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/* Max number of HYP stub hypercalls */
44#define HVC_STUB_HCALL_NR 4
45
46/* Error returned when an invalid stub number is passed into x0 */
47#define HVC_STUB_ERR 0xbadca11
48
49#define BOOT_CPU_MODE_EL1 (0xe11)
50#define BOOT_CPU_MODE_EL2 (0xe12)
51
52/*
53 * Flags returned together with the boot mode, but not preserved in
54 * __boot_cpu_mode. Used by the idreg override code to work out the
55 * boot state.
56 */
57#define BOOT_CPU_FLAG_E2H BIT_ULL(32)
58
59#ifndef __ASSEMBLY__
60
61#include <asm/ptrace.h>
62#include <asm/sections.h>
63#include <asm/sysreg.h>
64#include <asm/cpufeature.h>
65
66/*
67 * __boot_cpu_mode records what mode CPUs were booted in.
68 * A correctly-implemented bootloader must start all CPUs in the same mode:
69 * In this case, both 32bit halves of __boot_cpu_mode will contain the
70 * same value (either 0 if booted in EL1, BOOT_CPU_MODE_EL2 if booted in EL2).
71 *
72 * Should the bootloader fail to do this, the two values will be different.
73 * This allows the kernel to flag an error when the secondaries have come up.
74 */
75extern u32 __boot_cpu_mode[2];
76
77#define ARM64_VECTOR_TABLE_LEN SZ_2K
78
79void __hyp_set_vectors(phys_addr_t phys_vector_base);
80void __hyp_reset_vectors(void);
81bool is_kvm_arm_initialised(void);
82
83DECLARE_STATIC_KEY_FALSE(kvm_protected_mode_initialized);
84
85static inline bool is_pkvm_initialized(void)
86{
87 return IS_ENABLED(CONFIG_KVM) &&
88 static_branch_likely(&kvm_protected_mode_initialized);
89}
90
91/* Reports the availability of HYP mode */
92static inline bool is_hyp_mode_available(void)
93{
94 /*
95 * If KVM protected mode is initialized, all CPUs must have been booted
96 * in EL2. Avoid checking __boot_cpu_mode as CPUs now come up in EL1.
97 */
98 if (is_pkvm_initialized())
99 return true;
100
101 return (__boot_cpu_mode[0] == BOOT_CPU_MODE_EL2 &&
102 __boot_cpu_mode[1] == BOOT_CPU_MODE_EL2);
103}
104
105/* Check if the bootloader has booted CPUs in different modes */
106static inline bool is_hyp_mode_mismatched(void)
107{
108 /*
109 * If KVM protected mode is initialized, all CPUs must have been booted
110 * in EL2. Avoid checking __boot_cpu_mode as CPUs now come up in EL1.
111 */
112 if (is_pkvm_initialized())
113 return false;
114
115 return __boot_cpu_mode[0] != __boot_cpu_mode[1];
116}
117
118static __always_inline bool is_kernel_in_hyp_mode(void)
119{
120 BUILD_BUG_ON(__is_defined(__KVM_NVHE_HYPERVISOR__) ||
121 __is_defined(__KVM_VHE_HYPERVISOR__));
122 return read_sysreg(CurrentEL) == CurrentEL_EL2;
123}
124
125static __always_inline bool has_vhe(void)
126{
127 /*
128 * Code only run in VHE/NVHE hyp context can assume VHE is present or
129 * absent. Otherwise fall back to caps.
130 * This allows the compiler to discard VHE-specific code from the
131 * nVHE object, reducing the number of external symbol references
132 * needed to link.
133 */
134 if (is_vhe_hyp_code())
135 return true;
136 else if (is_nvhe_hyp_code())
137 return false;
138 else
139 return cpus_have_final_cap(ARM64_HAS_VIRT_HOST_EXTN);
140}
141
142static __always_inline bool is_protected_kvm_enabled(void)
143{
144 if (is_vhe_hyp_code())
145 return false;
146 else
147 return cpus_have_final_cap(ARM64_KVM_PROTECTED_MODE);
148}
149
150static __always_inline bool has_hvhe(void)
151{
152 if (is_vhe_hyp_code())
153 return false;
154
155 return cpus_have_final_cap(ARM64_KVM_HVHE);
156}
157
158static inline bool is_hyp_nvhe(void)
159{
160 return is_hyp_mode_available() && !is_kernel_in_hyp_mode();
161}
162
163#endif /* __ASSEMBLY__ */
164
165#endif /* ! __ASM__VIRT_H */