1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2020 - Google LLC
4 * Author: Quentin Perret <qperret@google.com>
5 */
6
7 #include <linux/init.h>
8 #include <linux/kmemleak.h>
9 #include <linux/kvm_host.h>
10 #include <linux/memblock.h>
11 #include <linux/mutex.h>
12 #include <linux/sort.h>
13
14 #include <asm/kvm_pkvm.h>
15
16 #include "hyp_constants.h"
17
18 DEFINE_STATIC_KEY_FALSE(kvm_protected_mode_initialized);
19
20 static struct memblock_region *hyp_memory = kvm_nvhe_sym(hyp_memory);
21 static unsigned int *hyp_memblock_nr_ptr = &kvm_nvhe_sym(hyp_memblock_nr);
22
23 phys_addr_t hyp_mem_base;
24 phys_addr_t hyp_mem_size;
25
26 static int cmp_hyp_memblock(const void *p1, const void *p2)
27 {
28 const struct memblock_region *r1 = p1;
29 const struct memblock_region *r2 = p2;
30
31 return r1->base < r2->base ? -1 : (r1->base > r2->base);
32 }
33
34 static void __init sort_memblock_regions(void)
35 {
36 sort(hyp_memory,
37 *hyp_memblock_nr_ptr,
38 sizeof(struct memblock_region),
39 cmp_hyp_memblock,
40 NULL);
41 }
42
43 static int __init register_memblock_regions(void)
44 {
45 struct memblock_region *reg;
46
47 for_each_mem_region(reg) {
48 if (*hyp_memblock_nr_ptr >= HYP_MEMBLOCK_REGIONS)
49 return -ENOMEM;
50
51 hyp_memory[*hyp_memblock_nr_ptr] = *reg;
52 (*hyp_memblock_nr_ptr)++;
53 }
54 sort_memblock_regions();
55
56 return 0;
57 }
58
59 void __init kvm_hyp_reserve(void)
60 {
61 u64 hyp_mem_pages = 0;
62 int ret;
63
64 if (!is_hyp_mode_available() || is_kernel_in_hyp_mode())
65 return;
66
67 if (kvm_get_mode() != KVM_MODE_PROTECTED)
68 return;
69
70 ret = register_memblock_regions();
71 if (ret) {
72 *hyp_memblock_nr_ptr = 0;
73 kvm_err("Failed to register hyp memblocks: %d\n", ret);
74 return;
75 }
76
77 hyp_mem_pages += hyp_s1_pgtable_pages();
78 hyp_mem_pages += host_s2_pgtable_pages();
79 hyp_mem_pages += hyp_vm_table_pages();
80 hyp_mem_pages += hyp_vmemmap_pages(STRUCT_HYP_PAGE_SIZE);
81 hyp_mem_pages += hyp_ffa_proxy_pages();
82
83 /*
84 * Try to allocate a PMD-aligned region to reduce TLB pressure once
85 * this is unmapped from the host stage-2, and fallback to PAGE_SIZE.
86 */
87 hyp_mem_size = hyp_mem_pages << PAGE_SHIFT;
88 hyp_mem_base = memblock_phys_alloc(ALIGN(hyp_mem_size, PMD_SIZE),
89 PMD_SIZE);
90 if (!hyp_mem_base)
91 hyp_mem_base = memblock_phys_alloc(hyp_mem_size, PAGE_SIZE);
92 else
93 hyp_mem_size = ALIGN(hyp_mem_size, PMD_SIZE);
94
95 if (!hyp_mem_base) {
96 kvm_err("Failed to reserve hyp memory\n");
97 return;
98 }
99
100 kvm_info("Reserved %lld MiB at 0x%llx\n", hyp_mem_size >> 20,
101 hyp_mem_base);
102 }
103
104 static void __pkvm_destroy_hyp_vm(struct kvm *host_kvm)
105 {
106 if (host_kvm->arch.pkvm.handle) {
107 WARN_ON(kvm_call_hyp_nvhe(__pkvm_teardown_vm,
108 host_kvm->arch.pkvm.handle));
109 }
110
111 host_kvm->arch.pkvm.handle = 0;
112 free_hyp_memcache(&host_kvm->arch.pkvm.teardown_mc);
113 }
114
115 /*
116 * Allocates and donates memory for hypervisor VM structs at EL2.
117 *
118 * Allocates space for the VM state, which includes the hyp vm as well as
119 * the hyp vcpus.
120 *
121 * Stores an opaque handler in the kvm struct for future reference.
122 *
123 * Return 0 on success, negative error code on failure.
124 */
125 static int __pkvm_create_hyp_vm(struct kvm *host_kvm)
126 {
127 size_t pgd_sz, hyp_vm_sz, hyp_vcpu_sz;
128 struct kvm_vcpu *host_vcpu;
129 pkvm_handle_t handle;
130 void *pgd, *hyp_vm;
131 unsigned long idx;
132 int ret;
133
134 if (host_kvm->created_vcpus < 1)
135 return -EINVAL;
136
137 pgd_sz = kvm_pgtable_stage2_pgd_size(host_kvm->arch.mmu.vtcr);
138
139 /*
140 * The PGD pages will be reclaimed using a hyp_memcache which implies
141 * page granularity. So, use alloc_pages_exact() to get individual
142 * refcounts.
143 */
144 pgd = alloc_pages_exact(pgd_sz, GFP_KERNEL_ACCOUNT);
145 if (!pgd)
146 return -ENOMEM;
147
148 /* Allocate memory to donate to hyp for vm and vcpu pointers. */
149 hyp_vm_sz = PAGE_ALIGN(size_add(PKVM_HYP_VM_SIZE,
150 size_mul(sizeof(void *),
151 host_kvm->created_vcpus)));
152 hyp_vm = alloc_pages_exact(hyp_vm_sz, GFP_KERNEL_ACCOUNT);
153 if (!hyp_vm) {
154 ret = -ENOMEM;
155 goto free_pgd;
156 }
157
158 /* Donate the VM memory to hyp and let hyp initialize it. */
159 ret = kvm_call_hyp_nvhe(__pkvm_init_vm, host_kvm, hyp_vm, pgd);
160 if (ret < 0)
161 goto free_vm;
162
163 handle = ret;
164
165 host_kvm->arch.pkvm.handle = handle;
166
167 /* Donate memory for the vcpus at hyp and initialize it. */
168 hyp_vcpu_sz = PAGE_ALIGN(PKVM_HYP_VCPU_SIZE);
169 kvm_for_each_vcpu(idx, host_vcpu, host_kvm) {
170 void *hyp_vcpu;
171
172 /* Indexing of the vcpus to be sequential starting at 0. */
173 if (WARN_ON(host_vcpu->vcpu_idx != idx)) {
174 ret = -EINVAL;
175 goto destroy_vm;
176 }
177
178 hyp_vcpu = alloc_pages_exact(hyp_vcpu_sz, GFP_KERNEL_ACCOUNT);
179 if (!hyp_vcpu) {
180 ret = -ENOMEM;
181 goto destroy_vm;
182 }
183
184 ret = kvm_call_hyp_nvhe(__pkvm_init_vcpu, handle, host_vcpu,
185 hyp_vcpu);
186 if (ret) {
187 free_pages_exact(hyp_vcpu, hyp_vcpu_sz);
188 goto destroy_vm;
189 }
190 }
191
192 return 0;
193
194 destroy_vm:
195 __pkvm_destroy_hyp_vm(host_kvm);
196 return ret;
197 free_vm:
198 free_pages_exact(hyp_vm, hyp_vm_sz);
199 free_pgd:
200 free_pages_exact(pgd, pgd_sz);
201 return ret;
202 }
203
204 int pkvm_create_hyp_vm(struct kvm *host_kvm)
205 {
206 int ret = 0;
207
208 mutex_lock(&host_kvm->arch.config_lock);
209 if (!host_kvm->arch.pkvm.handle)
210 ret = __pkvm_create_hyp_vm(host_kvm);
211 mutex_unlock(&host_kvm->arch.config_lock);
212
213 return ret;
214 }
215
216 void pkvm_destroy_hyp_vm(struct kvm *host_kvm)
217 {
218 mutex_lock(&host_kvm->arch.config_lock);
219 __pkvm_destroy_hyp_vm(host_kvm);
220 mutex_unlock(&host_kvm->arch.config_lock);
221 }
222
223 int pkvm_init_host_vm(struct kvm *host_kvm)
224 {
225 return 0;
226 }
227
228 static void __init _kvm_host_prot_finalize(void *arg)
229 {
230 int *err = arg;
231
232 if (WARN_ON(kvm_call_hyp_nvhe(__pkvm_prot_finalize)))
233 WRITE_ONCE(*err, -EINVAL);
234 }
235
236 static int __init pkvm_drop_host_privileges(void)
237 {
238 int ret = 0;
239
240 /*
241 * Flip the static key upfront as that may no longer be possible
242 * once the host stage 2 is installed.
243 */
244 static_branch_enable(&kvm_protected_mode_initialized);
245 on_each_cpu(_kvm_host_prot_finalize, &ret, 1);
246 return ret;
247 }
248
249 static int __init finalize_pkvm(void)
250 {
251 int ret;
252
253 if (!is_protected_kvm_enabled() || !is_kvm_arm_initialised())
254 return 0;
255
256 /*
257 * Exclude HYP sections from kmemleak so that they don't get peeked
258 * at, which would end badly once inaccessible.
259 */
260 kmemleak_free_part(__hyp_bss_start, __hyp_bss_end - __hyp_bss_start);
261 kmemleak_free_part(__hyp_rodata_start, __hyp_rodata_end - __hyp_rodata_start);
262 kmemleak_free_part_phys(hyp_mem_base, hyp_mem_size);
263
264 ret = pkvm_drop_host_privileges();
265 if (ret)
266 pr_err("Failed to finalize Hyp protection: %d\n", ret);
267
268 return ret;
269 }
270 device_initcall_sync(finalize_pkvm);
271
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