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_emulate.h>
8
9#include <kvm/arm_hypercalls.h>
10#include <kvm/arm_psci.h>
11
12int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
13{
14	u32 func_id = smccc_get_function(vcpu);
15	long val = SMCCC_RET_NOT_SUPPORTED;
16	u32 feature;
17	gpa_t gpa;
18
19	switch (func_id) {
20	case ARM_SMCCC_VERSION_FUNC_ID:
21		val = ARM_SMCCC_VERSION_1_1;
22		break;
23	case ARM_SMCCC_ARCH_FEATURES_FUNC_ID:
24		feature = smccc_get_arg1(vcpu);
25		switch (feature) {
26		case ARM_SMCCC_ARCH_WORKAROUND_1:
27			switch (arm64_get_spectre_v2_state()) {
28			case SPECTRE_VULNERABLE:
29				break;
30			case SPECTRE_MITIGATED:
31				val = SMCCC_RET_SUCCESS;
32				break;
33			case SPECTRE_UNAFFECTED:
34				val = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
35				break;
36			}
37			break;
38		case ARM_SMCCC_ARCH_WORKAROUND_2:
39			switch (arm64_get_spectre_v4_state()) {
40			case SPECTRE_VULNERABLE:
41				break;
42			case SPECTRE_MITIGATED:
43				/*
44				 * SSBS everywhere: Indicate no firmware
45				 * support, as the SSBS support will be
46				 * indicated to the guest and the default is
47				 * safe.
48				 *
49				 * Otherwise, expose a permanent mitigation
50				 * to the guest, and hide SSBS so that the
51				 * guest stays protected.
52				 */
53				if (cpus_have_final_cap(ARM64_SSBS))
54					break;
55				fallthrough;
56			case SPECTRE_UNAFFECTED:
57				val = SMCCC_RET_NOT_REQUIRED;
58				break;
59			}
60			break;
61		case ARM_SMCCC_ARCH_WORKAROUND_3:
62			switch (arm64_get_spectre_bhb_state()) {
63			case SPECTRE_VULNERABLE:
64				break;
65			case SPECTRE_MITIGATED:
66				val = SMCCC_RET_SUCCESS;
67				break;
68			case SPECTRE_UNAFFECTED:
69				val = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
70				break;
71			}
72			break;
73		case ARM_SMCCC_HV_PV_TIME_FEATURES:
74			val = SMCCC_RET_SUCCESS;
75			break;
76		}
77		break;
78	case ARM_SMCCC_HV_PV_TIME_FEATURES:
79		val = kvm_hypercall_pv_features(vcpu);
80		break;
81	case ARM_SMCCC_HV_PV_TIME_ST:
82		gpa = kvm_init_stolen_time(vcpu);
83		if (gpa != GPA_INVALID)
84			val = gpa;
85		break;
86	default:
87		return kvm_psci_call(vcpu);
88	}
89
90	smccc_set_retval(vcpu, val, 0, 0, 0);
91	return 1;
92}
93