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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright 2010
4 * by Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
5 *
6 * This code provides a IOMMU for Xen PV guests with PCI passthrough.
7 *
8 * PV guests under Xen are running in an non-contiguous memory architecture.
9 *
10 * When PCI pass-through is utilized, this necessitates an IOMMU for
11 * translating bus (DMA) to virtual and vice-versa and also providing a
12 * mechanism to have contiguous pages for device drivers operations (say DMA
13 * operations).
14 *
15 * Specifically, under Xen the Linux idea of pages is an illusion. It
16 * assumes that pages start at zero and go up to the available memory. To
17 * help with that, the Linux Xen MMU provides a lookup mechanism to
18 * translate the page frame numbers (PFN) to machine frame numbers (MFN)
19 * and vice-versa. The MFN are the "real" frame numbers. Furthermore
20 * memory is not contiguous. Xen hypervisor stitches memory for guests
21 * from different pools, which means there is no guarantee that PFN==MFN
22 * and PFN+1==MFN+1. Lastly with Xen 4.0, pages (in debug mode) are
23 * allocated in descending order (high to low), meaning the guest might
24 * never get any MFN's under the 4GB mark.
25 */
26
27#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
28
29#include <linux/memblock.h>
30#include <linux/dma-direct.h>
31#include <linux/dma-noncoherent.h>
32#include <linux/export.h>
33#include <xen/swiotlb-xen.h>
34#include <xen/page.h>
35#include <xen/xen-ops.h>
36#include <xen/hvc-console.h>
37
38#include <asm/dma-mapping.h>
39#include <asm/xen/page-coherent.h>
40
41#include <trace/events/swiotlb.h>
42#define MAX_DMA_BITS 32
43/*
44 * Used to do a quick range check in swiotlb_tbl_unmap_single and
45 * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
46 * API.
47 */
48
49static char *xen_io_tlb_start, *xen_io_tlb_end;
50static unsigned long xen_io_tlb_nslabs;
51/*
52 * Quick lookup value of the bus address of the IOTLB.
53 */
54
55static u64 start_dma_addr;
56
57/*
58 * Both of these functions should avoid XEN_PFN_PHYS because phys_addr_t
59 * can be 32bit when dma_addr_t is 64bit leading to a loss in
60 * information if the shift is done before casting to 64bit.
61 */
62static inline dma_addr_t xen_phys_to_bus(phys_addr_t paddr)
63{
64 unsigned long bfn = pfn_to_bfn(XEN_PFN_DOWN(paddr));
65 dma_addr_t dma = (dma_addr_t)bfn << XEN_PAGE_SHIFT;
66
67 dma |= paddr & ~XEN_PAGE_MASK;
68
69 return dma;
70}
71
72static inline phys_addr_t xen_bus_to_phys(dma_addr_t baddr)
73{
74 unsigned long xen_pfn = bfn_to_pfn(XEN_PFN_DOWN(baddr));
75 dma_addr_t dma = (dma_addr_t)xen_pfn << XEN_PAGE_SHIFT;
76 phys_addr_t paddr = dma;
77
78 paddr |= baddr & ~XEN_PAGE_MASK;
79
80 return paddr;
81}
82
83static inline dma_addr_t xen_virt_to_bus(void *address)
84{
85 return xen_phys_to_bus(virt_to_phys(address));
86}
87
88static inline int range_straddles_page_boundary(phys_addr_t p, size_t size)
89{
90 unsigned long next_bfn, xen_pfn = XEN_PFN_DOWN(p);
91 unsigned int i, nr_pages = XEN_PFN_UP(xen_offset_in_page(p) + size);
92
93 next_bfn = pfn_to_bfn(xen_pfn);
94
95 for (i = 1; i < nr_pages; i++)
96 if (pfn_to_bfn(++xen_pfn) != ++next_bfn)
97 return 1;
98
99 return 0;
100}
101
102static int is_xen_swiotlb_buffer(dma_addr_t dma_addr)
103{
104 unsigned long bfn = XEN_PFN_DOWN(dma_addr);
105 unsigned long xen_pfn = bfn_to_local_pfn(bfn);
106 phys_addr_t paddr = XEN_PFN_PHYS(xen_pfn);
107
108 /* If the address is outside our domain, it CAN
109 * have the same virtual address as another address
110 * in our domain. Therefore _only_ check address within our domain.
111 */
112 if (pfn_valid(PFN_DOWN(paddr))) {
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
119static int
120xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
121{
122 int i, rc;
123 int dma_bits;
124 dma_addr_t dma_handle;
125 phys_addr_t p = virt_to_phys(buf);
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 p + (i << IO_TLB_SHIFT),
136 get_order(slabs << IO_TLB_SHIFT),
137 dma_bits, &dma_handle);
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}
146static unsigned long xen_set_nslabs(unsigned long nr_tbl)
147{
148 if (!nr_tbl) {
149 xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
150 xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
151 } else
152 xen_io_tlb_nslabs = nr_tbl;
153
154 return xen_io_tlb_nslabs << IO_TLB_SHIFT;
155}
156
157enum xen_swiotlb_err {
158 XEN_SWIOTLB_UNKNOWN = 0,
159 XEN_SWIOTLB_ENOMEM,
160 XEN_SWIOTLB_EFIXUP
161};
162
163static const char *xen_swiotlb_error(enum xen_swiotlb_err err)
164{
165 switch (err) {
166 case XEN_SWIOTLB_ENOMEM:
167 return "Cannot allocate Xen-SWIOTLB buffer\n";
168 case XEN_SWIOTLB_EFIXUP:
169 return "Failed to get contiguous memory for DMA from Xen!\n"\
170 "You either: don't have the permissions, do not have"\
171 " enough free memory under 4GB, or the hypervisor memory"\
172 " is too fragmented!";
173 default:
174 break;
175 }
176 return "";
177}
178int __ref xen_swiotlb_init(int verbose, bool early)
179{
180 unsigned long bytes, order;
181 int rc = -ENOMEM;
182 enum xen_swiotlb_err m_ret = XEN_SWIOTLB_UNKNOWN;
183 unsigned int repeat = 3;
184
185 xen_io_tlb_nslabs = swiotlb_nr_tbl();
186retry:
187 bytes = xen_set_nslabs(xen_io_tlb_nslabs);
188 order = get_order(xen_io_tlb_nslabs << IO_TLB_SHIFT);
189
190 /*
191 * IO TLB memory already allocated. Just use it.
192 */
193 if (io_tlb_start != 0) {
194 xen_io_tlb_start = phys_to_virt(io_tlb_start);
195 goto end;
196 }
197
198 /*
199 * Get IO TLB memory from any location.
200 */
201 if (early) {
202 xen_io_tlb_start = memblock_alloc(PAGE_ALIGN(bytes),
203 PAGE_SIZE);
204 if (!xen_io_tlb_start)
205 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
206 __func__, PAGE_ALIGN(bytes), PAGE_SIZE);
207 } else {
208#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
209#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
210 while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
211 xen_io_tlb_start = (void *)xen_get_swiotlb_free_pages(order);
212 if (xen_io_tlb_start)
213 break;
214 order--;
215 }
216 if (order != get_order(bytes)) {
217 pr_warn("Warning: only able to allocate %ld MB for software IO TLB\n",
218 (PAGE_SIZE << order) >> 20);
219 xen_io_tlb_nslabs = SLABS_PER_PAGE << order;
220 bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;
221 }
222 }
223 if (!xen_io_tlb_start) {
224 m_ret = XEN_SWIOTLB_ENOMEM;
225 goto error;
226 }
227 /*
228 * And replace that memory with pages under 4GB.
229 */
230 rc = xen_swiotlb_fixup(xen_io_tlb_start,
231 bytes,
232 xen_io_tlb_nslabs);
233 if (rc) {
234 if (early)
235 memblock_free(__pa(xen_io_tlb_start),
236 PAGE_ALIGN(bytes));
237 else {
238 free_pages((unsigned long)xen_io_tlb_start, order);
239 xen_io_tlb_start = NULL;
240 }
241 m_ret = XEN_SWIOTLB_EFIXUP;
242 goto error;
243 }
244 start_dma_addr = xen_virt_to_bus(xen_io_tlb_start);
245 if (early) {
246 if (swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs,
247 verbose))
248 panic("Cannot allocate SWIOTLB buffer");
249 rc = 0;
250 } else
251 rc = swiotlb_late_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs);
252
253end:
254 xen_io_tlb_end = xen_io_tlb_start + bytes;
255 if (!rc)
256 swiotlb_set_max_segment(PAGE_SIZE);
257
258 return rc;
259error:
260 if (repeat--) {
261 xen_io_tlb_nslabs = max(1024UL, /* Min is 2MB */
262 (xen_io_tlb_nslabs >> 1));
263 pr_info("Lowering to %luMB\n",
264 (xen_io_tlb_nslabs << IO_TLB_SHIFT) >> 20);
265 goto retry;
266 }
267 pr_err("%s (rc:%d)\n", xen_swiotlb_error(m_ret), rc);
268 if (early)
269 panic("%s (rc:%d)", xen_swiotlb_error(m_ret), rc);
270 else
271 free_pages((unsigned long)xen_io_tlb_start, order);
272 return rc;
273}
274
275static void *
276xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
277 dma_addr_t *dma_handle, gfp_t flags,
278 unsigned long attrs)
279{
280 void *ret;
281 int order = get_order(size);
282 u64 dma_mask = DMA_BIT_MASK(32);
283 phys_addr_t phys;
284 dma_addr_t dev_addr;
285
286 /*
287 * Ignore region specifiers - the kernel's ideas of
288 * pseudo-phys memory layout has nothing to do with the
289 * machine physical layout. We can't allocate highmem
290 * because we can't return a pointer to it.
291 */
292 flags &= ~(__GFP_DMA | __GFP_HIGHMEM);
293
294 /* Convert the size to actually allocated. */
295 size = 1UL << (order + XEN_PAGE_SHIFT);
296
297 /* On ARM this function returns an ioremap'ped virtual address for
298 * which virt_to_phys doesn't return the corresponding physical
299 * address. In fact on ARM virt_to_phys only works for kernel direct
300 * mapped RAM memory. Also see comment below.
301 */
302 ret = xen_alloc_coherent_pages(hwdev, size, dma_handle, flags, attrs);
303
304 if (!ret)
305 return ret;
306
307 if (hwdev && hwdev->coherent_dma_mask)
308 dma_mask = hwdev->coherent_dma_mask;
309
310 /* At this point dma_handle is the physical address, next we are
311 * going to set it to the machine address.
312 * Do not use virt_to_phys(ret) because on ARM it doesn't correspond
313 * to *dma_handle. */
314 phys = *dma_handle;
315 dev_addr = xen_phys_to_bus(phys);
316 if (((dev_addr + size - 1 <= dma_mask)) &&
317 !range_straddles_page_boundary(phys, size))
318 *dma_handle = dev_addr;
319 else {
320 if (xen_create_contiguous_region(phys, order,
321 fls64(dma_mask), dma_handle) != 0) {
322 xen_free_coherent_pages(hwdev, size, ret, (dma_addr_t)phys, attrs);
323 return NULL;
324 }
325 SetPageXenRemapped(virt_to_page(ret));
326 }
327 memset(ret, 0, size);
328 return ret;
329}
330
331static void
332xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
333 dma_addr_t dev_addr, unsigned long attrs)
334{
335 int order = get_order(size);
336 phys_addr_t phys;
337 u64 dma_mask = DMA_BIT_MASK(32);
338
339 if (hwdev && hwdev->coherent_dma_mask)
340 dma_mask = hwdev->coherent_dma_mask;
341
342 /* do not use virt_to_phys because on ARM it doesn't return you the
343 * physical address */
344 phys = xen_bus_to_phys(dev_addr);
345
346 /* Convert the size to actually allocated. */
347 size = 1UL << (order + XEN_PAGE_SHIFT);
348
349 if (!WARN_ON((dev_addr + size - 1 > dma_mask) ||
350 range_straddles_page_boundary(phys, size)) &&
351 TestClearPageXenRemapped(virt_to_page(vaddr)))
352 xen_destroy_contiguous_region(phys, order);
353
354 xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs);
355}
356
357/*
358 * Map a single buffer of the indicated size for DMA in streaming mode. The
359 * physical address to use is returned.
360 *
361 * Once the device is given the dma address, the device owns this memory until
362 * either xen_swiotlb_unmap_page or xen_swiotlb_dma_sync_single is performed.
363 */
364static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
365 unsigned long offset, size_t size,
366 enum dma_data_direction dir,
367 unsigned long attrs)
368{
369 phys_addr_t map, phys = page_to_phys(page) + offset;
370 dma_addr_t dev_addr = xen_phys_to_bus(phys);
371
372 BUG_ON(dir == DMA_NONE);
373 /*
374 * If the address happens to be in the device's DMA window,
375 * we can safely return the device addr and not worry about bounce
376 * buffering it.
377 */
378 if (dma_capable(dev, dev_addr, size) &&
379 !range_straddles_page_boundary(phys, size) &&
380 !xen_arch_need_swiotlb(dev, phys, dev_addr) &&
381 swiotlb_force != SWIOTLB_FORCE)
382 goto done;
383
384 /*
385 * Oh well, have to allocate and map a bounce buffer.
386 */
387 trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);
388
389 map = swiotlb_tbl_map_single(dev, start_dma_addr, phys,
390 size, size, dir, attrs);
391 if (map == (phys_addr_t)DMA_MAPPING_ERROR)
392 return DMA_MAPPING_ERROR;
393
394 phys = map;
395 dev_addr = xen_phys_to_bus(map);
396
397 /*
398 * Ensure that the address returned is DMA'ble
399 */
400 if (unlikely(!dma_capable(dev, dev_addr, size))) {
401 swiotlb_tbl_unmap_single(dev, map, size, size, dir,
402 attrs | DMA_ATTR_SKIP_CPU_SYNC);
403 return DMA_MAPPING_ERROR;
404 }
405
406done:
407 if (!dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
408 xen_dma_sync_for_device(dev, dev_addr, phys, size, dir);
409 return dev_addr;
410}
411
412/*
413 * Unmap a single streaming mode DMA translation. The dma_addr and size must
414 * match what was provided for in a previous xen_swiotlb_map_page call. All
415 * other usages are undefined.
416 *
417 * After this call, reads by the cpu to the buffer are guaranteed to see
418 * whatever the device wrote there.
419 */
420static void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
421 size_t size, enum dma_data_direction dir, unsigned long attrs)
422{
423 phys_addr_t paddr = xen_bus_to_phys(dev_addr);
424
425 BUG_ON(dir == DMA_NONE);
426
427 if (!dev_is_dma_coherent(hwdev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
428 xen_dma_sync_for_cpu(hwdev, dev_addr, paddr, size, dir);
429
430 /* NOTE: We use dev_addr here, not paddr! */
431 if (is_xen_swiotlb_buffer(dev_addr))
432 swiotlb_tbl_unmap_single(hwdev, paddr, size, size, dir, attrs);
433}
434
435static void
436xen_swiotlb_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr,
437 size_t size, enum dma_data_direction dir)
438{
439 phys_addr_t paddr = xen_bus_to_phys(dma_addr);
440
441 if (!dev_is_dma_coherent(dev))
442 xen_dma_sync_for_cpu(dev, dma_addr, paddr, size, dir);
443
444 if (is_xen_swiotlb_buffer(dma_addr))
445 swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_CPU);
446}
447
448static void
449xen_swiotlb_sync_single_for_device(struct device *dev, dma_addr_t dma_addr,
450 size_t size, enum dma_data_direction dir)
451{
452 phys_addr_t paddr = xen_bus_to_phys(dma_addr);
453
454 if (is_xen_swiotlb_buffer(dma_addr))
455 swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_DEVICE);
456
457 if (!dev_is_dma_coherent(dev))
458 xen_dma_sync_for_device(dev, dma_addr, paddr, size, dir);
459}
460
461/*
462 * Unmap a set of streaming mode DMA translations. Again, cpu read rules
463 * concerning calls here are the same as for swiotlb_unmap_page() above.
464 */
465static void
466xen_swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
467 enum dma_data_direction dir, unsigned long attrs)
468{
469 struct scatterlist *sg;
470 int i;
471
472 BUG_ON(dir == DMA_NONE);
473
474 for_each_sg(sgl, sg, nelems, i)
475 xen_swiotlb_unmap_page(hwdev, sg->dma_address, sg_dma_len(sg),
476 dir, attrs);
477
478}
479
480static int
481xen_swiotlb_map_sg(struct device *dev, struct scatterlist *sgl, int nelems,
482 enum dma_data_direction dir, unsigned long attrs)
483{
484 struct scatterlist *sg;
485 int i;
486
487 BUG_ON(dir == DMA_NONE);
488
489 for_each_sg(sgl, sg, nelems, i) {
490 sg->dma_address = xen_swiotlb_map_page(dev, sg_page(sg),
491 sg->offset, sg->length, dir, attrs);
492 if (sg->dma_address == DMA_MAPPING_ERROR)
493 goto out_unmap;
494 sg_dma_len(sg) = sg->length;
495 }
496
497 return nelems;
498out_unmap:
499 xen_swiotlb_unmap_sg(dev, sgl, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC);
500 sg_dma_len(sgl) = 0;
501 return 0;
502}
503
504static void
505xen_swiotlb_sync_sg_for_cpu(struct device *dev, struct scatterlist *sgl,
506 int nelems, enum dma_data_direction dir)
507{
508 struct scatterlist *sg;
509 int i;
510
511 for_each_sg(sgl, sg, nelems, i) {
512 xen_swiotlb_sync_single_for_cpu(dev, sg->dma_address,
513 sg->length, dir);
514 }
515}
516
517static void
518xen_swiotlb_sync_sg_for_device(struct device *dev, struct scatterlist *sgl,
519 int nelems, enum dma_data_direction dir)
520{
521 struct scatterlist *sg;
522 int i;
523
524 for_each_sg(sgl, sg, nelems, i) {
525 xen_swiotlb_sync_single_for_device(dev, sg->dma_address,
526 sg->length, dir);
527 }
528}
529
530/*
531 * Return whether the given device DMA address mask can be supported
532 * properly. For example, if your device can only drive the low 24-bits
533 * during bus mastering, then you would pass 0x00ffffff as the mask to
534 * this function.
535 */
536static int
537xen_swiotlb_dma_supported(struct device *hwdev, u64 mask)
538{
539 return xen_virt_to_bus(xen_io_tlb_end - 1) <= mask;
540}
541
542const struct dma_map_ops xen_swiotlb_dma_ops = {
543 .alloc = xen_swiotlb_alloc_coherent,
544 .free = xen_swiotlb_free_coherent,
545 .sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu,
546 .sync_single_for_device = xen_swiotlb_sync_single_for_device,
547 .sync_sg_for_cpu = xen_swiotlb_sync_sg_for_cpu,
548 .sync_sg_for_device = xen_swiotlb_sync_sg_for_device,
549 .map_sg = xen_swiotlb_map_sg,
550 .unmap_sg = xen_swiotlb_unmap_sg,
551 .map_page = xen_swiotlb_map_page,
552 .unmap_page = xen_swiotlb_unmap_page,
553 .dma_supported = xen_swiotlb_dma_supported,
554 .mmap = dma_common_mmap,
555 .get_sgtable = dma_common_get_sgtable,
556};
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright 2010
4 * by Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
5 *
6 * This code provides a IOMMU for Xen PV guests with PCI passthrough.
7 *
8 * PV guests under Xen are running in an non-contiguous memory architecture.
9 *
10 * When PCI pass-through is utilized, this necessitates an IOMMU for
11 * translating bus (DMA) to virtual and vice-versa and also providing a
12 * mechanism to have contiguous pages for device drivers operations (say DMA
13 * operations).
14 *
15 * Specifically, under Xen the Linux idea of pages is an illusion. It
16 * assumes that pages start at zero and go up to the available memory. To
17 * help with that, the Linux Xen MMU provides a lookup mechanism to
18 * translate the page frame numbers (PFN) to machine frame numbers (MFN)
19 * and vice-versa. The MFN are the "real" frame numbers. Furthermore
20 * memory is not contiguous. Xen hypervisor stitches memory for guests
21 * from different pools, which means there is no guarantee that PFN==MFN
22 * and PFN+1==MFN+1. Lastly with Xen 4.0, pages (in debug mode) are
23 * allocated in descending order (high to low), meaning the guest might
24 * never get any MFN's under the 4GB mark.
25 */
26
27#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
28
29#include <linux/memblock.h>
30#include <linux/dma-direct.h>
31#include <linux/dma-map-ops.h>
32#include <linux/export.h>
33#include <xen/swiotlb-xen.h>
34#include <xen/page.h>
35#include <xen/xen-ops.h>
36#include <xen/hvc-console.h>
37
38#include <asm/dma-mapping.h>
39
40#include <trace/events/swiotlb.h>
41#define MAX_DMA_BITS 32
42
43/*
44 * Quick lookup value of the bus address of the IOTLB.
45 */
46
47static inline phys_addr_t xen_phys_to_bus(struct device *dev, phys_addr_t paddr)
48{
49 unsigned long bfn = pfn_to_bfn(XEN_PFN_DOWN(paddr));
50 phys_addr_t baddr = (phys_addr_t)bfn << XEN_PAGE_SHIFT;
51
52 baddr |= paddr & ~XEN_PAGE_MASK;
53 return baddr;
54}
55
56static inline dma_addr_t xen_phys_to_dma(struct device *dev, phys_addr_t paddr)
57{
58 return phys_to_dma(dev, xen_phys_to_bus(dev, paddr));
59}
60
61static inline phys_addr_t xen_bus_to_phys(struct device *dev,
62 phys_addr_t baddr)
63{
64 unsigned long xen_pfn = bfn_to_pfn(XEN_PFN_DOWN(baddr));
65 phys_addr_t paddr = (xen_pfn << XEN_PAGE_SHIFT) |
66 (baddr & ~XEN_PAGE_MASK);
67
68 return paddr;
69}
70
71static inline phys_addr_t xen_dma_to_phys(struct device *dev,
72 dma_addr_t dma_addr)
73{
74 return xen_bus_to_phys(dev, dma_to_phys(dev, dma_addr));
75}
76
77static inline int range_straddles_page_boundary(phys_addr_t p, size_t size)
78{
79 unsigned long next_bfn, xen_pfn = XEN_PFN_DOWN(p);
80 unsigned int i, nr_pages = XEN_PFN_UP(xen_offset_in_page(p) + size);
81
82 next_bfn = pfn_to_bfn(xen_pfn);
83
84 for (i = 1; i < nr_pages; i++)
85 if (pfn_to_bfn(++xen_pfn) != ++next_bfn)
86 return 1;
87
88 return 0;
89}
90
91static int is_xen_swiotlb_buffer(struct device *dev, dma_addr_t dma_addr)
92{
93 unsigned long bfn = XEN_PFN_DOWN(dma_to_phys(dev, dma_addr));
94 unsigned long xen_pfn = bfn_to_local_pfn(bfn);
95 phys_addr_t paddr = (phys_addr_t)xen_pfn << XEN_PAGE_SHIFT;
96
97 /* If the address is outside our domain, it CAN
98 * have the same virtual address as another address
99 * in our domain. Therefore _only_ check address within our domain.
100 */
101 if (pfn_valid(PFN_DOWN(paddr)))
102 return is_swiotlb_buffer(dev, paddr);
103 return 0;
104}
105
106#ifdef CONFIG_X86
107int xen_swiotlb_fixup(void *buf, unsigned long nslabs)
108{
109 int rc;
110 unsigned int order = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT);
111 unsigned int i, dma_bits = order + PAGE_SHIFT;
112 dma_addr_t dma_handle;
113 phys_addr_t p = virt_to_phys(buf);
114
115 BUILD_BUG_ON(IO_TLB_SEGSIZE & (IO_TLB_SEGSIZE - 1));
116 BUG_ON(nslabs % IO_TLB_SEGSIZE);
117
118 i = 0;
119 do {
120 do {
121 rc = xen_create_contiguous_region(
122 p + (i << IO_TLB_SHIFT), order,
123 dma_bits, &dma_handle);
124 } while (rc && dma_bits++ < MAX_DMA_BITS);
125 if (rc)
126 return rc;
127
128 i += IO_TLB_SEGSIZE;
129 } while (i < nslabs);
130 return 0;
131}
132
133static void *
134xen_swiotlb_alloc_coherent(struct device *dev, size_t size,
135 dma_addr_t *dma_handle, gfp_t flags, unsigned long attrs)
136{
137 u64 dma_mask = dev->coherent_dma_mask;
138 int order = get_order(size);
139 phys_addr_t phys;
140 void *ret;
141
142 /* Align the allocation to the Xen page size */
143 size = 1UL << (order + XEN_PAGE_SHIFT);
144
145 ret = (void *)__get_free_pages(flags, get_order(size));
146 if (!ret)
147 return ret;
148 phys = virt_to_phys(ret);
149
150 *dma_handle = xen_phys_to_dma(dev, phys);
151 if (*dma_handle + size - 1 > dma_mask ||
152 range_straddles_page_boundary(phys, size)) {
153 if (xen_create_contiguous_region(phys, order, fls64(dma_mask),
154 dma_handle) != 0)
155 goto out_free_pages;
156 SetPageXenRemapped(virt_to_page(ret));
157 }
158
159 memset(ret, 0, size);
160 return ret;
161
162out_free_pages:
163 free_pages((unsigned long)ret, get_order(size));
164 return NULL;
165}
166
167static void
168xen_swiotlb_free_coherent(struct device *dev, size_t size, void *vaddr,
169 dma_addr_t dma_handle, unsigned long attrs)
170{
171 phys_addr_t phys = virt_to_phys(vaddr);
172 int order = get_order(size);
173
174 /* Convert the size to actually allocated. */
175 size = 1UL << (order + XEN_PAGE_SHIFT);
176
177 if (WARN_ON_ONCE(dma_handle + size - 1 > dev->coherent_dma_mask) ||
178 WARN_ON_ONCE(range_straddles_page_boundary(phys, size)))
179 return;
180
181 if (TestClearPageXenRemapped(virt_to_page(vaddr)))
182 xen_destroy_contiguous_region(phys, order);
183 free_pages((unsigned long)vaddr, get_order(size));
184}
185#endif /* CONFIG_X86 */
186
187/*
188 * Map a single buffer of the indicated size for DMA in streaming mode. The
189 * physical address to use is returned.
190 *
191 * Once the device is given the dma address, the device owns this memory until
192 * either xen_swiotlb_unmap_page or xen_swiotlb_dma_sync_single is performed.
193 */
194static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
195 unsigned long offset, size_t size,
196 enum dma_data_direction dir,
197 unsigned long attrs)
198{
199 phys_addr_t map, phys = page_to_phys(page) + offset;
200 dma_addr_t dev_addr = xen_phys_to_dma(dev, phys);
201
202 BUG_ON(dir == DMA_NONE);
203 /*
204 * If the address happens to be in the device's DMA window,
205 * we can safely return the device addr and not worry about bounce
206 * buffering it.
207 */
208 if (dma_capable(dev, dev_addr, size, true) &&
209 !range_straddles_page_boundary(phys, size) &&
210 !xen_arch_need_swiotlb(dev, phys, dev_addr) &&
211 !is_swiotlb_force_bounce(dev))
212 goto done;
213
214 /*
215 * Oh well, have to allocate and map a bounce buffer.
216 */
217 trace_swiotlb_bounced(dev, dev_addr, size);
218
219 map = swiotlb_tbl_map_single(dev, phys, size, size, 0, dir, attrs);
220 if (map == (phys_addr_t)DMA_MAPPING_ERROR)
221 return DMA_MAPPING_ERROR;
222
223 phys = map;
224 dev_addr = xen_phys_to_dma(dev, map);
225
226 /*
227 * Ensure that the address returned is DMA'ble
228 */
229 if (unlikely(!dma_capable(dev, dev_addr, size, true))) {
230 swiotlb_tbl_unmap_single(dev, map, size, dir,
231 attrs | DMA_ATTR_SKIP_CPU_SYNC);
232 return DMA_MAPPING_ERROR;
233 }
234
235done:
236 if (!dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
237 if (pfn_valid(PFN_DOWN(dma_to_phys(dev, dev_addr))))
238 arch_sync_dma_for_device(phys, size, dir);
239 else
240 xen_dma_sync_for_device(dev, dev_addr, size, dir);
241 }
242 return dev_addr;
243}
244
245/*
246 * Unmap a single streaming mode DMA translation. The dma_addr and size must
247 * match what was provided for in a previous xen_swiotlb_map_page call. All
248 * other usages are undefined.
249 *
250 * After this call, reads by the cpu to the buffer are guaranteed to see
251 * whatever the device wrote there.
252 */
253static void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
254 size_t size, enum dma_data_direction dir, unsigned long attrs)
255{
256 phys_addr_t paddr = xen_dma_to_phys(hwdev, dev_addr);
257
258 BUG_ON(dir == DMA_NONE);
259
260 if (!dev_is_dma_coherent(hwdev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
261 if (pfn_valid(PFN_DOWN(dma_to_phys(hwdev, dev_addr))))
262 arch_sync_dma_for_cpu(paddr, size, dir);
263 else
264 xen_dma_sync_for_cpu(hwdev, dev_addr, size, dir);
265 }
266
267 /* NOTE: We use dev_addr here, not paddr! */
268 if (is_xen_swiotlb_buffer(hwdev, dev_addr))
269 swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs);
270}
271
272static void
273xen_swiotlb_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr,
274 size_t size, enum dma_data_direction dir)
275{
276 phys_addr_t paddr = xen_dma_to_phys(dev, dma_addr);
277
278 if (!dev_is_dma_coherent(dev)) {
279 if (pfn_valid(PFN_DOWN(dma_to_phys(dev, dma_addr))))
280 arch_sync_dma_for_cpu(paddr, size, dir);
281 else
282 xen_dma_sync_for_cpu(dev, dma_addr, size, dir);
283 }
284
285 if (is_xen_swiotlb_buffer(dev, dma_addr))
286 swiotlb_sync_single_for_cpu(dev, paddr, size, dir);
287}
288
289static void
290xen_swiotlb_sync_single_for_device(struct device *dev, dma_addr_t dma_addr,
291 size_t size, enum dma_data_direction dir)
292{
293 phys_addr_t paddr = xen_dma_to_phys(dev, dma_addr);
294
295 if (is_xen_swiotlb_buffer(dev, dma_addr))
296 swiotlb_sync_single_for_device(dev, paddr, size, dir);
297
298 if (!dev_is_dma_coherent(dev)) {
299 if (pfn_valid(PFN_DOWN(dma_to_phys(dev, dma_addr))))
300 arch_sync_dma_for_device(paddr, size, dir);
301 else
302 xen_dma_sync_for_device(dev, dma_addr, size, dir);
303 }
304}
305
306/*
307 * Unmap a set of streaming mode DMA translations. Again, cpu read rules
308 * concerning calls here are the same as for swiotlb_unmap_page() above.
309 */
310static void
311xen_swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
312 enum dma_data_direction dir, unsigned long attrs)
313{
314 struct scatterlist *sg;
315 int i;
316
317 BUG_ON(dir == DMA_NONE);
318
319 for_each_sg(sgl, sg, nelems, i)
320 xen_swiotlb_unmap_page(hwdev, sg->dma_address, sg_dma_len(sg),
321 dir, attrs);
322
323}
324
325static int
326xen_swiotlb_map_sg(struct device *dev, struct scatterlist *sgl, int nelems,
327 enum dma_data_direction dir, unsigned long attrs)
328{
329 struct scatterlist *sg;
330 int i;
331
332 BUG_ON(dir == DMA_NONE);
333
334 for_each_sg(sgl, sg, nelems, i) {
335 sg->dma_address = xen_swiotlb_map_page(dev, sg_page(sg),
336 sg->offset, sg->length, dir, attrs);
337 if (sg->dma_address == DMA_MAPPING_ERROR)
338 goto out_unmap;
339 sg_dma_len(sg) = sg->length;
340 }
341
342 return nelems;
343out_unmap:
344 xen_swiotlb_unmap_sg(dev, sgl, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC);
345 sg_dma_len(sgl) = 0;
346 return -EIO;
347}
348
349static void
350xen_swiotlb_sync_sg_for_cpu(struct device *dev, struct scatterlist *sgl,
351 int nelems, enum dma_data_direction dir)
352{
353 struct scatterlist *sg;
354 int i;
355
356 for_each_sg(sgl, sg, nelems, i) {
357 xen_swiotlb_sync_single_for_cpu(dev, sg->dma_address,
358 sg->length, dir);
359 }
360}
361
362static void
363xen_swiotlb_sync_sg_for_device(struct device *dev, struct scatterlist *sgl,
364 int nelems, enum dma_data_direction dir)
365{
366 struct scatterlist *sg;
367 int i;
368
369 for_each_sg(sgl, sg, nelems, i) {
370 xen_swiotlb_sync_single_for_device(dev, sg->dma_address,
371 sg->length, dir);
372 }
373}
374
375/*
376 * Return whether the given device DMA address mask can be supported
377 * properly. For example, if your device can only drive the low 24-bits
378 * during bus mastering, then you would pass 0x00ffffff as the mask to
379 * this function.
380 */
381static int
382xen_swiotlb_dma_supported(struct device *hwdev, u64 mask)
383{
384 return xen_phys_to_dma(hwdev, io_tlb_default_mem.end - 1) <= mask;
385}
386
387const struct dma_map_ops xen_swiotlb_dma_ops = {
388#ifdef CONFIG_X86
389 .alloc = xen_swiotlb_alloc_coherent,
390 .free = xen_swiotlb_free_coherent,
391#else
392 .alloc = dma_direct_alloc,
393 .free = dma_direct_free,
394#endif
395 .sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu,
396 .sync_single_for_device = xen_swiotlb_sync_single_for_device,
397 .sync_sg_for_cpu = xen_swiotlb_sync_sg_for_cpu,
398 .sync_sg_for_device = xen_swiotlb_sync_sg_for_device,
399 .map_sg = xen_swiotlb_map_sg,
400 .unmap_sg = xen_swiotlb_unmap_sg,
401 .map_page = xen_swiotlb_map_page,
402 .unmap_page = xen_swiotlb_unmap_page,
403 .dma_supported = xen_swiotlb_dma_supported,
404 .mmap = dma_common_mmap,
405 .get_sgtable = dma_common_get_sgtable,
406 .alloc_pages = dma_common_alloc_pages,
407 .free_pages = dma_common_free_pages,
408};