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	trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
 42		      kvm_vcpu_hvc_get_imm(vcpu));
 43
 44	if (kvm_psci_call(vcpu))
 45		return 1;
 46
 47	kvm_inject_undefined(vcpu);
 48	return 1;
 49}
 50
 51static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
 52{
 53	kvm_inject_undefined(vcpu);
 54	return 1;
 55}
 56
 57static int handle_pabt_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
 58{
 59	/* The hypervisor should never cause aborts */
 60	kvm_err("Prefetch Abort taken from Hyp mode at %#08lx (HSR: %#08x)\n",
 61		kvm_vcpu_get_hfar(vcpu), kvm_vcpu_get_hsr(vcpu));
 62	return -EFAULT;
 63}
 64
 65static int handle_dabt_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
 66{
 67	/* This is either an error in the ws. code or an external abort */
 68	kvm_err("Data Abort taken from Hyp mode at %#08lx (HSR: %#08x)\n",
 69		kvm_vcpu_get_hfar(vcpu), kvm_vcpu_get_hsr(vcpu));
 70	return -EFAULT;
 71}
 72
 73/**
 74 * kvm_handle_wfx - handle a WFI or WFE instructions trapped in guests
 75 * @vcpu:	the vcpu pointer
 76 * @run:	the kvm_run structure pointer
 77 *
 78 * WFE: Yield the CPU and come back to this vcpu when the scheduler
 79 * decides to.
 80 * WFI: Simply call kvm_vcpu_block(), which will halt execution of
 81 * world-switches and schedule other host processes until there is an
 82 * incoming IRQ or FIQ to the VM.
 83 */
 84static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
 85{
 86	trace_kvm_wfi(*vcpu_pc(vcpu));
 87	if (kvm_vcpu_get_hsr(vcpu) & HSR_WFI_IS_WFE)
 88		kvm_vcpu_on_spin(vcpu);
 89	else
 90		kvm_vcpu_block(vcpu);
 91
 92	return 1;
 93}
 94
 95static exit_handle_fn arm_exit_handlers[] = {
 96	[HSR_EC_WFI]		= kvm_handle_wfx,
 97	[HSR_EC_CP15_32]	= kvm_handle_cp15_32,
 98	[HSR_EC_CP15_64]	= kvm_handle_cp15_64,
 99	[HSR_EC_CP14_MR]	= kvm_handle_cp14_access,
100	[HSR_EC_CP14_LS]	= kvm_handle_cp14_load_store,
101	[HSR_EC_CP14_64]	= kvm_handle_cp14_access,
102	[HSR_EC_CP_0_13]	= kvm_handle_cp_0_13_access,
103	[HSR_EC_CP10_ID]	= kvm_handle_cp10_id,
104	[HSR_EC_SVC_HYP]	= handle_svc_hyp,
105	[HSR_EC_HVC]		= handle_hvc,
106	[HSR_EC_SMC]		= handle_smc,
107	[HSR_EC_IABT]		= kvm_handle_guest_abort,
108	[HSR_EC_IABT_HYP]	= handle_pabt_hyp,
109	[HSR_EC_DABT]		= kvm_handle_guest_abort,
110	[HSR_EC_DABT_HYP]	= handle_dabt_hyp,
111};
112
113static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
114{
115	u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
116
117	if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) ||
118	    !arm_exit_handlers[hsr_ec]) {
119		kvm_err("Unknown exception class: hsr: %#08x\n",
120			(unsigned int)kvm_vcpu_get_hsr(vcpu));
121		BUG();
122	}
123
124	return arm_exit_handlers[hsr_ec];
125}
126
127/*
128 * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
129 * proper exit to userspace.
130 */
131int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
132		       int exception_index)
133{
134	exit_handle_fn exit_handler;
135
136	switch (exception_index) {
137	case ARM_EXCEPTION_IRQ:
138		return 1;
139	case ARM_EXCEPTION_UNDEFINED:
140		kvm_err("Undefined exception in Hyp mode at: %#08lx\n",
141			kvm_vcpu_get_hyp_pc(vcpu));
142		BUG();
143		panic("KVM: Hypervisor undefined exception!\n");
144	case ARM_EXCEPTION_DATA_ABORT:
145	case ARM_EXCEPTION_PREF_ABORT:
146	case ARM_EXCEPTION_HVC:
147		/*
148		 * See ARM ARM B1.14.1: "Hyp traps on instructions
149		 * that fail their condition code check"
150		 */
151		if (!kvm_condition_valid(vcpu)) {
152			kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
153			return 1;
154		}
155
156		exit_handler = kvm_get_exit_handler(vcpu);
157
158		return exit_handler(vcpu, run);
159	default:
160		kvm_pr_unimpl("Unsupported exception type: %d",
161			      exception_index);
162		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
163		return 0;
164	}
165}