1/*
2 * Copyright (C) 2012,2013 - ARM Ltd
3 * Author: Marc Zyngier <marc.zyngier@arm.com>
4 *
5 * Derived from arch/arm/kvm/handle_exit.c:
6 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
7 * Author: Christoffer Dall <c.dall@virtualopensystems.com>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
20 */
21
22#include <linux/kvm.h>
23#include <linux/kvm_host.h>
24
25#include <asm/esr.h>
26#include <asm/kvm_coproc.h>
27#include <asm/kvm_emulate.h>
28#include <asm/kvm_mmu.h>
29#include <asm/kvm_psci.h>
30
31#define CREATE_TRACE_POINTS
32#include "trace.h"
33
34typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
35
36static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
37{
38	int ret;
39
40	trace_kvm_hvc_arm64(*vcpu_pc(vcpu), vcpu_get_reg(vcpu, 0),
41			    kvm_vcpu_hvc_get_imm(vcpu));
42
43	ret = kvm_psci_call(vcpu);
44	if (ret < 0) {
45		kvm_inject_undefined(vcpu);
46		return 1;
47	}
48
49	return ret;
50}
51
52static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
53{
54	kvm_inject_undefined(vcpu);
55	return 1;
56}
57
58/**
59 * kvm_handle_wfx - handle a wait-for-interrupts or wait-for-event
60 *		    instruction executed by a guest
61 *
62 * @vcpu:	the vcpu pointer
63 *
64 * WFE: Yield the CPU and come back to this vcpu when the scheduler
65 * decides to.
66 * WFI: Simply call kvm_vcpu_block(), which will halt execution of
67 * world-switches and schedule other host processes until there is an
68 * incoming IRQ or FIQ to the VM.
69 */
70static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
71{
72	if (kvm_vcpu_get_hsr(vcpu) & ESR_ELx_WFx_ISS_WFE) {
73		trace_kvm_wfx_arm64(*vcpu_pc(vcpu), true);
74		kvm_vcpu_on_spin(vcpu);
75	} else {
76		trace_kvm_wfx_arm64(*vcpu_pc(vcpu), false);
77		kvm_vcpu_block(vcpu);
78	}
79
80	kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
81
82	return 1;
83}
84
85/**
86 * kvm_handle_guest_debug - handle a debug exception instruction
87 *
88 * @vcpu:	the vcpu pointer
89 * @run:	access to the kvm_run structure for results
90 *
91 * We route all debug exceptions through the same handler. If both the
92 * guest and host are using the same debug facilities it will be up to
93 * userspace to re-inject the correct exception for guest delivery.
94 *
95 * @return: 0 (while setting run->exit_reason), -1 for error
96 */
97static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run)
98{
99	u32 hsr = kvm_vcpu_get_hsr(vcpu);
100	int ret = 0;
101
102	run->exit_reason = KVM_EXIT_DEBUG;
103	run->debug.arch.hsr = hsr;
104
105	switch (hsr >> ESR_ELx_EC_SHIFT) {
106	case ESR_ELx_EC_WATCHPT_LOW:
107		run->debug.arch.far = vcpu->arch.fault.far_el2;
108		/* fall through */
109	case ESR_ELx_EC_SOFTSTP_LOW:
110	case ESR_ELx_EC_BREAKPT_LOW:
111	case ESR_ELx_EC_BKPT32:
112	case ESR_ELx_EC_BRK64:
113		break;
114	default:
115		kvm_err("%s: un-handled case hsr: %#08x\n",
116			__func__, (unsigned int) hsr);
117		ret = -1;
118		break;
119	}
120
121	return ret;
122}
123
124static exit_handle_fn arm_exit_handlers[] = {
125	[ESR_ELx_EC_WFx]	= kvm_handle_wfx,
126	[ESR_ELx_EC_CP15_32]	= kvm_handle_cp15_32,
127	[ESR_ELx_EC_CP15_64]	= kvm_handle_cp15_64,
128	[ESR_ELx_EC_CP14_MR]	= kvm_handle_cp14_32,
129	[ESR_ELx_EC_CP14_LS]	= kvm_handle_cp14_load_store,
130	[ESR_ELx_EC_CP14_64]	= kvm_handle_cp14_64,
131	[ESR_ELx_EC_HVC32]	= handle_hvc,
132	[ESR_ELx_EC_SMC32]	= handle_smc,
133	[ESR_ELx_EC_HVC64]	= handle_hvc,
134	[ESR_ELx_EC_SMC64]	= handle_smc,
135	[ESR_ELx_EC_SYS64]	= kvm_handle_sys_reg,
136	[ESR_ELx_EC_IABT_LOW]	= kvm_handle_guest_abort,
137	[ESR_ELx_EC_DABT_LOW]	= kvm_handle_guest_abort,
138	[ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug,
139	[ESR_ELx_EC_WATCHPT_LOW]= kvm_handle_guest_debug,
140	[ESR_ELx_EC_BREAKPT_LOW]= kvm_handle_guest_debug,
141	[ESR_ELx_EC_BKPT32]	= kvm_handle_guest_debug,
142	[ESR_ELx_EC_BRK64]	= kvm_handle_guest_debug,
143};
144
145static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
146{
147	u32 hsr = kvm_vcpu_get_hsr(vcpu);
148	u8 hsr_ec = hsr >> ESR_ELx_EC_SHIFT;
149
150	if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) ||
151	    !arm_exit_handlers[hsr_ec]) {
152		kvm_err("Unknown exception class: hsr: %#08x -- %s\n",
153			hsr, esr_get_class_string(hsr));
154		BUG();
155	}
156
157	return arm_exit_handlers[hsr_ec];
158}
159
160/*
161 * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
162 * proper exit to userspace.
163 */
164int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
165		       int exception_index)
166{
167	exit_handle_fn exit_handler;
168
169	switch (exception_index) {
170	case ARM_EXCEPTION_IRQ:
171		return 1;
172	case ARM_EXCEPTION_TRAP:
173		/*
174		 * See ARM ARM B1.14.1: "Hyp traps on instructions
175		 * that fail their condition code check"
176		 */
177		if (!kvm_condition_valid(vcpu)) {
178			kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
179			return 1;
180		}
181
182		exit_handler = kvm_get_exit_handler(vcpu);
183
184		return exit_handler(vcpu, run);
185	default:
186		kvm_pr_unimpl("Unsupported exception type: %d",
187			      exception_index);
188		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
189		return 0;
190	}
191}
192