1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2020 Google LLC
4 * Author: Quentin Perret <qperret@google.com>
5 */
6
7 #include <linux/kvm_host.h>
8 #include <asm/kvm_hyp.h>
9 #include <asm/kvm_mmu.h>
10 #include <asm/kvm_pgtable.h>
11 #include <asm/kvm_pkvm.h>
12
13 #include <nvhe/early_alloc.h>
14 #include <nvhe/ffa.h>
15 #include <nvhe/fixed_config.h>
16 #include <nvhe/gfp.h>
17 #include <nvhe/memory.h>
18 #include <nvhe/mem_protect.h>
19 #include <nvhe/mm.h>
20 #include <nvhe/pkvm.h>
21 #include <nvhe/trap_handler.h>
22
23 unsigned long hyp_nr_cpus;
24
25 #define hyp_percpu_size ((unsigned long)__per_cpu_end - \
26 (unsigned long)__per_cpu_start)
27
28 static void *vmemmap_base;
29 static void *vm_table_base;
30 static void *hyp_pgt_base;
31 static void *host_s2_pgt_base;
32 static void *ffa_proxy_pages;
33 static struct kvm_pgtable_mm_ops pkvm_pgtable_mm_ops;
34 static struct hyp_pool hpool;
35
divide_memory_pool(void * virt,unsigned long size)36 static int divide_memory_pool(void *virt, unsigned long size)
37 {
38 unsigned long nr_pages;
39
40 hyp_early_alloc_init(virt, size);
41
42 nr_pages = hyp_vmemmap_pages(sizeof(struct hyp_page));
43 vmemmap_base = hyp_early_alloc_contig(nr_pages);
44 if (!vmemmap_base)
45 return -ENOMEM;
46
47 nr_pages = hyp_vm_table_pages();
48 vm_table_base = hyp_early_alloc_contig(nr_pages);
49 if (!vm_table_base)
50 return -ENOMEM;
51
52 nr_pages = hyp_s1_pgtable_pages();
53 hyp_pgt_base = hyp_early_alloc_contig(nr_pages);
54 if (!hyp_pgt_base)
55 return -ENOMEM;
56
57 nr_pages = host_s2_pgtable_pages();
58 host_s2_pgt_base = hyp_early_alloc_contig(nr_pages);
59 if (!host_s2_pgt_base)
60 return -ENOMEM;
61
62 nr_pages = hyp_ffa_proxy_pages();
63 ffa_proxy_pages = hyp_early_alloc_contig(nr_pages);
64 if (!ffa_proxy_pages)
65 return -ENOMEM;
66
67 return 0;
68 }
69
recreate_hyp_mappings(phys_addr_t phys,unsigned long size,unsigned long * per_cpu_base,u32 hyp_va_bits)70 static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size,
71 unsigned long *per_cpu_base,
72 u32 hyp_va_bits)
73 {
74 void *start, *end, *virt = hyp_phys_to_virt(phys);
75 unsigned long pgt_size = hyp_s1_pgtable_pages() << PAGE_SHIFT;
76 enum kvm_pgtable_prot prot;
77 int ret, i;
78
79 /* Recreate the hyp page-table using the early page allocator */
80 hyp_early_alloc_init(hyp_pgt_base, pgt_size);
81 ret = kvm_pgtable_hyp_init(&pkvm_pgtable, hyp_va_bits,
82 &hyp_early_alloc_mm_ops);
83 if (ret)
84 return ret;
85
86 ret = hyp_create_idmap(hyp_va_bits);
87 if (ret)
88 return ret;
89
90 ret = hyp_map_vectors();
91 if (ret)
92 return ret;
93
94 ret = hyp_back_vmemmap(hyp_virt_to_phys(vmemmap_base));
95 if (ret)
96 return ret;
97
98 ret = pkvm_create_mappings(__hyp_text_start, __hyp_text_end, PAGE_HYP_EXEC);
99 if (ret)
100 return ret;
101
102 ret = pkvm_create_mappings(__hyp_rodata_start, __hyp_rodata_end, PAGE_HYP_RO);
103 if (ret)
104 return ret;
105
106 ret = pkvm_create_mappings(__hyp_bss_start, __hyp_bss_end, PAGE_HYP);
107 if (ret)
108 return ret;
109
110 ret = pkvm_create_mappings(virt, virt + size, PAGE_HYP);
111 if (ret)
112 return ret;
113
114 for (i = 0; i < hyp_nr_cpus; i++) {
115 struct kvm_nvhe_init_params *params = per_cpu_ptr(&kvm_init_params, i);
116
117 start = (void *)kern_hyp_va(per_cpu_base[i]);
118 end = start + PAGE_ALIGN(hyp_percpu_size);
119 ret = pkvm_create_mappings(start, end, PAGE_HYP);
120 if (ret)
121 return ret;
122
123 ret = pkvm_create_stack(params->stack_pa, ¶ms->stack_hyp_va);
124 if (ret)
125 return ret;
126 }
127
128 /*
129 * Map the host sections RO in the hypervisor, but transfer the
130 * ownership from the host to the hypervisor itself to make sure they
131 * can't be donated or shared with another entity.
132 *
133 * The ownership transition requires matching changes in the host
134 * stage-2. This will be done later (see finalize_host_mappings()) once
135 * the hyp_vmemmap is addressable.
136 */
137 prot = pkvm_mkstate(PAGE_HYP_RO, PKVM_PAGE_SHARED_OWNED);
138 ret = pkvm_create_mappings(&kvm_vgic_global_state,
139 &kvm_vgic_global_state + 1, prot);
140 if (ret)
141 return ret;
142
143 return 0;
144 }
145
update_nvhe_init_params(void)146 static void update_nvhe_init_params(void)
147 {
148 struct kvm_nvhe_init_params *params;
149 unsigned long i;
150
151 for (i = 0; i < hyp_nr_cpus; i++) {
152 params = per_cpu_ptr(&kvm_init_params, i);
153 params->pgd_pa = __hyp_pa(pkvm_pgtable.pgd);
154 dcache_clean_inval_poc((unsigned long)params,
155 (unsigned long)params + sizeof(*params));
156 }
157 }
158
hyp_zalloc_hyp_page(void * arg)159 static void *hyp_zalloc_hyp_page(void *arg)
160 {
161 return hyp_alloc_pages(&hpool, 0);
162 }
163
hpool_get_page(void * addr)164 static void hpool_get_page(void *addr)
165 {
166 hyp_get_page(&hpool, addr);
167 }
168
hpool_put_page(void * addr)169 static void hpool_put_page(void *addr)
170 {
171 hyp_put_page(&hpool, addr);
172 }
173
fix_host_ownership_walker(const struct kvm_pgtable_visit_ctx * ctx,enum kvm_pgtable_walk_flags visit)174 static int fix_host_ownership_walker(const struct kvm_pgtable_visit_ctx *ctx,
175 enum kvm_pgtable_walk_flags visit)
176 {
177 enum kvm_pgtable_prot prot;
178 enum pkvm_page_state state;
179 phys_addr_t phys;
180
181 if (!kvm_pte_valid(ctx->old))
182 return 0;
183
184 if (ctx->level != (KVM_PGTABLE_MAX_LEVELS - 1))
185 return -EINVAL;
186
187 phys = kvm_pte_to_phys(ctx->old);
188 if (!addr_is_memory(phys))
189 return -EINVAL;
190
191 /*
192 * Adjust the host stage-2 mappings to match the ownership attributes
193 * configured in the hypervisor stage-1.
194 */
195 state = pkvm_getstate(kvm_pgtable_hyp_pte_prot(ctx->old));
196 switch (state) {
197 case PKVM_PAGE_OWNED:
198 return host_stage2_set_owner_locked(phys, PAGE_SIZE, PKVM_ID_HYP);
199 case PKVM_PAGE_SHARED_OWNED:
200 prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_BORROWED);
201 break;
202 case PKVM_PAGE_SHARED_BORROWED:
203 prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_OWNED);
204 break;
205 default:
206 return -EINVAL;
207 }
208
209 return host_stage2_idmap_locked(phys, PAGE_SIZE, prot);
210 }
211
fix_hyp_pgtable_refcnt_walker(const struct kvm_pgtable_visit_ctx * ctx,enum kvm_pgtable_walk_flags visit)212 static int fix_hyp_pgtable_refcnt_walker(const struct kvm_pgtable_visit_ctx *ctx,
213 enum kvm_pgtable_walk_flags visit)
214 {
215 /*
216 * Fix-up the refcount for the page-table pages as the early allocator
217 * was unable to access the hyp_vmemmap and so the buddy allocator has
218 * initialised the refcount to '1'.
219 */
220 if (kvm_pte_valid(ctx->old))
221 ctx->mm_ops->get_page(ctx->ptep);
222
223 return 0;
224 }
225
fix_host_ownership(void)226 static int fix_host_ownership(void)
227 {
228 struct kvm_pgtable_walker walker = {
229 .cb = fix_host_ownership_walker,
230 .flags = KVM_PGTABLE_WALK_LEAF,
231 };
232 int i, ret;
233
234 for (i = 0; i < hyp_memblock_nr; i++) {
235 struct memblock_region *reg = &hyp_memory[i];
236 u64 start = (u64)hyp_phys_to_virt(reg->base);
237
238 ret = kvm_pgtable_walk(&pkvm_pgtable, start, reg->size, &walker);
239 if (ret)
240 return ret;
241 }
242
243 return 0;
244 }
245
fix_hyp_pgtable_refcnt(void)246 static int fix_hyp_pgtable_refcnt(void)
247 {
248 struct kvm_pgtable_walker walker = {
249 .cb = fix_hyp_pgtable_refcnt_walker,
250 .flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST,
251 .arg = pkvm_pgtable.mm_ops,
252 };
253
254 return kvm_pgtable_walk(&pkvm_pgtable, 0, BIT(pkvm_pgtable.ia_bits),
255 &walker);
256 }
257
__pkvm_init_finalise(void)258 void __noreturn __pkvm_init_finalise(void)
259 {
260 struct kvm_host_data *host_data = this_cpu_ptr(&kvm_host_data);
261 struct kvm_cpu_context *host_ctxt = &host_data->host_ctxt;
262 unsigned long nr_pages, reserved_pages, pfn;
263 int ret;
264
265 /* Now that the vmemmap is backed, install the full-fledged allocator */
266 pfn = hyp_virt_to_pfn(hyp_pgt_base);
267 nr_pages = hyp_s1_pgtable_pages();
268 reserved_pages = hyp_early_alloc_nr_used_pages();
269 ret = hyp_pool_init(&hpool, pfn, nr_pages, reserved_pages);
270 if (ret)
271 goto out;
272
273 ret = kvm_host_prepare_stage2(host_s2_pgt_base);
274 if (ret)
275 goto out;
276
277 pkvm_pgtable_mm_ops = (struct kvm_pgtable_mm_ops) {
278 .zalloc_page = hyp_zalloc_hyp_page,
279 .phys_to_virt = hyp_phys_to_virt,
280 .virt_to_phys = hyp_virt_to_phys,
281 .get_page = hpool_get_page,
282 .put_page = hpool_put_page,
283 .page_count = hyp_page_count,
284 };
285 pkvm_pgtable.mm_ops = &pkvm_pgtable_mm_ops;
286
287 ret = fix_host_ownership();
288 if (ret)
289 goto out;
290
291 ret = fix_hyp_pgtable_refcnt();
292 if (ret)
293 goto out;
294
295 ret = hyp_create_pcpu_fixmap();
296 if (ret)
297 goto out;
298
299 ret = hyp_ffa_init(ffa_proxy_pages);
300 if (ret)
301 goto out;
302
303 pkvm_hyp_vm_table_init(vm_table_base);
304 out:
305 /*
306 * We tail-called to here from handle___pkvm_init() and will not return,
307 * so make sure to propagate the return value to the host.
308 */
309 cpu_reg(host_ctxt, 1) = ret;
310
311 __host_enter(host_ctxt);
312 }
313
__pkvm_init(phys_addr_t phys,unsigned long size,unsigned long nr_cpus,unsigned long * per_cpu_base,u32 hyp_va_bits)314 int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
315 unsigned long *per_cpu_base, u32 hyp_va_bits)
316 {
317 struct kvm_nvhe_init_params *params;
318 void *virt = hyp_phys_to_virt(phys);
319 void (*fn)(phys_addr_t params_pa, void *finalize_fn_va);
320 int ret;
321
322 BUG_ON(kvm_check_pvm_sysreg_table());
323
324 if (!PAGE_ALIGNED(phys) || !PAGE_ALIGNED(size))
325 return -EINVAL;
326
327 hyp_spin_lock_init(&pkvm_pgd_lock);
328 hyp_nr_cpus = nr_cpus;
329
330 ret = divide_memory_pool(virt, size);
331 if (ret)
332 return ret;
333
334 ret = recreate_hyp_mappings(phys, size, per_cpu_base, hyp_va_bits);
335 if (ret)
336 return ret;
337
338 update_nvhe_init_params();
339
340 /* Jump in the idmap page to switch to the new page-tables */
341 params = this_cpu_ptr(&kvm_init_params);
342 fn = (typeof(fn))__hyp_pa(__pkvm_init_switch_pgd);
343 fn(__hyp_pa(params), __pkvm_init_finalise);
344
345 unreachable();
346 }
347