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	vcpu->stat.hvc_exit_stat++;
 46
 47	ret = kvm_psci_call(vcpu);
 48	if (ret < 0) {
 49		kvm_inject_undefined(vcpu);
 50		return 1;
 51	}
 52
 53	return ret;
 54}
 55
 56static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
 57{
 58	kvm_inject_undefined(vcpu);
 59	return 1;
 60}
 61
 62static int handle_pabt_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
 63{
 64	/* The hypervisor should never cause aborts */
 65	kvm_err("Prefetch Abort taken from Hyp mode at %#08lx (HSR: %#08x)\n",
 66		kvm_vcpu_get_hfar(vcpu), kvm_vcpu_get_hsr(vcpu));
 67	return -EFAULT;
 68}
 69
 70static int handle_dabt_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
 71{
 72	/* This is either an error in the ws. code or an external abort */
 73	kvm_err("Data Abort taken from Hyp mode at %#08lx (HSR: %#08x)\n",
 74		kvm_vcpu_get_hfar(vcpu), kvm_vcpu_get_hsr(vcpu));
 75	return -EFAULT;
 76}
 77
 78/**
 79 * kvm_handle_wfx - handle a WFI or WFE instructions trapped in guests
 80 * @vcpu:	the vcpu pointer
 81 * @run:	the kvm_run structure pointer
 82 *
 83 * WFE: Yield the CPU and come back to this vcpu when the scheduler
 84 * decides to.
 85 * WFI: Simply call kvm_vcpu_block(), which will halt execution of
 86 * world-switches and schedule other host processes until there is an
 87 * incoming IRQ or FIQ to the VM.
 88 */
 89static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
 90{
 91	if (kvm_vcpu_get_hsr(vcpu) & HSR_WFI_IS_WFE) {
 92		trace_kvm_wfx(*vcpu_pc(vcpu), true);
 93		vcpu->stat.wfe_exit_stat++;
 94		kvm_vcpu_on_spin(vcpu);
 95	} else {
 96		trace_kvm_wfx(*vcpu_pc(vcpu), false);
 97		vcpu->stat.wfi_exit_stat++;
 98		kvm_vcpu_block(vcpu);
 99	}
100
101	kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
102
103	return 1;
104}
105
106static exit_handle_fn arm_exit_handlers[] = {
107	[HSR_EC_WFI]		= kvm_handle_wfx,
108	[HSR_EC_CP15_32]	= kvm_handle_cp15_32,
109	[HSR_EC_CP15_64]	= kvm_handle_cp15_64,
110	[HSR_EC_CP14_MR]	= kvm_handle_cp14_access,
111	[HSR_EC_CP14_LS]	= kvm_handle_cp14_load_store,
112	[HSR_EC_CP14_64]	= kvm_handle_cp14_access,
113	[HSR_EC_CP_0_13]	= kvm_handle_cp_0_13_access,
114	[HSR_EC_CP10_ID]	= kvm_handle_cp10_id,
115	[HSR_EC_SVC_HYP]	= handle_svc_hyp,
116	[HSR_EC_HVC]		= handle_hvc,
117	[HSR_EC_SMC]		= handle_smc,
118	[HSR_EC_IABT]		= kvm_handle_guest_abort,
119	[HSR_EC_IABT_HYP]	= handle_pabt_hyp,
120	[HSR_EC_DABT]		= kvm_handle_guest_abort,
121	[HSR_EC_DABT_HYP]	= handle_dabt_hyp,
122};
123
124static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
125{
126	u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
127
128	if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) ||
129	    !arm_exit_handlers[hsr_ec]) {
130		kvm_err("Unknown exception class: hsr: %#08x\n",
131			(unsigned int)kvm_vcpu_get_hsr(vcpu));
132		BUG();
133	}
134
135	return arm_exit_handlers[hsr_ec];
136}
137
138/*
139 * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
140 * proper exit to userspace.
141 */
142int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
143		       int exception_index)
144{
145	exit_handle_fn exit_handler;
146
147	switch (exception_index) {
148	case ARM_EXCEPTION_IRQ:
149		return 1;
150	case ARM_EXCEPTION_HVC:
151		/*
152		 * See ARM ARM B1.14.1: "Hyp traps on instructions
153		 * that fail their condition code check"
154		 */
155		if (!kvm_condition_valid(vcpu)) {
156			kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
157			return 1;
158		}
159
160		exit_handler = kvm_get_exit_handler(vcpu);
161
162		return exit_handler(vcpu, run);
163	default:
164		kvm_pr_unimpl("Unsupported exception type: %d",
165			      exception_index);
166		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
167		return 0;
168	}
169}