xref: /linux/drivers/iommu/amd/io_pgtable_v2.c (revision 4e94ddfe2aab72139acb8d5372fac9e6c3f3e383) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * CPU-agnostic AMD IO page table v2 allocator.
4  *
5  * Copyright (C) 2022, 2023 Advanced Micro Devices, Inc.
6  * Author: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
7  * Author: Vasant Hegde <vasant.hegde@amd.com>
8  */
9 
10 #define pr_fmt(fmt)	"AMD-Vi: " fmt
11 #define dev_fmt(fmt)	pr_fmt(fmt)
12 
13 #include <linux/bitops.h>
14 #include <linux/io-pgtable.h>
15 #include <linux/kernel.h>
16 
17 #include <asm/barrier.h>
18 
19 #include "amd_iommu_types.h"
20 #include "amd_iommu.h"
21 
22 #define IOMMU_PAGE_PRESENT	BIT_ULL(0)	/* Is present */
23 #define IOMMU_PAGE_RW		BIT_ULL(1)	/* Writeable */
24 #define IOMMU_PAGE_USER		BIT_ULL(2)	/* Userspace addressable */
25 #define IOMMU_PAGE_PWT		BIT_ULL(3)	/* Page write through */
26 #define IOMMU_PAGE_PCD		BIT_ULL(4)	/* Page cache disabled */
27 #define IOMMU_PAGE_ACCESS	BIT_ULL(5)	/* Was accessed (updated by IOMMU) */
28 #define IOMMU_PAGE_DIRTY	BIT_ULL(6)	/* Was written to (updated by IOMMU) */
29 #define IOMMU_PAGE_PSE		BIT_ULL(7)	/* Page Size Extensions */
30 #define IOMMU_PAGE_NX		BIT_ULL(63)	/* No execute */
31 
32 #define MAX_PTRS_PER_PAGE	512
33 
34 #define IOMMU_PAGE_SIZE_2M	BIT_ULL(21)
35 #define IOMMU_PAGE_SIZE_1G	BIT_ULL(30)
36 
37 
38 static inline int get_pgtable_level(void)
39 {
40 	return amd_iommu_gpt_level;
41 }
42 
43 static inline bool is_large_pte(u64 pte)
44 {
45 	return (pte & IOMMU_PAGE_PSE);
46 }
47 
48 static inline u64 set_pgtable_attr(u64 *page)
49 {
50 	u64 prot;
51 
52 	prot = IOMMU_PAGE_PRESENT | IOMMU_PAGE_RW | IOMMU_PAGE_USER;
53 	prot |= IOMMU_PAGE_ACCESS | IOMMU_PAGE_DIRTY;
54 
55 	return (iommu_virt_to_phys(page) | prot);
56 }
57 
58 static inline void *get_pgtable_pte(u64 pte)
59 {
60 	return iommu_phys_to_virt(pte & PM_ADDR_MASK);
61 }
62 
63 static u64 set_pte_attr(u64 paddr, u64 pg_size, int prot)
64 {
65 	u64 pte;
66 
67 	pte = __sme_set(paddr & PM_ADDR_MASK);
68 	pte |= IOMMU_PAGE_PRESENT | IOMMU_PAGE_USER;
69 	pte |= IOMMU_PAGE_ACCESS | IOMMU_PAGE_DIRTY;
70 
71 	if (prot & IOMMU_PROT_IW)
72 		pte |= IOMMU_PAGE_RW;
73 
74 	/* Large page */
75 	if (pg_size == IOMMU_PAGE_SIZE_1G || pg_size == IOMMU_PAGE_SIZE_2M)
76 		pte |= IOMMU_PAGE_PSE;
77 
78 	return pte;
79 }
80 
81 static inline u64 get_alloc_page_size(u64 size)
82 {
83 	if (size >= IOMMU_PAGE_SIZE_1G)
84 		return IOMMU_PAGE_SIZE_1G;
85 
86 	if (size >= IOMMU_PAGE_SIZE_2M)
87 		return IOMMU_PAGE_SIZE_2M;
88 
89 	return PAGE_SIZE;
90 }
91 
92 static inline int page_size_to_level(u64 pg_size)
93 {
94 	if (pg_size == IOMMU_PAGE_SIZE_1G)
95 		return PAGE_MODE_3_LEVEL;
96 	if (pg_size == IOMMU_PAGE_SIZE_2M)
97 		return PAGE_MODE_2_LEVEL;
98 
99 	return PAGE_MODE_1_LEVEL;
100 }
101 
102 static inline void free_pgtable_page(u64 *pt)
103 {
104 	free_page((unsigned long)pt);
105 }
106 
107 static void free_pgtable(u64 *pt, int level)
108 {
109 	u64 *p;
110 	int i;
111 
112 	for (i = 0; i < MAX_PTRS_PER_PAGE; i++) {
113 		/* PTE present? */
114 		if (!IOMMU_PTE_PRESENT(pt[i]))
115 			continue;
116 
117 		if (is_large_pte(pt[i]))
118 			continue;
119 
120 		/*
121 		 * Free the next level. No need to look at l1 tables here since
122 		 * they can only contain leaf PTEs; just free them directly.
123 		 */
124 		p = get_pgtable_pte(pt[i]);
125 		if (level > 2)
126 			free_pgtable(p, level - 1);
127 		else
128 			free_pgtable_page(p);
129 	}
130 
131 	free_pgtable_page(pt);
132 }
133 
134 /* Allocate page table */
135 static u64 *v2_alloc_pte(int nid, u64 *pgd, unsigned long iova,
136 			 unsigned long pg_size, gfp_t gfp, bool *updated)
137 {
138 	u64 *pte, *page;
139 	int level, end_level;
140 
141 	level = get_pgtable_level() - 1;
142 	end_level = page_size_to_level(pg_size);
143 	pte = &pgd[PM_LEVEL_INDEX(level, iova)];
144 	iova = PAGE_SIZE_ALIGN(iova, PAGE_SIZE);
145 
146 	while (level >= end_level) {
147 		u64 __pte, __npte;
148 
149 		__pte = *pte;
150 
151 		if (IOMMU_PTE_PRESENT(__pte) && is_large_pte(__pte)) {
152 			/* Unmap large pte */
153 			cmpxchg64(pte, *pte, 0ULL);
154 			*updated = true;
155 			continue;
156 		}
157 
158 		if (!IOMMU_PTE_PRESENT(__pte)) {
159 			page = alloc_pgtable_page(nid, gfp);
160 			if (!page)
161 				return NULL;
162 
163 			__npte = set_pgtable_attr(page);
164 			/* pte could have been changed somewhere. */
165 			if (cmpxchg64(pte, __pte, __npte) != __pte)
166 				free_pgtable_page(page);
167 			else if (IOMMU_PTE_PRESENT(__pte))
168 				*updated = true;
169 
170 			continue;
171 		}
172 
173 		level -= 1;
174 		pte = get_pgtable_pte(__pte);
175 		pte = &pte[PM_LEVEL_INDEX(level, iova)];
176 	}
177 
178 	/* Tear down existing pte entries */
179 	if (IOMMU_PTE_PRESENT(*pte)) {
180 		u64 *__pte;
181 
182 		*updated = true;
183 		__pte = get_pgtable_pte(*pte);
184 		cmpxchg64(pte, *pte, 0ULL);
185 		if (pg_size == IOMMU_PAGE_SIZE_1G)
186 			free_pgtable(__pte, end_level - 1);
187 		else if (pg_size == IOMMU_PAGE_SIZE_2M)
188 			free_pgtable_page(__pte);
189 	}
190 
191 	return pte;
192 }
193 
194 /*
195  * This function checks if there is a PTE for a given dma address.
196  * If there is one, it returns the pointer to it.
197  */
198 static u64 *fetch_pte(struct amd_io_pgtable *pgtable,
199 		      unsigned long iova, unsigned long *page_size)
200 {
201 	u64 *pte;
202 	int level;
203 
204 	level = get_pgtable_level() - 1;
205 	pte = &pgtable->pgd[PM_LEVEL_INDEX(level, iova)];
206 	/* Default page size is 4K */
207 	*page_size = PAGE_SIZE;
208 
209 	while (level) {
210 		/* Not present */
211 		if (!IOMMU_PTE_PRESENT(*pte))
212 			return NULL;
213 
214 		/* Walk to the next level */
215 		pte = get_pgtable_pte(*pte);
216 		pte = &pte[PM_LEVEL_INDEX(level - 1, iova)];
217 
218 		/* Large page */
219 		if (is_large_pte(*pte)) {
220 			if (level == PAGE_MODE_3_LEVEL)
221 				*page_size = IOMMU_PAGE_SIZE_1G;
222 			else if (level == PAGE_MODE_2_LEVEL)
223 				*page_size = IOMMU_PAGE_SIZE_2M;
224 			else
225 				return NULL;	/* Wrongly set PSE bit in PTE */
226 
227 			break;
228 		}
229 
230 		level -= 1;
231 	}
232 
233 	return pte;
234 }
235 
236 static int iommu_v2_map_pages(struct io_pgtable_ops *ops, unsigned long iova,
237 			      phys_addr_t paddr, size_t pgsize, size_t pgcount,
238 			      int prot, gfp_t gfp, size_t *mapped)
239 {
240 	struct protection_domain *pdom = io_pgtable_ops_to_domain(ops);
241 	struct io_pgtable_cfg *cfg = &pdom->iop.iop.cfg;
242 	u64 *pte;
243 	unsigned long map_size;
244 	unsigned long mapped_size = 0;
245 	unsigned long o_iova = iova;
246 	size_t size = pgcount << __ffs(pgsize);
247 	int count = 0;
248 	int ret = 0;
249 	bool updated = false;
250 
251 	if (WARN_ON(!pgsize || (pgsize & cfg->pgsize_bitmap) != pgsize) || !pgcount)
252 		return -EINVAL;
253 
254 	if (!(prot & IOMMU_PROT_MASK))
255 		return -EINVAL;
256 
257 	while (mapped_size < size) {
258 		map_size = get_alloc_page_size(pgsize);
259 		pte = v2_alloc_pte(pdom->nid, pdom->iop.pgd,
260 				   iova, map_size, gfp, &updated);
261 		if (!pte) {
262 			ret = -EINVAL;
263 			goto out;
264 		}
265 
266 		*pte = set_pte_attr(paddr, map_size, prot);
267 
268 		count++;
269 		iova += map_size;
270 		paddr += map_size;
271 		mapped_size += map_size;
272 	}
273 
274 out:
275 	if (updated) {
276 		if (count > 1)
277 			amd_iommu_flush_tlb(&pdom->domain, 0);
278 		else
279 			amd_iommu_flush_page(&pdom->domain, 0, o_iova);
280 	}
281 
282 	if (mapped)
283 		*mapped += mapped_size;
284 
285 	return ret;
286 }
287 
288 static unsigned long iommu_v2_unmap_pages(struct io_pgtable_ops *ops,
289 					  unsigned long iova,
290 					  size_t pgsize, size_t pgcount,
291 					  struct iommu_iotlb_gather *gather)
292 {
293 	struct amd_io_pgtable *pgtable = io_pgtable_ops_to_data(ops);
294 	struct io_pgtable_cfg *cfg = &pgtable->iop.cfg;
295 	unsigned long unmap_size;
296 	unsigned long unmapped = 0;
297 	size_t size = pgcount << __ffs(pgsize);
298 	u64 *pte;
299 
300 	if (WARN_ON(!pgsize || (pgsize & cfg->pgsize_bitmap) != pgsize || !pgcount))
301 		return 0;
302 
303 	while (unmapped < size) {
304 		pte = fetch_pte(pgtable, iova, &unmap_size);
305 		if (!pte)
306 			return unmapped;
307 
308 		*pte = 0ULL;
309 
310 		iova = (iova & ~(unmap_size - 1)) + unmap_size;
311 		unmapped += unmap_size;
312 	}
313 
314 	return unmapped;
315 }
316 
317 static phys_addr_t iommu_v2_iova_to_phys(struct io_pgtable_ops *ops, unsigned long iova)
318 {
319 	struct amd_io_pgtable *pgtable = io_pgtable_ops_to_data(ops);
320 	unsigned long offset_mask, pte_pgsize;
321 	u64 *pte, __pte;
322 
323 	pte = fetch_pte(pgtable, iova, &pte_pgsize);
324 	if (!pte || !IOMMU_PTE_PRESENT(*pte))
325 		return 0;
326 
327 	offset_mask = pte_pgsize - 1;
328 	__pte = __sme_clr(*pte & PM_ADDR_MASK);
329 
330 	return (__pte & ~offset_mask) | (iova & offset_mask);
331 }
332 
333 /*
334  * ----------------------------------------------------
335  */
336 static void v2_tlb_flush_all(void *cookie)
337 {
338 }
339 
340 static void v2_tlb_flush_walk(unsigned long iova, size_t size,
341 			      size_t granule, void *cookie)
342 {
343 }
344 
345 static void v2_tlb_add_page(struct iommu_iotlb_gather *gather,
346 			    unsigned long iova, size_t granule,
347 			    void *cookie)
348 {
349 }
350 
351 static const struct iommu_flush_ops v2_flush_ops = {
352 	.tlb_flush_all	= v2_tlb_flush_all,
353 	.tlb_flush_walk = v2_tlb_flush_walk,
354 	.tlb_add_page	= v2_tlb_add_page,
355 };
356 
357 static void v2_free_pgtable(struct io_pgtable *iop)
358 {
359 	struct protection_domain *pdom;
360 	struct amd_io_pgtable *pgtable = container_of(iop, struct amd_io_pgtable, iop);
361 
362 	pdom = container_of(pgtable, struct protection_domain, iop);
363 	if (!(pdom->flags & PD_IOMMUV2_MASK))
364 		return;
365 
366 	/* Clear gcr3 entry */
367 	amd_iommu_domain_clear_gcr3(&pdom->domain, 0);
368 
369 	/* Make changes visible to IOMMUs */
370 	amd_iommu_domain_update(pdom);
371 
372 	/* Free page table */
373 	free_pgtable(pgtable->pgd, get_pgtable_level());
374 }
375 
376 static struct io_pgtable *v2_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
377 {
378 	struct amd_io_pgtable *pgtable = io_pgtable_cfg_to_data(cfg);
379 	struct protection_domain *pdom = (struct protection_domain *)cookie;
380 	int ret;
381 	int ias = IOMMU_IN_ADDR_BIT_SIZE;
382 
383 	pgtable->pgd = alloc_pgtable_page(pdom->nid, GFP_ATOMIC);
384 	if (!pgtable->pgd)
385 		return NULL;
386 
387 	ret = amd_iommu_domain_set_gcr3(&pdom->domain, 0, iommu_virt_to_phys(pgtable->pgd));
388 	if (ret)
389 		goto err_free_pgd;
390 
391 	if (get_pgtable_level() == PAGE_MODE_5_LEVEL)
392 		ias = 57;
393 
394 	pgtable->iop.ops.map_pages    = iommu_v2_map_pages;
395 	pgtable->iop.ops.unmap_pages  = iommu_v2_unmap_pages;
396 	pgtable->iop.ops.iova_to_phys = iommu_v2_iova_to_phys;
397 
398 	cfg->pgsize_bitmap = AMD_IOMMU_PGSIZES_V2,
399 	cfg->ias           = ias,
400 	cfg->oas           = IOMMU_OUT_ADDR_BIT_SIZE,
401 	cfg->tlb           = &v2_flush_ops;
402 
403 	return &pgtable->iop;
404 
405 err_free_pgd:
406 	free_pgtable_page(pgtable->pgd);
407 
408 	return NULL;
409 }
410 
411 struct io_pgtable_init_fns io_pgtable_amd_iommu_v2_init_fns = {
412 	.alloc	= v2_alloc_pgtable,
413 	.free	= v2_free_pgtable,
414 };
415