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
  40         val = CPTR_EL2_DEFAULT;
  41         val |= CPTR_EL2_TTA | CPTR_EL2_TFP;
  42         write_sysreg(val, cptr_el2);
  43
  44         write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
  45 }
  46
  47 static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu)
  48 {
  49         write_sysreg(HCR_RW, hcr_el2);
  50         write_sysreg(0, hstr_el2);
  51         write_sysreg(read_sysreg(mdcr_el2) & MDCR_EL2_HPMN_MASK, mdcr_el2);
  52         write_sysreg(CPTR_EL2_DEFAULT, cptr_el2);
  53 }
  54
  55 static void __hyp_text __activate_vm(struct kvm_vcpu *vcpu)
  56 {
  57         struct kvm *kvm = kern_hyp_va(vcpu->kvm);
  58         write_sysreg(kvm->arch.vttbr, vttbr_el2);
  59 }
  60
  61 static void __hyp_text __deactivate_vm(struct kvm_vcpu *vcpu)
  62 {
  63         write_sysreg(0, vttbr_el2);
  64 }
  65
  66 static hyp_alternate_select(__vgic_call_save_state,
  67                             __vgic_v2_save_state, __vgic_v3_save_state,
  68                             ARM64_HAS_SYSREG_GIC_CPUIF);
  69
  70 static hyp_alternate_select(__vgic_call_restore_state,
  71                             __vgic_v2_restore_state, __vgic_v3_restore_state,
  72                             ARM64_HAS_SYSREG_GIC_CPUIF);
  73
  74 static void __hyp_text __vgic_save_state(struct kvm_vcpu *vcpu)
  75 {
  76         __vgic_call_save_state()(vcpu);
  77         write_sysreg(read_sysreg(hcr_el2) & ~HCR_INT_OVERRIDE, hcr_el2);
  78 }
  79
  80 static void __hyp_text __vgic_restore_state(struct kvm_vcpu *vcpu)
  81 {
  82         u64 val;
  83
  84         val = read_sysreg(hcr_el2);
  85         val |=  HCR_INT_OVERRIDE;
  86         val |= vcpu->arch.irq_lines;
  87         write_sysreg(val, hcr_el2);
  88
  89         __vgic_call_restore_state()(vcpu);
  90 }
  91
  92 static int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
  93 {
  94         struct kvm_cpu_context *host_ctxt;
  95         struct kvm_cpu_context *guest_ctxt;
  96         bool fp_enabled;
  97         u64 exit_code;
  98
  99         vcpu = kern_hyp_va(vcpu);
 100         write_sysreg(vcpu, tpidr_el2);
 101
 102         host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
 103         guest_ctxt = &vcpu->arch.ctxt;
 104
 105         __sysreg_save_state(host_ctxt);
 106         __debug_cond_save_host_state(vcpu);
 107
 108         __activate_traps(vcpu);
 109         __activate_vm(vcpu);
 110
 111         __vgic_restore_state(vcpu);
 112         __timer_restore_state(vcpu);
 113
 114         /*
 115          * We must restore the 32-bit state before the sysregs, thanks
 116          * to Cortex-A57 erratum #852523.
 117          */
 118         __sysreg32_restore_state(vcpu);
 119         __sysreg_restore_state(guest_ctxt);
 120         __debug_restore_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt);
 121
 122         /* Jump in the fire! */
 123         exit_code = __guest_enter(vcpu, host_ctxt);
 124         /* And we're baaack! */
 125
 126         fp_enabled = __fpsimd_enabled();
 127
 128         __sysreg_save_state(guest_ctxt);
 129         __sysreg32_save_state(vcpu);
 130         __timer_save_state(vcpu);
 131         __vgic_save_state(vcpu);
 132
 133         __deactivate_traps(vcpu);
 134         __deactivate_vm(vcpu);
 135
 136         __sysreg_restore_state(host_ctxt);
 137
 138         if (fp_enabled) {
 139                 __fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs);
 140                 __fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs);
 141         }
 142
 143         __debug_save_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt);
 144         __debug_cond_restore_host_state(vcpu);
 145
 146         return exit_code;
 147 }
 148
 149 __alias(__guest_run) int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
 150
 151 static const char __hyp_panic_string[] = "HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%p\n";
 152
 153 void __hyp_text __noreturn __hyp_panic(void)
 154 {
 155         unsigned long str_va = (unsigned long)__hyp_panic_string;
 156         u64 spsr = read_sysreg(spsr_el2);
 157         u64 elr = read_sysreg(elr_el2);
 158         u64 par = read_sysreg(par_el1);
 159
 160         if (read_sysreg(vttbr_el2)) {
 161                 struct kvm_vcpu *vcpu;
 162                 struct kvm_cpu_context *host_ctxt;
 163
 164                 vcpu = (struct kvm_vcpu *)read_sysreg(tpidr_el2);
 165                 host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
 166                 __deactivate_traps(vcpu);
 167                 __deactivate_vm(vcpu);
 168                 __sysreg_restore_state(host_ctxt);
 169         }
 170
 171         /* Call panic for real */
 172         __hyp_do_panic(hyp_kern_va(str_va),
 173                        spsr,  elr,
 174                        read_sysreg(esr_el2),   read_sysreg(far_el2),
 175                        read_sysreg(hpfar_el2), par,
 176                        (void *)read_sysreg(tpidr_el2));
 177
 178         unreachable();
 179 }