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Diffstat (limited to '')
| -rw-r--r-- | arch/arm64/kvm/handle_exit.c | 315 |
1 files changed, 315 insertions, 0 deletions
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c new file mode 100644 index 000000000..e5e741bff --- /dev/null +++ b/arch/arm64/kvm/handle_exit.c @@ -0,0 +1,315 @@ +/* + * Copyright (C) 2012,2013 - ARM Ltd + * Author: Marc Zyngier <marc.zyngier@arm.com> + * + * Derived from arch/arm/kvm/handle_exit.c: + * 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, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/kvm.h> +#include <linux/kvm_host.h> + +#include <kvm/arm_psci.h> + +#include <asm/esr.h> +#include <asm/exception.h> +#include <asm/kvm_asm.h> +#include <asm/kvm_coproc.h> +#include <asm/kvm_emulate.h> +#include <asm/kvm_mmu.h> +#include <asm/debug-monitors.h> +#include <asm/traps.h> + +#define CREATE_TRACE_POINTS +#include "trace.h" + +typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *); + +static void kvm_handle_guest_serror(struct kvm_vcpu *vcpu, u32 esr) +{ + if (!arm64_is_ras_serror(esr) || arm64_is_fatal_ras_serror(NULL, esr)) + kvm_inject_vabt(vcpu); +} + +static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run) +{ + int ret; + + trace_kvm_hvc_arm64(*vcpu_pc(vcpu), vcpu_get_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; +} + +/* + * Guest access to FP/ASIMD registers are routed to this handler only + * when the system doesn't support FP/ASIMD. + */ +static int handle_no_fpsimd(struct kvm_vcpu *vcpu, struct kvm_run *run) +{ + kvm_inject_undefined(vcpu); + return 1; +} + +/** + * kvm_handle_wfx - handle a wait-for-interrupts or wait-for-event + * instruction executed by a guest + * + * @vcpu: the vcpu 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) & ESR_ELx_WFx_ISS_WFE) { + trace_kvm_wfx_arm64(*vcpu_pc(vcpu), true); + vcpu->stat.wfe_exit_stat++; + kvm_vcpu_on_spin(vcpu, vcpu_mode_priv(vcpu)); + } else { + trace_kvm_wfx_arm64(*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; +} + +/** + * kvm_handle_guest_debug - handle a debug exception instruction + * + * @vcpu: the vcpu pointer + * @run: access to the kvm_run structure for results + * + * We route all debug exceptions through the same handler. If both the + * guest and host are using the same debug facilities it will be up to + * userspace to re-inject the correct exception for guest delivery. + * + * @return: 0 (while setting run->exit_reason), -1 for error + */ +static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run) +{ + u32 hsr = kvm_vcpu_get_hsr(vcpu); + int ret = 0; + + run->exit_reason = KVM_EXIT_DEBUG; + run->debug.arch.hsr = hsr; + + switch (ESR_ELx_EC(hsr)) { + case ESR_ELx_EC_WATCHPT_LOW: + run->debug.arch.far = vcpu->arch.fault.far_el2; + /* fall through */ + case ESR_ELx_EC_SOFTSTP_LOW: + case ESR_ELx_EC_BREAKPT_LOW: + case ESR_ELx_EC_BKPT32: + case ESR_ELx_EC_BRK64: + break; + default: + kvm_err("%s: un-handled case hsr: %#08x\n", + __func__, (unsigned int) hsr); + ret = -1; + break; + } + + return ret; +} + +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 -- %s\n", + hsr, esr_get_class_string(hsr)); + + kvm_inject_undefined(vcpu); + return 1; +} + +static int handle_sve(struct kvm_vcpu *vcpu, struct kvm_run *run) +{ + /* Until SVE is supported for guests: */ + kvm_inject_undefined(vcpu); + return 1; +} + +static exit_handle_fn arm_exit_handlers[] = { + [0 ... ESR_ELx_EC_MAX] = kvm_handle_unknown_ec, + [ESR_ELx_EC_WFx] = kvm_handle_wfx, + [ESR_ELx_EC_CP15_32] = kvm_handle_cp15_32, + [ESR_ELx_EC_CP15_64] = kvm_handle_cp15_64, + [ESR_ELx_EC_CP14_MR] = kvm_handle_cp14_32, + [ESR_ELx_EC_CP14_LS] = kvm_handle_cp14_load_store, + [ESR_ELx_EC_CP14_64] = kvm_handle_cp14_64, + [ESR_ELx_EC_HVC32] = handle_hvc, + [ESR_ELx_EC_SMC32] = handle_smc, + [ESR_ELx_EC_HVC64] = handle_hvc, + [ESR_ELx_EC_SMC64] = handle_smc, + [ESR_ELx_EC_SYS64] = kvm_handle_sys_reg, + [ESR_ELx_EC_SVE] = handle_sve, + [ESR_ELx_EC_IABT_LOW] = kvm_handle_guest_abort, + [ESR_ELx_EC_DABT_LOW] = kvm_handle_guest_abort, + [ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug, + [ESR_ELx_EC_WATCHPT_LOW]= kvm_handle_guest_debug, + [ESR_ELx_EC_BREAKPT_LOW]= kvm_handle_guest_debug, + [ESR_ELx_EC_BKPT32] = kvm_handle_guest_debug, + [ESR_ELx_EC_BRK64] = kvm_handle_guest_debug, + [ESR_ELx_EC_FP_ASIMD] = handle_no_fpsimd, +}; + +static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu) +{ + u32 hsr = kvm_vcpu_get_hsr(vcpu); + u8 hsr_ec = ESR_ELx_EC(hsr); + + return arm_exit_handlers[hsr_ec]; +} + +/* + * We may be single-stepping an emulated instruction. If the emulation + * has been completed in the kernel, we can return to userspace with a + * KVM_EXIT_DEBUG, otherwise userspace needs to complete its + * emulation first. + */ +static int handle_trap_exceptions(struct kvm_vcpu *vcpu, struct kvm_run *run) +{ + int handled; + + /* + * 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)); + handled = 1; + } else { + exit_handle_fn exit_handler; + + exit_handler = kvm_get_exit_handler(vcpu); + handled = exit_handler(vcpu, run); + } + + /* + * kvm_arm_handle_step_debug() sets the exit_reason on the kvm_run + * structure if we need to return to userspace. + */ + if (handled > 0 && kvm_arm_handle_step_debug(vcpu, run)) + handled = 0; + + return handled; +} + +/* + * 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) +{ + if (ARM_SERROR_PENDING(exception_index)) { + u8 hsr_ec = ESR_ELx_EC(kvm_vcpu_get_hsr(vcpu)); + + /* + * HVC/SMC already have an adjusted PC, which we need + * to correct in order to return to after having + * injected the SError. + */ + if (hsr_ec == ESR_ELx_EC_HVC32 || hsr_ec == ESR_ELx_EC_HVC64 || + hsr_ec == ESR_ELx_EC_SMC32 || hsr_ec == ESR_ELx_EC_SMC64) { + u32 adj = kvm_vcpu_trap_il_is32bit(vcpu) ? 4 : 2; + *vcpu_pc(vcpu) -= adj; + } + + return 1; + } + + exception_index = ARM_EXCEPTION_CODE(exception_index); + + switch (exception_index) { + case ARM_EXCEPTION_IRQ: + return 1; + case ARM_EXCEPTION_EL1_SERROR: + /* We may still need to return for single-step */ + if (!(*vcpu_cpsr(vcpu) & DBG_SPSR_SS) + && kvm_arm_handle_step_debug(vcpu, run)) + return 0; + else + return 1; + case ARM_EXCEPTION_TRAP: + return handle_trap_exceptions(vcpu, run); + case ARM_EXCEPTION_HYP_GONE: + /* + * EL2 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; + } +} + +/* For exit types that need handling before we can be preempted */ +void handle_exit_early(struct kvm_vcpu *vcpu, struct kvm_run *run, + int exception_index) +{ + if (ARM_SERROR_PENDING(exception_index)) { + if (this_cpu_has_cap(ARM64_HAS_RAS_EXTN)) { + u64 disr = kvm_vcpu_get_disr(vcpu); + + kvm_handle_guest_serror(vcpu, disr_to_esr(disr)); + } else { + kvm_inject_vabt(vcpu); + } + + return; + } + + exception_index = ARM_EXCEPTION_CODE(exception_index); + + if (exception_index == ARM_EXCEPTION_EL1_SERROR) + kvm_handle_guest_serror(vcpu, kvm_vcpu_get_hsr(vcpu)); +} |