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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-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 bool range_requires_alignment(phys_addr_t p, size_t size)
78{
79 phys_addr_t algn = 1ULL << (get_order(size) + PAGE_SHIFT);
80 phys_addr_t bus_addr = pfn_to_bfn(XEN_PFN_DOWN(p)) << XEN_PAGE_SHIFT;
81
82 return IS_ALIGNED(p, algn) && !IS_ALIGNED(bus_addr, algn);
83}
84
85static inline int range_straddles_page_boundary(phys_addr_t p, size_t size)
86{
87 unsigned long next_bfn, xen_pfn = XEN_PFN_DOWN(p);
88 unsigned int i, nr_pages = XEN_PFN_UP(xen_offset_in_page(p) + size);
89
90 next_bfn = pfn_to_bfn(xen_pfn);
91
92 for (i = 1; i < nr_pages; i++)
93 if (pfn_to_bfn(++xen_pfn) != ++next_bfn)
94 return 1;
95
96 return 0;
97}
98
99static struct io_tlb_pool *xen_swiotlb_find_pool(struct device *dev,
100 dma_addr_t dma_addr)
101{
102 unsigned long bfn = XEN_PFN_DOWN(dma_to_phys(dev, dma_addr));
103 unsigned long xen_pfn = bfn_to_local_pfn(bfn);
104 phys_addr_t paddr = (phys_addr_t)xen_pfn << XEN_PAGE_SHIFT;
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_DOWN(paddr)))
111 return swiotlb_find_pool(dev, paddr);
112 return NULL;
113}
114
115#ifdef CONFIG_X86
116int xen_swiotlb_fixup(void *buf, unsigned long nslabs)
117{
118 int rc;
119 unsigned int order = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT);
120 unsigned int i, dma_bits = order + PAGE_SHIFT;
121 dma_addr_t dma_handle;
122 phys_addr_t p = virt_to_phys(buf);
123
124 BUILD_BUG_ON(IO_TLB_SEGSIZE & (IO_TLB_SEGSIZE - 1));
125 BUG_ON(nslabs % IO_TLB_SEGSIZE);
126
127 i = 0;
128 do {
129 do {
130 rc = xen_create_contiguous_region(
131 p + (i << IO_TLB_SHIFT), order,
132 dma_bits, &dma_handle);
133 } while (rc && dma_bits++ < MAX_DMA_BITS);
134 if (rc)
135 return rc;
136
137 i += IO_TLB_SEGSIZE;
138 } while (i < nslabs);
139 return 0;
140}
141
142static void *
143xen_swiotlb_alloc_coherent(struct device *dev, size_t size,
144 dma_addr_t *dma_handle, gfp_t flags, unsigned long attrs)
145{
146 u64 dma_mask = dev->coherent_dma_mask;
147 int order = get_order(size);
148 phys_addr_t phys;
149 void *ret;
150
151 /* Align the allocation to the Xen page size */
152 size = ALIGN(size, XEN_PAGE_SIZE);
153
154 ret = (void *)__get_free_pages(flags, get_order(size));
155 if (!ret)
156 return ret;
157 phys = virt_to_phys(ret);
158
159 *dma_handle = xen_phys_to_dma(dev, phys);
160 if (*dma_handle + size - 1 > dma_mask ||
161 range_straddles_page_boundary(phys, size) ||
162 range_requires_alignment(phys, size)) {
163 if (xen_create_contiguous_region(phys, order, fls64(dma_mask),
164 dma_handle) != 0)
165 goto out_free_pages;
166 SetPageXenRemapped(virt_to_page(ret));
167 }
168
169 memset(ret, 0, size);
170 return ret;
171
172out_free_pages:
173 free_pages((unsigned long)ret, get_order(size));
174 return NULL;
175}
176
177static void
178xen_swiotlb_free_coherent(struct device *dev, size_t size, void *vaddr,
179 dma_addr_t dma_handle, unsigned long attrs)
180{
181 phys_addr_t phys = virt_to_phys(vaddr);
182 int order = get_order(size);
183
184 /* Convert the size to actually allocated. */
185 size = ALIGN(size, XEN_PAGE_SIZE);
186
187 if (WARN_ON_ONCE(dma_handle + size - 1 > dev->coherent_dma_mask) ||
188 WARN_ON_ONCE(range_straddles_page_boundary(phys, size) ||
189 range_requires_alignment(phys, size)))
190 return;
191
192 if (TestClearPageXenRemapped(virt_to_page(vaddr)))
193 xen_destroy_contiguous_region(phys, order);
194 free_pages((unsigned long)vaddr, get_order(size));
195}
196#endif /* CONFIG_X86 */
197
198/*
199 * Map a single buffer of the indicated size for DMA in streaming mode. The
200 * physical address to use is returned.
201 *
202 * Once the device is given the dma address, the device owns this memory until
203 * either xen_swiotlb_unmap_page or xen_swiotlb_dma_sync_single is performed.
204 */
205static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
206 unsigned long offset, size_t size,
207 enum dma_data_direction dir,
208 unsigned long attrs)
209{
210 phys_addr_t map, phys = page_to_phys(page) + offset;
211 dma_addr_t dev_addr = xen_phys_to_dma(dev, phys);
212
213 BUG_ON(dir == DMA_NONE);
214 /*
215 * If the address happens to be in the device's DMA window,
216 * we can safely return the device addr and not worry about bounce
217 * buffering it.
218 */
219 if (dma_capable(dev, dev_addr, size, true) &&
220 !range_straddles_page_boundary(phys, size) &&
221 !xen_arch_need_swiotlb(dev, phys, dev_addr) &&
222 !is_swiotlb_force_bounce(dev))
223 goto done;
224
225 /*
226 * Oh well, have to allocate and map a bounce buffer.
227 */
228 trace_swiotlb_bounced(dev, dev_addr, size);
229
230 map = swiotlb_tbl_map_single(dev, phys, size, 0, dir, attrs);
231 if (map == (phys_addr_t)DMA_MAPPING_ERROR)
232 return DMA_MAPPING_ERROR;
233
234 phys = map;
235 dev_addr = xen_phys_to_dma(dev, map);
236
237 /*
238 * Ensure that the address returned is DMA'ble
239 */
240 if (unlikely(!dma_capable(dev, dev_addr, size, true))) {
241 __swiotlb_tbl_unmap_single(dev, map, size, dir,
242 attrs | DMA_ATTR_SKIP_CPU_SYNC,
243 swiotlb_find_pool(dev, map));
244 return DMA_MAPPING_ERROR;
245 }
246
247done:
248 if (!dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
249 if (pfn_valid(PFN_DOWN(dma_to_phys(dev, dev_addr))))
250 arch_sync_dma_for_device(phys, size, dir);
251 else
252 xen_dma_sync_for_device(dev, dev_addr, size, dir);
253 }
254 return dev_addr;
255}
256
257/*
258 * Unmap a single streaming mode DMA translation. The dma_addr and size must
259 * match what was provided for in a previous xen_swiotlb_map_page call. All
260 * other usages are undefined.
261 *
262 * After this call, reads by the cpu to the buffer are guaranteed to see
263 * whatever the device wrote there.
264 */
265static void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
266 size_t size, enum dma_data_direction dir, unsigned long attrs)
267{
268 phys_addr_t paddr = xen_dma_to_phys(hwdev, dev_addr);
269 struct io_tlb_pool *pool;
270
271 BUG_ON(dir == DMA_NONE);
272
273 if (!dev_is_dma_coherent(hwdev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
274 if (pfn_valid(PFN_DOWN(dma_to_phys(hwdev, dev_addr))))
275 arch_sync_dma_for_cpu(paddr, size, dir);
276 else
277 xen_dma_sync_for_cpu(hwdev, dev_addr, size, dir);
278 }
279
280 /* NOTE: We use dev_addr here, not paddr! */
281 pool = xen_swiotlb_find_pool(hwdev, dev_addr);
282 if (pool)
283 __swiotlb_tbl_unmap_single(hwdev, paddr, size, dir,
284 attrs, pool);
285}
286
287static void
288xen_swiotlb_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr,
289 size_t size, enum dma_data_direction dir)
290{
291 phys_addr_t paddr = xen_dma_to_phys(dev, dma_addr);
292 struct io_tlb_pool *pool;
293
294 if (!dev_is_dma_coherent(dev)) {
295 if (pfn_valid(PFN_DOWN(dma_to_phys(dev, dma_addr))))
296 arch_sync_dma_for_cpu(paddr, size, dir);
297 else
298 xen_dma_sync_for_cpu(dev, dma_addr, size, dir);
299 }
300
301 pool = xen_swiotlb_find_pool(dev, dma_addr);
302 if (pool)
303 __swiotlb_sync_single_for_cpu(dev, paddr, size, dir, pool);
304}
305
306static void
307xen_swiotlb_sync_single_for_device(struct device *dev, dma_addr_t dma_addr,
308 size_t size, enum dma_data_direction dir)
309{
310 phys_addr_t paddr = xen_dma_to_phys(dev, dma_addr);
311 struct io_tlb_pool *pool;
312
313 pool = xen_swiotlb_find_pool(dev, dma_addr);
314 if (pool)
315 __swiotlb_sync_single_for_device(dev, paddr, size, dir, pool);
316
317 if (!dev_is_dma_coherent(dev)) {
318 if (pfn_valid(PFN_DOWN(dma_to_phys(dev, dma_addr))))
319 arch_sync_dma_for_device(paddr, size, dir);
320 else
321 xen_dma_sync_for_device(dev, dma_addr, size, dir);
322 }
323}
324
325/*
326 * Unmap a set of streaming mode DMA translations. Again, cpu read rules
327 * concerning calls here are the same as for swiotlb_unmap_page() above.
328 */
329static void
330xen_swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
331 enum dma_data_direction dir, unsigned long attrs)
332{
333 struct scatterlist *sg;
334 int i;
335
336 BUG_ON(dir == DMA_NONE);
337
338 for_each_sg(sgl, sg, nelems, i)
339 xen_swiotlb_unmap_page(hwdev, sg->dma_address, sg_dma_len(sg),
340 dir, attrs);
341
342}
343
344static int
345xen_swiotlb_map_sg(struct device *dev, struct scatterlist *sgl, int nelems,
346 enum dma_data_direction dir, unsigned long attrs)
347{
348 struct scatterlist *sg;
349 int i;
350
351 BUG_ON(dir == DMA_NONE);
352
353 for_each_sg(sgl, sg, nelems, i) {
354 sg->dma_address = xen_swiotlb_map_page(dev, sg_page(sg),
355 sg->offset, sg->length, dir, attrs);
356 if (sg->dma_address == DMA_MAPPING_ERROR)
357 goto out_unmap;
358 sg_dma_len(sg) = sg->length;
359 }
360
361 return nelems;
362out_unmap:
363 xen_swiotlb_unmap_sg(dev, sgl, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC);
364 sg_dma_len(sgl) = 0;
365 return -EIO;
366}
367
368static void
369xen_swiotlb_sync_sg_for_cpu(struct device *dev, struct scatterlist *sgl,
370 int nelems, enum dma_data_direction dir)
371{
372 struct scatterlist *sg;
373 int i;
374
375 for_each_sg(sgl, sg, nelems, i) {
376 xen_swiotlb_sync_single_for_cpu(dev, sg->dma_address,
377 sg->length, dir);
378 }
379}
380
381static void
382xen_swiotlb_sync_sg_for_device(struct device *dev, struct scatterlist *sgl,
383 int nelems, enum dma_data_direction dir)
384{
385 struct scatterlist *sg;
386 int i;
387
388 for_each_sg(sgl, sg, nelems, i) {
389 xen_swiotlb_sync_single_for_device(dev, sg->dma_address,
390 sg->length, dir);
391 }
392}
393
394/*
395 * Return whether the given device DMA address mask can be supported
396 * properly. For example, if your device can only drive the low 24-bits
397 * during bus mastering, then you would pass 0x00ffffff as the mask to
398 * this function.
399 */
400static int
401xen_swiotlb_dma_supported(struct device *hwdev, u64 mask)
402{
403 return xen_phys_to_dma(hwdev, default_swiotlb_limit()) <= mask;
404}
405
406const struct dma_map_ops xen_swiotlb_dma_ops = {
407#ifdef CONFIG_X86
408 .alloc = xen_swiotlb_alloc_coherent,
409 .free = xen_swiotlb_free_coherent,
410#else
411 .alloc = dma_direct_alloc,
412 .free = dma_direct_free,
413#endif
414 .sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu,
415 .sync_single_for_device = xen_swiotlb_sync_single_for_device,
416 .sync_sg_for_cpu = xen_swiotlb_sync_sg_for_cpu,
417 .sync_sg_for_device = xen_swiotlb_sync_sg_for_device,
418 .map_sg = xen_swiotlb_map_sg,
419 .unmap_sg = xen_swiotlb_unmap_sg,
420 .map_page = xen_swiotlb_map_page,
421 .unmap_page = xen_swiotlb_unmap_page,
422 .dma_supported = xen_swiotlb_dma_supported,
423 .mmap = dma_common_mmap,
424 .get_sgtable = dma_common_get_sgtable,
425 .alloc_pages_op = dma_common_alloc_pages,
426 .free_pages = dma_common_free_pages,
427 .max_mapping_size = swiotlb_max_mapping_size,
428};
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, default_swiotlb_limit()) <= 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 .max_mapping_size = swiotlb_max_mapping_size,
409};