LXR linux/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
  13void 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
  35long 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
  51gpa_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
  70bool kvm_arm_pvtime_supported(void)
  71{
  72        return !!sched_info_on();
  73}
  74
  75int 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
 107int 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
 124int 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}
 134