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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/*
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);