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/hyp_image.h>
  11 #include <asm/virt.h>
  12
  13 #define ARM_EXIT_WITH_SERROR_BIT  31
  14 #define ARM_EXCEPTION_CODE(x)     ((x) & ~(1U << ARM_EXIT_WITH_SERROR_BIT))
  15 #define ARM_EXCEPTION_IS_TRAP(x)  (ARM_EXCEPTION_CODE((x)) == ARM_EXCEPTION_TRAP)
  16 #define ARM_SERROR_PENDING(x)     !!((x) & (1U << ARM_EXIT_WITH_SERROR_BIT))
  17
  18 #define ARM_EXCEPTION_IRQ         0
  19 #define ARM_EXCEPTION_EL1_SERROR  1
  20 #define ARM_EXCEPTION_TRAP        2
  21 #define ARM_EXCEPTION_IL          3
  22 /* The hyp-stub will return this for any kvm_call_hyp() call */
  23 #define ARM_EXCEPTION_HYP_GONE    HVC_STUB_ERR
  24
  25 #define kvm_arm_exception_type                                  \
  26         {ARM_EXCEPTION_IRQ,             "IRQ"           },      \
  27         {ARM_EXCEPTION_EL1_SERROR,      "SERROR"        },      \
  28         {ARM_EXCEPTION_TRAP,            "TRAP"          },      \
  29         {ARM_EXCEPTION_HYP_GONE,        "HYP_GONE"      }
  30
  31 /*
  32  * Size of the HYP vectors preamble. kvm_patch_vector_branch() generates code
  33  * that jumps over this.
  34  */
  35 #define KVM_VECTOR_PREAMBLE     (2 * AARCH64_INSN_SIZE)
  36
  37 #define __SMCCC_WORKAROUND_1_SMC_SZ 36
  38
  39 #define KVM_HOST_SMCCC_ID(id)                                           \
  40         ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,                         \
  41                            ARM_SMCCC_SMC_64,                            \
  42                            ARM_SMCCC_OWNER_VENDOR_HYP,                  \
  43                            (id))
  44
  45 #define KVM_HOST_SMCCC_FUNC(name) KVM_HOST_SMCCC_ID(__KVM_HOST_SMCCC_FUNC_##name)
  46
  47 #define __KVM_HOST_SMCCC_FUNC___kvm_hyp_init                    0
  48 #define __KVM_HOST_SMCCC_FUNC___kvm_vcpu_run                    1
  49 #define __KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context            2
  50 #define __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_ipa          3
  51 #define __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid              4
  52 #define __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_local_vmid        5
  53 #define __KVM_HOST_SMCCC_FUNC___kvm_timer_set_cntvoff           6
  54 #define __KVM_HOST_SMCCC_FUNC___kvm_enable_ssbs                 7
  55 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_get_ich_vtr_el2         8
  56 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_read_vmcr               9
  57 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_write_vmcr              10
  58 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_init_lrs                11
  59 #define __KVM_HOST_SMCCC_FUNC___kvm_get_mdcr_el2                12
  60 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_save_aprs               13
  61 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_restore_aprs            14
  62
  63 #ifndef __ASSEMBLY__
  64
  65 #include <linux/mm.h>
  66
  67 #define DECLARE_KVM_VHE_SYM(sym)        extern char sym[]
  68 #define DECLARE_KVM_NVHE_SYM(sym)       extern char kvm_nvhe_sym(sym)[]
  69
  70 /*
  71  * Define a pair of symbols sharing the same name but one defined in
  72  * VHE and the other in nVHE hyp implementations.
  73  */
  74 #define DECLARE_KVM_HYP_SYM(sym)                \
  75         DECLARE_KVM_VHE_SYM(sym);               \
  76         DECLARE_KVM_NVHE_SYM(sym)
  77
  78 #define DECLARE_KVM_VHE_PER_CPU(type, sym)      \
  79         DECLARE_PER_CPU(type, sym)
  80 #define DECLARE_KVM_NVHE_PER_CPU(type, sym)     \
  81         DECLARE_PER_CPU(type, kvm_nvhe_sym(sym))
  82
  83 #define DECLARE_KVM_HYP_PER_CPU(type, sym)      \
  84         DECLARE_KVM_VHE_PER_CPU(type, sym);     \
  85         DECLARE_KVM_NVHE_PER_CPU(type, sym)
  86
  87 /*
  88  * Compute pointer to a symbol defined in nVHE percpu region.
  89  * Returns NULL if percpu memory has not been allocated yet.
  90  */
  91 #define this_cpu_ptr_nvhe_sym(sym)      per_cpu_ptr_nvhe_sym(sym, smp_processor_id())
  92 #define per_cpu_ptr_nvhe_sym(sym, cpu)                                          \
  93         ({                                                                      \
  94                 unsigned long base, off;                                        \
  95                 base = kvm_arm_hyp_percpu_base[cpu];                            \
  96                 off = (unsigned long)&CHOOSE_NVHE_SYM(sym) -                    \
  97                       (unsigned long)&CHOOSE_NVHE_SYM(__per_cpu_start);         \
  98                 base ? (typeof(CHOOSE_NVHE_SYM(sym))*)(base + off) : NULL;      \
  99         })
 100
 101 #if defined(__KVM_NVHE_HYPERVISOR__)
 102
 103 #define CHOOSE_NVHE_SYM(sym)    sym
 104 #define CHOOSE_HYP_SYM(sym)     CHOOSE_NVHE_SYM(sym)
 105
 106 /* The nVHE hypervisor shouldn't even try to access VHE symbols */
 107 extern void *__nvhe_undefined_symbol;
 108 #define CHOOSE_VHE_SYM(sym)             __nvhe_undefined_symbol
 109 #define this_cpu_ptr_hyp_sym(sym)       (&__nvhe_undefined_symbol)
 110 #define per_cpu_ptr_hyp_sym(sym, cpu)   (&__nvhe_undefined_symbol)
 111
 112 #elif defined(__KVM_VHE_HYPERVISOR__)
 113
 114 #define CHOOSE_VHE_SYM(sym)     sym
 115 #define CHOOSE_HYP_SYM(sym)     CHOOSE_VHE_SYM(sym)
 116
 117 /* The VHE hypervisor shouldn't even try to access nVHE symbols */
 118 extern void *__vhe_undefined_symbol;
 119 #define CHOOSE_NVHE_SYM(sym)            __vhe_undefined_symbol
 120 #define this_cpu_ptr_hyp_sym(sym)       (&__vhe_undefined_symbol)
 121 #define per_cpu_ptr_hyp_sym(sym, cpu)   (&__vhe_undefined_symbol)
 122
 123 #else
 124
 125 /*
 126  * BIG FAT WARNINGS:
 127  *
 128  * - Don't be tempted to change the following is_kernel_in_hyp_mode()
 129  *   to has_vhe(). has_vhe() is implemented as a *final* capability,
 130  *   while this is used early at boot time, when the capabilities are
 131  *   not final yet....
 132  *
 133  * - Don't let the nVHE hypervisor have access to this, as it will
 134  *   pick the *wrong* symbol (yes, it runs at EL2...).
 135  */
 136 #define CHOOSE_HYP_SYM(sym)             (is_kernel_in_hyp_mode()        \
 137                                            ? CHOOSE_VHE_SYM(sym)        \
 138                                            : CHOOSE_NVHE_SYM(sym))
 139
 140 #define this_cpu_ptr_hyp_sym(sym)       (is_kernel_in_hyp_mode()        \
 141                                            ? this_cpu_ptr(&sym)         \
 142                                            : this_cpu_ptr_nvhe_sym(sym))
 143
 144 #define per_cpu_ptr_hyp_sym(sym, cpu)   (is_kernel_in_hyp_mode()        \
 145                                            ? per_cpu_ptr(&sym, cpu)     \
 146                                            : per_cpu_ptr_nvhe_sym(sym, cpu))
 147
 148 #define CHOOSE_VHE_SYM(sym)     sym
 149 #define CHOOSE_NVHE_SYM(sym)    kvm_nvhe_sym(sym)
 150
 151 #endif
 152
 153 /* Translate a kernel address @ptr into its equivalent linear mapping */
 154 #define kvm_ksym_ref(ptr)                                               \
 155         ({                                                              \
 156                 void *val = (ptr);                                      \
 157                 if (!is_kernel_in_hyp_mode())                           \
 158                         val = lm_alias((ptr));                          \
 159                 val;                                                    \
 160          })
 161 #define kvm_ksym_ref_nvhe(sym)  kvm_ksym_ref(kvm_nvhe_sym(sym))
 162
 163 struct kvm;
 164 struct kvm_vcpu;
 165 struct kvm_s2_mmu;
 166
 167 DECLARE_KVM_NVHE_SYM(__kvm_hyp_init);
 168 DECLARE_KVM_NVHE_SYM(__kvm_hyp_host_vector);
 169 DECLARE_KVM_HYP_SYM(__kvm_hyp_vector);
 170 #define __kvm_hyp_init          CHOOSE_NVHE_SYM(__kvm_hyp_init)
 171 #define __kvm_hyp_host_vector   CHOOSE_NVHE_SYM(__kvm_hyp_host_vector)
 172 #define __kvm_hyp_vector        CHOOSE_HYP_SYM(__kvm_hyp_vector)
 173
 174 extern unsigned long kvm_arm_hyp_percpu_base[NR_CPUS];
 175 DECLARE_KVM_NVHE_SYM(__per_cpu_start);
 176 DECLARE_KVM_NVHE_SYM(__per_cpu_end);
 177
 178 extern atomic_t arm64_el2_vector_last_slot;
 179 DECLARE_KVM_HYP_SYM(__bp_harden_hyp_vecs);
 180 #define __bp_harden_hyp_vecs    CHOOSE_HYP_SYM(__bp_harden_hyp_vecs)
 181
 182 extern void __kvm_flush_vm_context(void);
 183 extern void __kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu, phys_addr_t ipa,
 184                                      int level);
 185 extern void __kvm_tlb_flush_vmid(struct kvm_s2_mmu *mmu);
 186 extern void __kvm_tlb_flush_local_vmid(struct kvm_s2_mmu *mmu);
 187
 188 extern void __kvm_timer_set_cntvoff(u64 cntvoff);
 189
 190 extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
 191
 192 extern void __kvm_enable_ssbs(void);
 193
 194 extern u64 __vgic_v3_get_ich_vtr_el2(void);
 195 extern u64 __vgic_v3_read_vmcr(void);
 196 extern void __vgic_v3_write_vmcr(u32 vmcr);
 197 extern void __vgic_v3_init_lrs(void);
 198
 199 extern u32 __kvm_get_mdcr_el2(void);
 200
 201 extern char __smccc_workaround_1_smc[__SMCCC_WORKAROUND_1_SMC_SZ];
 202
 203 #if defined(GCC_VERSION) && GCC_VERSION < 50000
 204 #define SYM_CONSTRAINT  "i"
 205 #else
 206 #define SYM_CONSTRAINT  "S"
 207 #endif
 208
 209 /*
 210  * Obtain the PC-relative address of a kernel symbol
 211  * s: symbol
 212  *
 213  * The goal of this macro is to return a symbol's address based on a
 214  * PC-relative computation, as opposed to a loading the VA from a
 215  * constant pool or something similar. This works well for HYP, as an
 216  * absolute VA is guaranteed to be wrong. Only use this if trying to
 217  * obtain the address of a symbol (i.e. not something you obtained by
 218  * following a pointer).
 219  */
 220 #define hyp_symbol_addr(s)                                              \
 221         ({                                                              \
 222                 typeof(s) *addr;                                        \
 223                 asm("adrp       %0, %1\n"                               \
 224                     "add        %0, %0, :lo12:%1\n"                     \
 225                     : "=r" (addr) : SYM_CONSTRAINT (&s));               \
 226                 addr;                                                   \
 227         })
 228
 229 #define __KVM_EXTABLE(from, to)                                         \
 230         "       .pushsection    __kvm_ex_table, \"a\"\n"                \
 231         "       .align          3\n"                                    \
 232         "       .long           (" #from " - .), (" #to " - .)\n"       \
 233         "       .popsection\n"
 234
 235
 236 #define __kvm_at(at_op, addr)                                           \
 237 ( {                                                                     \
 238         int __kvm_at_err = 0;                                           \
 239         u64 spsr, elr;                                                  \
 240         asm volatile(                                                   \
 241         "       mrs     %1, spsr_el2\n"                                 \
 242         "       mrs     %2, elr_el2\n"                                  \
 243         "1:     at      "at_op", %3\n"                                  \
 244         "       isb\n"                                                  \
 245         "       b       9f\n"                                           \
 246         "2:     msr     spsr_el2, %1\n"                                 \
 247         "       msr     elr_el2, %2\n"                                  \
 248         "       mov     %w0, %4\n"                                      \
 249         "9:\n"                                                          \
 250         __KVM_EXTABLE(1b, 2b)                                           \
 251         : "+r" (__kvm_at_err), "=&r" (spsr), "=&r" (elr)                \
 252         : "r" (addr), "i" (-EFAULT));                                   \
 253         __kvm_at_err;                                                   \
 254 } )
 255
 256
 257 #else /* __ASSEMBLY__ */
 258
 259 .macro get_host_ctxt reg, tmp
 260         adr_this_cpu \reg, kvm_host_data, \tmp
 261         add     \reg, \reg, #HOST_DATA_CONTEXT
 262 .endm
 263
 264 .macro get_vcpu_ptr vcpu, ctxt
 265         get_host_ctxt \ctxt, \vcpu
 266         ldr     \vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
 267 .endm
 268
 269 .macro get_loaded_vcpu vcpu, ctxt
 270         adr_this_cpu \ctxt, kvm_hyp_ctxt, \vcpu
 271         ldr     \vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
 272 .endm
 273
 274 .macro set_loaded_vcpu vcpu, ctxt, tmp
 275         adr_this_cpu \ctxt, kvm_hyp_ctxt, \tmp
 276         str     \vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
 277 .endm
 278
 279 /*
 280  * KVM extable for unexpected exceptions.
 281  * In the same format _asm_extable, but output to a different section so that
 282  * it can be mapped to EL2. The KVM version is not sorted. The caller must
 283  * ensure:
 284  * x18 has the hypervisor value to allow any Shadow-Call-Stack instrumented
 285  * code to write to it, and that SPSR_EL2 and ELR_EL2 are restored by the fixup.
 286  */
 287 .macro  _kvm_extable, from, to
 288         .pushsection    __kvm_ex_table, "a"
 289         .align          3
 290         .long           (\from - .), (\to - .)
 291         .popsection
 292 .endm
 293
 294 #define CPU_XREG_OFFSET(x)      (CPU_USER_PT_REGS + 8*x)
 295 #define CPU_LR_OFFSET           CPU_XREG_OFFSET(30)
 296 #define CPU_SP_EL0_OFFSET       (CPU_LR_OFFSET + 8)
 297
 298 /*
 299  * We treat x18 as callee-saved as the host may use it as a platform
 300  * register (e.g. for shadow call stack).
 301  */
 302 .macro save_callee_saved_regs ctxt
 303         str     x18,      [\ctxt, #CPU_XREG_OFFSET(18)]
 304         stp     x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
 305         stp     x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
 306         stp     x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
 307         stp     x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
 308         stp     x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
 309         stp     x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]
 310 .endm
 311
 312 .macro restore_callee_saved_regs ctxt
 313         // We require \ctxt is not x18-x28
 314         ldr     x18,      [\ctxt, #CPU_XREG_OFFSET(18)]
 315         ldp     x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
 316         ldp     x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
 317         ldp     x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
 318         ldp     x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
 319         ldp     x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
 320         ldp     x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]
 321 .endm
 322
 323 .macro save_sp_el0 ctxt, tmp
 324         mrs     \tmp,   sp_el0
 325         str     \tmp,   [\ctxt, #CPU_SP_EL0_OFFSET]
 326 .endm
 327
 328 .macro restore_sp_el0 ctxt, tmp
 329         ldr     \tmp,     [\ctxt, #CPU_SP_EL0_OFFSET]
 330         msr     sp_el0, \tmp
 331 .endm
 332
 333 #endif
 334
 335 #endif /* __ARM_KVM_ASM_H__ */