summaryrefslogtreecommitdiffstats
path: root/arch/arm64/include/asm/kvm_mmu.h
blob: a79b969c26fca7dcd73e06c4bfc36c6519cb646b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
/*
 * Copyright (C) 2012,2013 - ARM Ltd
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef __ARM64_KVM_MMU_H__
#define __ARM64_KVM_MMU_H__

#include <asm/page.h>
#include <asm/memory.h>
#include <asm/cpufeature.h>

/*
 * As ARMv8.0 only has the TTBR0_EL2 register, we cannot express
 * "negative" addresses. This makes it impossible to directly share
 * mappings with the kernel.
 *
 * Instead, give the HYP mode its own VA region at a fixed offset from
 * the kernel by just masking the top bits (which are all ones for a
 * kernel address). We need to find out how many bits to mask.
 *
 * We want to build a set of page tables that cover both parts of the
 * idmap (the trampoline page used to initialize EL2), and our normal
 * runtime VA space, at the same time.
 *
 * Given that the kernel uses VA_BITS for its entire address space,
 * and that half of that space (VA_BITS - 1) is used for the linear
 * mapping, we can also limit the EL2 space to (VA_BITS - 1).
 *
 * The main question is "Within the VA_BITS space, does EL2 use the
 * top or the bottom half of that space to shadow the kernel's linear
 * mapping?". As we need to idmap the trampoline page, this is
 * determined by the range in which this page lives.
 *
 * If the page is in the bottom half, we have to use the top half. If
 * the page is in the top half, we have to use the bottom half:
 *
 * T = __virt_to_phys(__hyp_idmap_text_start)
 * if (T & BIT(VA_BITS - 1))
 *	HYP_VA_MIN = 0  //idmap in upper half
 * else
 *	HYP_VA_MIN = 1 << (VA_BITS - 1)
 * HYP_VA_MAX = HYP_VA_MIN + (1 << (VA_BITS - 1)) - 1
 *
 * This of course assumes that the trampoline page exists within the
 * VA_BITS range. If it doesn't, then it means we're in the odd case
 * where the kernel idmap (as well as HYP) uses more levels than the
 * kernel runtime page tables (as seen when the kernel is configured
 * for 4k pages, 39bits VA, and yet memory lives just above that
 * limit, forcing the idmap to use 4 levels of page tables while the
 * kernel itself only uses 3). In this particular case, it doesn't
 * matter which side of VA_BITS we use, as we're guaranteed not to
 * conflict with anything.
 *
 * When using VHE, there are no separate hyp mappings and all KVM
 * functionality is already mapped as part of the main kernel
 * mappings, and none of this applies in that case.
 */

#define HYP_PAGE_OFFSET_HIGH_MASK	((UL(1) << VA_BITS) - 1)
#define HYP_PAGE_OFFSET_LOW_MASK	((UL(1) << (VA_BITS - 1)) - 1)

#ifdef __ASSEMBLY__

#include <asm/alternative.h>
#include <asm/cpufeature.h>

/*
 * Convert a kernel VA into a HYP VA.
 * reg: VA to be converted.
 *
 * This generates the following sequences:
 * - High mask:
 *		and x0, x0, #HYP_PAGE_OFFSET_HIGH_MASK
 *		nop
 * - Low mask:
 *		and x0, x0, #HYP_PAGE_OFFSET_HIGH_MASK
 *		and x0, x0, #HYP_PAGE_OFFSET_LOW_MASK
 * - VHE:
 *		nop
 *		nop
 *
 * The "low mask" version works because the mask is a strict subset of
 * the "high mask", hence performing the first mask for nothing.
 * Should be completely invisible on any viable CPU.
 */
.macro kern_hyp_va	reg
alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
	and     \reg, \reg, #HYP_PAGE_OFFSET_HIGH_MASK
alternative_else_nop_endif
alternative_if ARM64_HYP_OFFSET_LOW
	and     \reg, \reg, #HYP_PAGE_OFFSET_LOW_MASK
alternative_else_nop_endif
.endm

#else

#include <asm/pgalloc.h>
#include <asm/cachetype.h>
#include <asm/cacheflush.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>

static inline unsigned long __kern_hyp_va(unsigned long v)
{
	asm volatile(ALTERNATIVE("and %0, %0, %1",
				 "nop",
				 ARM64_HAS_VIRT_HOST_EXTN)
		     : "+r" (v)
		     : "i" (HYP_PAGE_OFFSET_HIGH_MASK));
	asm volatile(ALTERNATIVE("nop",
				 "and %0, %0, %1",
				 ARM64_HYP_OFFSET_LOW)
		     : "+r" (v)
		     : "i" (HYP_PAGE_OFFSET_LOW_MASK));
	return v;
}

#define kern_hyp_va(v) 	(typeof(v))(__kern_hyp_va((unsigned long)(v)))

/*
 * We currently only support a 40bit IPA.
 */
#define KVM_PHYS_SHIFT	(40)
#define KVM_PHYS_SIZE	(1UL << KVM_PHYS_SHIFT)
#define KVM_PHYS_MASK	(KVM_PHYS_SIZE - 1UL)

#include <asm/stage2_pgtable.h>

int create_hyp_mappings(void *from, void *to, pgprot_t prot);
int create_hyp_io_mappings(void *from, void *to, phys_addr_t);
void free_hyp_pgds(void);

void stage2_unmap_vm(struct kvm *kvm);
int kvm_alloc_stage2_pgd(struct kvm *kvm);
void kvm_free_stage2_pgd(struct kvm *kvm);
int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
			  phys_addr_t pa, unsigned long size, bool writable);

int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run);

void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);

phys_addr_t kvm_mmu_get_httbr(void);
phys_addr_t kvm_get_idmap_vector(void);
phys_addr_t kvm_get_idmap_start(void);
int kvm_mmu_init(void);
void kvm_clear_hyp_idmap(void);

#define	kvm_set_pte(ptep, pte)		set_pte(ptep, pte)
#define	kvm_set_pmd(pmdp, pmd)		set_pmd(pmdp, pmd)

static inline pte_t kvm_s2pte_mkwrite(pte_t pte)
{
	pte_val(pte) |= PTE_S2_RDWR;
	return pte;
}

static inline pmd_t kvm_s2pmd_mkwrite(pmd_t pmd)
{
	pmd_val(pmd) |= PMD_S2_RDWR;
	return pmd;
}

static inline void kvm_set_s2pte_readonly(pte_t *pte)
{
	pteval_t pteval;
	unsigned long tmp;

	asm volatile("//	kvm_set_s2pte_readonly\n"
	"	prfm	pstl1strm, %2\n"
	"1:	ldxr	%0, %2\n"
	"	and	%0, %0, %3		// clear PTE_S2_RDWR\n"
	"	orr	%0, %0, %4		// set PTE_S2_RDONLY\n"
	"	stxr	%w1, %0, %2\n"
	"	cbnz	%w1, 1b\n"
	: "=&r" (pteval), "=&r" (tmp), "+Q" (pte_val(*pte))
	: "L" (~PTE_S2_RDWR), "L" (PTE_S2_RDONLY));
}

static inline bool kvm_s2pte_readonly(pte_t *pte)
{
	return (pte_val(*pte) & PTE_S2_RDWR) == PTE_S2_RDONLY;
}

static inline void kvm_set_s2pmd_readonly(pmd_t *pmd)
{
	kvm_set_s2pte_readonly((pte_t *)pmd);
}

static inline bool kvm_s2pmd_readonly(pmd_t *pmd)
{
	return kvm_s2pte_readonly((pte_t *)pmd);
}

static inline bool kvm_page_empty(void *ptr)
{
	struct page *ptr_page = virt_to_page(ptr);
	return page_count(ptr_page) == 1;
}

#define hyp_pte_table_empty(ptep) kvm_page_empty(ptep)

#ifdef __PAGETABLE_PMD_FOLDED
#define hyp_pmd_table_empty(pmdp) (0)
#else
#define hyp_pmd_table_empty(pmdp) kvm_page_empty(pmdp)
#endif

#ifdef __PAGETABLE_PUD_FOLDED
#define hyp_pud_table_empty(pudp) (0)
#else
#define hyp_pud_table_empty(pudp) kvm_page_empty(pudp)
#endif

struct kvm;

#define kvm_flush_dcache_to_poc(a,l)	__flush_dcache_area((a), (l))

static inline bool vcpu_has_cache_enabled(struct kvm_vcpu *vcpu)
{
	return (vcpu_sys_reg(vcpu, SCTLR_EL1) & 0b101) == 0b101;
}

static inline void __coherent_cache_guest_page(struct kvm_vcpu *vcpu,
					       kvm_pfn_t pfn,
					       unsigned long size,
					       bool ipa_uncached)
{
	void *va = page_address(pfn_to_page(pfn));

	if (!vcpu_has_cache_enabled(vcpu) || ipa_uncached)
		kvm_flush_dcache_to_poc(va, size);

	if (!icache_is_aliasing()) {		/* PIPT */
		flush_icache_range((unsigned long)va,
				   (unsigned long)va + size);
	} else if (!icache_is_aivivt()) {	/* non ASID-tagged VIVT */
		/* any kind of VIPT cache */
		__flush_icache_all();
	}
}

static inline void __kvm_flush_dcache_pte(pte_t pte)
{
	struct page *page = pte_page(pte);
	kvm_flush_dcache_to_poc(page_address(page), PAGE_SIZE);
}

static inline void __kvm_flush_dcache_pmd(pmd_t pmd)
{
	struct page *page = pmd_page(pmd);
	kvm_flush_dcache_to_poc(page_address(page), PMD_SIZE);
}

static inline void __kvm_flush_dcache_pud(pud_t pud)
{
	struct page *page = pud_page(pud);
	kvm_flush_dcache_to_poc(page_address(page), PUD_SIZE);
}

#define kvm_virt_to_phys(x)		__virt_to_phys((unsigned long)(x))

void kvm_set_way_flush(struct kvm_vcpu *vcpu);
void kvm_toggle_cache(struct kvm_vcpu *vcpu, bool was_enabled);

static inline bool __kvm_cpu_uses_extended_idmap(void)
{
	return __cpu_uses_extended_idmap();
}

static inline void __kvm_extend_hypmap(pgd_t *boot_hyp_pgd,
				       pgd_t *hyp_pgd,
				       pgd_t *merged_hyp_pgd,
				       unsigned long hyp_idmap_start)
{
	int idmap_idx;

	/*
	 * Use the first entry to access the HYP mappings. It is
	 * guaranteed to be free, otherwise we wouldn't use an
	 * extended idmap.
	 */
	VM_BUG_ON(pgd_val(merged_hyp_pgd[0]));
	merged_hyp_pgd[0] = __pgd(__pa(hyp_pgd) | PMD_TYPE_TABLE);

	/*
	 * Create another extended level entry that points to the boot HYP map,
	 * which contains an ID mapping of the HYP init code. We essentially
	 * merge the boot and runtime HYP maps by doing so, but they don't
	 * overlap anyway, so this is fine.
	 */
	idmap_idx = hyp_idmap_start >> VA_BITS;
	VM_BUG_ON(pgd_val(merged_hyp_pgd[idmap_idx]));
	merged_hyp_pgd[idmap_idx] = __pgd(__pa(boot_hyp_pgd) | PMD_TYPE_TABLE);
}

static inline unsigned int kvm_get_vmid_bits(void)
{
	int reg = read_system_reg(SYS_ID_AA64MMFR1_EL1);

	return (cpuid_feature_extract_unsigned_field(reg, ID_AA64MMFR1_VMIDBITS_SHIFT) == 2) ? 16 : 8;
}

#endif /* __ASSEMBLY__ */
#endif /* __ARM64_KVM_MMU_H__ */
OpenPOWER on IntegriCloud