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
12 #include <nvhe/early_alloc.h>
13 #include <nvhe/gfp.h>
14 #include <nvhe/memory.h>
15 #include <nvhe/mem_protect.h>
16 #include <nvhe/mm.h>
17 #include <nvhe/trap_handler.h>
18
19 struct hyp_pool hpool;
20 unsigned long hyp_nr_cpus;
21
22 #define hyp_percpu_size ((unsigned long)__per_cpu_end - \
23 (unsigned long)__per_cpu_start)
24
25 static void *vmemmap_base;
26 static void *hyp_pgt_base;
27 static void *host_s2_pgt_base;
28 static struct kvm_pgtable_mm_ops pkvm_pgtable_mm_ops;
29
divide_memory_pool(void * virt,unsigned long size)30 static int divide_memory_pool(void *virt, unsigned long size)
31 {
32 unsigned long vstart, vend, nr_pages;
33
34 hyp_early_alloc_init(virt, size);
35
36 hyp_vmemmap_range(__hyp_pa(virt), size, &vstart, &vend);
37 nr_pages = (vend - vstart) >> PAGE_SHIFT;
38 vmemmap_base = hyp_early_alloc_contig(nr_pages);
39 if (!vmemmap_base)
40 return -ENOMEM;
41
42 nr_pages = hyp_s1_pgtable_pages();
43 hyp_pgt_base = hyp_early_alloc_contig(nr_pages);
44 if (!hyp_pgt_base)
45 return -ENOMEM;
46
47 nr_pages = host_s2_pgtable_pages();
48 host_s2_pgt_base = hyp_early_alloc_contig(nr_pages);
49 if (!host_s2_pgt_base)
50 return -ENOMEM;
51
52 return 0;
53 }
54
recreate_hyp_mappings(phys_addr_t phys,unsigned long size,unsigned long * per_cpu_base,u32 hyp_va_bits)55 static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size,
56 unsigned long *per_cpu_base,
57 u32 hyp_va_bits)
58 {
59 void *start, *end, *virt = hyp_phys_to_virt(phys);
60 unsigned long pgt_size = hyp_s1_pgtable_pages() << PAGE_SHIFT;
61 enum kvm_pgtable_prot prot;
62 int ret, i;
63
64 /* Recreate the hyp page-table using the early page allocator */
65 hyp_early_alloc_init(hyp_pgt_base, pgt_size);
66 ret = kvm_pgtable_hyp_init(&pkvm_pgtable, hyp_va_bits,
67 &hyp_early_alloc_mm_ops);
68 if (ret)
69 return ret;
70
71 ret = hyp_create_idmap(hyp_va_bits);
72 if (ret)
73 return ret;
74
75 ret = hyp_map_vectors();
76 if (ret)
77 return ret;
78
79 ret = hyp_back_vmemmap(phys, size, hyp_virt_to_phys(vmemmap_base));
80 if (ret)
81 return ret;
82
83 ret = pkvm_create_mappings(__hyp_text_start, __hyp_text_end, PAGE_HYP_EXEC);
84 if (ret)
85 return ret;
86
87 ret = pkvm_create_mappings(__hyp_rodata_start, __hyp_rodata_end, PAGE_HYP_RO);
88 if (ret)
89 return ret;
90
91 ret = pkvm_create_mappings(__hyp_bss_start, __hyp_bss_end, PAGE_HYP);
92 if (ret)
93 return ret;
94
95 ret = pkvm_create_mappings(virt, virt + size, PAGE_HYP);
96 if (ret)
97 return ret;
98
99 for (i = 0; i < hyp_nr_cpus; i++) {
100 start = (void *)kern_hyp_va(per_cpu_base[i]);
101 end = start + PAGE_ALIGN(hyp_percpu_size);
102 ret = pkvm_create_mappings(start, end, PAGE_HYP);
103 if (ret)
104 return ret;
105
106 end = (void *)per_cpu_ptr(&kvm_init_params, i)->stack_hyp_va;
107 start = end - PAGE_SIZE;
108 ret = pkvm_create_mappings(start, end, PAGE_HYP);
109 if (ret)
110 return ret;
111 }
112
113 /*
114 * Map the host's .bss and .rodata sections RO in the hypervisor, but
115 * transfer the ownership from the host to the hypervisor itself to
116 * make sure it can't be donated or shared with another entity.
117 *
118 * The ownership transition requires matching changes in the host
119 * stage-2. This will be done later (see finalize_host_mappings()) once
120 * the hyp_vmemmap is addressable.
121 */
122 prot = pkvm_mkstate(PAGE_HYP_RO, PKVM_PAGE_SHARED_OWNED);
123 ret = pkvm_create_mappings(__start_rodata, __end_rodata, prot);
124 if (ret)
125 return ret;
126
127 ret = pkvm_create_mappings(__hyp_bss_end, __bss_stop, prot);
128 if (ret)
129 return ret;
130
131 return 0;
132 }
133
update_nvhe_init_params(void)134 static void update_nvhe_init_params(void)
135 {
136 struct kvm_nvhe_init_params *params;
137 unsigned long i;
138
139 for (i = 0; i < hyp_nr_cpus; i++) {
140 params = per_cpu_ptr(&kvm_init_params, i);
141 params->pgd_pa = __hyp_pa(pkvm_pgtable.pgd);
142 dcache_clean_inval_poc((unsigned long)params,
143 (unsigned long)params + sizeof(*params));
144 }
145 }
146
hyp_zalloc_hyp_page(void * arg)147 static void *hyp_zalloc_hyp_page(void *arg)
148 {
149 return hyp_alloc_pages(&hpool, 0);
150 }
151
hpool_get_page(void * addr)152 static void hpool_get_page(void *addr)
153 {
154 hyp_get_page(&hpool, addr);
155 }
156
hpool_put_page(void * addr)157 static void hpool_put_page(void *addr)
158 {
159 hyp_put_page(&hpool, addr);
160 }
161
finalize_host_mappings_walker(u64 addr,u64 end,u32 level,kvm_pte_t * ptep,enum kvm_pgtable_walk_flags flag,void * const arg)162 static int finalize_host_mappings_walker(u64 addr, u64 end, u32 level,
163 kvm_pte_t *ptep,
164 enum kvm_pgtable_walk_flags flag,
165 void * const arg)
166 {
167 enum kvm_pgtable_prot prot;
168 enum pkvm_page_state state;
169 kvm_pte_t pte = *ptep;
170 phys_addr_t phys;
171
172 if (!kvm_pte_valid(pte))
173 return 0;
174
175 if (level != (KVM_PGTABLE_MAX_LEVELS - 1))
176 return -EINVAL;
177
178 phys = kvm_pte_to_phys(pte);
179 if (!addr_is_memory(phys))
180 return 0;
181
182 /*
183 * Adjust the host stage-2 mappings to match the ownership attributes
184 * configured in the hypervisor stage-1.
185 */
186 state = pkvm_getstate(kvm_pgtable_hyp_pte_prot(pte));
187 switch (state) {
188 case PKVM_PAGE_OWNED:
189 return host_stage2_set_owner_locked(phys, PAGE_SIZE, pkvm_hyp_id);
190 case PKVM_PAGE_SHARED_OWNED:
191 prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_BORROWED);
192 break;
193 case PKVM_PAGE_SHARED_BORROWED:
194 prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_OWNED);
195 break;
196 default:
197 return -EINVAL;
198 }
199
200 return host_stage2_idmap_locked(phys, PAGE_SIZE, prot);
201 }
202
finalize_host_mappings(void)203 static int finalize_host_mappings(void)
204 {
205 struct kvm_pgtable_walker walker = {
206 .cb = finalize_host_mappings_walker,
207 .flags = KVM_PGTABLE_WALK_LEAF,
208 };
209
210 return kvm_pgtable_walk(&pkvm_pgtable, 0, BIT(pkvm_pgtable.ia_bits), &walker);
211 }
212
__pkvm_init_finalise(void)213 void __noreturn __pkvm_init_finalise(void)
214 {
215 struct kvm_host_data *host_data = this_cpu_ptr(&kvm_host_data);
216 struct kvm_cpu_context *host_ctxt = &host_data->host_ctxt;
217 unsigned long nr_pages, reserved_pages, pfn;
218 int ret;
219
220 /* Now that the vmemmap is backed, install the full-fledged allocator */
221 pfn = hyp_virt_to_pfn(hyp_pgt_base);
222 nr_pages = hyp_s1_pgtable_pages();
223 reserved_pages = hyp_early_alloc_nr_used_pages();
224 ret = hyp_pool_init(&hpool, pfn, nr_pages, reserved_pages);
225 if (ret)
226 goto out;
227
228 ret = kvm_host_prepare_stage2(host_s2_pgt_base);
229 if (ret)
230 goto out;
231
232 ret = finalize_host_mappings();
233 if (ret)
234 goto out;
235
236 pkvm_pgtable_mm_ops = (struct kvm_pgtable_mm_ops) {
237 .zalloc_page = hyp_zalloc_hyp_page,
238 .phys_to_virt = hyp_phys_to_virt,
239 .virt_to_phys = hyp_virt_to_phys,
240 .get_page = hpool_get_page,
241 .put_page = hpool_put_page,
242 };
243 pkvm_pgtable.mm_ops = &pkvm_pgtable_mm_ops;
244
245 out:
246 /*
247 * We tail-called to here from handle___pkvm_init() and will not return,
248 * so make sure to propagate the return value to the host.
249 */
250 cpu_reg(host_ctxt, 1) = ret;
251
252 __host_enter(host_ctxt);
253 }
254
__pkvm_init(phys_addr_t phys,unsigned long size,unsigned long nr_cpus,unsigned long * per_cpu_base,u32 hyp_va_bits)255 int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
256 unsigned long *per_cpu_base, u32 hyp_va_bits)
257 {
258 struct kvm_nvhe_init_params *params;
259 void *virt = hyp_phys_to_virt(phys);
260 void (*fn)(phys_addr_t params_pa, void *finalize_fn_va);
261 int ret;
262
263 if (!PAGE_ALIGNED(phys) || !PAGE_ALIGNED(size))
264 return -EINVAL;
265
266 hyp_spin_lock_init(&pkvm_pgd_lock);
267 hyp_nr_cpus = nr_cpus;
268
269 ret = divide_memory_pool(virt, size);
270 if (ret)
271 return ret;
272
273 ret = recreate_hyp_mappings(phys, size, per_cpu_base, hyp_va_bits);
274 if (ret)
275 return ret;
276
277 update_nvhe_init_params();
278
279 /* Jump in the idmap page to switch to the new page-tables */
280 params = this_cpu_ptr(&kvm_init_params);
281 fn = (typeof(fn))__hyp_pa(__pkvm_init_switch_pgd);
282 fn(__hyp_pa(params), __pkvm_init_finalise);
283
284 unreachable();
285 }
286
