arch/arm64/kvm/hyp/switch.c

   1 /*
   2  * Copyright (C) 2015 - ARM Ltd
   3  * Author: Marc Zyngier <marc.zyngier@arm.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "hyp.h"
  19
  20 static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu)
  21 {
  22         u64 val;
  23
  24         /*
  25          * We are about to set CPTR_EL2.TFP to trap all floating point
  26          * register accesses to EL2, however, the ARM ARM clearly states that
  27          * traps are only taken to EL2 if the operation would not otherwise
  28          * trap to EL1.  Therefore, always make sure that for 32-bit guests,
  29          * we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit.
  30          */
  31         val = vcpu->arch.hcr_el2;
  32         if (!(val & HCR_RW)) {
  33                 write_sysreg(1 << 30, fpexc32_el2);
  34                 isb();
  35         }
  36         write_sysreg(val, hcr_el2);
  37         /* Trap on AArch32 cp15 c15 accesses (EL1 or EL0) */
  38         write_sysreg(1 << 15, hstr_el2);
  39         write_sysreg(CPTR_EL2_TTA | CPTR_EL2_TFP, cptr_el2);
  40         write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
  41 }
  42
  43 static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu)
  44 {
  45         write_sysreg(HCR_RW, hcr_el2);
  46         write_sysreg(0, hstr_el2);
  47         write_sysreg(read_sysreg(mdcr_el2) & MDCR_EL2_HPMN_MASK, mdcr_el2);
  48         write_sysreg(0, cptr_el2);
  49 }
  50
  51 static void __hyp_text __activate_vm(struct kvm_vcpu *vcpu)
  52 {
  53         struct kvm *kvm = kern_hyp_va(vcpu->kvm);
  54         write_sysreg(kvm->arch.vttbr, vttbr_el2);
  55 }
  56
  57 static void __hyp_text __deactivate_vm(struct kvm_vcpu *vcpu)
  58 {
  59         write_sysreg(0, vttbr_el2);
  60 }
  61
  62 static hyp_alternate_select(__vgic_call_save_state,
  63                             __vgic_v2_save_state, __vgic_v3_save_state,
  64                             ARM64_HAS_SYSREG_GIC_CPUIF);
  65
  66 static hyp_alternate_select(__vgic_call_restore_state,
  67                             __vgic_v2_restore_state, __vgic_v3_restore_state,
  68                             ARM64_HAS_SYSREG_GIC_CPUIF);
  69
  70 static void __hyp_text __vgic_save_state(struct kvm_vcpu *vcpu)
  71 {
  72         __vgic_call_save_state()(vcpu);
  73         write_sysreg(read_sysreg(hcr_el2) & ~HCR_INT_OVERRIDE, hcr_el2);
  74 }
  75
  76 static void __hyp_text __vgic_restore_state(struct kvm_vcpu *vcpu)
  77 {
  78         u64 val;
  79
  80         val = read_sysreg(hcr_el2);
  81         val |=  HCR_INT_OVERRIDE;
  82         val |= vcpu->arch.irq_lines;
  83         write_sysreg(val, hcr_el2);
  84
  85         __vgic_call_restore_state()(vcpu);
  86 }
  87
  88 static int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
  89 {
  90         struct kvm_cpu_context *host_ctxt;
  91         struct kvm_cpu_context *guest_ctxt;
  92         bool fp_enabled;
  93         u64 exit_code;
  94
  95         vcpu = kern_hyp_va(vcpu);
  96         write_sysreg(vcpu, tpidr_el2);
  97
  98         host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
  99         guest_ctxt = &vcpu->arch.ctxt;
 100
 101         __sysreg_save_state(host_ctxt);
 102         __debug_cond_save_host_state(vcpu);
 103
 104         __activate_traps(vcpu);
 105         __activate_vm(vcpu);
 106
 107         __vgic_restore_state(vcpu);
 108         __timer_restore_state(vcpu);
 109
 110         /*
 111          * We must restore the 32-bit state before the sysregs, thanks
 112          * to Cortex-A57 erratum #852523.
 113          */
 114         __sysreg32_restore_state(vcpu);
 115         __sysreg_restore_state(guest_ctxt);
 116         __debug_restore_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt);
 117
 118         /* Jump in the fire! */
 119         exit_code = __guest_enter(vcpu, host_ctxt);
 120         /* And we're baaack! */
 121
 122         fp_enabled = __fpsimd_enabled();
 123
 124         __sysreg_save_state(guest_ctxt);
 125         __sysreg32_save_state(vcpu);
 126         __timer_save_state(vcpu);
 127         __vgic_save_state(vcpu);
 128
 129         __deactivate_traps(vcpu);
 130         __deactivate_vm(vcpu);
 131
 132         __sysreg_restore_state(host_ctxt);
 133
 134         if (fp_enabled) {
 135                 __fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs);
 136                 __fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs);
 137         }
 138
 139         __debug_save_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt);
 140         __debug_cond_restore_host_state(vcpu);
 141
 142         return exit_code;
 143 }
 144
 145 __alias(__guest_run) int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
 146
 147 static const char __hyp_panic_string[] = "HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%p\n";
 148
 149 void __hyp_text __noreturn __hyp_panic(void)
 150 {
 151         unsigned long str_va = (unsigned long)__hyp_panic_string;
 152         u64 spsr = read_sysreg(spsr_el2);
 153         u64 elr = read_sysreg(elr_el2);
 154         u64 par = read_sysreg(par_el1);
 155
 156         if (read_sysreg(vttbr_el2)) {
 157                 struct kvm_vcpu *vcpu;
 158                 struct kvm_cpu_context *host_ctxt;
 159
 160                 vcpu = (struct kvm_vcpu *)read_sysreg(tpidr_el2);
 161                 host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
 162                 __deactivate_traps(vcpu);
 163                 __deactivate_vm(vcpu);
 164                 __sysreg_restore_state(host_ctxt);
 165         }
 166
 167         /* Call panic for real */
 168         __hyp_do_panic(hyp_kern_va(str_va),
 169                        spsr,  elr,
 170                        read_sysreg(esr_el2),   read_sysreg(far_el2),
 171                        read_sysreg(hpfar_el2), par,
 172                        (void *)read_sysreg(tpidr_el2));
 173
 174         unreachable();
 175 }