Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2012 ARM Ltd.
4 * Author: Marc Zyngier <marc.zyngier@arm.com>
5 */
6
7#ifndef __ASM__VIRT_H
8#define __ASM__VIRT_H
9
10/*
11 * The arm64 hcall implementation uses x0 to specify the hcall
12 * number. A value less than HVC_STUB_HCALL_NR indicates a special
13 * hcall, such as set vector. Any other value is handled in a
14 * hypervisor specific way.
15 *
16 * The hypercall is allowed to clobber any of the caller-saved
17 * registers (x0-x18), so it is advisable to use it through the
18 * indirection of a function call (as implemented in hyp-stub.S).
19 */
20
21/*
22 * HVC_SET_VECTORS - Set the value of the vbar_el2 register.
23 *
24 * @x1: Physical address of the new vector table.
25 */
26#define HVC_SET_VECTORS 0
27
28/*
29 * HVC_SOFT_RESTART - CPU soft reset, used by the cpu_soft_restart routine.
30 */
31#define HVC_SOFT_RESTART 1
32
33/*
34 * HVC_RESET_VECTORS - Restore the vectors to the original HYP stubs
35 */
36#define HVC_RESET_VECTORS 2
37
38/*
39 * HVC_FINALISE_EL2 - Upgrade the CPU from EL1 to EL2, if possible
40 */
41#define HVC_FINALISE_EL2 3
42
43/*
44 * HVC_GET_ICH_VTR_EL2 - Retrieve the ICH_VTR_EL2 value
45 */
46#define HVC_GET_ICH_VTR_EL2 4
47
48/* Max number of HYP stub hypercalls */
49#define HVC_STUB_HCALL_NR 5
50
51/* Error returned when an invalid stub number is passed into x0 */
52#define HVC_STUB_ERR 0xbadca11
53
54#define BOOT_CPU_MODE_EL1 (0xe11)
55#define BOOT_CPU_MODE_EL2 (0xe12)
56
57/*
58 * Flags returned together with the boot mode, but not preserved in
59 * __boot_cpu_mode. Used by the idreg override code to work out the
60 * boot state.
61 */
62#define BOOT_CPU_FLAG_E2H BIT_ULL(32)
63
64#ifndef __ASSEMBLER__
65
66#include <asm/ptrace.h>
67#include <asm/sections.h>
68#include <asm/sysreg.h>
69#include <asm/cpufeature.h>
70
71/*
72 * __boot_cpu_mode records what mode CPUs were booted in.
73 * A correctly-implemented bootloader must start all CPUs in the same mode:
74 * In this case, both 32bit halves of __boot_cpu_mode will contain the
75 * same value (either BOOT_CPU_MODE_EL1 if booted in EL1, BOOT_CPU_MODE_EL2 if
76 * booted in EL2).
77 *
78 * Should the bootloader fail to do this, the two values will be different.
79 * This allows the kernel to flag an error when the secondaries have come up.
80 */
81extern u32 __boot_cpu_mode[2];
82
83#define ARM64_VECTOR_TABLE_LEN SZ_2K
84
85void __hyp_set_vectors(phys_addr_t phys_vector_base);
86void __hyp_reset_vectors(void);
87bool is_kvm_arm_initialised(void);
88
89DECLARE_STATIC_KEY_FALSE(kvm_protected_mode_initialized);
90
91static inline bool is_pkvm_initialized(void)
92{
93 return IS_ENABLED(CONFIG_KVM) &&
94 static_branch_likely(&kvm_protected_mode_initialized);
95}
96
97/* Reports the availability of HYP mode */
98static inline bool is_hyp_mode_available(void)
99{
100 /*
101 * If KVM protected mode is initialized, all CPUs must have been booted
102 * in EL2. Avoid checking __boot_cpu_mode as CPUs now come up in EL1.
103 */
104 if (is_pkvm_initialized())
105 return true;
106
107 return (__boot_cpu_mode[0] == BOOT_CPU_MODE_EL2 &&
108 __boot_cpu_mode[1] == BOOT_CPU_MODE_EL2);
109}
110
111/* Check if the bootloader has booted CPUs in different modes */
112static inline bool is_hyp_mode_mismatched(void)
113{
114 /*
115 * If KVM protected mode is initialized, all CPUs must have been booted
116 * in EL2. Avoid checking __boot_cpu_mode as CPUs now come up in EL1.
117 */
118 if (is_pkvm_initialized())
119 return false;
120
121 return __boot_cpu_mode[0] != __boot_cpu_mode[1];
122}
123
124static __always_inline bool is_kernel_in_hyp_mode(void)
125{
126 BUILD_BUG_ON(__is_defined(__KVM_NVHE_HYPERVISOR__) ||
127 __is_defined(__KVM_VHE_HYPERVISOR__));
128 return read_sysreg(CurrentEL) == CurrentEL_EL2;
129}
130
131static __always_inline bool has_vhe(void)
132{
133 /*
134 * Code only run in VHE/NVHE hyp context can assume VHE is present or
135 * absent. Otherwise fall back to caps.
136 * This allows the compiler to discard VHE-specific code from the
137 * nVHE object, reducing the number of external symbol references
138 * needed to link.
139 */
140 if (is_vhe_hyp_code())
141 return true;
142 else if (is_nvhe_hyp_code())
143 return false;
144 else
145 return cpus_have_final_cap(ARM64_HAS_VIRT_HOST_EXTN);
146}
147
148static __always_inline bool is_protected_kvm_enabled(void)
149{
150 if (is_vhe_hyp_code())
151 return false;
152 else
153 return cpus_have_final_cap(ARM64_KVM_PROTECTED_MODE);
154}
155
156static __always_inline bool has_hvhe(void)
157{
158 if (is_vhe_hyp_code())
159 return false;
160
161 return cpus_have_final_cap(ARM64_KVM_HVHE);
162}
163
164static inline bool is_hyp_nvhe(void)
165{
166 return is_hyp_mode_available() && !is_kernel_in_hyp_mode();
167}
168
169#endif /* __ASSEMBLER__ */
170
171#endif /* ! __ASM__VIRT_H */