arch/arm64/kvm/hyp/nvhe/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 #include <hyp/sysreg-sr.h>
   9
  10 #include <linux/arm-smccc.h>
  11 #include <linux/kvm_host.h>
  12 #include <linux/types.h>
  13 #include <linux/jump_label.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
  30 #include <nvhe/mem_protect.h>
  31
  32 /* Non-VHE specific context */
  33 DEFINE_PER_CPU(struct kvm_host_data, kvm_host_data);
  34 DEFINE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt);
  35 DEFINE_PER_CPU(unsigned long, kvm_hyp_vector);
  36
  37 static void __activate_traps(struct kvm_vcpu *vcpu)
  38 {
  39         u64 val;
  40
  41         ___activate_traps(vcpu);
  42         __activate_traps_common(vcpu);
  43
  44         val = vcpu->arch.cptr_el2;
  45         val |= CPTR_EL2_TTA | CPTR_EL2_TAM;
  46         if (!update_fp_enabled(vcpu)) {
  47                 val |= CPTR_EL2_TFP | CPTR_EL2_TZ;
  48                 __activate_traps_fpsimd32(vcpu);
  49         }
  50
  51         write_sysreg(val, cptr_el2);
  52         write_sysreg(__this_cpu_read(kvm_hyp_vector), vbar_el2);
  53
  54         if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
  55                 struct kvm_cpu_context *ctxt = &vcpu->arch.ctxt;
  56
  57                 isb();
  58                 /*
  59                  * At this stage, and thanks to the above isb(), S2 is
  60                  * configured and enabled. We can now restore the guest's S1
  61                  * configuration: SCTLR, and only then TCR.
  62                  */
  63                 write_sysreg_el1(ctxt_sys_reg(ctxt, SCTLR_EL1), SYS_SCTLR);
  64                 isb();
  65                 write_sysreg_el1(ctxt_sys_reg(ctxt, TCR_EL1),   SYS_TCR);
  66         }
  67 }
  68
  69 static void __deactivate_traps(struct kvm_vcpu *vcpu)
  70 {
  71         extern char __kvm_hyp_host_vector[];
  72         u64 cptr;
  73
  74         ___deactivate_traps(vcpu);
  75
  76         if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
  77                 u64 val;
  78
  79                 /*
  80                  * Set the TCR and SCTLR registers in the exact opposite
  81                  * sequence as __activate_traps (first prevent walks,
  82                  * then force the MMU on). A generous sprinkling of isb()
  83                  * ensure that things happen in this exact order.
  84                  */
  85                 val = read_sysreg_el1(SYS_TCR);
  86                 write_sysreg_el1(val | TCR_EPD1_MASK | TCR_EPD0_MASK, SYS_TCR);
  87                 isb();
  88                 val = read_sysreg_el1(SYS_SCTLR);
  89                 write_sysreg_el1(val | SCTLR_ELx_M, SYS_SCTLR);
  90                 isb();
  91         }
  92
  93         __deactivate_traps_common(vcpu);
  94
  95         write_sysreg(this_cpu_ptr(&kvm_init_params)->hcr_el2, hcr_el2);
  96
  97         cptr = CPTR_EL2_DEFAULT;
  98         if (vcpu_has_sve(vcpu) && (vcpu->arch.flags & KVM_ARM64_FP_ENABLED))
  99                 cptr |= CPTR_EL2_TZ;
 100
 101         write_sysreg(cptr, cptr_el2);
 102         write_sysreg(__kvm_hyp_host_vector, vbar_el2);
 103 }
 104
 105 /* Save VGICv3 state on non-VHE systems */
 106 static void __hyp_vgic_save_state(struct kvm_vcpu *vcpu)
 107 {
 108         if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
 109                 __vgic_v3_save_state(&vcpu->arch.vgic_cpu.vgic_v3);
 110                 __vgic_v3_deactivate_traps(&vcpu->arch.vgic_cpu.vgic_v3);
 111         }
 112 }
 113
 114 /* Restore VGICv3 state on non_VEH systems */
 115 static void __hyp_vgic_restore_state(struct kvm_vcpu *vcpu)
 116 {
 117         if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
 118                 __vgic_v3_activate_traps(&vcpu->arch.vgic_cpu.vgic_v3);
 119                 __vgic_v3_restore_state(&vcpu->arch.vgic_cpu.vgic_v3);
 120         }
 121 }
 122
 123 /**
 124  * Disable host events, enable guest events
 125  */
 126 static bool __pmu_switch_to_guest(struct kvm_cpu_context *host_ctxt)
 127 {
 128         struct kvm_host_data *host;
 129         struct kvm_pmu_events *pmu;
 130
 131         host = container_of(host_ctxt, struct kvm_host_data, host_ctxt);
 132         pmu = &host->pmu_events;
 133
 134         if (pmu->events_host)
 135                 write_sysreg(pmu->events_host, pmcntenclr_el0);
 136
 137         if (pmu->events_guest)
 138                 write_sysreg(pmu->events_guest, pmcntenset_el0);
 139
 140         return (pmu->events_host || pmu->events_guest);
 141 }
 142
 143 /**
 144  * Disable guest events, enable host events
 145  */
 146 static void __pmu_switch_to_host(struct kvm_cpu_context *host_ctxt)
 147 {
 148         struct kvm_host_data *host;
 149         struct kvm_pmu_events *pmu;
 150
 151         host = container_of(host_ctxt, struct kvm_host_data, host_ctxt);
 152         pmu = &host->pmu_events;
 153
 154         if (pmu->events_guest)
 155                 write_sysreg(pmu->events_guest, pmcntenclr_el0);
 156
 157         if (pmu->events_host)
 158                 write_sysreg(pmu->events_host, pmcntenset_el0);
 159 }
 160
 161 /* Switch to the guest for legacy non-VHE systems */
 162 int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
 163 {
 164         struct kvm_cpu_context *host_ctxt;
 165         struct kvm_cpu_context *guest_ctxt;
 166         struct kvm_s2_mmu *mmu;
 167         bool pmu_switch_needed;
 168         u64 exit_code;
 169
 170         /*
 171          * Having IRQs masked via PMR when entering the guest means the GIC
 172          * will not signal the CPU of interrupts of lower priority, and the
 173          * only way to get out will be via guest exceptions.
 174          * Naturally, we want to avoid this.
 175          */
 176         if (system_uses_irq_prio_masking()) {
 177                 gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
 178                 pmr_sync();
 179         }
 180
 181         host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
 182         host_ctxt->__hyp_running_vcpu = vcpu;
 183         guest_ctxt = &vcpu->arch.ctxt;
 184
 185         pmu_switch_needed = __pmu_switch_to_guest(host_ctxt);
 186
 187         __sysreg_save_state_nvhe(host_ctxt);
 188         /*
 189          * We must flush and disable the SPE buffer for nVHE, as
 190          * the translation regime(EL1&0) is going to be loaded with
 191          * that of the guest. And we must do this before we change the
 192          * translation regime to EL2 (via MDCR_EL2_E2PB == 0) and
 193          * before we load guest Stage1.
 194          */
 195         __debug_save_host_buffers_nvhe(vcpu);
 196
 197         __kvm_adjust_pc(vcpu);
 198
 199         /*
 200          * We must restore the 32-bit state before the sysregs, thanks
 201          * to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
 202          *
 203          * Also, and in order to be able to deal with erratum #1319537 (A57)
 204          * and #1319367 (A72), we must ensure that all VM-related sysreg are
 205          * restored before we enable S2 translation.
 206          */
 207         __sysreg32_restore_state(vcpu);
 208         __sysreg_restore_state_nvhe(guest_ctxt);
 209
 210         mmu = kern_hyp_va(vcpu->arch.hw_mmu);
 211         __load_stage2(mmu, kern_hyp_va(mmu->arch));
 212         __activate_traps(vcpu);
 213
 214         __hyp_vgic_restore_state(vcpu);
 215         __timer_enable_traps(vcpu);
 216
 217         __debug_switch_to_guest(vcpu);
 218
 219         do {
 220                 /* Jump in the fire! */
 221                 exit_code = __guest_enter(vcpu);
 222
 223                 /* And we're baaack! */
 224         } while (fixup_guest_exit(vcpu, &exit_code));
 225
 226         __sysreg_save_state_nvhe(guest_ctxt);
 227         __sysreg32_save_state(vcpu);
 228         __timer_disable_traps(vcpu);
 229         __hyp_vgic_save_state(vcpu);
 230
 231         __deactivate_traps(vcpu);
 232         __load_host_stage2();
 233
 234         __sysreg_restore_state_nvhe(host_ctxt);
 235
 236         if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED)
 237                 __fpsimd_save_fpexc32(vcpu);
 238
 239         __debug_switch_to_host(vcpu);
 240         /*
 241          * This must come after restoring the host sysregs, since a non-VHE
 242          * system may enable SPE here and make use of the TTBRs.
 243          */
 244         __debug_restore_host_buffers_nvhe(vcpu);
 245
 246         if (pmu_switch_needed)
 247                 __pmu_switch_to_host(host_ctxt);
 248
 249         /* Returning to host will clear PSR.I, remask PMR if needed */
 250         if (system_uses_irq_prio_masking())
 251                 gic_write_pmr(GIC_PRIO_IRQOFF);
 252
 253         host_ctxt->__hyp_running_vcpu = NULL;
 254
 255         return exit_code;
 256 }
 257
 258 void __noreturn hyp_panic(void)
 259 {
 260         u64 spsr = read_sysreg_el2(SYS_SPSR);
 261         u64 elr = read_sysreg_el2(SYS_ELR);
 262         u64 par = read_sysreg_par();
 263         struct kvm_cpu_context *host_ctxt;
 264         struct kvm_vcpu *vcpu;
 265
 266         host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
 267         vcpu = host_ctxt->__hyp_running_vcpu;
 268
 269         if (vcpu) {
 270                 __timer_disable_traps(vcpu);
 271                 __deactivate_traps(vcpu);
 272                 __load_host_stage2();
 273                 __sysreg_restore_state_nvhe(host_ctxt);
 274         }
 275
 276         __hyp_do_panic(host_ctxt, spsr, elr, par);
 277         unreachable();
 278 }
 279
 280 asmlinkage void kvm_unexpected_el2_exception(void)
 281 {
 282         return __kvm_unexpected_el2_exception();
 283 }