| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * 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> |
| */ |
| |
| #include <linux/kvm.h> |
| #include <linux/kvm_host.h> |
| |
| #include <asm/esr.h> |
| #include <asm/exception.h> |
| #include <asm/kvm_asm.h> |
| #include <asm/kvm_emulate.h> |
| #include <asm/kvm_mmu.h> |
| #include <asm/debug-monitors.h> |
| #include <asm/traps.h> |
| |
| #include <kvm/arm_hypercalls.h> |
| |
| #define CREATE_TRACE_POINTS |
| #include "trace_handle_exit.h" |
| |
| typedef int (*exit_handle_fn)(struct kvm_vcpu *); |
| |
| 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) |
| { |
| 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) |
| { |
| /* |
| * "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_incr_pc(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) |
| { |
| 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) |
| { |
| if (kvm_vcpu_get_esr(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_incr_pc(vcpu); |
| |
| return 1; |
| } |
| |
| /** |
| * kvm_handle_guest_debug - handle a debug exception instruction |
| * |
| * @vcpu: the vcpu pointer |
| * |
| * 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 vcpu->run->exit_reason) |
| */ |
| static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu) |
| { |
| struct kvm_run *run = vcpu->run; |
| u32 esr = kvm_vcpu_get_esr(vcpu); |
| |
| run->exit_reason = KVM_EXIT_DEBUG; |
| run->debug.arch.hsr = esr; |
| |
| if (ESR_ELx_EC(esr) == ESR_ELx_EC_WATCHPT_LOW) |
| run->debug.arch.far = vcpu->arch.fault.far_el2; |
| |
| return 0; |
| } |
| |
| static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu) |
| { |
| u32 esr = kvm_vcpu_get_esr(vcpu); |
| |
| kvm_pr_unimpl("Unknown exception class: esr: %#08x -- %s\n", |
| esr, esr_get_class_string(esr)); |
| |
| kvm_inject_undefined(vcpu); |
| return 1; |
| } |
| |
| static int handle_sve(struct kvm_vcpu *vcpu) |
| { |
| /* Until SVE is supported for guests: */ |
| kvm_inject_undefined(vcpu); |
| return 1; |
| } |
| |
| /* |
| * Guest usage of a ptrauth instruction (which the guest EL1 did not turn into |
| * a NOP). If we get here, it is that we didn't fixup ptrauth on exit, and all |
| * that we can do is give the guest an UNDEF. |
| */ |
| static int kvm_handle_ptrauth(struct kvm_vcpu *vcpu) |
| { |
| 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, |
| [ESR_ELx_EC_PAC] = kvm_handle_ptrauth, |
| }; |
| |
| static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu) |
| { |
| u32 esr = kvm_vcpu_get_esr(vcpu); |
| u8 esr_ec = ESR_ELx_EC(esr); |
| |
| return arm_exit_handlers[esr_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) |
| { |
| int handled; |
| |
| /* |
| * If we run a non-protected VM when protection is enabled |
| * system-wide, resync the state from the hypervisor and mark |
| * it as dirty on the host side if it wasn't dirty already |
| * (which could happen if preemption has taken place). |
| */ |
| if (is_protected_kvm_enabled() && !kvm_vm_is_protected(vcpu->kvm)) { |
| preempt_disable(); |
| if (!(vcpu->arch.flags & KVM_ARM64_PKVM_STATE_DIRTY)) { |
| kvm_call_hyp_nvhe(__pkvm_vcpu_sync_state); |
| vcpu->arch.flags |= KVM_ARM64_PKVM_STATE_DIRTY; |
| } |
| preempt_enable(); |
| } |
| |
| /* |
| * See ARM ARM B1.14.1: "Hyp traps on instructions |
| * that fail their condition code check" |
| */ |
| if (!kvm_condition_valid(vcpu)) { |
| kvm_incr_pc(vcpu); |
| handled = 1; |
| } else { |
| exit_handle_fn exit_handler; |
| |
| exit_handler = kvm_get_exit_handler(vcpu); |
| handled = exit_handler(vcpu); |
| } |
| |
| 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, int exception_index) |
| { |
| struct kvm_run *run = vcpu->run; |
| |
| exception_index = ARM_EXCEPTION_CODE(exception_index); |
| |
| switch (exception_index) { |
| case ARM_EXCEPTION_IRQ: |
| return 1; |
| case ARM_EXCEPTION_EL1_SERROR: |
| return 1; |
| case ARM_EXCEPTION_TRAP: |
| return handle_trap_exceptions(vcpu); |
| 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; |
| case ARM_EXCEPTION_IL: |
| /* |
| * We attempted an illegal exception return. Guest state must |
| * have been corrupted somehow. Give up. |
| */ |
| run->exit_reason = KVM_EXIT_FAIL_ENTRY; |
| return -EINVAL; |
| 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, int exception_index) |
| { |
| /* |
| * We just exited, so the state is clean from a hypervisor |
| * perspective. |
| */ |
| if (is_protected_kvm_enabled()) |
| vcpu->arch.flags &= ~KVM_ARM64_PKVM_STATE_DIRTY; |
| |
| 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_esr(vcpu)); |
| } |
| |
| void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr, |
| u64 elr_virt, u64 elr_phys, |
| u64 par, uintptr_t vcpu, |
| u64 far, u64 hpfar) { |
| u64 elr_in_kimg = __phys_to_kimg(elr_phys); |
| u64 hyp_offset = elr_in_kimg - kaslr_offset() - elr_virt; |
| u64 mode = spsr & PSR_MODE_MASK; |
| |
| /* |
| * The nVHE hyp symbols are not included by kallsyms to avoid issues |
| * with aliasing. That means that the symbols cannot be printed with the |
| * "%pS" format specifier, so fall back to the vmlinux address if |
| * there's no better option. |
| */ |
| if (mode != PSR_MODE_EL2t && mode != PSR_MODE_EL2h) { |
| kvm_err("Invalid host exception to nVHE hyp!\n"); |
| } else if (ESR_ELx_EC(esr) == ESR_ELx_EC_BRK64 && |
| (esr & ESR_ELx_BRK64_ISS_COMMENT_MASK) == BUG_BRK_IMM) { |
| const char *file = NULL; |
| unsigned int line = 0; |
| |
| /* All hyp bugs, including warnings, are treated as fatal. */ |
| if (!is_protected_kvm_enabled() || |
| IS_ENABLED(CONFIG_NVHE_EL2_DEBUG)) { |
| struct bug_entry *bug = find_bug(elr_in_kimg); |
| |
| if (bug) |
| bug_get_file_line(bug, &file, &line); |
| } |
| |
| if (file) |
| kvm_err("nVHE hyp BUG at: %s:%u!\n", file, line); |
| else |
| kvm_err("nVHE hyp BUG at: %016llx!\n", elr_virt + hyp_offset); |
| } else { |
| kvm_err("nVHE hyp panic at: %016llx!\n", elr_virt + hyp_offset); |
| } |
| |
| /* |
| * Hyp has panicked and we're going to handle that by panicking the |
| * kernel. The kernel offset will be revealed in the panic so we're |
| * also safe to reveal the hyp offset as a debugging aid for translating |
| * hyp VAs to vmlinux addresses. |
| */ |
| kvm_err("Hyp Offset: 0x%llx\n", hyp_offset); |
| |
| panic("HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%016lx\n", |
| spsr, elr_virt, esr, far, hpfar, par, vcpu); |
| } |