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 == 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
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 != INVALID_GPA)
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 == 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
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 != 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
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 }
134
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