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 == INVALID_GPA)
 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 != INVALID_GPA)
 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 == INVALID_GPA)
 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 != INVALID_GPA)
 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}