summaryrefslogtreecommitdiffstats
path: root/arch/arm64/kvm/inject_fault.c
blob: e9e0e6db73f6bdad6fbe77b7dda51ba04bf6734b (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
/*
 * Fault injection for both 32 and 64bit guests.
 *
 * Copyright (C) 2012,2013 - ARM Ltd
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 *
 * Based on arch/arm/kvm/emulate.c
 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
 * Author: Christoffer Dall <c.dall@virtualopensystems.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/>.
 */

#include <linux/kvm_host.h>
#include <asm/kvm_emulate.h>
#include <asm/esr.h>

#define PSTATE_FAULT_BITS_64 	(PSR_MODE_EL1h | PSR_A_BIT | PSR_F_BIT | \
				 PSR_I_BIT | PSR_D_BIT)

#define CURRENT_EL_SP_EL0_VECTOR	0x0
#define CURRENT_EL_SP_ELx_VECTOR	0x200
#define LOWER_EL_AArch64_VECTOR		0x400
#define LOWER_EL_AArch32_VECTOR		0x600

static void prepare_fault32(struct kvm_vcpu *vcpu, u32 mode, u32 vect_offset)
{
	unsigned long cpsr;
	unsigned long new_spsr_value = *vcpu_cpsr(vcpu);
	bool is_thumb = (new_spsr_value & COMPAT_PSR_T_BIT);
	u32 return_offset = (is_thumb) ? 4 : 0;
	u32 sctlr = vcpu_cp15(vcpu, c1_SCTLR);

	cpsr = mode | COMPAT_PSR_I_BIT;

	if (sctlr & (1 << 30))
		cpsr |= COMPAT_PSR_T_BIT;
	if (sctlr & (1 << 25))
		cpsr |= COMPAT_PSR_E_BIT;

	*vcpu_cpsr(vcpu) = cpsr;

	/* Note: These now point to the banked copies */
	*vcpu_spsr(vcpu) = new_spsr_value;
	*vcpu_reg32(vcpu, 14) = *vcpu_pc(vcpu) + return_offset;

	/* Branch to exception vector */
	if (sctlr & (1 << 13))
		vect_offset += 0xffff0000;
	else /* always have security exceptions */
		vect_offset += vcpu_cp15(vcpu, c12_VBAR);

	*vcpu_pc(vcpu) = vect_offset;
}

static void inject_undef32(struct kvm_vcpu *vcpu)
{
	prepare_fault32(vcpu, COMPAT_PSR_MODE_UND, 4);
}

/*
 * Modelled after TakeDataAbortException() and TakePrefetchAbortException
 * pseudocode.
 */
static void inject_abt32(struct kvm_vcpu *vcpu, bool is_pabt,
			 unsigned long addr)
{
	u32 vect_offset;
	u32 *far, *fsr;
	bool is_lpae;

	if (is_pabt) {
		vect_offset = 12;
		far = &vcpu_cp15(vcpu, c6_IFAR);
		fsr = &vcpu_cp15(vcpu, c5_IFSR);
	} else { /* !iabt */
		vect_offset = 16;
		far = &vcpu_cp15(vcpu, c6_DFAR);
		fsr = &vcpu_cp15(vcpu, c5_DFSR);
	}

	prepare_fault32(vcpu, COMPAT_PSR_MODE_ABT | COMPAT_PSR_A_BIT, vect_offset);

	*far = addr;

	/* Give the guest an IMPLEMENTATION DEFINED exception */
	is_lpae = (vcpu_cp15(vcpu, c2_TTBCR) >> 31);
	if (is_lpae)
		*fsr = 1 << 9 | 0x34;
	else
		*fsr = 0x14;
}

enum exception_type {
	except_type_sync	= 0,
	except_type_irq		= 0x80,
	except_type_fiq		= 0x100,
	except_type_serror	= 0x180,
};

static u64 get_except_vector(struct kvm_vcpu *vcpu, enum exception_type type)
{
	u64 exc_offset;

	switch (*vcpu_cpsr(vcpu) & (PSR_MODE_MASK | PSR_MODE32_BIT)) {
	case PSR_MODE_EL1t:
		exc_offset = CURRENT_EL_SP_EL0_VECTOR;
		break;
	case PSR_MODE_EL1h:
		exc_offset = CURRENT_EL_SP_ELx_VECTOR;
		break;
	case PSR_MODE_EL0t:
		exc_offset = LOWER_EL_AArch64_VECTOR;
		break;
	default:
		exc_offset = LOWER_EL_AArch32_VECTOR;
	}

	return vcpu_sys_reg(vcpu, VBAR_EL1) + exc_offset + type;
}

static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr)
{
	unsigned long cpsr = *vcpu_cpsr(vcpu);
	bool is_aarch32;
	u32 esr = 0;

	is_aarch32 = vcpu_mode_is_32bit(vcpu);

	*vcpu_spsr(vcpu) = cpsr;
	*vcpu_elr_el1(vcpu) = *vcpu_pc(vcpu);

	*vcpu_pc(vcpu) = get_except_vector(vcpu, except_type_sync);
	*vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64;

	vcpu_sys_reg(vcpu, FAR_EL1) = addr;

	/*
	 * Build an {i,d}abort, depending on the level and the
	 * instruction set. Report an external synchronous abort.
	 */
	if (kvm_vcpu_trap_il_is32bit(vcpu))
		esr |= ESR_ELx_IL;

	/*
	 * Here, the guest runs in AArch64 mode when in EL1. If we get
	 * an AArch32 fault, it means we managed to trap an EL0 fault.
	 */
	if (is_aarch32 || (cpsr & PSR_MODE_MASK) == PSR_MODE_EL0t)
		esr |= (ESR_ELx_EC_IABT_LOW << ESR_ELx_EC_SHIFT);
	else
		esr |= (ESR_ELx_EC_IABT_CUR << ESR_ELx_EC_SHIFT);

	if (!is_iabt)
		esr |= ESR_ELx_EC_DABT_LOW << ESR_ELx_EC_SHIFT;

	vcpu_sys_reg(vcpu, ESR_EL1) = esr | ESR_ELx_FSC_EXTABT;
}

static void inject_undef64(struct kvm_vcpu *vcpu)
{
	unsigned long cpsr = *vcpu_cpsr(vcpu);
	u32 esr = (ESR_ELx_EC_UNKNOWN << ESR_ELx_EC_SHIFT);

	*vcpu_spsr(vcpu) = cpsr;
	*vcpu_elr_el1(vcpu) = *vcpu_pc(vcpu);

	*vcpu_pc(vcpu) = get_except_vector(vcpu, except_type_sync);
	*vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64;

	/*
	 * Build an unknown exception, depending on the instruction
	 * set.
	 */
	if (kvm_vcpu_trap_il_is32bit(vcpu))
		esr |= ESR_ELx_IL;

	vcpu_sys_reg(vcpu, ESR_EL1) = esr;
}

/**
 * kvm_inject_dabt - inject a data abort into the guest
 * @vcpu: The VCPU to receive the undefined exception
 * @addr: The address to report in the DFAR
 *
 * It is assumed that this code is called from the VCPU thread and that the
 * VCPU therefore is not currently executing guest code.
 */
void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr)
{
	if (!(vcpu->arch.hcr_el2 & HCR_RW))
		inject_abt32(vcpu, false, addr);
	else
		inject_abt64(vcpu, false, addr);
}

/**
 * kvm_inject_pabt - inject a prefetch abort into the guest
 * @vcpu: The VCPU to receive the undefined exception
 * @addr: The address to report in the DFAR
 *
 * It is assumed that this code is called from the VCPU thread and that the
 * VCPU therefore is not currently executing guest code.
 */
void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr)
{
	if (!(vcpu->arch.hcr_el2 & HCR_RW))
		inject_abt32(vcpu, true, addr);
	else
		inject_abt64(vcpu, true, addr);
}

/**
 * kvm_inject_undefined - inject an undefined instruction into the guest
 *
 * It is assumed that this code is called from the VCPU thread and that the
 * VCPU therefore is not currently executing guest code.
 */
void kvm_inject_undefined(struct kvm_vcpu *vcpu)
{
	if (!(vcpu->arch.hcr_el2 & HCR_RW))
		inject_undef32(vcpu);
	else
		inject_undef64(vcpu);
}