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