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_VHE_RESTART - Upgrade the CPU from EL1 to EL2, if possible
40 */
41 #define HVC_VHE_RESTART 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 #ifndef __ASSEMBLY__
53
54 #include <asm/ptrace.h>
55 #include <asm/sections.h>
56 #include <asm/sysreg.h>
57 #include <asm/cpufeature.h>
58
59 /*
60 * __boot_cpu_mode records what mode CPUs were booted in.
61 * A correctly-implemented bootloader must start all CPUs in the same mode:
62 * In this case, both 32bit halves of __boot_cpu_mode will contain the
63 * same value (either 0 if booted in EL1, BOOT_CPU_MODE_EL2 if booted in EL2).
64 *
65 * Should the bootloader fail to do this, the two values will be different.
66 * This allows the kernel to flag an error when the secondaries have come up.
67 */
68 extern u32 __boot_cpu_mode[2];
69
70 void __hyp_set_vectors(phys_addr_t phys_vector_base);
71 void __hyp_reset_vectors(void);
72
73 DECLARE_STATIC_KEY_FALSE(kvm_protected_mode_initialized);
74
is_pkvm_initialized(void)75 static inline bool is_pkvm_initialized(void)
76 {
77 return IS_ENABLED(CONFIG_KVM) &&
78 static_branch_likely(&kvm_protected_mode_initialized);
79 }
80
81 /* Reports the availability of HYP mode */
is_hyp_mode_available(void)82 static inline bool is_hyp_mode_available(void)
83 {
84 /*
85 * If KVM protected mode is initialized, all CPUs must have been booted
86 * in EL2. Avoid checking __boot_cpu_mode as CPUs now come up in EL1.
87 */
88 if (is_pkvm_initialized())
89 return true;
90
91 return (__boot_cpu_mode[0] == BOOT_CPU_MODE_EL2 &&
92 __boot_cpu_mode[1] == BOOT_CPU_MODE_EL2);
93 }
94
95 /* Check if the bootloader has booted CPUs in different modes */
is_hyp_mode_mismatched(void)96 static inline bool is_hyp_mode_mismatched(void)
97 {
98 /*
99 * If KVM protected mode is initialized, all CPUs must have been booted
100 * in EL2. Avoid checking __boot_cpu_mode as CPUs now come up in EL1.
101 */
102 if (is_pkvm_initialized())
103 return false;
104
105 return __boot_cpu_mode[0] != __boot_cpu_mode[1];
106 }
107
is_kernel_in_hyp_mode(void)108 static inline bool is_kernel_in_hyp_mode(void)
109 {
110 return read_sysreg(CurrentEL) == CurrentEL_EL2;
111 }
112
has_vhe(void)113 static __always_inline bool has_vhe(void)
114 {
115 /*
116 * Code only run in VHE/NVHE hyp context can assume VHE is present or
117 * absent. Otherwise fall back to caps.
118 * This allows the compiler to discard VHE-specific code from the
119 * nVHE object, reducing the number of external symbol references
120 * needed to link.
121 */
122 if (is_vhe_hyp_code())
123 return true;
124 else if (is_nvhe_hyp_code())
125 return false;
126 else
127 return cpus_have_final_cap(ARM64_HAS_VIRT_HOST_EXTN);
128 }
129
is_protected_kvm_enabled(void)130 static __always_inline bool is_protected_kvm_enabled(void)
131 {
132 if (is_vhe_hyp_code())
133 return false;
134 else
135 return cpus_have_final_cap(ARM64_KVM_PROTECTED_MODE);
136 }
137
138 #endif /* __ASSEMBLY__ */
139
140 #endif /* ! __ASM__VIRT_H */
141