to_phys(xen_io_tlb_start) && | |
114 | paddr < virt_to_phys(xen_io_tlb_end); | |
115 | } | |
116 | return 0; | |
117 | } | |
118 | ||
119 | static int max_dma_bits = 32; | |
120 | ||
121 | static int | |
122 | xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs) | |
123 | { | |
124 | int i, rc; | |
125 | int dma_bits; | |
126 | ||
127 | dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT; | |
128 | ||
129 | i = 0; | |
130 | do { | |
131 | int slabs = min(nslabs - i, (unsigned long)IO_TLB_SEGSIZE); | |
132 | ||
133 | do { | |
134 | rc = xen_create_contiguous_region( | |
135 | (unsigned long)buf + (i << IO_TLB_SHIFT), | |
136 | get_order(slabs << IO_TLB_SHIFT), | |
137 | dma_bits); | |
138 | } while (rc && dma_bits++ < max_dma_bits); | |
139 | if (rc) | |
140 | return rc; | |
141 | ||
142 | i += slabs; | |
143 | } while (i < nslabs); | |
144 | return 0; | |
145 | } | |
146 | ||
147 | void __init xen_swiotlb_init(int verbose) | |
148 | { | |
149 | unsigned long bytes; | |
f4b2f07b | 150 | int rc = -ENOMEM; |
5f98ecdb | 151 | unsigned long nr_tbl; |
f4b2f07b KRW |
152 | char *m = NULL; |
153 | unsigned int repeat = 3; | |
5f98ecdb FT |
154 | |
155 | nr_tbl = swioltb_nr_tbl(); | |
156 | if (nr_tbl) | |
157 | xen_io_tlb_nslabs = nr_tbl; | |
158 | else { | |
159 | xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT); | |
160 | xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE); | |
161 | } | |
f4b2f07b | 162 | retry: |
b097186f KRW |
163 | bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT; |
164 | ||
165 | /* | |
166 | * Get IO TLB memory from any location. | |
167 | */ | |
168 | xen_io_tlb_start = alloc_bootmem(bytes); | |
f4b2f07b KRW |
169 | if (!xen_io_tlb_start) { |
170 | m = "Cannot allocate Xen-SWIOTLB buffer!\n"; | |
171 | goto error; | |
172 | } | |
b097186f KRW |
173 | xen_io_tlb_end = xen_io_tlb_start + bytes; |
174 | /* | |
175 | * And replace that memory with pages under 4GB. | |
176 | */ | |
177 | rc = xen_swiotlb_fixup(xen_io_tlb_start, | |
178 | bytes, | |
179 | xen_io_tlb_nslabs); | |
f4b2f07b KRW |
180 | if (rc) { |
181 | free_bootmem(__pa(xen_io_tlb_start), bytes); | |
182 | m = "Failed to get contiguous memory for DMA from Xen!\n"\ | |
183 | "You either: don't have the permissions, do not have"\ | |
184 | " enough free memory under 4GB, or the hypervisor memory"\ | |
185 | "is too fragmented!"; | |
b097186f | 186 | goto error; |
f4b2f07b | 187 | } |
b097186f KRW |
188 | start_dma_addr = xen_virt_to_bus(xen_io_tlb_start); |
189 | swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs, verbose); | |
190 | ||
191 | return; | |
192 | error: | |
f4b2f07b KRW |
193 | if (repeat--) { |
194 | xen_io_tlb_nslabs = max(1024UL, /* Min is 2MB */ | |
195 | (xen_io_tlb_nslabs >> 1)); | |
196 | printk(KERN_INFO "Xen-SWIOTLB: Lowering to %luMB\n", | |
197 | (xen_io_tlb_nslabs << IO_TLB_SHIFT) >> 20); | |
198 | goto retry; | |
199 | } | |
200 | xen_raw_printk("%s (rc:%d)", rc, m); | |
201 | panic("%s (rc:%d)", rc, m); | |
b097186f KRW |
202 | } |
203 | ||
204 | void * | |
205 | xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size, | |
206 | dma_addr_t *dma_handle, gfp_t flags) | |
207 | { | |
208 | void *ret; | |
209 | int order = get_order(size); | |
210 | u64 dma_mask = DMA_BIT_MASK(32); | |
211 | unsigned long vstart; | |
212 | ||
213 | /* | |
214 | * Ignore region specifiers - the kernel's ideas of | |
215 | * pseudo-phys memory layout has nothing to do with the | |
216 | * machine physical layout. We can't allocate highmem | |
217 | * because we can't return a pointer to it. | |
218 | */ | |
219 | flags &= ~(__GFP_DMA | __GFP_HIGHMEM); | |
220 | ||
221 | if (dma_alloc_from_coherent(hwdev, size, dma_handle, &ret)) | |
222 | return ret; | |
223 | ||
224 | vstart = __get_free_pages(flags, order); | |
225 | ret = (void *)vstart; | |
226 | ||
227 | if (hwdev && hwdev->coherent_dma_mask) | |
228 | dma_mask = dma_alloc_coherent_mask(hwdev, flags); | |
229 | ||
230 | if (ret) { | |
231 | if (xen_create_contiguous_region(vstart, order, | |
232 | fls64(dma_mask)) != 0) { | |
233 | free_pages(vstart, order); | |
234 | return NULL; | |
235 | } | |
236 | memset(ret, 0, size); | |
237 | *dma_handle = virt_to_machine(ret).maddr; | |
238 | } | |
239 | return ret; | |
240 | } | |
241 | EXPORT_SYMBOL_GPL(xen_swiotlb_alloc_coherent); | |
242 | ||
243 | void | |
244 | xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr, | |
245 | dma_addr_t dev_addr) | |
246 | { | |
247 | int order = get_order(size); | |
248 | ||
249 | if (dma_release_from_coherent(hwdev, order, vaddr)) | |
250 | return; | |
251 | ||
252 | xen_destroy_contiguous_region((unsigned long)vaddr, order); | |
253 | free_pages((unsigned long)vaddr, order); | |
254 | } | |
255 | EXPORT_SYMBOL_GPL(xen_swiotlb_free_coherent); | |
256 | ||
257 | ||
258 | /* | |
259 | * Map a single buffer of the indicated size for DMA in streaming mode. The | |
260 | * physical address to use is returned. | |
261 | * | |
262 | * Once the device is given the dma address, the device owns this memory until | |
263 | * either xen_swiotlb_unmap_page or xen_swiotlb_dma_sync_single is performed. | |
264 | */ | |
265 | dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, | |
266 | unsigned long offset, size_t size, | |
267 | enum dma_data_direction dir, | |
268 | struct dma_attrs *attrs) | |
269 | { | |
270 | phys_addr_t phys = page_to_phys(page) + offset; | |
271 | dma_addr_t dev_addr = xen_phys_to_bus(phys); | |
272 | void *map; | |
273 | ||
274 | BUG_ON(dir == DMA_NONE); | |
275 | /* | |
276 | * If the address happens to be in the device's DMA window, | |
277 | * we can safely return the device addr and not worry about bounce | |
278 | * buffering it. | |
279 | */ | |
280 | if (dma_capable(dev, dev_addr, size) && | |
281 | !range_straddles_page_boundary(phys, size) && !swiotlb_force) | |
282 | return dev_addr; | |
283 | ||
284 | /* | |
285 | * Oh well, have to allocate and map a bounce buffer. | |
286 | */ | |
287 | map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir); | |
288 | if (!map) | |
289 | return DMA_ERROR_CODE; | |
290 | ||
291 | dev_addr = xen_virt_to_bus(map); | |
292 | ||
293 | /* | |
294 | * Ensure that the address returned is DMA'ble | |
295 | */ | |
ab2a47bd KRW |
296 | if (!dma_capable(dev, dev_addr, size)) { |
297 | swiotlb_tbl_unmap_single(dev, map, size, dir); | |
298 | dev_addr = 0; | |
299 | } | |
b097186f KRW |
300 | return dev_addr; |
301 | } | |
302 | EXPORT_SYMBOL_GPL(xen_swiotlb_map_page); | |
303 | ||
304 | /* | |
305 | * Unmap a single streaming mode DMA translation. The dma_addr and size must | |
306 | * match what was provided for in a previous xen_swiotlb_map_page call. All | |
307 | * other usages are undefined. | |
308 | * | |
309 | * After this call, reads by the cpu to the buffer are guaranteed to see | |
310 | * whatever the device wrote there. | |
311 | */ | |
312 | static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr, | |
313 | size_t size, enum dma_data_direction dir) | |
314 | { | |
315 | phys_addr_t paddr = xen_bus_to_phys(dev_addr); | |
316 | ||
317 | BUG_ON(dir == DMA_NONE); | |
318 | ||
319 | /* NOTE: We use dev_addr here, not paddr! */ | |
320 | if (is_xen_swiotlb_buffer(dev_addr)) { | |
321 | swiotlb_tbl_unmap_single(hwdev, phys_to_virt(paddr), size, dir); | |
322 | return; | |
323 | } | |
324 | ||
325 | if (dir != DMA_FROM_DEVICE) | |
326 | return; | |
327 | ||
328 | /* | |
329 | * phys_to_virt doesn't work with hihgmem page but we could | |
330 | * call dma_mark_clean() with hihgmem page here. However, we | |
331 | * are fine since dma_mark_clean() is null on POWERPC. We can | |
332 | * make dma_mark_clean() take a physical address if necessary. | |
333 | */ | |
334 | dma_mark_clean(phys_to_virt(paddr), size); | |
335 | } | |
336 | ||
337 | void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, | |
338 | size_t size, enum dma_data_direction dir, | |
339 | struct dma_attrs *attrs) | |
340 | { | |
341 | xen_unmap_single(hwdev, dev_addr, size, dir); | |
342 | } | |
343 | EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_page); | |
344 | ||
345 | /* | |
346 | * Make physical memory consistent for a single streaming mode DMA translation | |
347 | * after a transfer. | |
348 | * | |
349 | * If you perform a xen_swiotlb_map_page() but wish to interrogate the buffer | |
350 | * using the cpu, yet do not wish to teardown the dma mapping, you must | |
351 | * call this function before doing so. At the next point you give the dma | |
352 | * address back to the card, you must first perform a | |
353 | * xen_swiotlb_dma_sync_for_device, and then the device again owns the buffer | |
354 | */ | |
355 | static void | |
356 | xen_swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr, | |
357 | size_t size, enum dma_data_direction dir, | |
358 | enum dma_sync_target target) | |
359 | { | |
360 | phys_addr_t paddr = xen_bus_to_phys(dev_addr); | |
361 | ||
362 | BUG_ON(dir == DMA_NONE); | |
363 | ||
364 | /* NOTE: We use dev_addr here, not paddr! */ | |
365 | if (is_xen_swiotlb_buffer(dev_addr)) { | |
366 | swiotlb_tbl_sync_single(hwdev, phys_to_virt(paddr), size, dir, | |
367 | target); | |
368 | return; | |
369 | } | |
370 | ||
371 | if (dir != DMA_FROM_DEVICE) | |
372 | return; | |
373 | ||
374 | dma_mark_clean(phys_to_virt(paddr), size); | |
375 | } | |
376 | ||
377 | void | |
378 | xen_swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr, | |
379 | size_t size, enum dma_data_direction dir) | |
380 | { | |
381 | xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU); | |
382 | } | |
383 | EXPORT_SYMBOL_GPL(xen_swiotlb_sync_single_for_cpu); | |
384 | ||
385 | void | |
386 | xen_swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr, | |
387 | size_t size, enum dma_data_direction dir) | |
388 | { | |
389 | xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE); | |
390 | } | |
391 | EXPORT_SYMBOL_GPL(xen_swiotlb_sync_single_for_device); | |
392 | ||
393 | /* | |
394 | * Map a set of buffers described by scatterlist in streaming mode for DMA. | |
395 | * This is the scatter-gather version of the above xen_swiotlb_map_page | |
396 | * interface. Here the scatter gather list elements are each tagged with the | |
397 | * appropriate dma address and length. They are obtained via | |
398 | * sg_dma_{address,length}(SG). | |
399 | * | |
400 | * NOTE: An implementation may be able to use a smaller number of | |
401 | * DMA address/length pairs than there are SG table elements. | |
402 | * (for example via virtual mapping capabilities) | |
403 | * The routine returns the number of addr/length pairs actually | |
404 | * used, at most nents. | |
405 | * | |
406 | * Device ownership issues as mentioned above for xen_swiotlb_map_page are the | |
407 | * same here. | |
408 | */ | |
409 | int | |
410 | xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, | |
411 | int nelems, enum dma_data_direction dir, | |
412 | struct dma_attrs *attrs) | |
413 | { | |
414 | struct scatterlist *sg; | |
415 | int i; | |
416 | ||
417 | BUG_ON(dir == DMA_NONE); | |
418 | ||
419 | for_each_sg(sgl, sg, nelems, i) { | |
420 | phys_addr_t paddr = sg_phys(sg); | |
421 | dma_addr_t dev_addr = xen_phys_to_bus(paddr); | |
422 | ||
423 | if (swiotlb_force || | |
424 | !dma_capable(hwdev, dev_addr, sg->length) || | |
425 | range_straddles_page_boundary(paddr, sg->length)) { | |
426 | void *map = swiotlb_tbl_map_single(hwdev, | |
427 | start_dma_addr, | |
428 | sg_phys(sg), | |
429 | sg->length, dir); | |
430 | if (!map) { | |
431 | /* Don't panic here, we expect map_sg users | |
432 | to do proper error handling. */ | |
433 | xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir, | |
434 | attrs); | |
435 | sgl[0].dma_length = 0; | |
436 | return DMA_ERROR_CODE; | |
437 | } | |
438 | sg->dma_address = xen_virt_to_bus(map); | |
439 | } else | |
440 | sg->dma_address = dev_addr; | |
441 | sg->dma_length = sg->length; | |
442 | } | |
443 | return nelems; | |
444 | } | |
445 | EXPORT_SYMBOL_GPL(xen_swiotlb_map_sg_attrs); | |
446 | ||
447 | int | |
448 | xen_swiotlb_map_sg(struct device *hwdev, struct scatterlist *sgl, int nelems, | |
449 | enum dma_data_direction dir) | |
450 | { | |
451 | return xen_swiotlb_map_sg_attrs(hwdev, sgl, nelems, dir, NULL); | |
452 | } | |
453 | EXPORT_SYMBOL_GPL(xen_swiotlb_map_sg); | |
454 | ||
455 | /* | |
456 | * Unmap a set of streaming mode DMA translations. Again, cpu read rules | |
457 | * concerning calls here are the same as for swiotlb_unmap_page() above. | |
458 | */ | |
459 | void | |
460 | xen_swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl, | |
461 | int nelems, enum dma_data_direction dir, | |
462 | struct dma_attrs *attrs) | |
463 | { | |
464 | struct scatterlist *sg; | |
465 | int i; | |
466 | ||
467 | BUG_ON(dir == DMA_NONE); | |
468 | ||
469 | for_each_sg(sgl, sg, nelems, i) | |
470 | xen_unmap_single(hwdev, sg->dma_address, sg->dma_length, dir); | |
471 | ||
472 | } | |
473 | EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_sg_attrs); | |
474 | ||
475 | void | |
476 | xen_swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems, | |
477 | enum dma_data_direction dir) | |
478 | { | |
479 | return xen_swiotlb_unmap_sg_attrs(hwdev, sgl, nelems, dir, NULL); | |
480 | } | |
481 | EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_sg); | |
482 | ||
483 | /* | |
484 | * Make physical memory consistent for a set of streaming mode DMA translations | |
485 | * after a transfer. | |
486 | * | |
487 | * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules | |
488 | * and usage. | |
489 | */ | |
490 | static void | |
491 | xen_swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl, | |
492 | int nelems, enum dma_data_direction dir, | |
493 | enum dma_sync_target target) | |
494 | { | |
495 | struct scatterlist *sg; | |
496 | int i; | |
497 | ||
498 | for_each_sg(sgl, sg, nelems, i) | |
499 | xen_swiotlb_sync_single(hwdev, sg->dma_address, | |
500 | sg->dma_length, dir, target); | |
501 | } | |
502 | ||
503 | void | |
504 | xen_swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg, | |
505 | int nelems, enum dma_data_direction dir) | |
506 | { | |
507 | xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU); | |
508 | } | |
509 | EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_cpu); | |
510 | ||
511 | void | |
512 | xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg, | |
513 | int nelems, enum dma_data_direction dir) | |
514 | { | |
515 | xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE); | |
516 | } | |
517 | EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_device); | |
518 | ||
519 | int | |
520 | xen_swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr) | |
521 | { | |
522 | return !dma_addr; | |
523 | } | |
524 | EXPORT_SYMBOL_GPL(xen_swiotlb_dma_mapping_error); | |
525 | ||
526 | /* | |
527 | * Return whether the given device DMA address mask can be supported | |
528 | * properly. For example, if your device can only drive the low 24-bits | |
529 | * during bus mastering, then you would pass 0x00ffffff as the mask to | |
530 | * this function. | |
531 | */ | |
532 | int | |
533 | xen_swiotlb_dma_supported(struct device *hwdev, u64 mask) | |
534 | { | |
535 | return xen_virt_to_bus(xen_io_tlb_end - 1) <= mask; | |
536 | } | |
537 | EXPORT_SYMBOL_GPL(xen_swiotlb_dma_supported); |