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/*
* Copyright (C) 2012 - Virtual Open Systems and Columbia University
* Author: Christoffer Dall <c.dall@virtualopensystems.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_coproc.h>
#include <asm/kvm_mmu.h>
#include <kvm/arm_psci.h>
#include <trace/events/kvm.h>
#include "trace.h"
typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
int ret;
trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
kvm_vcpu_hvc_get_imm(vcpu));
vcpu->stat.hvc_exit_stat++;
ret = kvm_psci_call(vcpu);
if (ret < 0) {
vcpu_set_reg(vcpu, 0, ~0UL);
return 1;
}
return ret;
}
static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
/*
* "If an SMC instruction executed at Non-secure EL1 is
* trapped to EL2 because HCR_EL2.TSC is 1, the exception is a
* Trap exception, not a Secure Monitor Call exception [...]"
*
* We need to advance the PC after the trap, as it would
* otherwise return to the same address...
*/
vcpu_set_reg(vcpu, 0, ~0UL);
kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
return 1;
}
/**
* kvm_handle_wfx - handle a WFI or WFE instructions trapped in guests
* @vcpu: the vcpu pointer
* @run: the kvm_run structure pointer
*
* WFE: Yield the CPU and come back to this vcpu when the scheduler
* decides to.
* WFI: Simply call kvm_vcpu_block(), which will halt execution of
* world-switches and schedule other host processes until there is an
* incoming IRQ or FIQ to the VM.
*/
static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
if (kvm_vcpu_get_hsr(vcpu) & HSR_WFI_IS_WFE) {
trace_kvm_wfx(*vcpu_pc(vcpu), true);
vcpu->stat.wfe_exit_stat++;
kvm_vcpu_on_spin(vcpu, vcpu_mode_priv(vcpu));
} else {
trace_kvm_wfx(*vcpu_pc(vcpu), false);
vcpu->stat.wfi_exit_stat++;
kvm_vcpu_block(vcpu);
kvm_clear_request(KVM_REQ_UNHALT, vcpu);
}
kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
return 1;
}
static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
u32 hsr = kvm_vcpu_get_hsr(vcpu);
kvm_pr_unimpl("Unknown exception class: hsr: %#08x\n",
hsr);
kvm_inject_undefined(vcpu);
return 1;
}
static exit_handle_fn arm_exit_handlers[] = {
[0 ... HSR_EC_MAX] = kvm_handle_unknown_ec,
[HSR_EC_WFI] = kvm_handle_wfx,
[HSR_EC_CP15_32] = kvm_handle_cp15_32,
[HSR_EC_CP15_64] = kvm_handle_cp15_64,
[HSR_EC_CP14_MR] = kvm_handle_cp14_32,
[HSR_EC_CP14_LS] = kvm_handle_cp14_load_store,
[HSR_EC_CP14_64] = kvm_handle_cp14_64,
[HSR_EC_CP_0_13] = kvm_handle_cp_0_13_access,
[HSR_EC_CP10_ID] = kvm_handle_cp10_id,
[HSR_EC_HVC] = handle_hvc,
[HSR_EC_SMC] = handle_smc,
[HSR_EC_IABT] = kvm_handle_guest_abort,
[HSR_EC_DABT] = kvm_handle_guest_abort,
};
static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
{
u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
return arm_exit_handlers[hsr_ec];
}
/*
* Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
* proper exit to userspace.
*/
int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
int exception_index)
{
exit_handle_fn exit_handler;
if (ARM_ABORT_PENDING(exception_index)) {
u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
/*
* HVC/SMC already have an adjusted PC, which we need
* to correct in order to return to after having
* injected the abort.
*/
if (hsr_ec == HSR_EC_HVC || hsr_ec == HSR_EC_SMC) {
u32 adj = kvm_vcpu_trap_il_is32bit(vcpu) ? 4 : 2;
*vcpu_pc(vcpu) -= adj;
}
kvm_inject_vabt(vcpu);
return 1;
}
exception_index = ARM_EXCEPTION_CODE(exception_index);
switch (exception_index) {
case ARM_EXCEPTION_IRQ:
return 1;
case ARM_EXCEPTION_HVC:
/*
* See ARM ARM B1.14.1: "Hyp traps on instructions
* that fail their condition code check"
*/
if (!kvm_condition_valid(vcpu)) {
kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
return 1;
}
exit_handler = kvm_get_exit_handler(vcpu);
return exit_handler(vcpu, run);
case ARM_EXCEPTION_DATA_ABORT:
kvm_inject_vabt(vcpu);
return 1;
case ARM_EXCEPTION_HYP_GONE:
/*
* HYP has been reset to the hyp-stub. This happens
* when a guest is pre-empted by kvm_reboot()'s
* shutdown call.
*/
run->exit_reason = KVM_EXIT_FAIL_ENTRY;
return 0;
default:
kvm_pr_unimpl("Unsupported exception type: %d",
exception_index);
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
return 0;
}
}
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