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 struct kvm_pgtable_mm_ops pkvm_pgtable_mm_ops;
21 unsigned long hyp_nr_cpus;
22
23 #define hyp_percpu_size ((unsigned long)__per_cpu_end - \
24 (unsigned long)__per_cpu_start)
25
26 static void *vmemmap_base;
27 static void *hyp_pgt_base;
28 static void *host_s2_mem_pgt_base;
29 static void *host_s2_dev_pgt_base;
30
divide_memory_pool(void * virt,unsigned long size)31 static int divide_memory_pool(void *virt, unsigned long size)
32 {
33 unsigned long vstart, vend, nr_pages;
34
35 hyp_early_alloc_init(virt, size);
36
37 hyp_vmemmap_range(__hyp_pa(virt), size, &vstart, &vend);
38 nr_pages = (vend - vstart) >> PAGE_SHIFT;
39 vmemmap_base = hyp_early_alloc_contig(nr_pages);
40 if (!vmemmap_base)
41 return -ENOMEM;
42
43 nr_pages = hyp_s1_pgtable_pages();
44 hyp_pgt_base = hyp_early_alloc_contig(nr_pages);
45 if (!hyp_pgt_base)
46 return -ENOMEM;
47
48 nr_pages = host_s2_mem_pgtable_pages();
49 host_s2_mem_pgt_base = hyp_early_alloc_contig(nr_pages);
50 if (!host_s2_mem_pgt_base)
51 return -ENOMEM;
52
53 nr_pages = host_s2_dev_pgtable_pages();
54 host_s2_dev_pgt_base = hyp_early_alloc_contig(nr_pages);
55 if (!host_s2_dev_pgt_base)
56 return -ENOMEM;
57
58 return 0;
59 }
60
recreate_hyp_mappings(phys_addr_t phys,unsigned long size,unsigned long * per_cpu_base,u32 hyp_va_bits)61 static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size,
62 unsigned long *per_cpu_base,
63 u32 hyp_va_bits)
64 {
65 void *start, *end, *virt = hyp_phys_to_virt(phys);
66 unsigned long pgt_size = hyp_s1_pgtable_pages() << PAGE_SHIFT;
67 int ret, i;
68
69 /* Recreate the hyp page-table using the early page allocator */
70 hyp_early_alloc_init(hyp_pgt_base, pgt_size);
71 ret = kvm_pgtable_hyp_init(&pkvm_pgtable, hyp_va_bits,
72 &hyp_early_alloc_mm_ops);
73 if (ret)
74 return ret;
75
76 ret = hyp_create_idmap(hyp_va_bits);
77 if (ret)
78 return ret;
79
80 ret = hyp_map_vectors();
81 if (ret)
82 return ret;
83
84 ret = hyp_back_vmemmap(phys, size, hyp_virt_to_phys(vmemmap_base));
85 if (ret)
86 return ret;
87
88 ret = pkvm_create_mappings(__hyp_text_start, __hyp_text_end, PAGE_HYP_EXEC);
89 if (ret)
90 return ret;
91
92 ret = pkvm_create_mappings(__start_rodata, __end_rodata, PAGE_HYP_RO);
93 if (ret)
94 return ret;
95
96 ret = pkvm_create_mappings(__hyp_rodata_start, __hyp_rodata_end, PAGE_HYP_RO);
97 if (ret)
98 return ret;
99
100 ret = pkvm_create_mappings(__hyp_bss_start, __hyp_bss_end, PAGE_HYP);
101 if (ret)
102 return ret;
103
104 ret = pkvm_create_mappings(__hyp_bss_end, __bss_stop, PAGE_HYP_RO);
105 if (ret)
106 return ret;
107
108 ret = pkvm_create_mappings(virt, virt + size, PAGE_HYP);
109 if (ret)
110 return ret;
111
112 for (i = 0; i < hyp_nr_cpus; i++) {
113 start = (void *)kern_hyp_va(per_cpu_base[i]);
114 end = start + PAGE_ALIGN(hyp_percpu_size);
115 ret = pkvm_create_mappings(start, end, PAGE_HYP);
116 if (ret)
117 return ret;
118
119 end = (void *)per_cpu_ptr(&kvm_init_params, i)->stack_hyp_va;
120 start = end - PAGE_SIZE;
121 ret = pkvm_create_mappings(start, end, PAGE_HYP);
122 if (ret)
123 return ret;
124 }
125
126 return 0;
127 }
128
update_nvhe_init_params(void)129 static void update_nvhe_init_params(void)
130 {
131 struct kvm_nvhe_init_params *params;
132 unsigned long i;
133
134 for (i = 0; i < hyp_nr_cpus; i++) {
135 params = per_cpu_ptr(&kvm_init_params, i);
136 params->pgd_pa = __hyp_pa(pkvm_pgtable.pgd);
137 __flush_dcache_area(params, sizeof(*params));
138 }
139 }
140
hyp_zalloc_hyp_page(void * arg)141 static void *hyp_zalloc_hyp_page(void *arg)
142 {
143 return hyp_alloc_pages(&hpool, 0);
144 }
145
__pkvm_init_finalise(void)146 void __noreturn __pkvm_init_finalise(void)
147 {
148 struct kvm_host_data *host_data = this_cpu_ptr(&kvm_host_data);
149 struct kvm_cpu_context *host_ctxt = &host_data->host_ctxt;
150 unsigned long nr_pages, reserved_pages, pfn;
151 int ret;
152
153 /* Now that the vmemmap is backed, install the full-fledged allocator */
154 pfn = hyp_virt_to_pfn(hyp_pgt_base);
155 nr_pages = hyp_s1_pgtable_pages();
156 reserved_pages = hyp_early_alloc_nr_used_pages();
157 ret = hyp_pool_init(&hpool, pfn, nr_pages, reserved_pages);
158 if (ret)
159 goto out;
160
161 ret = kvm_host_prepare_stage2(host_s2_mem_pgt_base, host_s2_dev_pgt_base);
162 if (ret)
163 goto out;
164
165 pkvm_pgtable_mm_ops = (struct kvm_pgtable_mm_ops) {
166 .zalloc_page = hyp_zalloc_hyp_page,
167 .phys_to_virt = hyp_phys_to_virt,
168 .virt_to_phys = hyp_virt_to_phys,
169 .get_page = hyp_get_page,
170 .put_page = hyp_put_page,
171 };
172 pkvm_pgtable.mm_ops = &pkvm_pgtable_mm_ops;
173
174 out:
175 /*
176 * We tail-called to here from handle___pkvm_init() and will not return,
177 * so make sure to propagate the return value to the host.
178 */
179 cpu_reg(host_ctxt, 1) = ret;
180
181 __host_enter(host_ctxt);
182 }
183
__pkvm_init(phys_addr_t phys,unsigned long size,unsigned long nr_cpus,unsigned long * per_cpu_base,u32 hyp_va_bits)184 int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
185 unsigned long *per_cpu_base, u32 hyp_va_bits)
186 {
187 struct kvm_nvhe_init_params *params;
188 void *virt = hyp_phys_to_virt(phys);
189 void (*fn)(phys_addr_t params_pa, void *finalize_fn_va);
190 int ret;
191
192 if (!PAGE_ALIGNED(phys) || !PAGE_ALIGNED(size))
193 return -EINVAL;
194
195 hyp_spin_lock_init(&pkvm_pgd_lock);
196 hyp_nr_cpus = nr_cpus;
197
198 ret = divide_memory_pool(virt, size);
199 if (ret)
200 return ret;
201
202 ret = recreate_hyp_mappings(phys, size, per_cpu_base, hyp_va_bits);
203 if (ret)
204 return ret;
205
206 update_nvhe_init_params();
207
208 /* Jump in the idmap page to switch to the new page-tables */
209 params = this_cpu_ptr(&kvm_init_params);
210 fn = (typeof(fn))__hyp_pa(__pkvm_init_switch_pgd);
211 fn(__hyp_pa(params), __pkvm_init_finalise);
212
213 unreachable();
214 }
215