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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>
41/*
42 * Used to do a quick range check in swiotlb_tbl_unmap_single and
43 * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
44 * API.
45 */
46
47static char *xen_io_tlb_start, *xen_io_tlb_end;
48static unsigned long xen_io_tlb_nslabs;
49/*
50 * Quick lookup value of the bus address of the IOTLB.
51 */
52
53u64 start_dma_addr;
54
55static dma_addr_t xen_phys_to_bus(phys_addr_t paddr)
56{
57 return phys_to_machine(XPADDR(paddr)).maddr;
58}
59
60static phys_addr_t xen_bus_to_phys(dma_addr_t baddr)
61{
62 return machine_to_phys(XMADDR(baddr)).paddr;
63}
64
65static dma_addr_t xen_virt_to_bus(void *address)
66{
67 return xen_phys_to_bus(virt_to_phys(address));
68}
69
70static int check_pages_physically_contiguous(unsigned long pfn,
71 unsigned int offset,
72 size_t length)
73{
74 unsigned long next_mfn;
75 int i;
76 int nr_pages;
77
78 next_mfn = pfn_to_mfn(pfn);
79 nr_pages = (offset + length + PAGE_SIZE-1) >> PAGE_SHIFT;
80
81 for (i = 1; i < nr_pages; i++) {
82 if (pfn_to_mfn(++pfn) != ++next_mfn)
83 return 0;
84 }
85 return 1;
86}
87
88static int range_straddles_page_boundary(phys_addr_t p, size_t size)
89{
90 unsigned long pfn = PFN_DOWN(p);
91 unsigned int offset = p & ~PAGE_MASK;
92
93 if (offset + size <= PAGE_SIZE)
94 return 0;
95 if (check_pages_physically_contiguous(pfn, offset, size))
96 return 0;
97 return 1;
98}
99
100static int is_xen_swiotlb_buffer(dma_addr_t dma_addr)
101{
102 unsigned long mfn = PFN_DOWN(dma_addr);
103 unsigned long pfn = mfn_to_local_pfn(mfn);
104 phys_addr_t paddr;
105
106 /* If the address is outside our domain, it CAN
107 * have the same virtual address as another address
108 * in our domain. Therefore _only_ check address within our domain.
109 */
110 if (pfn_valid(pfn)) {
111 paddr = PFN_PHYS(pfn);
112 return paddr >= virt_to_phys(xen_io_tlb_start) &&
113 paddr < virt_to_phys(xen_io_tlb_end);
114 }
115 return 0;
116}
117
118static int max_dma_bits = 32;
119
120static int
121xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
122{
123 int i, rc;
124 int dma_bits;
125
126 dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
127
128 i = 0;
129 do {
130 int slabs = min(nslabs - i, (unsigned long)IO_TLB_SEGSIZE);
131
132 do {
133 rc = xen_create_contiguous_region(
134 (unsigned long)buf + (i << IO_TLB_SHIFT),
135 get_order(slabs << IO_TLB_SHIFT),
136 dma_bits);
137 } while (rc && dma_bits++ < max_dma_bits);
138 if (rc)
139 return rc;
140
141 i += slabs;
142 } while (i < nslabs);
143 return 0;
144}
145
146void __init xen_swiotlb_init(int verbose)
147{
148 unsigned long bytes;
149 int rc;
150 unsigned long nr_tbl;
151
152 nr_tbl = swioltb_nr_tbl();
153 if (nr_tbl)
154 xen_io_tlb_nslabs = nr_tbl;
155 else {
156 xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
157 xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
158 }
159
160 bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;
161
162 /*
163 * Get IO TLB memory from any location.
164 */
165 xen_io_tlb_start = alloc_bootmem(bytes);
166 if (!xen_io_tlb_start)
167 panic("Cannot allocate SWIOTLB buffer");
168
169 xen_io_tlb_end = xen_io_tlb_start + bytes;
170 /*
171 * And replace that memory with pages under 4GB.
172 */
173 rc = xen_swiotlb_fixup(xen_io_tlb_start,
174 bytes,
175 xen_io_tlb_nslabs);
176 if (rc)
177 goto error;
178
179 start_dma_addr = xen_virt_to_bus(xen_io_tlb_start);
180 swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs, verbose);
181
182 return;
183error:
184 panic("DMA(%d): Failed to exchange pages allocated for DMA with Xen! "\
185 "We either don't have the permission or you do not have enough"\
186 "free memory under 4GB!\n", rc);
187}
188
189void *
190xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
191 dma_addr_t *dma_handle, gfp_t flags)
192{
193 void *ret;
194 int order = get_order(size);
195 u64 dma_mask = DMA_BIT_MASK(32);
196 unsigned long vstart;
197
198 /*
199 * Ignore region specifiers - the kernel's ideas of
200 * pseudo-phys memory layout has nothing to do with the
201 * machine physical layout. We can't allocate highmem
202 * because we can't return a pointer to it.
203 */
204 flags &= ~(__GFP_DMA | __GFP_HIGHMEM);
205
206 if (dma_alloc_from_coherent(hwdev, size, dma_handle, &ret))
207 return ret;
208
209 vstart = __get_free_pages(flags, order);
210 ret = (void *)vstart;
211
212 if (hwdev && hwdev->coherent_dma_mask)
213 dma_mask = dma_alloc_coherent_mask(hwdev, flags);
214
215 if (ret) {
216 if (xen_create_contiguous_region(vstart, order,
217 fls64(dma_mask)) != 0) {
218 free_pages(vstart, order);
219 return NULL;
220 }
221 memset(ret, 0, size);
222 *dma_handle = virt_to_machine(ret).maddr;
223 }
224 return ret;
225}
226EXPORT_SYMBOL_GPL(xen_swiotlb_alloc_coherent);
227
228void
229xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
230 dma_addr_t dev_addr)
231{
232 int order = get_order(size);
233
234 if (dma_release_from_coherent(hwdev, order, vaddr))
235 return;
236
237 xen_destroy_contiguous_region((unsigned long)vaddr, order);
238 free_pages((unsigned long)vaddr, order);
239}
240EXPORT_SYMBOL_GPL(xen_swiotlb_free_coherent);
241
242
243/*
244 * Map a single buffer of the indicated size for DMA in streaming mode. The
245 * physical address to use is returned.
246 *
247 * Once the device is given the dma address, the device owns this memory until
248 * either xen_swiotlb_unmap_page or xen_swiotlb_dma_sync_single is performed.
249 */
250dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
251 unsigned long offset, size_t size,
252 enum dma_data_direction dir,
253 struct dma_attrs *attrs)
254{
255 phys_addr_t phys = page_to_phys(page) + offset;
256 dma_addr_t dev_addr = xen_phys_to_bus(phys);
257 void *map;
258
259 BUG_ON(dir == DMA_NONE);
260 /*
261 * If the address happens to be in the device's DMA window,
262 * we can safely return the device addr and not worry about bounce
263 * buffering it.
264 */
265 if (dma_capable(dev, dev_addr, size) &&
266 !range_straddles_page_boundary(phys, size) && !swiotlb_force)
267 return dev_addr;
268
269 /*
270 * Oh well, have to allocate and map a bounce buffer.
271 */
272 map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir);
273 if (!map)
274 return DMA_ERROR_CODE;
275
276 dev_addr = xen_virt_to_bus(map);
277
278 /*
279 * Ensure that the address returned is DMA'ble
280 */
281 if (!dma_capable(dev, dev_addr, size))
282 panic("map_single: bounce buffer is not DMA'ble");
283
284 return dev_addr;
285}
286EXPORT_SYMBOL_GPL(xen_swiotlb_map_page);
287
288/*
289 * Unmap a single streaming mode DMA translation. The dma_addr and size must
290 * match what was provided for in a previous xen_swiotlb_map_page call. All
291 * other usages are undefined.
292 *
293 * After this call, reads by the cpu to the buffer are guaranteed to see
294 * whatever the device wrote there.
295 */
296static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr,
297 size_t size, enum dma_data_direction dir)
298{
299 phys_addr_t paddr = xen_bus_to_phys(dev_addr);
300
301 BUG_ON(dir == DMA_NONE);
302
303 /* NOTE: We use dev_addr here, not paddr! */
304 if (is_xen_swiotlb_buffer(dev_addr)) {
305 swiotlb_tbl_unmap_single(hwdev, phys_to_virt(paddr), size, dir);
306 return;
307 }
308
309 if (dir != DMA_FROM_DEVICE)
310 return;
311
312 /*
313 * phys_to_virt doesn't work with hihgmem page but we could
314 * call dma_mark_clean() with hihgmem page here. However, we
315 * are fine since dma_mark_clean() is null on POWERPC. We can
316 * make dma_mark_clean() take a physical address if necessary.
317 */
318 dma_mark_clean(phys_to_virt(paddr), size);
319}
320
321void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
322 size_t size, enum dma_data_direction dir,
323 struct dma_attrs *attrs)
324{
325 xen_unmap_single(hwdev, dev_addr, size, dir);
326}
327EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_page);
328
329/*
330 * Make physical memory consistent for a single streaming mode DMA translation
331 * after a transfer.
332 *
333 * If you perform a xen_swiotlb_map_page() but wish to interrogate the buffer
334 * using the cpu, yet do not wish to teardown the dma mapping, you must
335 * call this function before doing so. At the next point you give the dma
336 * address back to the card, you must first perform a
337 * xen_swiotlb_dma_sync_for_device, and then the device again owns the buffer
338 */
339static void
340xen_swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
341 size_t size, enum dma_data_direction dir,
342 enum dma_sync_target target)
343{
344 phys_addr_t paddr = xen_bus_to_phys(dev_addr);
345
346 BUG_ON(dir == DMA_NONE);
347
348 /* NOTE: We use dev_addr here, not paddr! */
349 if (is_xen_swiotlb_buffer(dev_addr)) {
350 swiotlb_tbl_sync_single(hwdev, phys_to_virt(paddr), size, dir,
351 target);
352 return;
353 }
354
355 if (dir != DMA_FROM_DEVICE)
356 return;
357
358 dma_mark_clean(phys_to_virt(paddr), size);
359}
360
361void
362xen_swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
363 size_t size, enum dma_data_direction dir)
364{
365 xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU);
366}
367EXPORT_SYMBOL_GPL(xen_swiotlb_sync_single_for_cpu);
368
369void
370xen_swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
371 size_t size, enum dma_data_direction dir)
372{
373 xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE);
374}
375EXPORT_SYMBOL_GPL(xen_swiotlb_sync_single_for_device);
376
377/*
378 * Map a set of buffers described by scatterlist in streaming mode for DMA.
379 * This is the scatter-gather version of the above xen_swiotlb_map_page
380 * interface. Here the scatter gather list elements are each tagged with the
381 * appropriate dma address and length. They are obtained via
382 * sg_dma_{address,length}(SG).
383 *
384 * NOTE: An implementation may be able to use a smaller number of
385 * DMA address/length pairs than there are SG table elements.
386 * (for example via virtual mapping capabilities)
387 * The routine returns the number of addr/length pairs actually
388 * used, at most nents.
389 *
390 * Device ownership issues as mentioned above for xen_swiotlb_map_page are the
391 * same here.
392 */
393int
394xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
395 int nelems, enum dma_data_direction dir,
396 struct dma_attrs *attrs)
397{
398 struct scatterlist *sg;
399 int i;
400
401 BUG_ON(dir == DMA_NONE);
402
403 for_each_sg(sgl, sg, nelems, i) {
404 phys_addr_t paddr = sg_phys(sg);
405 dma_addr_t dev_addr = xen_phys_to_bus(paddr);
406
407 if (swiotlb_force ||
408 !dma_capable(hwdev, dev_addr, sg->length) ||
409 range_straddles_page_boundary(paddr, sg->length)) {
410 void *map = swiotlb_tbl_map_single(hwdev,
411 start_dma_addr,
412 sg_phys(sg),
413 sg->length, dir);
414 if (!map) {
415 /* Don't panic here, we expect map_sg users
416 to do proper error handling. */
417 xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
418 attrs);
419 sgl[0].dma_length = 0;
420 return DMA_ERROR_CODE;
421 }
422 sg->dma_address = xen_virt_to_bus(map);
423 } else
424 sg->dma_address = dev_addr;
425 sg->dma_length = sg->length;
426 }
427 return nelems;
428}
429EXPORT_SYMBOL_GPL(xen_swiotlb_map_sg_attrs);
430
431int
432xen_swiotlb_map_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
433 enum dma_data_direction dir)
434{
435 return xen_swiotlb_map_sg_attrs(hwdev, sgl, nelems, dir, NULL);
436}
437EXPORT_SYMBOL_GPL(xen_swiotlb_map_sg);
438
439/*
440 * Unmap a set of streaming mode DMA translations. Again, cpu read rules
441 * concerning calls here are the same as for swiotlb_unmap_page() above.
442 */
443void
444xen_swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
445 int nelems, enum dma_data_direction dir,
446 struct dma_attrs *attrs)
447{
448 struct scatterlist *sg;
449 int i;
450
451 BUG_ON(dir == DMA_NONE);
452
453 for_each_sg(sgl, sg, nelems, i)
454 xen_unmap_single(hwdev, sg->dma_address, sg->dma_length, dir);
455
456}
457EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_sg_attrs);
458
459void
460xen_swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
461 enum dma_data_direction dir)
462{
463 return xen_swiotlb_unmap_sg_attrs(hwdev, sgl, nelems, dir, NULL);
464}
465EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_sg);
466
467/*
468 * Make physical memory consistent for a set of streaming mode DMA translations
469 * after a transfer.
470 *
471 * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules
472 * and usage.
473 */
474static void
475xen_swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
476 int nelems, enum dma_data_direction dir,
477 enum dma_sync_target target)
478{
479 struct scatterlist *sg;
480 int i;
481
482 for_each_sg(sgl, sg, nelems, i)
483 xen_swiotlb_sync_single(hwdev, sg->dma_address,
484 sg->dma_length, dir, target);
485}
486
487void
488xen_swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
489 int nelems, enum dma_data_direction dir)
490{
491 xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU);
492}
493EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_cpu);
494
495void
496xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
497 int nelems, enum dma_data_direction dir)
498{
499 xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE);
500}
501EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_device);
502
503int
504xen_swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
505{
506 return !dma_addr;
507}
508EXPORT_SYMBOL_GPL(xen_swiotlb_dma_mapping_error);
509
510/*
511 * Return whether the given device DMA address mask can be supported
512 * properly. For example, if your device can only drive the low 24-bits
513 * during bus mastering, then you would pass 0x00ffffff as the mask to
514 * this function.
515 */
516int
517xen_swiotlb_dma_supported(struct device *hwdev, u64 mask)
518{
519 return xen_virt_to_bus(xen_io_tlb_end - 1) <= mask;
520}
521EXPORT_SYMBOL_GPL(xen_swiotlb_dma_supported);
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/bootmem.h>
39#include <linux/dma-mapping.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#ifndef CONFIG_X86
57static unsigned long dma_alloc_coherent_mask(struct device *dev,
58 gfp_t gfp)
59{
60 unsigned long dma_mask = 0;
61
62 dma_mask = dev->coherent_dma_mask;
63 if (!dma_mask)
64 dma_mask = (gfp & GFP_DMA) ? DMA_BIT_MASK(24) : DMA_BIT_MASK(32);
65
66 return dma_mask;
67}
68#endif
69
70static char *xen_io_tlb_start, *xen_io_tlb_end;
71static unsigned long xen_io_tlb_nslabs;
72/*
73 * Quick lookup value of the bus address of the IOTLB.
74 */
75
76static u64 start_dma_addr;
77
78/*
79 * Both of these functions should avoid XEN_PFN_PHYS because phys_addr_t
80 * can be 32bit when dma_addr_t is 64bit leading to a loss in
81 * information if the shift is done before casting to 64bit.
82 */
83static inline dma_addr_t xen_phys_to_bus(phys_addr_t paddr)
84{
85 unsigned long bfn = pfn_to_bfn(XEN_PFN_DOWN(paddr));
86 dma_addr_t dma = (dma_addr_t)bfn << XEN_PAGE_SHIFT;
87
88 dma |= paddr & ~XEN_PAGE_MASK;
89
90 return dma;
91}
92
93static inline phys_addr_t xen_bus_to_phys(dma_addr_t baddr)
94{
95 unsigned long xen_pfn = bfn_to_pfn(XEN_PFN_DOWN(baddr));
96 dma_addr_t dma = (dma_addr_t)xen_pfn << XEN_PAGE_SHIFT;
97 phys_addr_t paddr = dma;
98
99 paddr |= baddr & ~XEN_PAGE_MASK;
100
101 return paddr;
102}
103
104static inline dma_addr_t xen_virt_to_bus(void *address)
105{
106 return xen_phys_to_bus(virt_to_phys(address));
107}
108
109static int check_pages_physically_contiguous(unsigned long xen_pfn,
110 unsigned int offset,
111 size_t length)
112{
113 unsigned long next_bfn;
114 int i;
115 int nr_pages;
116
117 next_bfn = pfn_to_bfn(xen_pfn);
118 nr_pages = (offset + length + XEN_PAGE_SIZE-1) >> XEN_PAGE_SHIFT;
119
120 for (i = 1; i < nr_pages; i++) {
121 if (pfn_to_bfn(++xen_pfn) != ++next_bfn)
122 return 0;
123 }
124 return 1;
125}
126
127static inline int range_straddles_page_boundary(phys_addr_t p, size_t size)
128{
129 unsigned long xen_pfn = XEN_PFN_DOWN(p);
130 unsigned int offset = p & ~XEN_PAGE_MASK;
131
132 if (offset + size <= XEN_PAGE_SIZE)
133 return 0;
134 if (check_pages_physically_contiguous(xen_pfn, offset, size))
135 return 0;
136 return 1;
137}
138
139static int is_xen_swiotlb_buffer(dma_addr_t dma_addr)
140{
141 unsigned long bfn = XEN_PFN_DOWN(dma_addr);
142 unsigned long xen_pfn = bfn_to_local_pfn(bfn);
143 phys_addr_t paddr = XEN_PFN_PHYS(xen_pfn);
144
145 /* If the address is outside our domain, it CAN
146 * have the same virtual address as another address
147 * in our domain. Therefore _only_ check address within our domain.
148 */
149 if (pfn_valid(PFN_DOWN(paddr))) {
150 return paddr >= virt_to_phys(xen_io_tlb_start) &&
151 paddr < virt_to_phys(xen_io_tlb_end);
152 }
153 return 0;
154}
155
156static int max_dma_bits = 32;
157
158static int
159xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
160{
161 int i, rc;
162 int dma_bits;
163 dma_addr_t dma_handle;
164 phys_addr_t p = virt_to_phys(buf);
165
166 dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
167
168 i = 0;
169 do {
170 int slabs = min(nslabs - i, (unsigned long)IO_TLB_SEGSIZE);
171
172 do {
173 rc = xen_create_contiguous_region(
174 p + (i << IO_TLB_SHIFT),
175 get_order(slabs << IO_TLB_SHIFT),
176 dma_bits, &dma_handle);
177 } while (rc && dma_bits++ < max_dma_bits);
178 if (rc)
179 return rc;
180
181 i += slabs;
182 } while (i < nslabs);
183 return 0;
184}
185static unsigned long xen_set_nslabs(unsigned long nr_tbl)
186{
187 if (!nr_tbl) {
188 xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
189 xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
190 } else
191 xen_io_tlb_nslabs = nr_tbl;
192
193 return xen_io_tlb_nslabs << IO_TLB_SHIFT;
194}
195
196enum xen_swiotlb_err {
197 XEN_SWIOTLB_UNKNOWN = 0,
198 XEN_SWIOTLB_ENOMEM,
199 XEN_SWIOTLB_EFIXUP
200};
201
202static const char *xen_swiotlb_error(enum xen_swiotlb_err err)
203{
204 switch (err) {
205 case XEN_SWIOTLB_ENOMEM:
206 return "Cannot allocate Xen-SWIOTLB buffer\n";
207 case XEN_SWIOTLB_EFIXUP:
208 return "Failed to get contiguous memory for DMA from Xen!\n"\
209 "You either: don't have the permissions, do not have"\
210 " enough free memory under 4GB, or the hypervisor memory"\
211 " is too fragmented!";
212 default:
213 break;
214 }
215 return "";
216}
217int __ref xen_swiotlb_init(int verbose, bool early)
218{
219 unsigned long bytes, order;
220 int rc = -ENOMEM;
221 enum xen_swiotlb_err m_ret = XEN_SWIOTLB_UNKNOWN;
222 unsigned int repeat = 3;
223
224 xen_io_tlb_nslabs = swiotlb_nr_tbl();
225retry:
226 bytes = xen_set_nslabs(xen_io_tlb_nslabs);
227 order = get_order(xen_io_tlb_nslabs << IO_TLB_SHIFT);
228 /*
229 * Get IO TLB memory from any location.
230 */
231 if (early)
232 xen_io_tlb_start = alloc_bootmem_pages(PAGE_ALIGN(bytes));
233 else {
234#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
235#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
236 while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
237 xen_io_tlb_start = (void *)xen_get_swiotlb_free_pages(order);
238 if (xen_io_tlb_start)
239 break;
240 order--;
241 }
242 if (order != get_order(bytes)) {
243 pr_warn("Warning: only able to allocate %ld MB for software IO TLB\n",
244 (PAGE_SIZE << order) >> 20);
245 xen_io_tlb_nslabs = SLABS_PER_PAGE << order;
246 bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;
247 }
248 }
249 if (!xen_io_tlb_start) {
250 m_ret = XEN_SWIOTLB_ENOMEM;
251 goto error;
252 }
253 xen_io_tlb_end = xen_io_tlb_start + bytes;
254 /*
255 * And replace that memory with pages under 4GB.
256 */
257 rc = xen_swiotlb_fixup(xen_io_tlb_start,
258 bytes,
259 xen_io_tlb_nslabs);
260 if (rc) {
261 if (early)
262 free_bootmem(__pa(xen_io_tlb_start), PAGE_ALIGN(bytes));
263 else {
264 free_pages((unsigned long)xen_io_tlb_start, order);
265 xen_io_tlb_start = NULL;
266 }
267 m_ret = XEN_SWIOTLB_EFIXUP;
268 goto error;
269 }
270 start_dma_addr = xen_virt_to_bus(xen_io_tlb_start);
271 if (early) {
272 if (swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs,
273 verbose))
274 panic("Cannot allocate SWIOTLB buffer");
275 rc = 0;
276 } else
277 rc = swiotlb_late_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs);
278 return rc;
279error:
280 if (repeat--) {
281 xen_io_tlb_nslabs = max(1024UL, /* Min is 2MB */
282 (xen_io_tlb_nslabs >> 1));
283 pr_info("Lowering to %luMB\n",
284 (xen_io_tlb_nslabs << IO_TLB_SHIFT) >> 20);
285 goto retry;
286 }
287 pr_err("%s (rc:%d)\n", xen_swiotlb_error(m_ret), rc);
288 if (early)
289 panic("%s (rc:%d)", xen_swiotlb_error(m_ret), rc);
290 else
291 free_pages((unsigned long)xen_io_tlb_start, order);
292 return rc;
293}
294void *
295xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
296 dma_addr_t *dma_handle, gfp_t flags,
297 struct dma_attrs *attrs)
298{
299 void *ret;
300 int order = get_order(size);
301 u64 dma_mask = DMA_BIT_MASK(32);
302 phys_addr_t phys;
303 dma_addr_t dev_addr;
304
305 /*
306 * Ignore region specifiers - the kernel's ideas of
307 * pseudo-phys memory layout has nothing to do with the
308 * machine physical layout. We can't allocate highmem
309 * because we can't return a pointer to it.
310 */
311 flags &= ~(__GFP_DMA | __GFP_HIGHMEM);
312
313 /* On ARM this function returns an ioremap'ped virtual address for
314 * which virt_to_phys doesn't return the corresponding physical
315 * address. In fact on ARM virt_to_phys only works for kernel direct
316 * mapped RAM memory. Also see comment below.
317 */
318 ret = xen_alloc_coherent_pages(hwdev, size, dma_handle, flags, attrs);
319
320 if (!ret)
321 return ret;
322
323 if (hwdev && hwdev->coherent_dma_mask)
324 dma_mask = dma_alloc_coherent_mask(hwdev, flags);
325
326 /* At this point dma_handle is the physical address, next we are
327 * going to set it to the machine address.
328 * Do not use virt_to_phys(ret) because on ARM it doesn't correspond
329 * to *dma_handle. */
330 phys = *dma_handle;
331 dev_addr = xen_phys_to_bus(phys);
332 if (((dev_addr + size - 1 <= dma_mask)) &&
333 !range_straddles_page_boundary(phys, size))
334 *dma_handle = dev_addr;
335 else {
336 if (xen_create_contiguous_region(phys, order,
337 fls64(dma_mask), dma_handle) != 0) {
338 xen_free_coherent_pages(hwdev, size, ret, (dma_addr_t)phys, attrs);
339 return NULL;
340 }
341 }
342 memset(ret, 0, size);
343 return ret;
344}
345EXPORT_SYMBOL_GPL(xen_swiotlb_alloc_coherent);
346
347void
348xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
349 dma_addr_t dev_addr, struct dma_attrs *attrs)
350{
351 int order = get_order(size);
352 phys_addr_t phys;
353 u64 dma_mask = DMA_BIT_MASK(32);
354
355 if (hwdev && hwdev->coherent_dma_mask)
356 dma_mask = hwdev->coherent_dma_mask;
357
358 /* do not use virt_to_phys because on ARM it doesn't return you the
359 * physical address */
360 phys = xen_bus_to_phys(dev_addr);
361
362 if (((dev_addr + size - 1 > dma_mask)) ||
363 range_straddles_page_boundary(phys, size))
364 xen_destroy_contiguous_region(phys, order);
365
366 xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs);
367}
368EXPORT_SYMBOL_GPL(xen_swiotlb_free_coherent);
369
370
371/*
372 * Map a single buffer of the indicated size for DMA in streaming mode. The
373 * physical address to use is returned.
374 *
375 * Once the device is given the dma address, the device owns this memory until
376 * either xen_swiotlb_unmap_page or xen_swiotlb_dma_sync_single is performed.
377 */
378dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
379 unsigned long offset, size_t size,
380 enum dma_data_direction dir,
381 struct dma_attrs *attrs)
382{
383 phys_addr_t map, phys = page_to_phys(page) + offset;
384 dma_addr_t dev_addr = xen_phys_to_bus(phys);
385
386 BUG_ON(dir == DMA_NONE);
387 /*
388 * If the address happens to be in the device's DMA window,
389 * we can safely return the device addr and not worry about bounce
390 * buffering it.
391 */
392 if (dma_capable(dev, dev_addr, size) &&
393 !range_straddles_page_boundary(phys, size) &&
394 !xen_arch_need_swiotlb(dev, phys, dev_addr) &&
395 !swiotlb_force) {
396 /* we are not interested in the dma_addr returned by
397 * xen_dma_map_page, only in the potential cache flushes executed
398 * by the function. */
399 xen_dma_map_page(dev, page, dev_addr, offset, size, dir, attrs);
400 return dev_addr;
401 }
402
403 /*
404 * Oh well, have to allocate and map a bounce buffer.
405 */
406 trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);
407
408 map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir);
409 if (map == SWIOTLB_MAP_ERROR)
410 return DMA_ERROR_CODE;
411
412 xen_dma_map_page(dev, pfn_to_page(map >> PAGE_SHIFT),
413 dev_addr, map & ~PAGE_MASK, size, dir, attrs);
414 dev_addr = xen_phys_to_bus(map);
415
416 /*
417 * Ensure that the address returned is DMA'ble
418 */
419 if (!dma_capable(dev, dev_addr, size)) {
420 swiotlb_tbl_unmap_single(dev, map, size, dir);
421 dev_addr = 0;
422 }
423 return dev_addr;
424}
425EXPORT_SYMBOL_GPL(xen_swiotlb_map_page);
426
427/*
428 * Unmap a single streaming mode DMA translation. The dma_addr and size must
429 * match what was provided for in a previous xen_swiotlb_map_page call. All
430 * other usages are undefined.
431 *
432 * After this call, reads by the cpu to the buffer are guaranteed to see
433 * whatever the device wrote there.
434 */
435static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr,
436 size_t size, enum dma_data_direction dir,
437 struct dma_attrs *attrs)
438{
439 phys_addr_t paddr = xen_bus_to_phys(dev_addr);
440
441 BUG_ON(dir == DMA_NONE);
442
443 xen_dma_unmap_page(hwdev, dev_addr, size, dir, attrs);
444
445 /* NOTE: We use dev_addr here, not paddr! */
446 if (is_xen_swiotlb_buffer(dev_addr)) {
447 swiotlb_tbl_unmap_single(hwdev, paddr, size, dir);
448 return;
449 }
450
451 if (dir != DMA_FROM_DEVICE)
452 return;
453
454 /*
455 * phys_to_virt doesn't work with hihgmem page but we could
456 * call dma_mark_clean() with hihgmem page here. However, we
457 * are fine since dma_mark_clean() is null on POWERPC. We can
458 * make dma_mark_clean() take a physical address if necessary.
459 */
460 dma_mark_clean(phys_to_virt(paddr), size);
461}
462
463void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
464 size_t size, enum dma_data_direction dir,
465 struct dma_attrs *attrs)
466{
467 xen_unmap_single(hwdev, dev_addr, size, dir, attrs);
468}
469EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_page);
470
471/*
472 * Make physical memory consistent for a single streaming mode DMA translation
473 * after a transfer.
474 *
475 * If you perform a xen_swiotlb_map_page() but wish to interrogate the buffer
476 * using the cpu, yet do not wish to teardown the dma mapping, you must
477 * call this function before doing so. At the next point you give the dma
478 * address back to the card, you must first perform a
479 * xen_swiotlb_dma_sync_for_device, and then the device again owns the buffer
480 */
481static void
482xen_swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
483 size_t size, enum dma_data_direction dir,
484 enum dma_sync_target target)
485{
486 phys_addr_t paddr = xen_bus_to_phys(dev_addr);
487
488 BUG_ON(dir == DMA_NONE);
489
490 if (target == SYNC_FOR_CPU)
491 xen_dma_sync_single_for_cpu(hwdev, dev_addr, size, dir);
492
493 /* NOTE: We use dev_addr here, not paddr! */
494 if (is_xen_swiotlb_buffer(dev_addr))
495 swiotlb_tbl_sync_single(hwdev, paddr, size, dir, target);
496
497 if (target == SYNC_FOR_DEVICE)
498 xen_dma_sync_single_for_device(hwdev, dev_addr, size, dir);
499
500 if (dir != DMA_FROM_DEVICE)
501 return;
502
503 dma_mark_clean(phys_to_virt(paddr), size);
504}
505
506void
507xen_swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
508 size_t size, enum dma_data_direction dir)
509{
510 xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU);
511}
512EXPORT_SYMBOL_GPL(xen_swiotlb_sync_single_for_cpu);
513
514void
515xen_swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
516 size_t size, enum dma_data_direction dir)
517{
518 xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE);
519}
520EXPORT_SYMBOL_GPL(xen_swiotlb_sync_single_for_device);
521
522/*
523 * Map a set of buffers described by scatterlist in streaming mode for DMA.
524 * This is the scatter-gather version of the above xen_swiotlb_map_page
525 * interface. Here the scatter gather list elements are each tagged with the
526 * appropriate dma address and length. They are obtained via
527 * sg_dma_{address,length}(SG).
528 *
529 * NOTE: An implementation may be able to use a smaller number of
530 * DMA address/length pairs than there are SG table elements.
531 * (for example via virtual mapping capabilities)
532 * The routine returns the number of addr/length pairs actually
533 * used, at most nents.
534 *
535 * Device ownership issues as mentioned above for xen_swiotlb_map_page are the
536 * same here.
537 */
538int
539xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
540 int nelems, enum dma_data_direction dir,
541 struct dma_attrs *attrs)
542{
543 struct scatterlist *sg;
544 int i;
545
546 BUG_ON(dir == DMA_NONE);
547
548 for_each_sg(sgl, sg, nelems, i) {
549 phys_addr_t paddr = sg_phys(sg);
550 dma_addr_t dev_addr = xen_phys_to_bus(paddr);
551
552 if (swiotlb_force ||
553 xen_arch_need_swiotlb(hwdev, paddr, dev_addr) ||
554 !dma_capable(hwdev, dev_addr, sg->length) ||
555 range_straddles_page_boundary(paddr, sg->length)) {
556 phys_addr_t map = swiotlb_tbl_map_single(hwdev,
557 start_dma_addr,
558 sg_phys(sg),
559 sg->length,
560 dir);
561 if (map == SWIOTLB_MAP_ERROR) {
562 dev_warn(hwdev, "swiotlb buffer is full\n");
563 /* Don't panic here, we expect map_sg users
564 to do proper error handling. */
565 xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
566 attrs);
567 sg_dma_len(sgl) = 0;
568 return 0;
569 }
570 xen_dma_map_page(hwdev, pfn_to_page(map >> PAGE_SHIFT),
571 dev_addr,
572 map & ~PAGE_MASK,
573 sg->length,
574 dir,
575 attrs);
576 sg->dma_address = xen_phys_to_bus(map);
577 } else {
578 /* we are not interested in the dma_addr returned by
579 * xen_dma_map_page, only in the potential cache flushes executed
580 * by the function. */
581 xen_dma_map_page(hwdev, pfn_to_page(paddr >> PAGE_SHIFT),
582 dev_addr,
583 paddr & ~PAGE_MASK,
584 sg->length,
585 dir,
586 attrs);
587 sg->dma_address = dev_addr;
588 }
589 sg_dma_len(sg) = sg->length;
590 }
591 return nelems;
592}
593EXPORT_SYMBOL_GPL(xen_swiotlb_map_sg_attrs);
594
595/*
596 * Unmap a set of streaming mode DMA translations. Again, cpu read rules
597 * concerning calls here are the same as for swiotlb_unmap_page() above.
598 */
599void
600xen_swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
601 int nelems, enum dma_data_direction dir,
602 struct dma_attrs *attrs)
603{
604 struct scatterlist *sg;
605 int i;
606
607 BUG_ON(dir == DMA_NONE);
608
609 for_each_sg(sgl, sg, nelems, i)
610 xen_unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir, attrs);
611
612}
613EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_sg_attrs);
614
615/*
616 * Make physical memory consistent for a set of streaming mode DMA translations
617 * after a transfer.
618 *
619 * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules
620 * and usage.
621 */
622static void
623xen_swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
624 int nelems, enum dma_data_direction dir,
625 enum dma_sync_target target)
626{
627 struct scatterlist *sg;
628 int i;
629
630 for_each_sg(sgl, sg, nelems, i)
631 xen_swiotlb_sync_single(hwdev, sg->dma_address,
632 sg_dma_len(sg), dir, target);
633}
634
635void
636xen_swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
637 int nelems, enum dma_data_direction dir)
638{
639 xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU);
640}
641EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_cpu);
642
643void
644xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
645 int nelems, enum dma_data_direction dir)
646{
647 xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE);
648}
649EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_device);
650
651int
652xen_swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
653{
654 return !dma_addr;
655}
656EXPORT_SYMBOL_GPL(xen_swiotlb_dma_mapping_error);
657
658/*
659 * Return whether the given device DMA address mask can be supported
660 * properly. For example, if your device can only drive the low 24-bits
661 * during bus mastering, then you would pass 0x00ffffff as the mask to
662 * this function.
663 */
664int
665xen_swiotlb_dma_supported(struct device *hwdev, u64 mask)
666{
667 return xen_virt_to_bus(xen_io_tlb_end - 1) <= mask;
668}
669EXPORT_SYMBOL_GPL(xen_swiotlb_dma_supported);
670
671int
672xen_swiotlb_set_dma_mask(struct device *dev, u64 dma_mask)
673{
674 if (!dev->dma_mask || !xen_swiotlb_dma_supported(dev, dma_mask))
675 return -EIO;
676
677 *dev->dma_mask = dma_mask;
678
679 return 0;
680}
681EXPORT_SYMBOL_GPL(xen_swiotlb_set_dma_mask);