arch/arm64/kvm/pvtime.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 #include <linux/sched/stat.h>
   7
   8 #include <asm/kvm_mmu.h>
   9 #include <asm/pvclock-abi.h>
  10
  11 #include <kvm/arm_hypercalls.h>
  12
  13 void kvm_update_stolen_time(struct kvm_vcpu *vcpu)
  14 {
  15         struct kvm *kvm = vcpu->kvm;
  16         u64 base = vcpu->arch.steal.base;
  17         u64 last_steal = vcpu->arch.steal.last_steal;
  18         u64 offset = offsetof(struct pvclock_vcpu_stolen_time, stolen_time);
  19         u64 steal = 0;
  20         int idx;
  21
  22         if (base == GPA_INVALID)
  23                 return;
  24
  25         idx = srcu_read_lock(&kvm->srcu);
  26         if (!kvm_get_guest(kvm, base + offset, steal)) {
  27                 steal = le64_to_cpu(steal);
  28                 vcpu->arch.steal.last_steal = READ_ONCE(current->sched_info.run_delay);
  29                 steal += vcpu->arch.steal.last_steal - last_steal;
  30                 kvm_put_guest(kvm, base + offset, cpu_to_le64(steal));
  31         }
  32         srcu_read_unlock(&kvm->srcu, idx);
  33 }
  34
  35 long kvm_hypercall_pv_features(struct kvm_vcpu *vcpu)
  36 {
  37         u32 feature = smccc_get_arg1(vcpu);
  38         long val = SMCCC_RET_NOT_SUPPORTED;
  39
  40         switch (feature) {
  41         case ARM_SMCCC_HV_PV_TIME_FEATURES:
  42         case ARM_SMCCC_HV_PV_TIME_ST:
  43                 if (vcpu->arch.steal.base != GPA_INVALID)
  44                         val = SMCCC_RET_SUCCESS;
  45                 break;
  46         }
  47
  48         return val;
  49 }
  50
  51 gpa_t kvm_init_stolen_time(struct kvm_vcpu *vcpu)
  52 {
  53         struct pvclock_vcpu_stolen_time init_values = {};
  54         struct kvm *kvm = vcpu->kvm;
  55         u64 base = vcpu->arch.steal.base;
  56
  57         if (base == GPA_INVALID)
  58                 return base;
  59
  60         /*
  61          * Start counting stolen time from the time the guest requests
  62          * the feature enabled.
  63          */
  64         vcpu->arch.steal.last_steal = current->sched_info.run_delay;
  65         kvm_write_guest_lock(kvm, base, &init_values, sizeof(init_values));
  66
  67         return base;
  68 }
  69
  70 bool kvm_arm_pvtime_supported(void)
  71 {
  72         return !!sched_info_on();
  73 }
  74
  75 int kvm_arm_pvtime_set_attr(struct kvm_vcpu *vcpu,
  76                             struct kvm_device_attr *attr)
  77 {
  78         u64 __user *user = (u64 __user *)attr->addr;
  79         struct kvm *kvm = vcpu->kvm;
  80         u64 ipa;
  81         int ret = 0;
  82         int idx;
  83
  84         if (!kvm_arm_pvtime_supported() ||
  85             attr->attr != KVM_ARM_VCPU_PVTIME_IPA)
  86                 return -ENXIO;
  87
  88         if (get_user(ipa, user))
  89                 return -EFAULT;
  90         if (!IS_ALIGNED(ipa, 64))
  91                 return -EINVAL;
  92         if (vcpu->arch.steal.base != GPA_INVALID)
  93                 return -EEXIST;
  94
  95         /* Check the address is in a valid memslot */
  96         idx = srcu_read_lock(&kvm->srcu);
  97         if (kvm_is_error_hva(gfn_to_hva(kvm, ipa >> PAGE_SHIFT)))
  98                 ret = -EINVAL;
  99         srcu_read_unlock(&kvm->srcu, idx);
 100
 101         if (!ret)
 102                 vcpu->arch.steal.base = ipa;
 103
 104         return ret;
 105 }
 106
 107 int kvm_arm_pvtime_get_attr(struct kvm_vcpu *vcpu,
 108                             struct kvm_device_attr *attr)
 109 {
 110         u64 __user *user = (u64 __user *)attr->addr;
 111         u64 ipa;
 112
 113         if (!kvm_arm_pvtime_supported() ||
 114             attr->attr != KVM_ARM_VCPU_PVTIME_IPA)
 115                 return -ENXIO;
 116
 117         ipa = vcpu->arch.steal.base;
 118
 119         if (put_user(ipa, user))
 120                 return -EFAULT;
 121         return 0;
 122 }
 123
 124 int kvm_arm_pvtime_has_attr(struct kvm_vcpu *vcpu,
 125                             struct kvm_device_attr *attr)
 126 {
 127         switch (attr->attr) {
 128         case KVM_ARM_VCPU_PVTIME_IPA:
 129                 if (kvm_arm_pvtime_supported())
 130                         return 0;
 131         }
 132         return -ENXIO;
 133 }