1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
4 * Author: Christoffer Dall <c.dall@virtualopensystems.com>
5 */
6
7 #include <linux/kvm.h>
8 #include <linux/kvm_host.h>
9 #include <asm/kvm_emulate.h>
10 #include <asm/kvm_coproc.h>
11 #include <asm/kvm_mmu.h>
12 #include <kvm/arm_psci.h>
13 #include <trace/events/kvm.h>
14
15 #include "trace.h"
16
17 typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
18
handle_hvc(struct kvm_vcpu * vcpu,struct kvm_run * run)19 static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
20 {
21 int ret;
22
23 trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
24 kvm_vcpu_hvc_get_imm(vcpu));
25 vcpu->stat.hvc_exit_stat++;
26
27 ret = kvm_hvc_call_handler(vcpu);
28 if (ret < 0) {
29 vcpu_set_reg(vcpu, 0, ~0UL);
30 return 1;
31 }
32
33 return ret;
34 }
35
handle_smc(struct kvm_vcpu * vcpu,struct kvm_run * run)36 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
37 {
38 /*
39 * "If an SMC instruction executed at Non-secure EL1 is
40 * trapped to EL2 because HCR_EL2.TSC is 1, the exception is a
41 * Trap exception, not a Secure Monitor Call exception [...]"
42 *
43 * We need to advance the PC after the trap, as it would
44 * otherwise return to the same address...
45 */
46 vcpu_set_reg(vcpu, 0, ~0UL);
47 kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
48 return 1;
49 }
50
51 /**
52 * kvm_handle_wfx - handle a WFI or WFE instructions trapped in guests
53 * @vcpu: the vcpu pointer
54 * @run: the kvm_run structure pointer
55 *
56 * WFE: Yield the CPU and come back to this vcpu when the scheduler
57 * decides to.
58 * WFI: Simply call kvm_vcpu_block(), which will halt execution of
59 * world-switches and schedule other host processes until there is an
60 * incoming IRQ or FIQ to the VM.
61 */
kvm_handle_wfx(struct kvm_vcpu * vcpu,struct kvm_run * run)62 static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
63 {
64 if (kvm_vcpu_get_hsr(vcpu) & HSR_WFI_IS_WFE) {
65 trace_kvm_wfx(*vcpu_pc(vcpu), true);
66 vcpu->stat.wfe_exit_stat++;
67 kvm_vcpu_on_spin(vcpu, vcpu_mode_priv(vcpu));
68 } else {
69 trace_kvm_wfx(*vcpu_pc(vcpu), false);
70 vcpu->stat.wfi_exit_stat++;
71 kvm_vcpu_block(vcpu);
72 kvm_clear_request(KVM_REQ_UNHALT, vcpu);
73 }
74
75 kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
76
77 return 1;
78 }
79
kvm_handle_unknown_ec(struct kvm_vcpu * vcpu,struct kvm_run * run)80 static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu, struct kvm_run *run)
81 {
82 u32 hsr = kvm_vcpu_get_hsr(vcpu);
83
84 kvm_pr_unimpl("Unknown exception class: hsr: %#08x\n",
85 hsr);
86
87 kvm_inject_undefined(vcpu);
88 return 1;
89 }
90
91 static exit_handle_fn arm_exit_handlers[] = {
92 [0 ... HSR_EC_MAX] = kvm_handle_unknown_ec,
93 [HSR_EC_WFI] = kvm_handle_wfx,
94 [HSR_EC_CP15_32] = kvm_handle_cp15_32,
95 [HSR_EC_CP15_64] = kvm_handle_cp15_64,
96 [HSR_EC_CP14_MR] = kvm_handle_cp14_32,
97 [HSR_EC_CP14_LS] = kvm_handle_cp14_load_store,
98 [HSR_EC_CP14_64] = kvm_handle_cp14_64,
99 [HSR_EC_CP_0_13] = kvm_handle_cp_0_13_access,
100 [HSR_EC_CP10_ID] = kvm_handle_cp10_id,
101 [HSR_EC_HVC] = handle_hvc,
102 [HSR_EC_SMC] = handle_smc,
103 [HSR_EC_IABT] = kvm_handle_guest_abort,
104 [HSR_EC_DABT] = kvm_handle_guest_abort,
105 };
106
kvm_get_exit_handler(struct kvm_vcpu * vcpu)107 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
108 {
109 u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
110
111 return arm_exit_handlers[hsr_ec];
112 }
113
114 /*
115 * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
116 * proper exit to userspace.
117 */
handle_exit(struct kvm_vcpu * vcpu,struct kvm_run * run,int exception_index)118 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
119 int exception_index)
120 {
121 exit_handle_fn exit_handler;
122
123 if (ARM_ABORT_PENDING(exception_index)) {
124 u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
125
126 /*
127 * HVC/SMC already have an adjusted PC, which we need
128 * to correct in order to return to after having
129 * injected the abort.
130 */
131 if (hsr_ec == HSR_EC_HVC || hsr_ec == HSR_EC_SMC) {
132 u32 adj = kvm_vcpu_trap_il_is32bit(vcpu) ? 4 : 2;
133 *vcpu_pc(vcpu) -= adj;
134 }
135
136 kvm_inject_vabt(vcpu);
137 return 1;
138 }
139
140 exception_index = ARM_EXCEPTION_CODE(exception_index);
141
142 switch (exception_index) {
143 case ARM_EXCEPTION_IRQ:
144 return 1;
145 case ARM_EXCEPTION_HVC:
146 /*
147 * See ARM ARM B1.14.1: "Hyp traps on instructions
148 * that fail their condition code check"
149 */
150 if (!kvm_condition_valid(vcpu)) {
151 kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
152 return 1;
153 }
154
155 exit_handler = kvm_get_exit_handler(vcpu);
156
157 return exit_handler(vcpu, run);
158 case ARM_EXCEPTION_DATA_ABORT:
159 kvm_inject_vabt(vcpu);
160 return 1;
161 case ARM_EXCEPTION_HYP_GONE:
162 /*
163 * HYP has been reset to the hyp-stub. This happens
164 * when a guest is pre-empted by kvm_reboot()'s
165 * shutdown call.
166 */
167 run->exit_reason = KVM_EXIT_FAIL_ENTRY;
168 return 0;
169 default:
170 kvm_pr_unimpl("Unsupported exception type: %d",
171 exception_index);
172 run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
173 return 0;
174 }
175 }
176