LXR linux/virt/kvm/arm/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
   7#include <asm/kvm_mmu.h>
   8#include <asm/pvclock-abi.h>
   9
  10#include <kvm/arm_hypercalls.h>
  11
  12void kvm_update_stolen_time(struct kvm_vcpu *vcpu)
  13{
  14        struct kvm *kvm = vcpu->kvm;
  15        u64 steal;
  16        __le64 steal_le;
  17        u64 offset;
  18        int idx;
  19        u64 base = vcpu->arch.steal.base;
  20
  21        if (base == GPA_INVALID)
  22                return;
  23
  24        /* Let's do the local bookkeeping */
  25        steal = vcpu->arch.steal.steal;
  26        steal += current->sched_info.run_delay - vcpu->arch.steal.last_steal;
  27        vcpu->arch.steal.last_steal = current->sched_info.run_delay;
  28        vcpu->arch.steal.steal = steal;
  29
  30        steal_le = cpu_to_le64(steal);
  31        idx = srcu_read_lock(&kvm->srcu);
  32        offset = offsetof(struct pvclock_vcpu_stolen_time, stolen_time);
  33        kvm_put_guest(kvm, base + offset, steal_le, u64);
  34        srcu_read_unlock(&kvm->srcu, idx);
  35}
  36
  37long kvm_hypercall_pv_features(struct kvm_vcpu *vcpu)
  38{
  39        u32 feature = smccc_get_arg1(vcpu);
  40        long val = SMCCC_RET_NOT_SUPPORTED;
  41
  42        switch (feature) {
  43        case ARM_SMCCC_HV_PV_TIME_FEATURES:
  44        case ARM_SMCCC_HV_PV_TIME_ST:
  45                val = SMCCC_RET_SUCCESS;
  46                break;
  47        }
  48
  49        return val;
  50}
  51
  52gpa_t kvm_init_stolen_time(struct kvm_vcpu *vcpu)
  53{
  54        struct pvclock_vcpu_stolen_time init_values = {};
  55        struct kvm *kvm = vcpu->kvm;
  56        u64 base = vcpu->arch.steal.base;
  57        int idx;
  58
  59        if (base == GPA_INVALID)
  60                return base;
  61
  62        /*
  63         * Start counting stolen time from the time the guest requests
  64         * the feature enabled.
  65         */
  66        vcpu->arch.steal.steal = 0;
  67        vcpu->arch.steal.last_steal = current->sched_info.run_delay;
  68
  69        idx = srcu_read_lock(&kvm->srcu);
  70        kvm_write_guest(kvm, base, &init_values, sizeof(init_values));
  71        srcu_read_unlock(&kvm->srcu, idx);
  72
  73        return base;
  74}
  75
  76int kvm_arm_pvtime_set_attr(struct kvm_vcpu *vcpu,
  77                            struct kvm_device_attr *attr)
  78{
  79        u64 __user *user = (u64 __user *)attr->addr;
  80        struct kvm *kvm = vcpu->kvm;
  81        u64 ipa;
  82        int ret = 0;
  83        int idx;
  84
  85        if (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 (attr->attr != KVM_ARM_VCPU_PVTIME_IPA)
 114                return -ENXIO;
 115
 116        ipa = vcpu->arch.steal.base;
 117
 118        if (put_user(ipa, user))
 119                return -EFAULT;
 120        return 0;
 121}
 122
 123int kvm_arm_pvtime_has_attr(struct kvm_vcpu *vcpu,
 124                            struct kvm_device_attr *attr)
 125{
 126        switch (attr->attr) {
 127        case KVM_ARM_VCPU_PVTIME_IPA:
 128                return 0;
 129        }
 130        return -ENXIO;
 131}
 132