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 <asm/kvm_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_svc_hyp(struct kvm_vcpu * vcpu,struct kvm_run * run)31 static int handle_svc_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
32 {
33 /* SVC called from Hyp mode should never get here */
34 kvm_debug("SVC called from Hyp mode shouldn't go here\n");
35 BUG();
36 return -EINVAL; /* Squash warning */
37 }
38
handle_hvc(struct kvm_vcpu * vcpu,struct kvm_run * run)39 static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
40 {
41 int ret;
42
43 trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
44 kvm_vcpu_hvc_get_imm(vcpu));
45
46 ret = kvm_psci_call(vcpu);
47 if (ret < 0) {
48 kvm_inject_undefined(vcpu);
49 return 1;
50 }
51
52 return ret;
53 }
54
handle_smc(struct kvm_vcpu * vcpu,struct kvm_run * run)55 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
56 {
57 kvm_inject_undefined(vcpu);
58 return 1;
59 }
60
handle_pabt_hyp(struct kvm_vcpu * vcpu,struct kvm_run * run)61 static int handle_pabt_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
62 {
63 /* The hypervisor should never cause aborts */
64 kvm_err("Prefetch Abort taken from Hyp mode at %#08lx (HSR: %#08x)\n",
65 kvm_vcpu_get_hfar(vcpu), kvm_vcpu_get_hsr(vcpu));
66 return -EFAULT;
67 }
68
handle_dabt_hyp(struct kvm_vcpu * vcpu,struct kvm_run * run)69 static int handle_dabt_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
70 {
71 /* This is either an error in the ws. code or an external abort */
72 kvm_err("Data Abort taken from Hyp mode at %#08lx (HSR: %#08x)\n",
73 kvm_vcpu_get_hfar(vcpu), kvm_vcpu_get_hsr(vcpu));
74 return -EFAULT;
75 }
76
77 /**
78 * kvm_handle_wfx - handle a WFI or WFE instructions trapped in guests
79 * @vcpu: the vcpu pointer
80 * @run: the kvm_run structure pointer
81 *
82 * WFE: Yield the CPU and come back to this vcpu when the scheduler
83 * decides to.
84 * WFI: Simply call kvm_vcpu_block(), which will halt execution of
85 * world-switches and schedule other host processes until there is an
86 * incoming IRQ or FIQ to the VM.
87 */
kvm_handle_wfx(struct kvm_vcpu * vcpu,struct kvm_run * run)88 static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
89 {
90 if (kvm_vcpu_get_hsr(vcpu) & HSR_WFI_IS_WFE) {
91 trace_kvm_wfx(*vcpu_pc(vcpu), true);
92 kvm_vcpu_on_spin(vcpu);
93 } else {
94 trace_kvm_wfx(*vcpu_pc(vcpu), false);
95 kvm_vcpu_block(vcpu);
96 }
97
98 kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
99
100 return 1;
101 }
102
103 static exit_handle_fn arm_exit_handlers[] = {
104 [HSR_EC_WFI] = kvm_handle_wfx,
105 [HSR_EC_CP15_32] = kvm_handle_cp15_32,
106 [HSR_EC_CP15_64] = kvm_handle_cp15_64,
107 [HSR_EC_CP14_MR] = kvm_handle_cp14_access,
108 [HSR_EC_CP14_LS] = kvm_handle_cp14_load_store,
109 [HSR_EC_CP14_64] = kvm_handle_cp14_access,
110 [HSR_EC_CP_0_13] = kvm_handle_cp_0_13_access,
111 [HSR_EC_CP10_ID] = kvm_handle_cp10_id,
112 [HSR_EC_SVC_HYP] = handle_svc_hyp,
113 [HSR_EC_HVC] = handle_hvc,
114 [HSR_EC_SMC] = handle_smc,
115 [HSR_EC_IABT] = kvm_handle_guest_abort,
116 [HSR_EC_IABT_HYP] = handle_pabt_hyp,
117 [HSR_EC_DABT] = kvm_handle_guest_abort,
118 [HSR_EC_DABT_HYP] = handle_dabt_hyp,
119 };
120
kvm_get_exit_handler(struct kvm_vcpu * vcpu)121 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
122 {
123 u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
124
125 if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) ||
126 !arm_exit_handlers[hsr_ec]) {
127 kvm_err("Unknown exception class: hsr: %#08x\n",
128 (unsigned int)kvm_vcpu_get_hsr(vcpu));
129 BUG();
130 }
131
132 return arm_exit_handlers[hsr_ec];
133 }
134
135 /*
136 * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
137 * proper exit to userspace.
138 */
handle_exit(struct kvm_vcpu * vcpu,struct kvm_run * run,int exception_index)139 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
140 int exception_index)
141 {
142 exit_handle_fn exit_handler;
143
144 switch (exception_index) {
145 case ARM_EXCEPTION_IRQ:
146 return 1;
147 case ARM_EXCEPTION_UNDEFINED:
148 kvm_err("Undefined exception in Hyp mode at: %#08lx\n",
149 kvm_vcpu_get_hyp_pc(vcpu));
150 BUG();
151 panic("KVM: Hypervisor undefined exception!\n");
152 case ARM_EXCEPTION_DATA_ABORT:
153 case ARM_EXCEPTION_PREF_ABORT:
154 case ARM_EXCEPTION_HVC:
155 /*
156 * See ARM ARM B1.14.1: "Hyp traps on instructions
157 * that fail their condition code check"
158 */
159 if (!kvm_condition_valid(vcpu)) {
160 kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
161 return 1;
162 }
163
164 exit_handler = kvm_get_exit_handler(vcpu);
165
166 return exit_handler(vcpu, run);
167 default:
168 kvm_pr_unimpl("Unsupported exception type: %d",
169 exception_index);
170 run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
171 return 0;
172 }
173 }
174