virt.h

  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 */