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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-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 inline phys_addr_t xen_phys_to_bus(struct device *dev, phys_addr_t paddr)
56{
57 unsigned long bfn = pfn_to_bfn(XEN_PFN_DOWN(paddr));
58 phys_addr_t baddr = (phys_addr_t)bfn << XEN_PAGE_SHIFT;
59
60 baddr |= paddr & ~XEN_PAGE_MASK;
61 return baddr;
62}
63
64static inline dma_addr_t xen_phys_to_dma(struct device *dev, phys_addr_t paddr)
65{
66 return phys_to_dma(dev, xen_phys_to_bus(dev, paddr));
67}
68
69static inline phys_addr_t xen_bus_to_phys(struct device *dev,
70 phys_addr_t baddr)
71{
72 unsigned long xen_pfn = bfn_to_pfn(XEN_PFN_DOWN(baddr));
73 phys_addr_t paddr = (xen_pfn << XEN_PAGE_SHIFT) |
74 (baddr & ~XEN_PAGE_MASK);
75
76 return paddr;
77}
78
79static inline phys_addr_t xen_dma_to_phys(struct device *dev,
80 dma_addr_t dma_addr)
81{
82 return xen_bus_to_phys(dev, dma_to_phys(dev, dma_addr));
83}
84
85static inline dma_addr_t xen_virt_to_bus(struct device *dev, void *address)
86{
87 return xen_phys_to_dma(dev, virt_to_phys(address));
88}
89
90static inline int range_straddles_page_boundary(phys_addr_t p, size_t size)
91{
92 unsigned long next_bfn, xen_pfn = XEN_PFN_DOWN(p);
93 unsigned int i, nr_pages = XEN_PFN_UP(xen_offset_in_page(p) + size);
94
95 next_bfn = pfn_to_bfn(xen_pfn);
96
97 for (i = 1; i < nr_pages; i++)
98 if (pfn_to_bfn(++xen_pfn) != ++next_bfn)
99 return 1;
100
101 return 0;
102}
103
104static int is_xen_swiotlb_buffer(struct device *dev, dma_addr_t dma_addr)
105{
106 unsigned long bfn = XEN_PFN_DOWN(dma_to_phys(dev, dma_addr));
107 unsigned long xen_pfn = bfn_to_local_pfn(bfn);
108 phys_addr_t paddr = (phys_addr_t)xen_pfn << XEN_PAGE_SHIFT;
109
110 /* If the address is outside our domain, it CAN
111 * have the same virtual address as another address
112 * in our domain. Therefore _only_ check address within our domain.
113 */
114 if (pfn_valid(PFN_DOWN(paddr))) {
115 return paddr >= virt_to_phys(xen_io_tlb_start) &&
116 paddr < virt_to_phys(xen_io_tlb_end);
117 }
118 return 0;
119}
120
121static int
122xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
123{
124 int i, rc;
125 int dma_bits;
126 dma_addr_t dma_handle;
127 phys_addr_t p = virt_to_phys(buf);
128
129 dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
130
131 i = 0;
132 do {
133 int slabs = min(nslabs - i, (unsigned long)IO_TLB_SEGSIZE);
134
135 do {
136 rc = xen_create_contiguous_region(
137 p + (i << IO_TLB_SHIFT),
138 get_order(slabs << IO_TLB_SHIFT),
139 dma_bits, &dma_handle);
140 } while (rc && dma_bits++ < MAX_DMA_BITS);
141 if (rc)
142 return rc;
143
144 i += slabs;
145 } while (i < nslabs);
146 return 0;
147}
148static unsigned long xen_set_nslabs(unsigned long nr_tbl)
149{
150 if (!nr_tbl) {
151 xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
152 xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
153 } else
154 xen_io_tlb_nslabs = nr_tbl;
155
156 return xen_io_tlb_nslabs << IO_TLB_SHIFT;
157}
158
159enum xen_swiotlb_err {
160 XEN_SWIOTLB_UNKNOWN = 0,
161 XEN_SWIOTLB_ENOMEM,
162 XEN_SWIOTLB_EFIXUP
163};
164
165static const char *xen_swiotlb_error(enum xen_swiotlb_err err)
166{
167 switch (err) {
168 case XEN_SWIOTLB_ENOMEM:
169 return "Cannot allocate Xen-SWIOTLB buffer\n";
170 case XEN_SWIOTLB_EFIXUP:
171 return "Failed to get contiguous memory for DMA from Xen!\n"\
172 "You either: don't have the permissions, do not have"\
173 " enough free memory under 4GB, or the hypervisor memory"\
174 " is too fragmented!";
175 default:
176 break;
177 }
178 return "";
179}
180int __ref xen_swiotlb_init(int verbose, bool early)
181{
182 unsigned long bytes, order;
183 int rc = -ENOMEM;
184 enum xen_swiotlb_err m_ret = XEN_SWIOTLB_UNKNOWN;
185 unsigned int repeat = 3;
186
187 xen_io_tlb_nslabs = swiotlb_nr_tbl();
188retry:
189 bytes = xen_set_nslabs(xen_io_tlb_nslabs);
190 order = get_order(xen_io_tlb_nslabs << IO_TLB_SHIFT);
191
192 /*
193 * IO TLB memory already allocated. Just use it.
194 */
195 if (io_tlb_start != 0) {
196 xen_io_tlb_start = phys_to_virt(io_tlb_start);
197 goto end;
198 }
199
200 /*
201 * Get IO TLB memory from any location.
202 */
203 if (early) {
204 xen_io_tlb_start = memblock_alloc(PAGE_ALIGN(bytes),
205 PAGE_SIZE);
206 if (!xen_io_tlb_start)
207 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
208 __func__, PAGE_ALIGN(bytes), PAGE_SIZE);
209 } else {
210#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
211#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
212 while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
213 xen_io_tlb_start = (void *)xen_get_swiotlb_free_pages(order);
214 if (xen_io_tlb_start)
215 break;
216 order--;
217 }
218 if (order != get_order(bytes)) {
219 pr_warn("Warning: only able to allocate %ld MB for software IO TLB\n",
220 (PAGE_SIZE << order) >> 20);
221 xen_io_tlb_nslabs = SLABS_PER_PAGE << order;
222 bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;
223 }
224 }
225 if (!xen_io_tlb_start) {
226 m_ret = XEN_SWIOTLB_ENOMEM;
227 goto error;
228 }
229 /*
230 * And replace that memory with pages under 4GB.
231 */
232 rc = xen_swiotlb_fixup(xen_io_tlb_start,
233 bytes,
234 xen_io_tlb_nslabs);
235 if (rc) {
236 if (early)
237 memblock_free(__pa(xen_io_tlb_start),
238 PAGE_ALIGN(bytes));
239 else {
240 free_pages((unsigned long)xen_io_tlb_start, order);
241 xen_io_tlb_start = NULL;
242 }
243 m_ret = XEN_SWIOTLB_EFIXUP;
244 goto error;
245 }
246 if (early) {
247 if (swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs,
248 verbose))
249 panic("Cannot allocate SWIOTLB buffer");
250 rc = 0;
251 } else
252 rc = swiotlb_late_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs);
253
254end:
255 xen_io_tlb_end = xen_io_tlb_start + bytes;
256 if (!rc)
257 swiotlb_set_max_segment(PAGE_SIZE);
258
259 return rc;
260error:
261 if (repeat--) {
262 xen_io_tlb_nslabs = max(1024UL, /* Min is 2MB */
263 (xen_io_tlb_nslabs >> 1));
264 pr_info("Lowering to %luMB\n",
265 (xen_io_tlb_nslabs << IO_TLB_SHIFT) >> 20);
266 goto retry;
267 }
268 pr_err("%s (rc:%d)\n", xen_swiotlb_error(m_ret), rc);
269 if (early)
270 panic("%s (rc:%d)", xen_swiotlb_error(m_ret), rc);
271 else
272 free_pages((unsigned long)xen_io_tlb_start, order);
273 return rc;
274}
275
276static void *
277xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
278 dma_addr_t *dma_handle, gfp_t flags,
279 unsigned long attrs)
280{
281 void *ret;
282 int order = get_order(size);
283 u64 dma_mask = DMA_BIT_MASK(32);
284 phys_addr_t phys;
285 dma_addr_t dev_addr;
286
287 /*
288 * Ignore region specifiers - the kernel's ideas of
289 * pseudo-phys memory layout has nothing to do with the
290 * machine physical layout. We can't allocate highmem
291 * because we can't return a pointer to it.
292 */
293 flags &= ~(__GFP_DMA | __GFP_HIGHMEM);
294
295 /* Convert the size to actually allocated. */
296 size = 1UL << (order + XEN_PAGE_SHIFT);
297
298 /* On ARM this function returns an ioremap'ped virtual address for
299 * which virt_to_phys doesn't return the corresponding physical
300 * address. In fact on ARM virt_to_phys only works for kernel direct
301 * mapped RAM memory. Also see comment below.
302 */
303 ret = xen_alloc_coherent_pages(hwdev, size, dma_handle, flags, attrs);
304
305 if (!ret)
306 return ret;
307
308 if (hwdev && hwdev->coherent_dma_mask)
309 dma_mask = hwdev->coherent_dma_mask;
310
311 /* At this point dma_handle is the dma address, next we are
312 * going to set it to the machine address.
313 * Do not use virt_to_phys(ret) because on ARM it doesn't correspond
314 * to *dma_handle. */
315 phys = dma_to_phys(hwdev, *dma_handle);
316 dev_addr = xen_phys_to_dma(hwdev, phys);
317 if (((dev_addr + size - 1 <= dma_mask)) &&
318 !range_straddles_page_boundary(phys, size))
319 *dma_handle = dev_addr;
320 else {
321 if (xen_create_contiguous_region(phys, order,
322 fls64(dma_mask), dma_handle) != 0) {
323 xen_free_coherent_pages(hwdev, size, ret, (dma_addr_t)phys, attrs);
324 return NULL;
325 }
326 *dma_handle = phys_to_dma(hwdev, *dma_handle);
327 SetPageXenRemapped(virt_to_page(ret));
328 }
329 memset(ret, 0, size);
330 return ret;
331}
332
333static void
334xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
335 dma_addr_t dev_addr, unsigned long attrs)
336{
337 int order = get_order(size);
338 phys_addr_t phys;
339 u64 dma_mask = DMA_BIT_MASK(32);
340 struct page *page;
341
342 if (hwdev && hwdev->coherent_dma_mask)
343 dma_mask = hwdev->coherent_dma_mask;
344
345 /* do not use virt_to_phys because on ARM it doesn't return you the
346 * physical address */
347 phys = xen_dma_to_phys(hwdev, dev_addr);
348
349 /* Convert the size to actually allocated. */
350 size = 1UL << (order + XEN_PAGE_SHIFT);
351
352 if (is_vmalloc_addr(vaddr))
353 page = vmalloc_to_page(vaddr);
354 else
355 page = virt_to_page(vaddr);
356
357 if (!WARN_ON((dev_addr + size - 1 > dma_mask) ||
358 range_straddles_page_boundary(phys, size)) &&
359 TestClearPageXenRemapped(page))
360 xen_destroy_contiguous_region(phys, order);
361
362 xen_free_coherent_pages(hwdev, size, vaddr, phys_to_dma(hwdev, phys),
363 attrs);
364}
365
366/*
367 * Map a single buffer of the indicated size for DMA in streaming mode. The
368 * physical address to use is returned.
369 *
370 * Once the device is given the dma address, the device owns this memory until
371 * either xen_swiotlb_unmap_page or xen_swiotlb_dma_sync_single is performed.
372 */
373static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
374 unsigned long offset, size_t size,
375 enum dma_data_direction dir,
376 unsigned long attrs)
377{
378 phys_addr_t map, phys = page_to_phys(page) + offset;
379 dma_addr_t dev_addr = xen_phys_to_dma(dev, phys);
380
381 BUG_ON(dir == DMA_NONE);
382 /*
383 * If the address happens to be in the device's DMA window,
384 * we can safely return the device addr and not worry about bounce
385 * buffering it.
386 */
387 if (dma_capable(dev, dev_addr, size, true) &&
388 !range_straddles_page_boundary(phys, size) &&
389 !xen_arch_need_swiotlb(dev, phys, dev_addr) &&
390 swiotlb_force != SWIOTLB_FORCE)
391 goto done;
392
393 /*
394 * Oh well, have to allocate and map a bounce buffer.
395 */
396 trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);
397
398 map = swiotlb_tbl_map_single(dev, virt_to_phys(xen_io_tlb_start),
399 phys, size, size, dir, attrs);
400 if (map == (phys_addr_t)DMA_MAPPING_ERROR)
401 return DMA_MAPPING_ERROR;
402
403 phys = map;
404 dev_addr = xen_phys_to_dma(dev, map);
405
406 /*
407 * Ensure that the address returned is DMA'ble
408 */
409 if (unlikely(!dma_capable(dev, dev_addr, size, true))) {
410 swiotlb_tbl_unmap_single(dev, map, size, size, dir,
411 attrs | DMA_ATTR_SKIP_CPU_SYNC);
412 return DMA_MAPPING_ERROR;
413 }
414
415done:
416 if (!dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
417 if (pfn_valid(PFN_DOWN(dma_to_phys(dev, dev_addr))))
418 arch_sync_dma_for_device(phys, size, dir);
419 else
420 xen_dma_sync_for_device(dev, dev_addr, size, dir);
421 }
422 return dev_addr;
423}
424
425/*
426 * Unmap a single streaming mode DMA translation. The dma_addr and size must
427 * match what was provided for in a previous xen_swiotlb_map_page call. All
428 * other usages are undefined.
429 *
430 * After this call, reads by the cpu to the buffer are guaranteed to see
431 * whatever the device wrote there.
432 */
433static void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
434 size_t size, enum dma_data_direction dir, unsigned long attrs)
435{
436 phys_addr_t paddr = xen_dma_to_phys(hwdev, dev_addr);
437
438 BUG_ON(dir == DMA_NONE);
439
440 if (!dev_is_dma_coherent(hwdev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
441 if (pfn_valid(PFN_DOWN(dma_to_phys(hwdev, dev_addr))))
442 arch_sync_dma_for_cpu(paddr, size, dir);
443 else
444 xen_dma_sync_for_cpu(hwdev, dev_addr, size, dir);
445 }
446
447 /* NOTE: We use dev_addr here, not paddr! */
448 if (is_xen_swiotlb_buffer(hwdev, dev_addr))
449 swiotlb_tbl_unmap_single(hwdev, paddr, size, size, dir, attrs);
450}
451
452static void
453xen_swiotlb_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr,
454 size_t size, enum dma_data_direction dir)
455{
456 phys_addr_t paddr = xen_dma_to_phys(dev, dma_addr);
457
458 if (!dev_is_dma_coherent(dev)) {
459 if (pfn_valid(PFN_DOWN(dma_to_phys(dev, dma_addr))))
460 arch_sync_dma_for_cpu(paddr, size, dir);
461 else
462 xen_dma_sync_for_cpu(dev, dma_addr, size, dir);
463 }
464
465 if (is_xen_swiotlb_buffer(dev, dma_addr))
466 swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_CPU);
467}
468
469static void
470xen_swiotlb_sync_single_for_device(struct device *dev, dma_addr_t dma_addr,
471 size_t size, enum dma_data_direction dir)
472{
473 phys_addr_t paddr = xen_dma_to_phys(dev, dma_addr);
474
475 if (is_xen_swiotlb_buffer(dev, dma_addr))
476 swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_DEVICE);
477
478 if (!dev_is_dma_coherent(dev)) {
479 if (pfn_valid(PFN_DOWN(dma_to_phys(dev, dma_addr))))
480 arch_sync_dma_for_device(paddr, size, dir);
481 else
482 xen_dma_sync_for_device(dev, dma_addr, size, dir);
483 }
484}
485
486/*
487 * Unmap a set of streaming mode DMA translations. Again, cpu read rules
488 * concerning calls here are the same as for swiotlb_unmap_page() above.
489 */
490static void
491xen_swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
492 enum dma_data_direction dir, unsigned long attrs)
493{
494 struct scatterlist *sg;
495 int i;
496
497 BUG_ON(dir == DMA_NONE);
498
499 for_each_sg(sgl, sg, nelems, i)
500 xen_swiotlb_unmap_page(hwdev, sg->dma_address, sg_dma_len(sg),
501 dir, attrs);
502
503}
504
505static int
506xen_swiotlb_map_sg(struct device *dev, struct scatterlist *sgl, int nelems,
507 enum dma_data_direction dir, unsigned long attrs)
508{
509 struct scatterlist *sg;
510 int i;
511
512 BUG_ON(dir == DMA_NONE);
513
514 for_each_sg(sgl, sg, nelems, i) {
515 sg->dma_address = xen_swiotlb_map_page(dev, sg_page(sg),
516 sg->offset, sg->length, dir, attrs);
517 if (sg->dma_address == DMA_MAPPING_ERROR)
518 goto out_unmap;
519 sg_dma_len(sg) = sg->length;
520 }
521
522 return nelems;
523out_unmap:
524 xen_swiotlb_unmap_sg(dev, sgl, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC);
525 sg_dma_len(sgl) = 0;
526 return 0;
527}
528
529static void
530xen_swiotlb_sync_sg_for_cpu(struct device *dev, struct scatterlist *sgl,
531 int nelems, enum dma_data_direction dir)
532{
533 struct scatterlist *sg;
534 int i;
535
536 for_each_sg(sgl, sg, nelems, i) {
537 xen_swiotlb_sync_single_for_cpu(dev, sg->dma_address,
538 sg->length, dir);
539 }
540}
541
542static void
543xen_swiotlb_sync_sg_for_device(struct device *dev, struct scatterlist *sgl,
544 int nelems, enum dma_data_direction dir)
545{
546 struct scatterlist *sg;
547 int i;
548
549 for_each_sg(sgl, sg, nelems, i) {
550 xen_swiotlb_sync_single_for_device(dev, sg->dma_address,
551 sg->length, dir);
552 }
553}
554
555/*
556 * Return whether the given device DMA address mask can be supported
557 * properly. For example, if your device can only drive the low 24-bits
558 * during bus mastering, then you would pass 0x00ffffff as the mask to
559 * this function.
560 */
561static int
562xen_swiotlb_dma_supported(struct device *hwdev, u64 mask)
563{
564 return xen_virt_to_bus(hwdev, xen_io_tlb_end - 1) <= mask;
565}
566
567const struct dma_map_ops xen_swiotlb_dma_ops = {
568 .alloc = xen_swiotlb_alloc_coherent,
569 .free = xen_swiotlb_free_coherent,
570 .sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu,
571 .sync_single_for_device = xen_swiotlb_sync_single_for_device,
572 .sync_sg_for_cpu = xen_swiotlb_sync_sg_for_cpu,
573 .sync_sg_for_device = xen_swiotlb_sync_sg_for_device,
574 .map_sg = xen_swiotlb_map_sg,
575 .unmap_sg = xen_swiotlb_unmap_sg,
576 .map_page = xen_swiotlb_map_page,
577 .unmap_page = xen_swiotlb_unmap_page,
578 .dma_supported = xen_swiotlb_dma_supported,
579 .mmap = dma_common_mmap,
580 .get_sgtable = dma_common_get_sgtable,
581};