xref: /openbmc/linux/arch/arm64/kvm/handle_exit.c (revision 31b90347)
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 #include <asm/kvm_emulate.h>
25 #include <asm/kvm_coproc.h>
26 #include <asm/kvm_mmu.h>
27 #include <asm/kvm_psci.h>
28 
29 typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
30 
31 static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
32 {
33 	if (kvm_psci_call(vcpu))
34 		return 1;
35 
36 	kvm_inject_undefined(vcpu);
37 	return 1;
38 }
39 
40 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
41 {
42 	if (kvm_psci_call(vcpu))
43 		return 1;
44 
45 	kvm_inject_undefined(vcpu);
46 	return 1;
47 }
48 
49 /**
50  * kvm_handle_wfx - handle a wait-for-interrupts or wait-for-event
51  *		    instruction executed by a guest
52  *
53  * @vcpu:	the vcpu pointer
54  *
55  * WFE: Yield the CPU and come back to this vcpu when the scheduler
56  * decides to.
57  * WFI: Simply call kvm_vcpu_block(), which will halt execution of
58  * world-switches and schedule other host processes until there is an
59  * incoming IRQ or FIQ to the VM.
60  */
61 static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
62 {
63 	if (kvm_vcpu_get_hsr(vcpu) & ESR_EL2_EC_WFI_ISS_WFE)
64 		kvm_vcpu_on_spin(vcpu);
65 	else
66 		kvm_vcpu_block(vcpu);
67 
68 	return 1;
69 }
70 
71 static exit_handle_fn arm_exit_handlers[] = {
72 	[ESR_EL2_EC_WFI]	= kvm_handle_wfx,
73 	[ESR_EL2_EC_CP15_32]	= kvm_handle_cp15_32,
74 	[ESR_EL2_EC_CP15_64]	= kvm_handle_cp15_64,
75 	[ESR_EL2_EC_CP14_MR]	= kvm_handle_cp14_access,
76 	[ESR_EL2_EC_CP14_LS]	= kvm_handle_cp14_load_store,
77 	[ESR_EL2_EC_CP14_64]	= kvm_handle_cp14_access,
78 	[ESR_EL2_EC_HVC32]	= handle_hvc,
79 	[ESR_EL2_EC_SMC32]	= handle_smc,
80 	[ESR_EL2_EC_HVC64]	= handle_hvc,
81 	[ESR_EL2_EC_SMC64]	= handle_smc,
82 	[ESR_EL2_EC_SYS64]	= kvm_handle_sys_reg,
83 	[ESR_EL2_EC_IABT]	= kvm_handle_guest_abort,
84 	[ESR_EL2_EC_DABT]	= kvm_handle_guest_abort,
85 };
86 
87 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
88 {
89 	u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
90 
91 	if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) ||
92 	    !arm_exit_handlers[hsr_ec]) {
93 		kvm_err("Unkown exception class: hsr: %#08x\n",
94 			(unsigned int)kvm_vcpu_get_hsr(vcpu));
95 		BUG();
96 	}
97 
98 	return arm_exit_handlers[hsr_ec];
99 }
100 
101 /*
102  * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
103  * proper exit to userspace.
104  */
105 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
106 		       int exception_index)
107 {
108 	exit_handle_fn exit_handler;
109 
110 	switch (exception_index) {
111 	case ARM_EXCEPTION_IRQ:
112 		return 1;
113 	case ARM_EXCEPTION_TRAP:
114 		/*
115 		 * See ARM ARM B1.14.1: "Hyp traps on instructions
116 		 * that fail their condition code check"
117 		 */
118 		if (!kvm_condition_valid(vcpu)) {
119 			kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
120 			return 1;
121 		}
122 
123 		exit_handler = kvm_get_exit_handler(vcpu);
124 
125 		return exit_handler(vcpu, run);
126 	default:
127 		kvm_pr_unimpl("Unsupported exception type: %d",
128 			      exception_index);
129 		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
130 		return 0;
131 	}
132 }
133