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Diffstat (limited to 'arch/arm/kvm/handle_exit.c')
| -rw-r--r-- | arch/arm/kvm/handle_exit.c | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c new file mode 100644 index 000000000..910bd8dab --- /dev/null +++ b/arch/arm/kvm/handle_exit.c @@ -0,0 +1,187 @@ +/* + * 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_hvc_call_handler(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; + } +} |