summaryrefslogtreecommitdiff
path: root/arch/arm64/kvm/hyp/entry.S
blob: ce9e5e5f28cfb782c15090aea84bb282cd0b56c2 (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
/*
 * Copyright (C) 2015 - 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/>.
 */

#include <linux/linkage.h>

#include <asm/asm-offsets.h>
#include <asm/assembler.h>
#include <asm/fpsimdmacros.h>
#include <asm/kvm.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_mmu.h>

#define CPU_GP_REG_OFFSET(x)	(CPU_GP_REGS + x)
#define CPU_XREG_OFFSET(x)	CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x)

	.text
	.pushsection	.hyp.text, "ax"

.macro save_callee_saved_regs ctxt
	stp	x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
	stp	x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
	stp	x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
	stp	x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
	stp	x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
	stp	x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]
.endm

.macro restore_callee_saved_regs ctxt
	ldp	x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
	ldp	x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
	ldp	x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
	ldp	x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
	ldp	x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
	ldp	x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]
.endm

/*
 * u64 __guest_enter(struct kvm_vcpu *vcpu,
 *		     struct kvm_cpu_context *host_ctxt);
 */
ENTRY(__guest_enter)
	// x0: vcpu
	// x1: host/guest context
	// x2-x18: clobbered by macros

	// Store the host regs
	save_callee_saved_regs x1

	// Preserve vcpu & host_ctxt for use at exit time
	stp	x0, x1, [sp, #-16]!

	add	x1, x0, #VCPU_CONTEXT

	// Prepare x0-x1 for later restore by pushing them onto the stack
	ldp	x2, x3, [x1, #CPU_XREG_OFFSET(0)]
	stp	x2, x3, [sp, #-16]!

	// x2-x18
	ldp	x2, x3,   [x1, #CPU_XREG_OFFSET(2)]
	ldp	x4, x5,   [x1, #CPU_XREG_OFFSET(4)]
	ldp	x6, x7,   [x1, #CPU_XREG_OFFSET(6)]
	ldp	x8, x9,   [x1, #CPU_XREG_OFFSET(8)]
	ldp	x10, x11, [x1, #CPU_XREG_OFFSET(10)]
	ldp	x12, x13, [x1, #CPU_XREG_OFFSET(12)]
	ldp	x14, x15, [x1, #CPU_XREG_OFFSET(14)]
	ldp	x16, x17, [x1, #CPU_XREG_OFFSET(16)]
	ldr	x18,      [x1, #CPU_XREG_OFFSET(18)]

	// x19-x29, lr
	restore_callee_saved_regs x1

	// Last bits of the 64bit state
	ldp	x0, x1, [sp], #16

	// Do not touch any register after this!
	eret
ENDPROC(__guest_enter)

ENTRY(__guest_exit)
	// x0: vcpu
	// x1: return code
	// x2-x3: free
	// x4-x29,lr: vcpu regs
	// vcpu x0-x3 on the stack

	add	x2, x0, #VCPU_CONTEXT

	stp	x4, x5,   [x2, #CPU_XREG_OFFSET(4)]
	stp	x6, x7,   [x2, #CPU_XREG_OFFSET(6)]
	stp	x8, x9,   [x2, #CPU_XREG_OFFSET(8)]
	stp	x10, x11, [x2, #CPU_XREG_OFFSET(10)]
	stp	x12, x13, [x2, #CPU_XREG_OFFSET(12)]
	stp	x14, x15, [x2, #CPU_XREG_OFFSET(14)]
	stp	x16, x17, [x2, #CPU_XREG_OFFSET(16)]
	str	x18,      [x2, #CPU_XREG_OFFSET(18)]

	ldp	x6, x7, [sp], #16	// x2, x3
	ldp	x4, x5, [sp], #16	// x0, x1

	stp	x4, x5, [x2, #CPU_XREG_OFFSET(0)]
	stp	x6, x7, [x2, #CPU_XREG_OFFSET(2)]

	save_callee_saved_regs x2

	// Restore vcpu & host_ctxt from the stack
	// (preserving return code in x1)
	ldp	x0, x2, [sp], #16
	// Now restore the host regs
	restore_callee_saved_regs x2

	mov	x0, x1
	ret
ENDPROC(__guest_exit)

ENTRY(__fpsimd_guest_restore)
	stp	x4, lr, [sp, #-16]!

alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
	mrs	x2, cptr_el2
	bic	x2, x2, #CPTR_EL2_TFP
	msr	cptr_el2, x2
alternative_else
	mrs	x2, cpacr_el1
	orr	x2, x2, #CPACR_EL1_FPEN
	msr	cpacr_el1, x2
alternative_endif
	isb

	mrs	x3, tpidr_el2

	ldr	x0, [x3, #VCPU_HOST_CONTEXT]
	kern_hyp_va x0
	add	x0, x0, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
	bl	__fpsimd_save_state

	add	x2, x3, #VCPU_CONTEXT
	add	x0, x2, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
	bl	__fpsimd_restore_state

	// Skip restoring fpexc32 for AArch64 guests
	mrs	x1, hcr_el2
	tbnz	x1, #HCR_RW_SHIFT, 1f
	ldr	x4, [x3, #VCPU_FPEXC32_EL2]
	msr	fpexc32_el2, x4
1:
	ldp	x4, lr, [sp], #16
	ldp	x2, x3, [sp], #16
	ldp	x0, x1, [sp], #16

	eret
ENDPROC(__fpsimd_guest_restore)