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 KVM_HOST_SMCCC_ID(id)                                           \
  38         ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,                         \
  39                            ARM_SMCCC_SMC_64,                            \
  40                            ARM_SMCCC_OWNER_VENDOR_HYP,                  \
  41                            (id))
  42
  43 #define KVM_HOST_SMCCC_FUNC(name) KVM_HOST_SMCCC_ID(__KVM_HOST_SMCCC_FUNC_##name)
  44
  45 #define __KVM_HOST_SMCCC_FUNC___kvm_hyp_init                    0
  46 #define __KVM_HOST_SMCCC_FUNC___kvm_vcpu_run                    1
  47 #define __KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context            2
  48 #define __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_ipa          3
  49 #define __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid              4
  50 #define __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_local_vmid        5
  51 #define __KVM_HOST_SMCCC_FUNC___kvm_timer_set_cntvoff           6
  52 #define __KVM_HOST_SMCCC_FUNC___kvm_enable_ssbs                 7
  53 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_get_ich_vtr_el2         8
  54 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_read_vmcr               9
  55 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_write_vmcr              10
  56 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_init_lrs                11
  57 #define __KVM_HOST_SMCCC_FUNC___kvm_get_mdcr_el2                12
  58 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_save_aprs               13
  59 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_restore_aprs            14
  60
  61 #ifndef __ASSEMBLY__
  62
  63 #include <linux/mm.h>
  64
  65 #define DECLARE_KVM_VHE_SYM(sym)        extern char sym[]
  66 #define DECLARE_KVM_NVHE_SYM(sym)       extern char kvm_nvhe_sym(sym)[]
  67
  68 /*
  69  * Define a pair of symbols sharing the same name but one defined in
  70  * VHE and the other in nVHE hyp implementations.
  71  */
  72 #define DECLARE_KVM_HYP_SYM(sym)                \
  73         DECLARE_KVM_VHE_SYM(sym);               \
  74         DECLARE_KVM_NVHE_SYM(sym)
  75
  76 #define DECLARE_KVM_VHE_PER_CPU(type, sym)      \
  77         DECLARE_PER_CPU(type, sym)
  78 #define DECLARE_KVM_NVHE_PER_CPU(type, sym)     \
  79         DECLARE_PER_CPU(type, kvm_nvhe_sym(sym))
  80
  81 #define DECLARE_KVM_HYP_PER_CPU(type, sym)      \
  82         DECLARE_KVM_VHE_PER_CPU(type, sym);     \
  83         DECLARE_KVM_NVHE_PER_CPU(type, sym)
  84
  85 /*
  86  * Compute pointer to a symbol defined in nVHE percpu region.
  87  * Returns NULL if percpu memory has not been allocated yet.
  88  */
  89 #define this_cpu_ptr_nvhe_sym(sym)      per_cpu_ptr_nvhe_sym(sym, smp_processor_id())
  90 #define per_cpu_ptr_nvhe_sym(sym, cpu)                                          \
  91         ({                                                                      \
  92                 unsigned long base, off;                                        \
  93                 base = kvm_arm_hyp_percpu_base[cpu];                            \
  94                 off = (unsigned long)&CHOOSE_NVHE_SYM(sym) -                    \
  95                       (unsigned long)&CHOOSE_NVHE_SYM(__per_cpu_start);         \
  96                 base ? (typeof(CHOOSE_NVHE_SYM(sym))*)(base + off) : NULL;      \
  97         })
  98
  99 #if defined(__KVM_NVHE_HYPERVISOR__)
 100
 101 #define CHOOSE_NVHE_SYM(sym)    sym
 102 #define CHOOSE_HYP_SYM(sym)     CHOOSE_NVHE_SYM(sym)
 103
 104 /* The nVHE hypervisor shouldn't even try to access VHE symbols */
 105 extern void *__nvhe_undefined_symbol;
 106 #define CHOOSE_VHE_SYM(sym)             __nvhe_undefined_symbol
 107 #define this_cpu_ptr_hyp_sym(sym)       (&__nvhe_undefined_symbol)
 108 #define per_cpu_ptr_hyp_sym(sym, cpu)   (&__nvhe_undefined_symbol)
 109
 110 #elif defined(__KVM_VHE_HYPERVISOR__)
 111
 112 #define CHOOSE_VHE_SYM(sym)     sym
 113 #define CHOOSE_HYP_SYM(sym)     CHOOSE_VHE_SYM(sym)
 114
 115 /* The VHE hypervisor shouldn't even try to access nVHE symbols */
 116 extern void *__vhe_undefined_symbol;
 117 #define CHOOSE_NVHE_SYM(sym)            __vhe_undefined_symbol
 118 #define this_cpu_ptr_hyp_sym(sym)       (&__vhe_undefined_symbol)
 119 #define per_cpu_ptr_hyp_sym(sym, cpu)   (&__vhe_undefined_symbol)
 120
 121 #else
 122
 123 /*
 124  * BIG FAT WARNINGS:
 125  *
 126  * - Don't be tempted to change the following is_kernel_in_hyp_mode()
 127  *   to has_vhe(). has_vhe() is implemented as a *final* capability,
 128  *   while this is used early at boot time, when the capabilities are
 129  *   not final yet....
 130  *
 131  * - Don't let the nVHE hypervisor have access to this, as it will
 132  *   pick the *wrong* symbol (yes, it runs at EL2...).
 133  */
 134 #define CHOOSE_HYP_SYM(sym)             (is_kernel_in_hyp_mode()        \
 135                                            ? CHOOSE_VHE_SYM(sym)        \
 136                                            : CHOOSE_NVHE_SYM(sym))
 137
 138 #define this_cpu_ptr_hyp_sym(sym)       (is_kernel_in_hyp_mode()        \
 139                                            ? this_cpu_ptr(&sym)         \
 140                                            : this_cpu_ptr_nvhe_sym(sym))
 141
 142 #define per_cpu_ptr_hyp_sym(sym, cpu)   (is_kernel_in_hyp_mode()        \
 143                                            ? per_cpu_ptr(&sym, cpu)     \
 144                                            : per_cpu_ptr_nvhe_sym(sym, cpu))
 145
 146 #define CHOOSE_VHE_SYM(sym)     sym
 147 #define CHOOSE_NVHE_SYM(sym)    kvm_nvhe_sym(sym)
 148
 149 #endif
 150
 151 struct kvm_nvhe_init_params {
 152         unsigned long mair_el2;
 153         unsigned long tcr_el2;
 154         unsigned long tpidr_el2;
 155         unsigned long stack_hyp_va;
 156         phys_addr_t pgd_pa;
 157 };
 158
 159 /* Translate a kernel address @ptr into its equivalent linear mapping */
 160 #define kvm_ksym_ref(ptr)                                               \
 161         ({                                                              \
 162                 void *val = (ptr);                                      \
 163                 if (!is_kernel_in_hyp_mode())                           \
 164                         val = lm_alias((ptr));                          \
 165                 val;                                                    \
 166          })
 167 #define kvm_ksym_ref_nvhe(sym)  kvm_ksym_ref(kvm_nvhe_sym(sym))
 168
 169 struct kvm;
 170 struct kvm_vcpu;
 171 struct kvm_s2_mmu;
 172
 173 DECLARE_KVM_NVHE_SYM(__kvm_hyp_init);
 174 DECLARE_KVM_HYP_SYM(__kvm_hyp_vector);
 175 #define __kvm_hyp_init          CHOOSE_NVHE_SYM(__kvm_hyp_init)
 176 #define __kvm_hyp_vector        CHOOSE_HYP_SYM(__kvm_hyp_vector)
 177
 178 extern unsigned long kvm_arm_hyp_percpu_base[NR_CPUS];
 179 DECLARE_KVM_NVHE_SYM(__per_cpu_start);
 180 DECLARE_KVM_NVHE_SYM(__per_cpu_end);
 181
 182 DECLARE_KVM_HYP_SYM(__bp_harden_hyp_vecs);
 183 #define __bp_harden_hyp_vecs    CHOOSE_HYP_SYM(__bp_harden_hyp_vecs)
 184
 185 extern void __kvm_flush_vm_context(void);
 186 extern void __kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu, phys_addr_t ipa,
 187                                      int level);
 188 extern void __kvm_tlb_flush_vmid(struct kvm_s2_mmu *mmu);
 189 extern void __kvm_tlb_flush_local_vmid(struct kvm_s2_mmu *mmu);
 190
 191 extern void __kvm_timer_set_cntvoff(u64 cntvoff);
 192
 193 extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
 194
 195 extern u64 __vgic_v3_get_ich_vtr_el2(void);
 196 extern u64 __vgic_v3_read_vmcr(void);
 197 extern void __vgic_v3_write_vmcr(u32 vmcr);
 198 extern void __vgic_v3_init_lrs(void);
 199
 200 extern u32 __kvm_get_mdcr_el2(void);
 201
 202 #if defined(GCC_VERSION) && GCC_VERSION < 50000
 203 #define SYM_CONSTRAINT  "i"
 204 #else
 205 #define SYM_CONSTRAINT  "S"
 206 #endif
 207
 208 /*
 209  * Obtain the PC-relative address of a kernel symbol
 210  * s: symbol
 211  *
 212  * The goal of this macro is to return a symbol's address based on a
 213  * PC-relative computation, as opposed to a loading the VA from a
 214  * constant pool or something similar. This works well for HYP, as an
 215  * absolute VA is guaranteed to be wrong. Only use this if trying to
 216  * obtain the address of a symbol (i.e. not something you obtained by
 217  * following a pointer).
 218  */
 219 #define hyp_symbol_addr(s)                                              \
 220         ({                                                              \
 221                 typeof(s) *addr;                                        \
 222                 asm("adrp       %0, %1\n"                               \
 223                     "add        %0, %0, :lo12:%1\n"                     \
 224                     : "=r" (addr) : SYM_CONSTRAINT (&s));               \
 225                 addr;                                                   \
 226         })
 227
 228 #define __KVM_EXTABLE(from, to)                                         \
 229         "       .pushsection    __kvm_ex_table, \"a\"\n"                \
 230         "       .align          3\n"                                    \
 231         "       .long           (" #from " - .), (" #to " - .)\n"       \
 232         "       .popsection\n"
 233
 234
 235 #define __kvm_at(at_op, addr)                                           \
 236 ( {                                                                     \
 237         int __kvm_at_err = 0;                                           \
 238         u64 spsr, elr;                                                  \
 239         asm volatile(                                                   \
 240         "       mrs     %1, spsr_el2\n"                                 \
 241         "       mrs     %2, elr_el2\n"                                  \
 242         "1:     at      "at_op", %3\n"                                  \
 243         "       isb\n"                                                  \
 244         "       b       9f\n"                                           \
 245         "2:     msr     spsr_el2, %1\n"                                 \
 246         "       msr     elr_el2, %2\n"                                  \
 247         "       mov     %w0, %4\n"                                      \
 248         "9:\n"                                                          \
 249         __KVM_EXTABLE(1b, 2b)                                           \
 250         : "+r" (__kvm_at_err), "=&r" (spsr), "=&r" (elr)                \
 251         : "r" (addr), "i" (-EFAULT));                                   \
 252         __kvm_at_err;                                                   \
 253 } )
 254
 255
 256 #else /* __ASSEMBLY__ */
 257
 258 .macro get_host_ctxt reg, tmp
 259         adr_this_cpu \reg, kvm_host_data, \tmp
 260         add     \reg, \reg, #HOST_DATA_CONTEXT
 261 .endm
 262
 263 .macro get_vcpu_ptr vcpu, ctxt
 264         get_host_ctxt \ctxt, \vcpu
 265         ldr     \vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
 266 .endm
 267
 268 .macro get_loaded_vcpu vcpu, ctxt
 269         adr_this_cpu \ctxt, kvm_hyp_ctxt, \vcpu
 270         ldr     \vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
 271 .endm
 272
 273 .macro set_loaded_vcpu vcpu, ctxt, tmp
 274         adr_this_cpu \ctxt, kvm_hyp_ctxt, \tmp
 275         str     \vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
 276 .endm
 277
 278 /*
 279  * KVM extable for unexpected exceptions.
 280  * In the same format _asm_extable, but output to a different section so that
 281  * it can be mapped to EL2. The KVM version is not sorted. The caller must
 282  * ensure:
 283  * x18 has the hypervisor value to allow any Shadow-Call-Stack instrumented
 284  * code to write to it, and that SPSR_EL2 and ELR_EL2 are restored by the fixup.
 285  */
 286 .macro  _kvm_extable, from, to
 287         .pushsection    __kvm_ex_table, "a"
 288         .align          3
 289         .long           (\from - .), (\to - .)
 290         .popsection
 291 .endm
 292
 293 #define CPU_XREG_OFFSET(x)      (CPU_USER_PT_REGS + 8*x)
 294 #define CPU_LR_OFFSET           CPU_XREG_OFFSET(30)
 295 #define CPU_SP_EL0_OFFSET       (CPU_LR_OFFSET + 8)
 296
 297 /*
 298  * We treat x18 as callee-saved as the host may use it as a platform
 299  * register (e.g. for shadow call stack).
 300  */
 301 .macro save_callee_saved_regs ctxt
 302         str     x18,      [\ctxt, #CPU_XREG_OFFSET(18)]
 303         stp     x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
 304         stp     x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
 305         stp     x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
 306         stp     x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
 307         stp     x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
 308         stp     x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]
 309 .endm
 310
 311 .macro restore_callee_saved_regs ctxt
 312         // We require \ctxt is not x18-x28
 313         ldr     x18,      [\ctxt, #CPU_XREG_OFFSET(18)]
 314         ldp     x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
 315         ldp     x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
 316         ldp     x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
 317         ldp     x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
 318         ldp     x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
 319         ldp     x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]
 320 .endm
 321
 322 .macro save_sp_el0 ctxt, tmp
 323         mrs     \tmp,   sp_el0
 324         str     \tmp,   [\ctxt, #CPU_SP_EL0_OFFSET]
 325 .endm
 326
 327 .macro restore_sp_el0 ctxt, tmp
 328         ldr     \tmp,     [\ctxt, #CPU_SP_EL0_OFFSET]
 329         msr     sp_el0, \tmp
 330 .endm
 331
 332 #endif
 333
 334 #endif /* __ARM_KVM_ASM_H__ */