arch/arm64/kvm/hypercalls.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2019 Arm Ltd.
   3
   4 #include <linux/arm-smccc.h>
   5 #include <linux/kvm_host.h>
   6
   7 #include <asm/kvm_emulate.h>
   8
   9 #include <kvm/arm_hypercalls.h>
  10 #include <kvm/arm_psci.h>
  11
  12 int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
  13 {
  14         u32 func_id = smccc_get_function(vcpu);
  15         long val = SMCCC_RET_NOT_SUPPORTED;
  16         u32 feature;
  17         gpa_t gpa;
  18
  19         switch (func_id) {
  20         case ARM_SMCCC_VERSION_FUNC_ID:
  21                 val = ARM_SMCCC_VERSION_1_1;
  22                 break;
  23         case ARM_SMCCC_ARCH_FEATURES_FUNC_ID:
  24                 feature = smccc_get_arg1(vcpu);
  25                 switch (feature) {
  26                 case ARM_SMCCC_ARCH_WORKAROUND_1:
  27                         switch (arm64_get_spectre_v2_state()) {
  28                         case SPECTRE_VULNERABLE:
  29                                 break;
  30                         case SPECTRE_MITIGATED:
  31                                 val = SMCCC_RET_SUCCESS;
  32                                 break;
  33                         case SPECTRE_UNAFFECTED:
  34                                 val = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
  35                                 break;
  36                         }
  37                         break;
  38                 case ARM_SMCCC_ARCH_WORKAROUND_2:
  39                         switch (arm64_get_spectre_v4_state()) {
  40                         case SPECTRE_VULNERABLE:
  41                                 break;
  42                         case SPECTRE_MITIGATED:
  43                                 /*
  44                                  * SSBS everywhere: Indicate no firmware
  45                                  * support, as the SSBS support will be
  46                                  * indicated to the guest and the default is
  47                                  * safe.
  48                                  *
  49                                  * Otherwise, expose a permanent mitigation
  50                                  * to the guest, and hide SSBS so that the
  51                                  * guest stays protected.
  52                                  */
  53                                 if (cpus_have_final_cap(ARM64_SSBS))
  54                                         break;
  55                                 fallthrough;
  56                         case SPECTRE_UNAFFECTED:
  57                                 val = SMCCC_RET_NOT_REQUIRED;
  58                                 break;
  59                         }
  60                         break;
  61                 case ARM_SMCCC_HV_PV_TIME_FEATURES:
  62                         val = SMCCC_RET_SUCCESS;
  63                         break;
  64                 }
  65                 break;
  66         case ARM_SMCCC_HV_PV_TIME_FEATURES:
  67                 val = kvm_hypercall_pv_features(vcpu);
  68                 break;
  69         case ARM_SMCCC_HV_PV_TIME_ST:
  70                 gpa = kvm_init_stolen_time(vcpu);
  71                 if (gpa != GPA_INVALID)
  72                         val = gpa;
  73                 break;
  74         default:
  75                 return kvm_psci_call(vcpu);
  76         }
  77
  78         smccc_set_retval(vcpu, val, 0, 0, 0);
  79         return 1;
  80 }