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 /* Non-VHE specific context */
  31 DEFINE_PER_CPU(struct kvm_host_data, kvm_host_data);
  32 DEFINE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt);
  33 DEFINE_PER_CPU(unsigned long, kvm_hyp_vector);
  34
  35 static void __activate_traps(struct kvm_vcpu *vcpu)
  36 {
  37         u64 val;
  38
  39         ___activate_traps(vcpu);
  40         __activate_traps_common(vcpu);
  41
  42         val = CPTR_EL2_DEFAULT;
  43         val |= CPTR_EL2_TTA | CPTR_EL2_TZ | CPTR_EL2_TAM;
  44         if (!update_fp_enabled(vcpu)) {
  45                 val |= CPTR_EL2_TFP;
  46                 __activate_traps_fpsimd32(vcpu);
  47         }
  48
  49         write_sysreg(val, cptr_el2);
  50         write_sysreg(__this_cpu_read(kvm_hyp_vector), vbar_el2);
  51
  52         if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
  53                 struct kvm_cpu_context *ctxt = &vcpu->arch.ctxt;
  54
  55                 isb();
  56                 /*
  57                  * At this stage, and thanks to the above isb(), S2 is
  58                  * configured and enabled. We can now restore the guest's S1
  59                  * configuration: SCTLR, and only then TCR.
  60                  */
  61                 write_sysreg_el1(ctxt_sys_reg(ctxt, SCTLR_EL1), SYS_SCTLR);
  62                 isb();
  63                 write_sysreg_el1(ctxt_sys_reg(ctxt, TCR_EL1),   SYS_TCR);
  64         }
  65 }
  66
  67 static void __deactivate_traps(struct kvm_vcpu *vcpu)
  68 {
  69         extern char __kvm_hyp_host_vector[];
  70         u64 mdcr_el2;
  71
  72         ___deactivate_traps(vcpu);
  73
  74         mdcr_el2 = read_sysreg(mdcr_el2);
  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();
  94
  95         mdcr_el2 &= MDCR_EL2_HPMN_MASK;
  96         mdcr_el2 |= MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT;
  97
  98         write_sysreg(mdcr_el2, mdcr_el2);
  99         write_sysreg(HCR_HOST_NVHE_FLAGS, hcr_el2);
 100         write_sysreg(CPTR_EL2_DEFAULT, cptr_el2);
 101         write_sysreg(__kvm_hyp_host_vector, vbar_el2);
 102 }
 103
 104 static void __load_host_stage2(void)
 105 {
 106         write_sysreg(0, vttbr_el2);
 107 }
 108
 109 /* Save VGICv3 state on non-VHE systems */
 110 static void __hyp_vgic_save_state(struct kvm_vcpu *vcpu)
 111 {
 112         if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
 113                 __vgic_v3_save_state(&vcpu->arch.vgic_cpu.vgic_v3);
 114                 __vgic_v3_deactivate_traps(&vcpu->arch.vgic_cpu.vgic_v3);
 115         }
 116 }
 117
 118 /* Restore VGICv3 state on non_VEH systems */
 119 static void __hyp_vgic_restore_state(struct kvm_vcpu *vcpu)
 120 {
 121         if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
 122                 __vgic_v3_activate_traps(&vcpu->arch.vgic_cpu.vgic_v3);
 123                 __vgic_v3_restore_state(&vcpu->arch.vgic_cpu.vgic_v3);
 124         }
 125 }
 126
 127 /**
 128  * Disable host events, enable guest events
 129  */
 130 static bool __pmu_switch_to_guest(struct kvm_cpu_context *host_ctxt)
 131 {
 132         struct kvm_host_data *host;
 133         struct kvm_pmu_events *pmu;
 134
 135         host = container_of(host_ctxt, struct kvm_host_data, host_ctxt);
 136         pmu = &host->pmu_events;
 137
 138         if (pmu->events_host)
 139                 write_sysreg(pmu->events_host, pmcntenclr_el0);
 140
 141         if (pmu->events_guest)
 142                 write_sysreg(pmu->events_guest, pmcntenset_el0);
 143
 144         return (pmu->events_host || pmu->events_guest);
 145 }
 146
 147 /**
 148  * Disable guest events, enable host events
 149  */
 150 static void __pmu_switch_to_host(struct kvm_cpu_context *host_ctxt)
 151 {
 152         struct kvm_host_data *host;
 153         struct kvm_pmu_events *pmu;
 154
 155         host = container_of(host_ctxt, struct kvm_host_data, host_ctxt);
 156         pmu = &host->pmu_events;
 157
 158         if (pmu->events_guest)
 159                 write_sysreg(pmu->events_guest, pmcntenclr_el0);
 160
 161         if (pmu->events_host)
 162                 write_sysreg(pmu->events_host, pmcntenset_el0);
 163 }
 164
 165 /* Switch to the guest for legacy non-VHE systems */
 166 int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
 167 {
 168         struct kvm_cpu_context *host_ctxt;
 169         struct kvm_cpu_context *guest_ctxt;
 170         bool pmu_switch_needed;
 171         u64 exit_code;
 172
 173         /*
 174          * Having IRQs masked via PMR when entering the guest means the GIC
 175          * will not signal the CPU of interrupts of lower priority, and the
 176          * only way to get out will be via guest exceptions.
 177          * Naturally, we want to avoid this.
 178          */
 179         if (system_uses_irq_prio_masking()) {
 180                 gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
 181                 pmr_sync();
 182         }
 183
 184         host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
 185         host_ctxt->__hyp_running_vcpu = vcpu;
 186         guest_ctxt = &vcpu->arch.ctxt;
 187
 188         pmu_switch_needed = __pmu_switch_to_guest(host_ctxt);
 189
 190         __sysreg_save_state_nvhe(host_ctxt);
 191
 192         /*
 193          * We must restore the 32-bit state before the sysregs, thanks
 194          * to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
 195          *
 196          * Also, and in order to be able to deal with erratum #1319537 (A57)
 197          * and #1319367 (A72), we must ensure that all VM-related sysreg are
 198          * restored before we enable S2 translation.
 199          */
 200         __sysreg32_restore_state(vcpu);
 201         __sysreg_restore_state_nvhe(guest_ctxt);
 202
 203         __load_guest_stage2(kern_hyp_va(vcpu->arch.hw_mmu));
 204         __activate_traps(vcpu);
 205
 206         __hyp_vgic_restore_state(vcpu);
 207         __timer_enable_traps(vcpu);
 208
 209         __debug_switch_to_guest(vcpu);
 210
 211         do {
 212                 /* Jump in the fire! */
 213                 exit_code = __guest_enter(vcpu);
 214
 215                 /* And we're baaack! */
 216         } while (fixup_guest_exit(vcpu, &exit_code));
 217
 218         __sysreg_save_state_nvhe(guest_ctxt);
 219         __sysreg32_save_state(vcpu);
 220         __timer_disable_traps(vcpu);
 221         __hyp_vgic_save_state(vcpu);
 222
 223         __deactivate_traps(vcpu);
 224         __load_host_stage2();
 225
 226         __sysreg_restore_state_nvhe(host_ctxt);
 227
 228         if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED)
 229                 __fpsimd_save_fpexc32(vcpu);
 230
 231         /*
 232          * This must come after restoring the host sysregs, since a non-VHE
 233          * system may enable SPE here and make use of the TTBRs.
 234          */
 235         __debug_switch_to_host(vcpu);
 236
 237         if (pmu_switch_needed)
 238                 __pmu_switch_to_host(host_ctxt);
 239
 240         /* Returning to host will clear PSR.I, remask PMR if needed */
 241         if (system_uses_irq_prio_masking())
 242                 gic_write_pmr(GIC_PRIO_IRQOFF);
 243
 244         host_ctxt->__hyp_running_vcpu = NULL;
 245
 246         return exit_code;
 247 }
 248
 249 void __noreturn hyp_panic(void)
 250 {
 251         u64 spsr = read_sysreg_el2(SYS_SPSR);
 252         u64 elr = read_sysreg_el2(SYS_ELR);
 253         u64 par = read_sysreg(par_el1);
 254         bool restore_host = true;
 255         struct kvm_cpu_context *host_ctxt;
 256         struct kvm_vcpu *vcpu;
 257
 258         host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
 259         vcpu = host_ctxt->__hyp_running_vcpu;
 260
 261         if (vcpu) {
 262                 __timer_disable_traps(vcpu);
 263                 __deactivate_traps(vcpu);
 264                 __load_host_stage2();
 265                 __sysreg_restore_state_nvhe(host_ctxt);
 266         }
 267
 268         __hyp_do_panic(restore_host, spsr, elr, par);
 269         unreachable();
 270 }
 271
 272 asmlinkage void kvm_unexpected_el2_exception(void)
 273 {
 274         return __kvm_unexpected_el2_exception();
 275 }