316 lines
8.6 KiB
C
316 lines
8.6 KiB
C
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/*
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* Copyright (C) 2012,2013 - ARM Ltd
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* Author: Marc Zyngier <marc.zyngier@arm.com>
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*
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* Derived from arch/arm/kvm/handle_exit.c:
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* Copyright (C) 2012 - Virtual Open Systems and Columbia University
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* Author: Christoffer Dall <c.dall@virtualopensystems.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/kvm.h>
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#include <linux/kvm_host.h>
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#include <kvm/arm_psci.h>
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#include <asm/esr.h>
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#include <asm/exception.h>
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#include <asm/kvm_asm.h>
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#include <asm/kvm_coproc.h>
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#include <asm/kvm_emulate.h>
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#include <asm/kvm_mmu.h>
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#include <asm/debug-monitors.h>
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#include <asm/traps.h>
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#define CREATE_TRACE_POINTS
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#include "trace.h"
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typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
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static void kvm_handle_guest_serror(struct kvm_vcpu *vcpu, u32 esr)
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{
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if (!arm64_is_ras_serror(esr) || arm64_is_fatal_ras_serror(NULL, esr))
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kvm_inject_vabt(vcpu);
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}
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static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
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{
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int ret;
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trace_kvm_hvc_arm64(*vcpu_pc(vcpu), vcpu_get_reg(vcpu, 0),
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kvm_vcpu_hvc_get_imm(vcpu));
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vcpu->stat.hvc_exit_stat++;
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ret = kvm_hvc_call_handler(vcpu);
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if (ret < 0) {
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vcpu_set_reg(vcpu, 0, ~0UL);
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return 1;
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}
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return ret;
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}
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static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
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{
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/*
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* "If an SMC instruction executed at Non-secure EL1 is
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* trapped to EL2 because HCR_EL2.TSC is 1, the exception is a
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* Trap exception, not a Secure Monitor Call exception [...]"
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*
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* We need to advance the PC after the trap, as it would
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* otherwise return to the same address...
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*/
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vcpu_set_reg(vcpu, 0, ~0UL);
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kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
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return 1;
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}
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/*
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* Guest access to FP/ASIMD registers are routed to this handler only
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* when the system doesn't support FP/ASIMD.
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*/
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static int handle_no_fpsimd(struct kvm_vcpu *vcpu, struct kvm_run *run)
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{
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kvm_inject_undefined(vcpu);
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return 1;
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}
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/**
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* kvm_handle_wfx - handle a wait-for-interrupts or wait-for-event
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* instruction executed by a guest
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*
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* @vcpu: the vcpu pointer
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*
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* WFE: Yield the CPU and come back to this vcpu when the scheduler
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* decides to.
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* WFI: Simply call kvm_vcpu_block(), which will halt execution of
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* world-switches and schedule other host processes until there is an
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* incoming IRQ or FIQ to the VM.
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*/
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static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
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{
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if (kvm_vcpu_get_hsr(vcpu) & ESR_ELx_WFx_ISS_WFE) {
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trace_kvm_wfx_arm64(*vcpu_pc(vcpu), true);
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vcpu->stat.wfe_exit_stat++;
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kvm_vcpu_on_spin(vcpu, vcpu_mode_priv(vcpu));
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} else {
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trace_kvm_wfx_arm64(*vcpu_pc(vcpu), false);
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vcpu->stat.wfi_exit_stat++;
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kvm_vcpu_block(vcpu);
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kvm_clear_request(KVM_REQ_UNHALT, vcpu);
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}
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kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
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return 1;
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}
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/**
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* kvm_handle_guest_debug - handle a debug exception instruction
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*
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* @vcpu: the vcpu pointer
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* @run: access to the kvm_run structure for results
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*
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* We route all debug exceptions through the same handler. If both the
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* guest and host are using the same debug facilities it will be up to
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* userspace to re-inject the correct exception for guest delivery.
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*
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* @return: 0 (while setting run->exit_reason), -1 for error
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*/
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static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run)
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{
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u32 hsr = kvm_vcpu_get_hsr(vcpu);
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int ret = 0;
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run->exit_reason = KVM_EXIT_DEBUG;
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run->debug.arch.hsr = hsr;
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switch (ESR_ELx_EC(hsr)) {
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case ESR_ELx_EC_WATCHPT_LOW:
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run->debug.arch.far = vcpu->arch.fault.far_el2;
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/* fall through */
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case ESR_ELx_EC_SOFTSTP_LOW:
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case ESR_ELx_EC_BREAKPT_LOW:
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case ESR_ELx_EC_BKPT32:
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case ESR_ELx_EC_BRK64:
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break;
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default:
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kvm_err("%s: un-handled case hsr: %#08x\n",
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__func__, (unsigned int) hsr);
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ret = -1;
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break;
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}
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return ret;
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}
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static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu, struct kvm_run *run)
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{
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u32 hsr = kvm_vcpu_get_hsr(vcpu);
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kvm_pr_unimpl("Unknown exception class: hsr: %#08x -- %s\n",
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hsr, esr_get_class_string(hsr));
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kvm_inject_undefined(vcpu);
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return 1;
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}
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static int handle_sve(struct kvm_vcpu *vcpu, struct kvm_run *run)
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{
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/* Until SVE is supported for guests: */
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kvm_inject_undefined(vcpu);
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return 1;
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}
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static exit_handle_fn arm_exit_handlers[] = {
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[0 ... ESR_ELx_EC_MAX] = kvm_handle_unknown_ec,
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[ESR_ELx_EC_WFx] = kvm_handle_wfx,
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[ESR_ELx_EC_CP15_32] = kvm_handle_cp15_32,
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[ESR_ELx_EC_CP15_64] = kvm_handle_cp15_64,
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[ESR_ELx_EC_CP14_MR] = kvm_handle_cp14_32,
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[ESR_ELx_EC_CP14_LS] = kvm_handle_cp14_load_store,
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[ESR_ELx_EC_CP14_64] = kvm_handle_cp14_64,
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[ESR_ELx_EC_HVC32] = handle_hvc,
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[ESR_ELx_EC_SMC32] = handle_smc,
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[ESR_ELx_EC_HVC64] = handle_hvc,
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[ESR_ELx_EC_SMC64] = handle_smc,
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[ESR_ELx_EC_SYS64] = kvm_handle_sys_reg,
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[ESR_ELx_EC_SVE] = handle_sve,
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[ESR_ELx_EC_IABT_LOW] = kvm_handle_guest_abort,
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[ESR_ELx_EC_DABT_LOW] = kvm_handle_guest_abort,
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[ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug,
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[ESR_ELx_EC_WATCHPT_LOW]= kvm_handle_guest_debug,
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[ESR_ELx_EC_BREAKPT_LOW]= kvm_handle_guest_debug,
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[ESR_ELx_EC_BKPT32] = kvm_handle_guest_debug,
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[ESR_ELx_EC_BRK64] = kvm_handle_guest_debug,
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[ESR_ELx_EC_FP_ASIMD] = handle_no_fpsimd,
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};
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static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
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{
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u32 hsr = kvm_vcpu_get_hsr(vcpu);
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u8 hsr_ec = ESR_ELx_EC(hsr);
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return arm_exit_handlers[hsr_ec];
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}
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/*
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* We may be single-stepping an emulated instruction. If the emulation
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* has been completed in the kernel, we can return to userspace with a
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* KVM_EXIT_DEBUG, otherwise userspace needs to complete its
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* emulation first.
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*/
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static int handle_trap_exceptions(struct kvm_vcpu *vcpu, struct kvm_run *run)
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{
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int handled;
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/*
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* See ARM ARM B1.14.1: "Hyp traps on instructions
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* that fail their condition code check"
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*/
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if (!kvm_condition_valid(vcpu)) {
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kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
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handled = 1;
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} else {
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exit_handle_fn exit_handler;
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exit_handler = kvm_get_exit_handler(vcpu);
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handled = exit_handler(vcpu, run);
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}
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/*
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* kvm_arm_handle_step_debug() sets the exit_reason on the kvm_run
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* structure if we need to return to userspace.
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*/
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if (handled > 0 && kvm_arm_handle_step_debug(vcpu, run))
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handled = 0;
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return handled;
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}
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/*
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* Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
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* proper exit to userspace.
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*/
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int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
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int exception_index)
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{
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if (ARM_SERROR_PENDING(exception_index)) {
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u8 hsr_ec = ESR_ELx_EC(kvm_vcpu_get_hsr(vcpu));
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/*
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* HVC/SMC already have an adjusted PC, which we need
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* to correct in order to return to after having
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* injected the SError.
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*/
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if (hsr_ec == ESR_ELx_EC_HVC32 || hsr_ec == ESR_ELx_EC_HVC64 ||
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hsr_ec == ESR_ELx_EC_SMC32 || hsr_ec == ESR_ELx_EC_SMC64) {
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u32 adj = kvm_vcpu_trap_il_is32bit(vcpu) ? 4 : 2;
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*vcpu_pc(vcpu) -= adj;
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}
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return 1;
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}
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exception_index = ARM_EXCEPTION_CODE(exception_index);
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switch (exception_index) {
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case ARM_EXCEPTION_IRQ:
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return 1;
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case ARM_EXCEPTION_EL1_SERROR:
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/* We may still need to return for single-step */
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if (!(*vcpu_cpsr(vcpu) & DBG_SPSR_SS)
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&& kvm_arm_handle_step_debug(vcpu, run))
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return 0;
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else
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return 1;
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case ARM_EXCEPTION_TRAP:
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return handle_trap_exceptions(vcpu, run);
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case ARM_EXCEPTION_HYP_GONE:
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/*
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* EL2 has been reset to the hyp-stub. This happens when a guest
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* is pre-empted by kvm_reboot()'s shutdown call.
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*/
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run->exit_reason = KVM_EXIT_FAIL_ENTRY;
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return 0;
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default:
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kvm_pr_unimpl("Unsupported exception type: %d",
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exception_index);
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run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
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return 0;
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}
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}
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/* For exit types that need handling before we can be preempted */
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void handle_exit_early(struct kvm_vcpu *vcpu, struct kvm_run *run,
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int exception_index)
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{
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if (ARM_SERROR_PENDING(exception_index)) {
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if (this_cpu_has_cap(ARM64_HAS_RAS_EXTN)) {
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u64 disr = kvm_vcpu_get_disr(vcpu);
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kvm_handle_guest_serror(vcpu, disr_to_esr(disr));
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} else {
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kvm_inject_vabt(vcpu);
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}
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return;
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}
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exception_index = ARM_EXCEPTION_CODE(exception_index);
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if (exception_index == ARM_EXCEPTION_EL1_SERROR)
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kvm_handle_guest_serror(vcpu, kvm_vcpu_get_hsr(vcpu));
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}
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