arch/arm64/include/asm/kvm_asm.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (C) 2012,2013 - ARM Ltd
   4  * Author: Marc Zyngier <marc.zyngier@arm.com>
   5  */
   6
   7 #ifndef __ARM_KVM_ASM_H__
   8 #define __ARM_KVM_ASM_H__
   9
  10 #include <asm/virt.h>
  11
  12 #define VCPU_WORKAROUND_2_FLAG_SHIFT    0
  13 #define VCPU_WORKAROUND_2_FLAG          (_AC(1, UL) << VCPU_WORKAROUND_2_FLAG_SHIFT)
  14
  15 #define ARM_EXIT_WITH_SERROR_BIT  31
  16 #define ARM_EXCEPTION_CODE(x)     ((x) & ~(1U << ARM_EXIT_WITH_SERROR_BIT))
  17 #define ARM_EXCEPTION_IS_TRAP(x)  (ARM_EXCEPTION_CODE((x)) == ARM_EXCEPTION_TRAP)
  18 #define ARM_SERROR_PENDING(x)     !!((x) & (1U << ARM_EXIT_WITH_SERROR_BIT))
  19
  20 #define ARM_EXCEPTION_IRQ         0
  21 #define ARM_EXCEPTION_EL1_SERROR  1
  22 #define ARM_EXCEPTION_TRAP        2
  23 #define ARM_EXCEPTION_IL          3
  24 /* The hyp-stub will return this for any kvm_call_hyp() call */
  25 #define ARM_EXCEPTION_HYP_GONE    HVC_STUB_ERR
  26
  27 #define kvm_arm_exception_type                                  \
  28         {ARM_EXCEPTION_IRQ,             "IRQ"           },      \
  29         {ARM_EXCEPTION_EL1_SERROR,      "SERROR"        },      \
  30         {ARM_EXCEPTION_TRAP,            "TRAP"          },      \
  31         {ARM_EXCEPTION_HYP_GONE,        "HYP_GONE"      }
  32
  33 /*
  34  * Size of the HYP vectors preamble. kvm_patch_vector_branch() generates code
  35  * that jumps over this.
  36  */
  37 #define KVM_VECTOR_PREAMBLE     (2 * AARCH64_INSN_SIZE)
  38
  39 #define __SMCCC_WORKAROUND_1_SMC_SZ 36
  40
  41 #ifndef __ASSEMBLY__
  42
  43 #include <linux/mm.h>
  44
  45 /*
  46  * Translate name of a symbol defined in nVHE hyp to the name seen
  47  * by kernel proper. All nVHE symbols are prefixed by the build system
  48  * to avoid clashes with the VHE variants.
  49  */
  50 #define kvm_nvhe_sym(sym)       __kvm_nvhe_##sym
  51
  52 #define DECLARE_KVM_VHE_SYM(sym)        extern char sym[]
  53 #define DECLARE_KVM_NVHE_SYM(sym)       extern char kvm_nvhe_sym(sym)[]
  54
  55 /*
  56  * Define a pair of symbols sharing the same name but one defined in
  57  * VHE and the other in nVHE hyp implementations.
  58  */
  59 #define DECLARE_KVM_HYP_SYM(sym)                \
  60         DECLARE_KVM_VHE_SYM(sym);               \
  61         DECLARE_KVM_NVHE_SYM(sym)
  62
  63 #define CHOOSE_VHE_SYM(sym)     sym
  64 #define CHOOSE_NVHE_SYM(sym)    kvm_nvhe_sym(sym)
  65
  66 #ifndef __KVM_NVHE_HYPERVISOR__
  67 /*
  68  * BIG FAT WARNINGS:
  69  *
  70  * - Don't be tempted to change the following is_kernel_in_hyp_mode()
  71  *   to has_vhe(). has_vhe() is implemented as a *final* capability,
  72  *   while this is used early at boot time, when the capabilities are
  73  *   not final yet....
  74  *
  75  * - Don't let the nVHE hypervisor have access to this, as it will
  76  *   pick the *wrong* symbol (yes, it runs at EL2...).
  77  */
  78 #define CHOOSE_HYP_SYM(sym)     (is_kernel_in_hyp_mode() ? CHOOSE_VHE_SYM(sym) \
  79                                            : CHOOSE_NVHE_SYM(sym))
  80 #else
  81 /* The nVHE hypervisor shouldn't even try to access anything */
  82 extern void *__nvhe_undefined_symbol;
  83 #define CHOOSE_HYP_SYM(sym)     __nvhe_undefined_symbol
  84 #endif
  85
  86 /* Translate a kernel address @ptr into its equivalent linear mapping */
  87 #define kvm_ksym_ref(ptr)                                               \
  88         ({                                                              \
  89                 void *val = (ptr);                                      \
  90                 if (!is_kernel_in_hyp_mode())                           \
  91                         val = lm_alias((ptr));                          \
  92                 val;                                                    \
  93          })
  94 #define kvm_ksym_ref_nvhe(sym)  kvm_ksym_ref(kvm_nvhe_sym(sym))
  95
  96 struct kvm;
  97 struct kvm_vcpu;
  98 struct kvm_s2_mmu;
  99
 100 DECLARE_KVM_NVHE_SYM(__kvm_hyp_init);
 101 DECLARE_KVM_HYP_SYM(__kvm_hyp_vector);
 102 #define __kvm_hyp_init          CHOOSE_NVHE_SYM(__kvm_hyp_init)
 103 #define __kvm_hyp_vector        CHOOSE_HYP_SYM(__kvm_hyp_vector)
 104
 105 #ifdef CONFIG_KVM_INDIRECT_VECTORS
 106 extern atomic_t arm64_el2_vector_last_slot;
 107 DECLARE_KVM_HYP_SYM(__bp_harden_hyp_vecs);
 108 #define __bp_harden_hyp_vecs    CHOOSE_HYP_SYM(__bp_harden_hyp_vecs)
 109 #endif
 110
 111 extern void __kvm_flush_vm_context(void);
 112 extern void __kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu, phys_addr_t ipa,
 113                                      int level);
 114 extern void __kvm_tlb_flush_vmid(struct kvm_s2_mmu *mmu);
 115 extern void __kvm_tlb_flush_local_vmid(struct kvm_s2_mmu *mmu);
 116
 117 extern void __kvm_timer_set_cntvoff(u64 cntvoff);
 118
 119 extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
 120
 121 extern void __kvm_enable_ssbs(void);
 122
 123 extern u64 __vgic_v3_get_ich_vtr_el2(void);
 124 extern u64 __vgic_v3_read_vmcr(void);
 125 extern void __vgic_v3_write_vmcr(u32 vmcr);
 126 extern void __vgic_v3_init_lrs(void);
 127
 128 extern u32 __kvm_get_mdcr_el2(void);
 129
 130 extern char __smccc_workaround_1_smc[__SMCCC_WORKAROUND_1_SMC_SZ];
 131
 132 /*
 133  * Obtain the PC-relative address of a kernel symbol
 134  * s: symbol
 135  *
 136  * The goal of this macro is to return a symbol's address based on a
 137  * PC-relative computation, as opposed to a loading the VA from a
 138  * constant pool or something similar. This works well for HYP, as an
 139  * absolute VA is guaranteed to be wrong. Only use this if trying to
 140  * obtain the address of a symbol (i.e. not something you obtained by
 141  * following a pointer).
 142  */
 143 #define hyp_symbol_addr(s)                                              \
 144         ({                                                              \
 145                 typeof(s) *addr;                                        \
 146                 asm("adrp       %0, %1\n"                               \
 147                     "add        %0, %0, :lo12:%1\n"                     \
 148                     : "=r" (addr) : "S" (&s));                          \
 149                 addr;                                                   \
 150         })
 151
 152 /*
 153  * Home-grown __this_cpu_{ptr,read} variants that always work at HYP,
 154  * provided that sym is really a *symbol* and not a pointer obtained from
 155  * a data structure. As for SHIFT_PERCPU_PTR(), the creative casting keeps
 156  * sparse quiet.
 157  */
 158 #define __hyp_this_cpu_ptr(sym)                                         \
 159         ({                                                              \
 160                 void *__ptr;                                            \
 161                 __verify_pcpu_ptr(&sym);                                \
 162                 __ptr = hyp_symbol_addr(sym);                           \
 163                 __ptr += read_sysreg(tpidr_el2);                        \
 164                 (typeof(sym) __kernel __force *)__ptr;                  \
 165          })
 166
 167 #define __hyp_this_cpu_read(sym)                                        \
 168         ({                                                              \
 169                 *__hyp_this_cpu_ptr(sym);                               \
 170          })
 171
 172 #define __KVM_EXTABLE(from, to)                                         \
 173         "       .pushsection    __kvm_ex_table, \"a\"\n"                \
 174         "       .align          3\n"                                    \
 175         "       .long           (" #from " - .), (" #to " - .)\n"       \
 176         "       .popsection\n"
 177
 178
 179 #define __kvm_at(at_op, addr)                                           \
 180 ( {                                                                     \
 181         int __kvm_at_err = 0;                                           \
 182         u64 spsr, elr;                                                  \
 183         asm volatile(                                                   \
 184         "       mrs     %1, spsr_el2\n"                                 \
 185         "       mrs     %2, elr_el2\n"                                  \
 186         "1:     at      "at_op", %3\n"                                  \
 187         "       isb\n"                                                  \
 188         "       b       9f\n"                                           \
 189         "2:     msr     spsr_el2, %1\n"                                 \
 190         "       msr     elr_el2, %2\n"                                  \
 191         "       mov     %w0, %4\n"                                      \
 192         "9:\n"                                                          \
 193         __KVM_EXTABLE(1b, 2b)                                           \
 194         : "+r" (__kvm_at_err), "=&r" (spsr), "=&r" (elr)                \
 195         : "r" (addr), "i" (-EFAULT));                                   \
 196         __kvm_at_err;                                                   \
 197 } )
 198
 199
 200 #else /* __ASSEMBLY__ */
 201
 202 .macro hyp_adr_this_cpu reg, sym, tmp
 203         adr_l   \reg, \sym
 204         mrs     \tmp, tpidr_el2
 205         add     \reg, \reg, \tmp
 206 .endm
 207
 208 .macro hyp_ldr_this_cpu reg, sym, tmp
 209         adr_l   \reg, \sym
 210         mrs     \tmp, tpidr_el2
 211         ldr     \reg,  [\reg, \tmp]
 212 .endm
 213
 214 .macro get_host_ctxt reg, tmp
 215         hyp_adr_this_cpu \reg, kvm_host_data, \tmp
 216         add     \reg, \reg, #HOST_DATA_CONTEXT
 217 .endm
 218
 219 .macro get_vcpu_ptr vcpu, ctxt
 220         get_host_ctxt \ctxt, \vcpu
 221         ldr     \vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
 222 .endm
 223
 224 /*
 225  * KVM extable for unexpected exceptions.
 226  * In the same format _asm_extable, but output to a different section so that
 227  * it can be mapped to EL2. The KVM version is not sorted. The caller must
 228  * ensure:
 229  * x18 has the hypervisor value to allow any Shadow-Call-Stack instrumented
 230  * code to write to it, and that SPSR_EL2 and ELR_EL2 are restored by the fixup.
 231  */
 232 .macro  _kvm_extable, from, to
 233         .pushsection    __kvm_ex_table, "a"
 234         .align          3
 235         .long           (\from - .), (\to - .)
 236         .popsection
 237 .endm
 238
 239 #endif
 240
 241 #endif /* __ARM_KVM_ASM_H__ */