1 /*
2 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
3 * Author: Christoffer Dall <c.dall@virtualopensystems.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License, version 2, as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
17 */
18
19 #include <linux/kvm.h>
20 #include <linux/kvm_host.h>
21 #include <asm/kvm_emulate.h>
22 #include <asm/kvm_coproc.h>
23 #include <asm/kvm_mmu.h>
24 #include <kvm/arm_psci.h>
25 #include <trace/events/kvm.h>
26
27 #include "trace.h"
28
29 typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
30
handle_hvc(struct kvm_vcpu * vcpu,struct kvm_run * run)31 static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
32 {
33 int ret;
34
35 trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
36 kvm_vcpu_hvc_get_imm(vcpu));
37 vcpu->stat.hvc_exit_stat++;
38
39 ret = kvm_hvc_call_handler(vcpu);
40 if (ret < 0) {
41 vcpu_set_reg(vcpu, 0, ~0UL);
42 return 1;
43 }
44
45 return ret;
46 }
47
handle_smc(struct kvm_vcpu * vcpu,struct kvm_run * run)48 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
49 {
50 /*
51 * "If an SMC instruction executed at Non-secure EL1 is
52 * trapped to EL2 because HCR_EL2.TSC is 1, the exception is a
53 * Trap exception, not a Secure Monitor Call exception [...]"
54 *
55 * We need to advance the PC after the trap, as it would
56 * otherwise return to the same address...
57 */
58 vcpu_set_reg(vcpu, 0, ~0UL);
59 kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
60 return 1;
61 }
62
63 /**
64 * kvm_handle_wfx - handle a WFI or WFE instructions trapped in guests
65 * @vcpu: the vcpu pointer
66 * @run: the kvm_run structure pointer
67 *
68 * WFE: Yield the CPU and come back to this vcpu when the scheduler
69 * decides to.
70 * WFI: Simply call kvm_vcpu_block(), which will halt execution of
71 * world-switches and schedule other host processes until there is an
72 * incoming IRQ or FIQ to the VM.
73 */
kvm_handle_wfx(struct kvm_vcpu * vcpu,struct kvm_run * run)74 static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
75 {
76 if (kvm_vcpu_get_hsr(vcpu) & HSR_WFI_IS_WFE) {
77 trace_kvm_wfx(*vcpu_pc(vcpu), true);
78 vcpu->stat.wfe_exit_stat++;
79 kvm_vcpu_on_spin(vcpu, vcpu_mode_priv(vcpu));
80 } else {
81 trace_kvm_wfx(*vcpu_pc(vcpu), false);
82 vcpu->stat.wfi_exit_stat++;
83 kvm_vcpu_block(vcpu);
84 kvm_clear_request(KVM_REQ_UNHALT, vcpu);
85 }
86
87 kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
88
89 return 1;
90 }
91
kvm_handle_unknown_ec(struct kvm_vcpu * vcpu,struct kvm_run * run)92 static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu, struct kvm_run *run)
93 {
94 u32 hsr = kvm_vcpu_get_hsr(vcpu);
95
96 kvm_pr_unimpl("Unknown exception class: hsr: %#08x\n",
97 hsr);
98
99 kvm_inject_undefined(vcpu);
100 return 1;
101 }
102
103 static exit_handle_fn arm_exit_handlers[] = {
104 [0 ... HSR_EC_MAX] = kvm_handle_unknown_ec,
105 [HSR_EC_WFI] = kvm_handle_wfx,
106 [HSR_EC_CP15_32] = kvm_handle_cp15_32,
107 [HSR_EC_CP15_64] = kvm_handle_cp15_64,
108 [HSR_EC_CP14_MR] = kvm_handle_cp14_32,
109 [HSR_EC_CP14_LS] = kvm_handle_cp14_load_store,
110 [HSR_EC_CP14_64] = kvm_handle_cp14_64,
111 [HSR_EC_CP_0_13] = kvm_handle_cp_0_13_access,
112 [HSR_EC_CP10_ID] = kvm_handle_cp10_id,
113 [HSR_EC_HVC] = handle_hvc,
114 [HSR_EC_SMC] = handle_smc,
115 [HSR_EC_IABT] = kvm_handle_guest_abort,
116 [HSR_EC_DABT] = kvm_handle_guest_abort,
117 };
118
kvm_get_exit_handler(struct kvm_vcpu * vcpu)119 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
120 {
121 u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
122
123 return arm_exit_handlers[hsr_ec];
124 }
125
126 /*
127 * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
128 * proper exit to userspace.
129 */
handle_exit(struct kvm_vcpu * vcpu,struct kvm_run * run,int exception_index)130 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
131 int exception_index)
132 {
133 exit_handle_fn exit_handler;
134
135 if (ARM_ABORT_PENDING(exception_index)) {
136 u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
137
138 /*
139 * HVC/SMC already have an adjusted PC, which we need
140 * to correct in order to return to after having
141 * injected the abort.
142 */
143 if (hsr_ec == HSR_EC_HVC || hsr_ec == HSR_EC_SMC) {
144 u32 adj = kvm_vcpu_trap_il_is32bit(vcpu) ? 4 : 2;
145 *vcpu_pc(vcpu) -= adj;
146 }
147
148 kvm_inject_vabt(vcpu);
149 return 1;
150 }
151
152 exception_index = ARM_EXCEPTION_CODE(exception_index);
153
154 switch (exception_index) {
155 case ARM_EXCEPTION_IRQ:
156 return 1;
157 case ARM_EXCEPTION_HVC:
158 /*
159 * See ARM ARM B1.14.1: "Hyp traps on instructions
160 * that fail their condition code check"
161 */
162 if (!kvm_condition_valid(vcpu)) {
163 kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
164 return 1;
165 }
166
167 exit_handler = kvm_get_exit_handler(vcpu);
168
169 return exit_handler(vcpu, run);
170 case ARM_EXCEPTION_DATA_ABORT:
171 kvm_inject_vabt(vcpu);
172 return 1;
173 case ARM_EXCEPTION_HYP_GONE:
174 /*
175 * HYP has been reset to the hyp-stub. This happens
176 * when a guest is pre-empted by kvm_reboot()'s
177 * shutdown call.
178 */
179 run->exit_reason = KVM_EXIT_FAIL_ENTRY;
180 return 0;
181 default:
182 kvm_pr_unimpl("Unsupported exception type: %d",
183 exception_index);
184 run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
185 return 0;
186 }
187 }
188
