arch/arm64/kvm/hyp/vhe/switch.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2015 - ARM Ltd
   4  * Author: Marc Zyngier <marc.zyngier@arm.com>
   5  */
   6
   7 #include <hyp/switch.h>
   8
   9 #include <linux/arm-smccc.h>
  10 #include <linux/kvm_host.h>
  11 #include <linux/types.h>
  12 #include <linux/jump_label.h>
  13 #include <linux/percpu.h>
  14 #include <uapi/linux/psci.h>
  15
  16 #include <kvm/arm_psci.h>
  17
  18 #include <asm/barrier.h>
  19 #include <asm/cpufeature.h>
  20 #include <asm/kprobes.h>
  21 #include <asm/kvm_asm.h>
  22 #include <asm/kvm_emulate.h>
  23 #include <asm/kvm_hyp.h>
  24 #include <asm/kvm_mmu.h>
  25 #include <asm/fpsimd.h>
  26 #include <asm/debug-monitors.h>
  27 #include <asm/processor.h>
  28 #include <asm/thread_info.h>
  29 #include <asm/vectors.h>
  30
  31 /* VHE specific context */
  32 DEFINE_PER_CPU(struct kvm_host_data, kvm_host_data);
  33 DEFINE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt);
  34 DEFINE_PER_CPU(unsigned long, kvm_hyp_vector);
  35
  36 static void __activate_traps(struct kvm_vcpu *vcpu)
  37 {
  38         u64 val;
  39
  40         ___activate_traps(vcpu);
  41
  42         val = read_sysreg(cpacr_el1);
  43         val |= CPACR_ELx_TTA;
  44         val &= ~(CPACR_EL1_ZEN_EL0EN | CPACR_EL1_ZEN_EL1EN |
  45                  CPACR_EL1_SMEN_EL0EN | CPACR_EL1_SMEN_EL1EN);
  46
  47         /*
  48          * With VHE (HCR.E2H == 1), accesses to CPACR_EL1 are routed to
  49          * CPTR_EL2. In general, CPACR_EL1 has the same layout as CPTR_EL2,
  50          * except for some missing controls, such as TAM.
  51          * In this case, CPTR_EL2.TAM has the same position with or without
  52          * VHE (HCR.E2H == 1) which allows us to use here the CPTR_EL2.TAM
  53          * shift value for trapping the AMU accesses.
  54          */
  55
  56         val |= CPTR_EL2_TAM;
  57
  58         if (guest_owns_fp_regs(vcpu)) {
  59                 if (vcpu_has_sve(vcpu))
  60                         val |= CPACR_EL1_ZEN_EL0EN | CPACR_EL1_ZEN_EL1EN;
  61         } else {
  62                 val &= ~(CPACR_EL1_FPEN_EL0EN | CPACR_EL1_FPEN_EL1EN);
  63                 __activate_traps_fpsimd32(vcpu);
  64         }
  65
  66         write_sysreg(val, cpacr_el1);
  67
  68         write_sysreg(__this_cpu_read(kvm_hyp_vector), vbar_el1);
  69 }
  70 NOKPROBE_SYMBOL(__activate_traps);
  71
  72 static void __deactivate_traps(struct kvm_vcpu *vcpu)
  73 {
  74         const char *host_vectors = vectors;
  75
  76         ___deactivate_traps(vcpu);
  77
  78         write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
  79
  80         /*
  81          * ARM errata 1165522 and 1530923 require the actual execution of the
  82          * above before we can switch to the EL2/EL0 translation regime used by
  83          * the host.
  84          */
  85         asm(ALTERNATIVE("nop", "isb", ARM64_WORKAROUND_SPECULATIVE_AT));
  86
  87         kvm_reset_cptr_el2(vcpu);
  88
  89         if (!arm64_kernel_unmapped_at_el0())
  90                 host_vectors = __this_cpu_read(this_cpu_vector);
  91         write_sysreg(host_vectors, vbar_el1);
  92 }
  93 NOKPROBE_SYMBOL(__deactivate_traps);
  94
  95 /*
  96  * Disable IRQs in {activate,deactivate}_traps_vhe_{load,put}() to
  97  * prevent a race condition between context switching of PMUSERENR_EL0
  98  * in __{activate,deactivate}_traps_common() and IPIs that attempts to
  99  * update PMUSERENR_EL0. See also kvm_set_pmuserenr().
 100  */
 101 void activate_traps_vhe_load(struct kvm_vcpu *vcpu)
 102 {
 103         unsigned long flags;
 104
 105         local_irq_save(flags);
 106         __activate_traps_common(vcpu);
 107         local_irq_restore(flags);
 108 }
 109
 110 void deactivate_traps_vhe_put(struct kvm_vcpu *vcpu)
 111 {
 112         unsigned long flags;
 113
 114         local_irq_save(flags);
 115         __deactivate_traps_common(vcpu);
 116         local_irq_restore(flags);
 117 }
 118
 119 static const exit_handler_fn hyp_exit_handlers[] = {
 120         [0 ... ESR_ELx_EC_MAX]          = NULL,
 121         [ESR_ELx_EC_CP15_32]            = kvm_hyp_handle_cp15_32,
 122         [ESR_ELx_EC_SYS64]              = kvm_hyp_handle_sysreg,
 123         [ESR_ELx_EC_SVE]                = kvm_hyp_handle_fpsimd,
 124         [ESR_ELx_EC_FP_ASIMD]           = kvm_hyp_handle_fpsimd,
 125         [ESR_ELx_EC_IABT_LOW]           = kvm_hyp_handle_iabt_low,
 126         [ESR_ELx_EC_DABT_LOW]           = kvm_hyp_handle_dabt_low,
 127         [ESR_ELx_EC_WATCHPT_LOW]        = kvm_hyp_handle_watchpt_low,
 128         [ESR_ELx_EC_PAC]                = kvm_hyp_handle_ptrauth,
 129 };
 130
 131 static const exit_handler_fn *kvm_get_exit_handler_array(struct kvm_vcpu *vcpu)
 132 {
 133         return hyp_exit_handlers;
 134 }
 135
 136 static void early_exit_filter(struct kvm_vcpu *vcpu, u64 *exit_code)
 137 {
 138         /*
 139          * If we were in HYP context on entry, adjust the PSTATE view
 140          * so that the usual helpers work correctly.
 141          */
 142         if (unlikely(vcpu_get_flag(vcpu, VCPU_HYP_CONTEXT))) {
 143                 u64 mode = *vcpu_cpsr(vcpu) & (PSR_MODE_MASK | PSR_MODE32_BIT);
 144
 145                 switch (mode) {
 146                 case PSR_MODE_EL1t:
 147                         mode = PSR_MODE_EL2t;
 148                         break;
 149                 case PSR_MODE_EL1h:
 150                         mode = PSR_MODE_EL2h;
 151                         break;
 152                 }
 153
 154                 *vcpu_cpsr(vcpu) &= ~(PSR_MODE_MASK | PSR_MODE32_BIT);
 155                 *vcpu_cpsr(vcpu) |= mode;
 156         }
 157 }
 158
 159 /* Switch to the guest for VHE systems running in EL2 */
 160 static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
 161 {
 162         struct kvm_cpu_context *host_ctxt;
 163         struct kvm_cpu_context *guest_ctxt;
 164         u64 exit_code;
 165
 166         host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
 167         host_ctxt->__hyp_running_vcpu = vcpu;
 168         guest_ctxt = &vcpu->arch.ctxt;
 169
 170         sysreg_save_host_state_vhe(host_ctxt);
 171
 172         /*
 173          * ARM erratum 1165522 requires us to configure both stage 1 and
 174          * stage 2 translation for the guest context before we clear
 175          * HCR_EL2.TGE.
 176          *
 177          * We have already configured the guest's stage 1 translation in
 178          * kvm_vcpu_load_sysregs_vhe above.  We must now call
 179          * __load_stage2 before __activate_traps, because
 180          * __load_stage2 configures stage 2 translation, and
 181          * __activate_traps clear HCR_EL2.TGE (among other things).
 182          */
 183         __load_stage2(vcpu->arch.hw_mmu, vcpu->arch.hw_mmu->arch);
 184         __activate_traps(vcpu);
 185
 186         __kvm_adjust_pc(vcpu);
 187
 188         sysreg_restore_guest_state_vhe(guest_ctxt);
 189         __debug_switch_to_guest(vcpu);
 190
 191         if (is_hyp_ctxt(vcpu))
 192                 vcpu_set_flag(vcpu, VCPU_HYP_CONTEXT);
 193         else
 194                 vcpu_clear_flag(vcpu, VCPU_HYP_CONTEXT);
 195
 196         do {
 197                 /* Jump in the fire! */
 198                 exit_code = __guest_enter(vcpu);
 199
 200                 /* And we're baaack! */
 201         } while (fixup_guest_exit(vcpu, &exit_code));
 202
 203         sysreg_save_guest_state_vhe(guest_ctxt);
 204
 205         __deactivate_traps(vcpu);
 206
 207         sysreg_restore_host_state_vhe(host_ctxt);
 208
 209         if (vcpu->arch.fp_state == FP_STATE_GUEST_OWNED)
 210                 __fpsimd_save_fpexc32(vcpu);
 211
 212         __debug_switch_to_host(vcpu);
 213
 214         return exit_code;
 215 }
 216 NOKPROBE_SYMBOL(__kvm_vcpu_run_vhe);
 217
 218 int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
 219 {
 220         int ret;
 221
 222         local_daif_mask();
 223
 224         /*
 225          * Having IRQs masked via PMR when entering the guest means the GIC
 226          * will not signal the CPU of interrupts of lower priority, and the
 227          * only way to get out will be via guest exceptions.
 228          * Naturally, we want to avoid this.
 229          *
 230          * local_daif_mask() already sets GIC_PRIO_PSR_I_SET, we just need a
 231          * dsb to ensure the redistributor is forwards EL2 IRQs to the CPU.
 232          */
 233         pmr_sync();
 234
 235         ret = __kvm_vcpu_run_vhe(vcpu);
 236
 237         /*
 238          * local_daif_restore() takes care to properly restore PSTATE.DAIF
 239          * and the GIC PMR if the host is using IRQ priorities.
 240          */
 241         local_daif_restore(DAIF_PROCCTX_NOIRQ);
 242
 243         /*
 244          * When we exit from the guest we change a number of CPU configuration
 245          * parameters, such as traps.  We rely on the isb() in kvm_call_hyp*()
 246          * to make sure these changes take effect before running the host or
 247          * additional guests.
 248          */
 249         return ret;
 250 }
 251
 252 static void __hyp_call_panic(u64 spsr, u64 elr, u64 par)
 253 {
 254         struct kvm_cpu_context *host_ctxt;
 255         struct kvm_vcpu *vcpu;
 256
 257         host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
 258         vcpu = host_ctxt->__hyp_running_vcpu;
 259
 260         __deactivate_traps(vcpu);
 261         sysreg_restore_host_state_vhe(host_ctxt);
 262
 263         panic("HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%p\n",
 264               spsr, elr,
 265               read_sysreg_el2(SYS_ESR), read_sysreg_el2(SYS_FAR),
 266               read_sysreg(hpfar_el2), par, vcpu);
 267 }
 268 NOKPROBE_SYMBOL(__hyp_call_panic);
 269
 270 void __noreturn hyp_panic(void)
 271 {
 272         u64 spsr = read_sysreg_el2(SYS_SPSR);
 273         u64 elr = read_sysreg_el2(SYS_ELR);
 274         u64 par = read_sysreg_par();
 275
 276         __hyp_call_panic(spsr, elr, par);
 277         unreachable();
 278 }
 279
 280 asmlinkage void kvm_unexpected_el2_exception(void)
 281 {
 282         __kvm_unexpected_el2_exception();
 283 }