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
29typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
30
31static 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
39static 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
55static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
56{
57	kvm_inject_undefined(vcpu);
58	return 1;
59}
60
61static 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
69static 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 */
88static 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
103static 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
121static 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 */
139int 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