setup.c

  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/gfp.h>
 16#include <nvhe/memory.h>
 17#include <nvhe/mem_protect.h>
 18#include <nvhe/mm.h>
 19#include <nvhe/pkvm.h>
 20#include <nvhe/trap_handler.h>
 21
 22unsigned long hyp_nr_cpus;
 23
 24#define hyp_percpu_size ((unsigned long)__per_cpu_end - \
 25			 (unsigned long)__per_cpu_start)
 26
 27static void *vmemmap_base;
 28static void *vm_table_base;
 29static void *hyp_pgt_base;
 30static void *host_s2_pgt_base;
 31static void *selftest_base;
 32static void *ffa_proxy_pages;
 33static struct kvm_pgtable_mm_ops pkvm_pgtable_mm_ops;
 34static struct hyp_pool hpool;
 35
 36static 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 = pkvm_selftest_pages();
 43	selftest_base = hyp_early_alloc_contig(nr_pages);
 44	if (nr_pages && !selftest_base)
 45		return -ENOMEM;
 46
 47	nr_pages = hyp_vmemmap_pages(sizeof(struct hyp_page));
 48	vmemmap_base = hyp_early_alloc_contig(nr_pages);
 49	if (!vmemmap_base)
 50		return -ENOMEM;
 51
 52	nr_pages = hyp_vm_table_pages();
 53	vm_table_base = hyp_early_alloc_contig(nr_pages);
 54	if (!vm_table_base)
 55		return -ENOMEM;
 56
 57	nr_pages = hyp_s1_pgtable_pages();
 58	hyp_pgt_base = hyp_early_alloc_contig(nr_pages);
 59	if (!hyp_pgt_base)
 60		return -ENOMEM;
 61
 62	nr_pages = host_s2_pgtable_pages();
 63	host_s2_pgt_base = hyp_early_alloc_contig(nr_pages);
 64	if (!host_s2_pgt_base)
 65		return -ENOMEM;
 66
 67	nr_pages = hyp_ffa_proxy_pages();
 68	ffa_proxy_pages = hyp_early_alloc_contig(nr_pages);
 69	if (!ffa_proxy_pages)
 70		return -ENOMEM;
 71
 72	return 0;
 73}
 74
 75static int pkvm_create_host_sve_mappings(void)
 76{
 77	void *start, *end;
 78	int ret, i;
 79
 80	if (!system_supports_sve())
 81		return 0;
 82
 83	for (i = 0; i < hyp_nr_cpus; i++) {
 84		struct kvm_host_data *host_data = per_cpu_ptr(&kvm_host_data, i);
 85		struct cpu_sve_state *sve_state = host_data->sve_state;
 86
 87		start = kern_hyp_va(sve_state);
 88		end = start + PAGE_ALIGN(pkvm_host_sve_state_size());
 89		ret = pkvm_create_mappings(start, end, PAGE_HYP);
 90		if (ret)
 91			return ret;
 92	}
 93
 94	return 0;
 95}
 96
 97static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size,
 98				 unsigned long *per_cpu_base,
 99				 u32 hyp_va_bits)
100{
101	void *start, *end, *virt = hyp_phys_to_virt(phys);
102	unsigned long pgt_size = hyp_s1_pgtable_pages() << PAGE_SHIFT;
103	int ret, i;
104
105	/* Recreate the hyp page-table using the early page allocator */
106	hyp_early_alloc_init(hyp_pgt_base, pgt_size);
107	ret = kvm_pgtable_hyp_init(&pkvm_pgtable, hyp_va_bits,
108				   &hyp_early_alloc_mm_ops);
109	if (ret)
110		return ret;
111
112	ret = hyp_create_idmap(hyp_va_bits);
113	if (ret)
114		return ret;
115
116	ret = hyp_map_vectors();
117	if (ret)
118		return ret;
119
120	ret = hyp_back_vmemmap(hyp_virt_to_phys(vmemmap_base));
121	if (ret)
122		return ret;
123
124	ret = pkvm_create_mappings(__hyp_text_start, __hyp_text_end, PAGE_HYP_EXEC);
125	if (ret)
126		return ret;
127
128	ret = pkvm_create_mappings(__hyp_data_start, __hyp_data_end, PAGE_HYP);
129	if (ret)
130		return ret;
131
132	ret = pkvm_create_mappings(__hyp_rodata_start, __hyp_rodata_end, PAGE_HYP_RO);
133	if (ret)
134		return ret;
135
136	ret = pkvm_create_mappings(__hyp_bss_start, __hyp_bss_end, PAGE_HYP);
137	if (ret)
138		return ret;
139
140	ret = pkvm_create_mappings(virt, virt + size, PAGE_HYP);
141	if (ret)
142		return ret;
143
144	for (i = 0; i < hyp_nr_cpus; i++) {
145		struct kvm_nvhe_init_params *params = per_cpu_ptr(&kvm_init_params, i);
146
147		start = (void *)kern_hyp_va(per_cpu_base[i]);
148		end = start + PAGE_ALIGN(hyp_percpu_size);
149		ret = pkvm_create_mappings(start, end, PAGE_HYP);
150		if (ret)
151			return ret;
152
153		ret = pkvm_create_stack(params->stack_pa, &params->stack_hyp_va);
154		if (ret)
155			return ret;
156	}
157
158	return pkvm_create_host_sve_mappings();
159}
160
161static void update_nvhe_init_params(void)
162{
163	struct kvm_nvhe_init_params *params;
164	unsigned long i;
165
166	for (i = 0; i < hyp_nr_cpus; i++) {
167		params = per_cpu_ptr(&kvm_init_params, i);
168		params->pgd_pa = __hyp_pa(pkvm_pgtable.pgd);
169		dcache_clean_inval_poc((unsigned long)params,
170				    (unsigned long)params + sizeof(*params));
171	}
172}
173
174static void *hyp_zalloc_hyp_page(void *arg)
175{
176	return hyp_alloc_pages(&hpool, 0);
177}
178
179static void hpool_get_page(void *addr)
180{
181	hyp_get_page(&hpool, addr);
182}
183
184static void hpool_put_page(void *addr)
185{
186	hyp_put_page(&hpool, addr);
187}
188
189static int fix_host_ownership_walker(const struct kvm_pgtable_visit_ctx *ctx,
190				     enum kvm_pgtable_walk_flags visit)
191{
192	enum pkvm_page_state state;
193	struct hyp_page *page;
194	phys_addr_t phys;
195	enum kvm_pgtable_prot prot;
196
197	if (!kvm_pte_valid(ctx->old))
198		return 0;
199
200	if (ctx->level != KVM_PGTABLE_LAST_LEVEL)
201		return -EINVAL;
202
203	phys = kvm_pte_to_phys(ctx->old);
204	if (!addr_is_memory(phys))
205		return -EINVAL;
206
207	page = hyp_phys_to_page(phys);
208
209	/*
210	 * Adjust the host stage-2 mappings to match the ownership attributes
211	 * configured in the hypervisor stage-1, and make sure to propagate them
212	 * to the hyp_vmemmap state.
213	 */
214	prot = kvm_pgtable_hyp_pte_prot(ctx->old);
215	state = pkvm_getstate(prot);
216	switch (state) {
217	case PKVM_PAGE_OWNED:
218		set_hyp_state(page, PKVM_PAGE_OWNED);
219		/* hyp text is RO in the host stage-2 to be inspected on panic. */
220		if (prot == PAGE_HYP_EXEC) {
221			set_host_state(page, PKVM_NOPAGE);
222			return host_stage2_idmap_locked(phys, PAGE_SIZE, KVM_PGTABLE_PROT_R);
223		} else {
224			return host_stage2_set_owner_locked(phys, PAGE_SIZE, PKVM_ID_HYP);
225		}
226	case PKVM_PAGE_SHARED_OWNED:
227		set_hyp_state(page, PKVM_PAGE_SHARED_OWNED);
228		set_host_state(page, PKVM_PAGE_SHARED_BORROWED);
229		break;
230	case PKVM_PAGE_SHARED_BORROWED:
231		set_hyp_state(page, PKVM_PAGE_SHARED_BORROWED);
232		set_host_state(page, PKVM_PAGE_SHARED_OWNED);
233		break;
234	default:
235		return -EINVAL;
236	}
237
238	return 0;
239}
240
241static int fix_hyp_pgtable_refcnt_walker(const struct kvm_pgtable_visit_ctx *ctx,
242					 enum kvm_pgtable_walk_flags visit)
243{
244	/*
245	 * Fix-up the refcount for the page-table pages as the early allocator
246	 * was unable to access the hyp_vmemmap and so the buddy allocator has
247	 * initialised the refcount to '1'.
248	 */
249	if (kvm_pte_valid(ctx->old))
250		ctx->mm_ops->get_page(ctx->ptep);
251
252	return 0;
253}
254
255static int fix_host_ownership(void)
256{
257	struct kvm_pgtable_walker walker = {
258		.cb	= fix_host_ownership_walker,
259		.flags	= KVM_PGTABLE_WALK_LEAF,
260	};
261	int i, ret;
262
263	for (i = 0; i < hyp_memblock_nr; i++) {
264		struct memblock_region *reg = &hyp_memory[i];
265		u64 start = (u64)hyp_phys_to_virt(reg->base);
266
267		ret = kvm_pgtable_walk(&pkvm_pgtable, start, reg->size, &walker);
268		if (ret)
269			return ret;
270	}
271
272	return 0;
273}
274
275static int fix_hyp_pgtable_refcnt(void)
276{
277	struct kvm_pgtable_walker walker = {
278		.cb	= fix_hyp_pgtable_refcnt_walker,
279		.flags	= KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST,
280		.arg	= pkvm_pgtable.mm_ops,
281	};
282
283	return kvm_pgtable_walk(&pkvm_pgtable, 0, BIT(pkvm_pgtable.ia_bits),
284				&walker);
285}
286
287void __noreturn __pkvm_init_finalise(void)
288{
289	struct kvm_cpu_context *host_ctxt = host_data_ptr(host_ctxt);
290	unsigned long nr_pages, reserved_pages, pfn;
291	int ret;
292
293	/* Now that the vmemmap is backed, install the full-fledged allocator */
294	pfn = hyp_virt_to_pfn(hyp_pgt_base);
295	nr_pages = hyp_s1_pgtable_pages();
296	reserved_pages = hyp_early_alloc_nr_used_pages();
297	ret = hyp_pool_init(&hpool, pfn, nr_pages, reserved_pages);
298	if (ret)
299		goto out;
300
301	ret = kvm_host_prepare_stage2(host_s2_pgt_base);
302	if (ret)
303		goto out;
304
305	pkvm_pgtable_mm_ops = (struct kvm_pgtable_mm_ops) {
306		.zalloc_page = hyp_zalloc_hyp_page,
307		.phys_to_virt = hyp_phys_to_virt,
308		.virt_to_phys = hyp_virt_to_phys,
309		.get_page = hpool_get_page,
310		.put_page = hpool_put_page,
311		.page_count = hyp_page_count,
312	};
313	pkvm_pgtable.mm_ops = &pkvm_pgtable_mm_ops;
314
315	ret = fix_host_ownership();
316	if (ret)
317		goto out;
318
319	ret = fix_hyp_pgtable_refcnt();
320	if (ret)
321		goto out;
322
323	ret = hyp_create_fixmap();
324	if (ret)
325		goto out;
326
327	ret = hyp_ffa_init(ffa_proxy_pages);
328	if (ret)
329		goto out;
330
331	pkvm_hyp_vm_table_init(vm_table_base);
332
333	pkvm_ownership_selftest(selftest_base);
334out:
335	/*
336	 * We tail-called to here from handle___pkvm_init() and will not return,
337	 * so make sure to propagate the return value to the host.
338	 */
339	cpu_reg(host_ctxt, 1) = ret;
340
341	__host_enter(host_ctxt);
342}
343
344int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
345		unsigned long *per_cpu_base, u32 hyp_va_bits)
346{
347	struct kvm_nvhe_init_params *params;
348	void *virt = hyp_phys_to_virt(phys);
349	typeof(__pkvm_init_switch_pgd) *fn;
350	int ret;
351
352	BUG_ON(kvm_check_pvm_sysreg_table());
353
354	if (!PAGE_ALIGNED(phys) || !PAGE_ALIGNED(size))
355		return -EINVAL;
356
357	hyp_spin_lock_init(&pkvm_pgd_lock);
358	hyp_nr_cpus = nr_cpus;
359
360	ret = divide_memory_pool(virt, size);
361	if (ret)
362		return ret;
363
364	ret = recreate_hyp_mappings(phys, size, per_cpu_base, hyp_va_bits);
365	if (ret)
366		return ret;
367
368	update_nvhe_init_params();
369
370	/* Jump in the idmap page to switch to the new page-tables */
371	params = this_cpu_ptr(&kvm_init_params);
372	fn = (typeof(fn))__hyp_pa(__pkvm_init_switch_pgd);
373	fn(params->pgd_pa, params->stack_hyp_va, __pkvm_init_finalise);
374
375	unreachable();
376}