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 | #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt |
37 | |
38 | #include <linux/memblock.h> |
39 | #include <linux/dma-direct.h> |
40 | #include <linux/export.h> |
41 | #include <xen/swiotlb-xen.h> |
42 | #include <xen/page.h> |
43 | #include <xen/xen-ops.h> |
44 | #include <xen/hvc-console.h> |
45 | |
46 | #include <asm/dma-mapping.h> |
47 | #include <asm/xen/page-coherent.h> |
48 | |
49 | #include <trace/events/swiotlb.h> |
50 | /* |
51 | * Used to do a quick range check in swiotlb_tbl_unmap_single and |
52 | * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this |
53 | * API. |
54 | */ |
55 | |
56 | static char *xen_io_tlb_start, *xen_io_tlb_end; |
57 | static unsigned long xen_io_tlb_nslabs; |
58 | /* |
59 | * Quick lookup value of the bus address of the IOTLB. |
60 | */ |
61 | |
62 | static u64 start_dma_addr; |
63 | |
64 | /* |
65 | * Both of these functions should avoid XEN_PFN_PHYS because phys_addr_t |
66 | * can be 32bit when dma_addr_t is 64bit leading to a loss in |
67 | * information if the shift is done before casting to 64bit. |
68 | */ |
69 | static inline dma_addr_t xen_phys_to_bus(phys_addr_t paddr) |
70 | { |
71 | unsigned long bfn = pfn_to_bfn(XEN_PFN_DOWN(paddr)); |
72 | dma_addr_t dma = (dma_addr_t)bfn << XEN_PAGE_SHIFT; |
73 | |
74 | dma |= paddr & ~XEN_PAGE_MASK; |
75 | |
76 | return dma; |
77 | } |
78 | |
79 | static inline phys_addr_t xen_bus_to_phys(dma_addr_t baddr) |
80 | { |
81 | unsigned long xen_pfn = bfn_to_pfn(XEN_PFN_DOWN(baddr)); |
82 | dma_addr_t dma = (dma_addr_t)xen_pfn << XEN_PAGE_SHIFT; |
83 | phys_addr_t paddr = dma; |
84 | |
85 | paddr |= baddr & ~XEN_PAGE_MASK; |
86 | |
87 | return paddr; |
88 | } |
89 | |
90 | static inline dma_addr_t xen_virt_to_bus(void *address) |
91 | { |
92 | return xen_phys_to_bus(virt_to_phys(address)); |
93 | } |
94 | |
95 | static int check_pages_physically_contiguous(unsigned long xen_pfn, |
96 | unsigned int offset, |
97 | size_t length) |
98 | { |
99 | unsigned long next_bfn; |
100 | int i; |
101 | int nr_pages; |
102 | |
103 | next_bfn = pfn_to_bfn(xen_pfn); |
104 | nr_pages = (offset + length + XEN_PAGE_SIZE-1) >> XEN_PAGE_SHIFT; |
105 | |
106 | for (i = 1; i < nr_pages; i++) { |
107 | if (pfn_to_bfn(++xen_pfn) != ++next_bfn) |
108 | return 0; |
109 | } |
110 | return 1; |
111 | } |
112 | |
113 | static inline int range_straddles_page_boundary(phys_addr_t p, size_t size) |
114 | { |
115 | unsigned long xen_pfn = XEN_PFN_DOWN(p); |
116 | unsigned int offset = p & ~XEN_PAGE_MASK; |
117 | |
118 | if (offset + size <= XEN_PAGE_SIZE) |
119 | return 0; |
120 | if (check_pages_physically_contiguous(xen_pfn, offset, size)) |
121 | return 0; |
122 | return 1; |
123 | } |
124 | |
125 | static int is_xen_swiotlb_buffer(dma_addr_t dma_addr) |
126 | { |
127 | unsigned long bfn = XEN_PFN_DOWN(dma_addr); |
128 | unsigned long xen_pfn = bfn_to_local_pfn(bfn); |
129 | phys_addr_t paddr = XEN_PFN_PHYS(xen_pfn); |
130 | |
131 | /* If the address is outside our domain, it CAN |
132 | * have the same virtual address as another address |
133 | * in our domain. Therefore _only_ check address within our domain. |
134 | */ |
135 | if (pfn_valid(PFN_DOWN(paddr))) { |
136 | return paddr >= virt_to_phys(xen_io_tlb_start) && |
137 | paddr < virt_to_phys(xen_io_tlb_end); |
138 | } |
139 | return 0; |
140 | } |
141 | |
142 | static int max_dma_bits = 32; |
143 | |
144 | static int |
145 | xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs) |
146 | { |
147 | int i, rc; |
148 | int dma_bits; |
149 | dma_addr_t dma_handle; |
150 | phys_addr_t p = virt_to_phys(buf); |
151 | |
152 | dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT; |
153 | |
154 | i = 0; |
155 | do { |
156 | int slabs = min(nslabs - i, (unsigned long)IO_TLB_SEGSIZE); |
157 | |
158 | do { |
159 | rc = xen_create_contiguous_region( |
160 | p + (i << IO_TLB_SHIFT), |
161 | get_order(slabs << IO_TLB_SHIFT), |
162 | dma_bits, &dma_handle); |
163 | } while (rc && dma_bits++ < max_dma_bits); |
164 | if (rc) |
165 | return rc; |
166 | |
167 | i += slabs; |
168 | } while (i < nslabs); |
169 | return 0; |
170 | } |
171 | static unsigned long xen_set_nslabs(unsigned long nr_tbl) |
172 | { |
173 | if (!nr_tbl) { |
174 | xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT); |
175 | xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE); |
176 | } else |
177 | xen_io_tlb_nslabs = nr_tbl; |
178 | |
179 | return xen_io_tlb_nslabs << IO_TLB_SHIFT; |
180 | } |
181 | |
182 | enum xen_swiotlb_err { |
183 | XEN_SWIOTLB_UNKNOWN = 0, |
184 | XEN_SWIOTLB_ENOMEM, |
185 | XEN_SWIOTLB_EFIXUP |
186 | }; |
187 | |
188 | static const char *xen_swiotlb_error(enum xen_swiotlb_err err) |
189 | { |
190 | switch (err) { |
191 | case XEN_SWIOTLB_ENOMEM: |
192 | return "Cannot allocate Xen-SWIOTLB buffer\n" ; |
193 | case XEN_SWIOTLB_EFIXUP: |
194 | return "Failed to get contiguous memory for DMA from Xen!\n" \ |
195 | "You either: don't have the permissions, do not have" \ |
196 | " enough free memory under 4GB, or the hypervisor memory" \ |
197 | " is too fragmented!" ; |
198 | default: |
199 | break; |
200 | } |
201 | return "" ; |
202 | } |
203 | int __ref xen_swiotlb_init(int verbose, bool early) |
204 | { |
205 | unsigned long bytes, order; |
206 | int rc = -ENOMEM; |
207 | enum xen_swiotlb_err m_ret = XEN_SWIOTLB_UNKNOWN; |
208 | unsigned int repeat = 3; |
209 | |
210 | xen_io_tlb_nslabs = swiotlb_nr_tbl(); |
211 | retry: |
212 | bytes = xen_set_nslabs(xen_io_tlb_nslabs); |
213 | order = get_order(xen_io_tlb_nslabs << IO_TLB_SHIFT); |
214 | /* |
215 | * Get IO TLB memory from any location. |
216 | */ |
217 | if (early) { |
218 | xen_io_tlb_start = memblock_alloc(PAGE_ALIGN(bytes), |
219 | PAGE_SIZE); |
220 | if (!xen_io_tlb_start) |
221 | panic("%s: Failed to allocate %lu bytes align=0x%lx\n" , |
222 | __func__, PAGE_ALIGN(bytes), PAGE_SIZE); |
223 | } else { |
224 | #define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT)) |
225 | #define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT) |
226 | while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) { |
227 | xen_io_tlb_start = (void *)xen_get_swiotlb_free_pages(order); |
228 | if (xen_io_tlb_start) |
229 | break; |
230 | order--; |
231 | } |
232 | if (order != get_order(bytes)) { |
233 | pr_warn("Warning: only able to allocate %ld MB for software IO TLB\n" , |
234 | (PAGE_SIZE << order) >> 20); |
235 | xen_io_tlb_nslabs = SLABS_PER_PAGE << order; |
236 | bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT; |
237 | } |
238 | } |
239 | if (!xen_io_tlb_start) { |
240 | m_ret = XEN_SWIOTLB_ENOMEM; |
241 | goto error; |
242 | } |
243 | xen_io_tlb_end = xen_io_tlb_start + bytes; |
244 | /* |
245 | * And replace that memory with pages under 4GB. |
246 | */ |
247 | rc = xen_swiotlb_fixup(xen_io_tlb_start, |
248 | bytes, |
249 | xen_io_tlb_nslabs); |
250 | if (rc) { |
251 | if (early) |
252 | memblock_free(__pa(xen_io_tlb_start), |
253 | PAGE_ALIGN(bytes)); |
254 | else { |
255 | free_pages((unsigned long)xen_io_tlb_start, order); |
256 | xen_io_tlb_start = NULL; |
257 | } |
258 | m_ret = XEN_SWIOTLB_EFIXUP; |
259 | goto error; |
260 | } |
261 | start_dma_addr = xen_virt_to_bus(xen_io_tlb_start); |
262 | if (early) { |
263 | if (swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs, |
264 | verbose)) |
265 | panic("Cannot allocate SWIOTLB buffer" ); |
266 | rc = 0; |
267 | } else |
268 | rc = swiotlb_late_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs); |
269 | |
270 | if (!rc) |
271 | swiotlb_set_max_segment(PAGE_SIZE); |
272 | |
273 | return rc; |
274 | error: |
275 | if (repeat--) { |
276 | xen_io_tlb_nslabs = max(1024UL, /* Min is 2MB */ |
277 | (xen_io_tlb_nslabs >> 1)); |
278 | pr_info("Lowering to %luMB\n" , |
279 | (xen_io_tlb_nslabs << IO_TLB_SHIFT) >> 20); |
280 | goto retry; |
281 | } |
282 | pr_err("%s (rc:%d)\n" , xen_swiotlb_error(m_ret), rc); |
283 | if (early) |
284 | panic("%s (rc:%d)" , xen_swiotlb_error(m_ret), rc); |
285 | else |
286 | free_pages((unsigned long)xen_io_tlb_start, order); |
287 | return rc; |
288 | } |
289 | |
290 | static void * |
291 | xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size, |
292 | dma_addr_t *dma_handle, gfp_t flags, |
293 | unsigned long attrs) |
294 | { |
295 | void *ret; |
296 | int order = get_order(size); |
297 | u64 dma_mask = DMA_BIT_MASK(32); |
298 | phys_addr_t phys; |
299 | dma_addr_t dev_addr; |
300 | |
301 | /* |
302 | * Ignore region specifiers - the kernel's ideas of |
303 | * pseudo-phys memory layout has nothing to do with the |
304 | * machine physical layout. We can't allocate highmem |
305 | * because we can't return a pointer to it. |
306 | */ |
307 | flags &= ~(__GFP_DMA | __GFP_HIGHMEM); |
308 | |
309 | /* Convert the size to actually allocated. */ |
310 | size = 1UL << (order + XEN_PAGE_SHIFT); |
311 | |
312 | /* On ARM this function returns an ioremap'ped virtual address for |
313 | * which virt_to_phys doesn't return the corresponding physical |
314 | * address. In fact on ARM virt_to_phys only works for kernel direct |
315 | * mapped RAM memory. Also see comment below. |
316 | */ |
317 | ret = xen_alloc_coherent_pages(hwdev, size, dma_handle, flags, attrs); |
318 | |
319 | if (!ret) |
320 | return ret; |
321 | |
322 | if (hwdev && hwdev->coherent_dma_mask) |
323 | dma_mask = hwdev->coherent_dma_mask; |
324 | |
325 | /* At this point dma_handle is the physical address, next we are |
326 | * going to set it to the machine address. |
327 | * Do not use virt_to_phys(ret) because on ARM it doesn't correspond |
328 | * to *dma_handle. */ |
329 | phys = *dma_handle; |
330 | dev_addr = xen_phys_to_bus(phys); |
331 | if (((dev_addr + size - 1 <= dma_mask)) && |
332 | !range_straddles_page_boundary(phys, size)) |
333 | *dma_handle = dev_addr; |
334 | else { |
335 | if (xen_create_contiguous_region(phys, order, |
336 | fls64(dma_mask), dma_handle) != 0) { |
337 | xen_free_coherent_pages(hwdev, size, ret, (dma_addr_t)phys, attrs); |
338 | return NULL; |
339 | } |
340 | } |
341 | memset(ret, 0, size); |
342 | return ret; |
343 | } |
344 | |
345 | static void |
346 | xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr, |
347 | dma_addr_t dev_addr, unsigned long attrs) |
348 | { |
349 | int order = get_order(size); |
350 | phys_addr_t phys; |
351 | u64 dma_mask = DMA_BIT_MASK(32); |
352 | |
353 | if (hwdev && hwdev->coherent_dma_mask) |
354 | dma_mask = hwdev->coherent_dma_mask; |
355 | |
356 | /* do not use virt_to_phys because on ARM it doesn't return you the |
357 | * physical address */ |
358 | phys = xen_bus_to_phys(dev_addr); |
359 | |
360 | /* Convert the size to actually allocated. */ |
361 | size = 1UL << (order + XEN_PAGE_SHIFT); |
362 | |
363 | if (((dev_addr + size - 1 <= dma_mask)) || |
364 | range_straddles_page_boundary(phys, size)) |
365 | xen_destroy_contiguous_region(phys, order); |
366 | |
367 | xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs); |
368 | } |
369 | |
370 | /* |
371 | * Map a single buffer of the indicated size for DMA in streaming mode. The |
372 | * physical address to use is returned. |
373 | * |
374 | * Once the device is given the dma address, the device owns this memory until |
375 | * either xen_swiotlb_unmap_page or xen_swiotlb_dma_sync_single is performed. |
376 | */ |
377 | static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, |
378 | unsigned long offset, size_t size, |
379 | enum dma_data_direction dir, |
380 | unsigned long attrs) |
381 | { |
382 | phys_addr_t map, phys = page_to_phys(page) + offset; |
383 | dma_addr_t dev_addr = xen_phys_to_bus(phys); |
384 | |
385 | BUG_ON(dir == DMA_NONE); |
386 | /* |
387 | * If the address happens to be in the device's DMA window, |
388 | * we can safely return the device addr and not worry about bounce |
389 | * buffering it. |
390 | */ |
391 | if (dma_capable(dev, dev_addr, size) && |
392 | !range_straddles_page_boundary(phys, size) && |
393 | !xen_arch_need_swiotlb(dev, phys, dev_addr) && |
394 | (swiotlb_force != SWIOTLB_FORCE)) { |
395 | /* we are not interested in the dma_addr returned by |
396 | * xen_dma_map_page, only in the potential cache flushes executed |
397 | * by the function. */ |
398 | xen_dma_map_page(dev, page, dev_addr, offset, size, dir, attrs); |
399 | return dev_addr; |
400 | } |
401 | |
402 | /* |
403 | * Oh well, have to allocate and map a bounce buffer. |
404 | */ |
405 | trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force); |
406 | |
407 | map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir, |
408 | attrs); |
409 | if (map == DMA_MAPPING_ERROR) |
410 | return DMA_MAPPING_ERROR; |
411 | |
412 | dev_addr = xen_phys_to_bus(map); |
413 | xen_dma_map_page(dev, pfn_to_page(map >> PAGE_SHIFT), |
414 | dev_addr, map & ~PAGE_MASK, size, dir, attrs); |
415 | |
416 | /* |
417 | * Ensure that the address returned is DMA'ble |
418 | */ |
419 | if (dma_capable(dev, dev_addr, size)) |
420 | return dev_addr; |
421 | |
422 | attrs |= DMA_ATTR_SKIP_CPU_SYNC; |
423 | swiotlb_tbl_unmap_single(dev, map, size, dir, attrs); |
424 | |
425 | return DMA_MAPPING_ERROR; |
426 | } |
427 | |
428 | /* |
429 | * Unmap a single streaming mode DMA translation. The dma_addr and size must |
430 | * match what was provided for in a previous xen_swiotlb_map_page call. All |
431 | * other usages are undefined. |
432 | * |
433 | * After this call, reads by the cpu to the buffer are guaranteed to see |
434 | * whatever the device wrote there. |
435 | */ |
436 | static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr, |
437 | size_t size, enum dma_data_direction dir, |
438 | unsigned long attrs) |
439 | { |
440 | phys_addr_t paddr = xen_bus_to_phys(dev_addr); |
441 | |
442 | BUG_ON(dir == DMA_NONE); |
443 | |
444 | xen_dma_unmap_page(hwdev, dev_addr, size, dir, attrs); |
445 | |
446 | /* NOTE: We use dev_addr here, not paddr! */ |
447 | if (is_xen_swiotlb_buffer(dev_addr)) |
448 | swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs); |
449 | } |
450 | |
451 | static void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, |
452 | size_t size, enum dma_data_direction dir, |
453 | unsigned long attrs) |
454 | { |
455 | xen_unmap_single(hwdev, dev_addr, size, dir, attrs); |
456 | } |
457 | |
458 | /* |
459 | * Make physical memory consistent for a single streaming mode DMA translation |
460 | * after a transfer. |
461 | * |
462 | * If you perform a xen_swiotlb_map_page() but wish to interrogate the buffer |
463 | * using the cpu, yet do not wish to teardown the dma mapping, you must |
464 | * call this function before doing so. At the next point you give the dma |
465 | * address back to the card, you must first perform a |
466 | * xen_swiotlb_dma_sync_for_device, and then the device again owns the buffer |
467 | */ |
468 | static void |
469 | xen_swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr, |
470 | size_t size, enum dma_data_direction dir, |
471 | enum dma_sync_target target) |
472 | { |
473 | phys_addr_t paddr = xen_bus_to_phys(dev_addr); |
474 | |
475 | BUG_ON(dir == DMA_NONE); |
476 | |
477 | if (target == SYNC_FOR_CPU) |
478 | xen_dma_sync_single_for_cpu(hwdev, dev_addr, size, dir); |
479 | |
480 | /* NOTE: We use dev_addr here, not paddr! */ |
481 | if (is_xen_swiotlb_buffer(dev_addr)) |
482 | swiotlb_tbl_sync_single(hwdev, paddr, size, dir, target); |
483 | |
484 | if (target == SYNC_FOR_DEVICE) |
485 | xen_dma_sync_single_for_device(hwdev, dev_addr, size, dir); |
486 | } |
487 | |
488 | void |
489 | xen_swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr, |
490 | size_t size, enum dma_data_direction dir) |
491 | { |
492 | xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU); |
493 | } |
494 | |
495 | void |
496 | xen_swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr, |
497 | size_t size, enum dma_data_direction dir) |
498 | { |
499 | xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE); |
500 | } |
501 | |
502 | /* |
503 | * Unmap a set of streaming mode DMA translations. Again, cpu read rules |
504 | * concerning calls here are the same as for swiotlb_unmap_page() above. |
505 | */ |
506 | static void |
507 | xen_swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl, |
508 | int nelems, enum dma_data_direction dir, |
509 | unsigned long attrs) |
510 | { |
511 | struct scatterlist *sg; |
512 | int i; |
513 | |
514 | BUG_ON(dir == DMA_NONE); |
515 | |
516 | for_each_sg(sgl, sg, nelems, i) |
517 | xen_unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir, attrs); |
518 | |
519 | } |
520 | |
521 | /* |
522 | * Map a set of buffers described by scatterlist in streaming mode for DMA. |
523 | * This is the scatter-gather version of the above xen_swiotlb_map_page |
524 | * interface. Here the scatter gather list elements are each tagged with the |
525 | * appropriate dma address and length. They are obtained via |
526 | * sg_dma_{address,length}(SG). |
527 | * |
528 | * NOTE: An implementation may be able to use a smaller number of |
529 | * DMA address/length pairs than there are SG table elements. |
530 | * (for example via virtual mapping capabilities) |
531 | * The routine returns the number of addr/length pairs actually |
532 | * used, at most nents. |
533 | * |
534 | * Device ownership issues as mentioned above for xen_swiotlb_map_page are the |
535 | * same here. |
536 | */ |
537 | static int |
538 | xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, |
539 | int nelems, enum dma_data_direction dir, |
540 | unsigned long attrs) |
541 | { |
542 | struct scatterlist *sg; |
543 | int i; |
544 | |
545 | BUG_ON(dir == DMA_NONE); |
546 | |
547 | for_each_sg(sgl, sg, nelems, i) { |
548 | phys_addr_t paddr = sg_phys(sg); |
549 | dma_addr_t dev_addr = xen_phys_to_bus(paddr); |
550 | |
551 | if (swiotlb_force == SWIOTLB_FORCE || |
552 | xen_arch_need_swiotlb(hwdev, paddr, dev_addr) || |
553 | !dma_capable(hwdev, dev_addr, sg->length) || |
554 | range_straddles_page_boundary(paddr, sg->length)) { |
555 | phys_addr_t map = swiotlb_tbl_map_single(hwdev, |
556 | start_dma_addr, |
557 | sg_phys(sg), |
558 | sg->length, |
559 | dir, attrs); |
560 | if (map == DMA_MAPPING_ERROR) { |
561 | dev_warn(hwdev, "swiotlb buffer is full\n" ); |
562 | /* Don't panic here, we expect map_sg users |
563 | to do proper error handling. */ |
564 | attrs |= DMA_ATTR_SKIP_CPU_SYNC; |
565 | xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir, |
566 | attrs); |
567 | sg_dma_len(sgl) = 0; |
568 | return 0; |
569 | } |
570 | dev_addr = xen_phys_to_bus(map); |
571 | xen_dma_map_page(hwdev, pfn_to_page(map >> PAGE_SHIFT), |
572 | dev_addr, |
573 | map & ~PAGE_MASK, |
574 | sg->length, |
575 | dir, |
576 | attrs); |
577 | sg->dma_address = dev_addr; |
578 | } else { |
579 | /* we are not interested in the dma_addr returned by |
580 | * xen_dma_map_page, only in the potential cache flushes executed |
581 | * by the function. */ |
582 | xen_dma_map_page(hwdev, pfn_to_page(paddr >> PAGE_SHIFT), |
583 | dev_addr, |
584 | paddr & ~PAGE_MASK, |
585 | sg->length, |
586 | dir, |
587 | attrs); |
588 | sg->dma_address = dev_addr; |
589 | } |
590 | sg_dma_len(sg) = sg->length; |
591 | } |
592 | return nelems; |
593 | } |
594 | |
595 | /* |
596 | * Make physical memory consistent for a set of streaming mode DMA translations |
597 | * after a transfer. |
598 | * |
599 | * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules |
600 | * and usage. |
601 | */ |
602 | static void |
603 | xen_swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl, |
604 | int nelems, enum dma_data_direction dir, |
605 | enum dma_sync_target target) |
606 | { |
607 | struct scatterlist *sg; |
608 | int i; |
609 | |
610 | for_each_sg(sgl, sg, nelems, i) |
611 | xen_swiotlb_sync_single(hwdev, sg->dma_address, |
612 | sg_dma_len(sg), dir, target); |
613 | } |
614 | |
615 | static void |
616 | xen_swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg, |
617 | int nelems, enum dma_data_direction dir) |
618 | { |
619 | xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU); |
620 | } |
621 | |
622 | static void |
623 | xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg, |
624 | int nelems, enum dma_data_direction dir) |
625 | { |
626 | xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE); |
627 | } |
628 | |
629 | /* |
630 | * Return whether the given device DMA address mask can be supported |
631 | * properly. For example, if your device can only drive the low 24-bits |
632 | * during bus mastering, then you would pass 0x00ffffff as the mask to |
633 | * this function. |
634 | */ |
635 | static int |
636 | xen_swiotlb_dma_supported(struct device *hwdev, u64 mask) |
637 | { |
638 | return xen_virt_to_bus(xen_io_tlb_end - 1) <= mask; |
639 | } |
640 | |
641 | /* |
642 | * Create userspace mapping for the DMA-coherent memory. |
643 | * This function should be called with the pages from the current domain only, |
644 | * passing pages mapped from other domains would lead to memory corruption. |
645 | */ |
646 | static int |
647 | xen_swiotlb_dma_mmap(struct device *dev, struct vm_area_struct *vma, |
648 | void *cpu_addr, dma_addr_t dma_addr, size_t size, |
649 | unsigned long attrs) |
650 | { |
651 | #ifdef CONFIG_ARM |
652 | if (xen_get_dma_ops(dev)->mmap) |
653 | return xen_get_dma_ops(dev)->mmap(dev, vma, cpu_addr, |
654 | dma_addr, size, attrs); |
655 | #endif |
656 | return dma_common_mmap(dev, vma, cpu_addr, dma_addr, size, attrs); |
657 | } |
658 | |
659 | /* |
660 | * This function should be called with the pages from the current domain only, |
661 | * passing pages mapped from other domains would lead to memory corruption. |
662 | */ |
663 | static int |
664 | xen_swiotlb_get_sgtable(struct device *dev, struct sg_table *sgt, |
665 | void *cpu_addr, dma_addr_t handle, size_t size, |
666 | unsigned long attrs) |
667 | { |
668 | #ifdef CONFIG_ARM |
669 | if (xen_get_dma_ops(dev)->get_sgtable) { |
670 | #if 0 |
671 | /* |
672 | * This check verifies that the page belongs to the current domain and |
673 | * is not one mapped from another domain. |
674 | * This check is for debug only, and should not go to production build |
675 | */ |
676 | unsigned long bfn = PHYS_PFN(dma_to_phys(dev, handle)); |
677 | BUG_ON (!page_is_ram(bfn)); |
678 | #endif |
679 | return xen_get_dma_ops(dev)->get_sgtable(dev, sgt, cpu_addr, |
680 | handle, size, attrs); |
681 | } |
682 | #endif |
683 | return dma_common_get_sgtable(dev, sgt, cpu_addr, handle, size, attrs); |
684 | } |
685 | |
686 | const struct dma_map_ops xen_swiotlb_dma_ops = { |
687 | .alloc = xen_swiotlb_alloc_coherent, |
688 | .free = xen_swiotlb_free_coherent, |
689 | .sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu, |
690 | .sync_single_for_device = xen_swiotlb_sync_single_for_device, |
691 | .sync_sg_for_cpu = xen_swiotlb_sync_sg_for_cpu, |
692 | .sync_sg_for_device = xen_swiotlb_sync_sg_for_device, |
693 | .map_sg = xen_swiotlb_map_sg_attrs, |
694 | .unmap_sg = xen_swiotlb_unmap_sg_attrs, |
695 | .map_page = xen_swiotlb_map_page, |
696 | .unmap_page = xen_swiotlb_unmap_page, |
697 | .dma_supported = xen_swiotlb_dma_supported, |
698 | .mmap = xen_swiotlb_dma_mmap, |
699 | .get_sgtable = xen_swiotlb_get_sgtable, |
700 | }; |
701 | |