diff options
Diffstat (limited to 'arch/arm64/kvm/handle_exit.c')
| -rw-r--r-- | arch/arm64/kvm/handle_exit.c | 359 |
1 files changed, 258 insertions, 101 deletions
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index aacfc55de44c..b73dc26bc44b 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -14,63 +14,99 @@ #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/kvm_nested.h> #include <asm/debug-monitors.h> +#include <asm/stacktrace/nvhe.h> #include <asm/traps.h> #include <kvm/arm_hypercalls.h> #define CREATE_TRACE_POINTS -#include "trace.h" +#include "trace_handle_exit.h" -typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *); +typedef int (*exit_handle_fn)(struct kvm_vcpu *); -static void kvm_handle_guest_serror(struct kvm_vcpu *vcpu, u32 esr) +static void kvm_handle_guest_serror(struct kvm_vcpu *vcpu, u64 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) +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); + /* Forward hvc instructions to the virtual EL2 if the guest has EL2. */ + if (vcpu_has_nv(vcpu)) { + if (vcpu_read_sys_reg(vcpu, HCR_EL2) & HCR_HCD) + kvm_inject_undefined(vcpu); + else + kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu)); + return 1; } - return ret; + return kvm_smccc_call_handler(vcpu); } -static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run) +static int handle_smc(struct kvm_vcpu *vcpu) { /* + * Forward this trapped smc instruction to the virtual EL2 if + * the guest has asked for it. + */ + if (forward_smc_trap(vcpu)) + return 1; + + /* * "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... + * otherwise return to the same address. Furthermore, pre-incrementing + * the PC before potentially exiting to userspace maintains the same + * abstraction for both SMCs and HVCs. */ - vcpu_set_reg(vcpu, 0, ~0UL); - kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); - return 1; + kvm_incr_pc(vcpu); + + /* + * SMCs with a nonzero immediate are reserved according to DEN0028E 2.9 + * "SMC and HVC immediate value". + */ + if (kvm_vcpu_hvc_get_imm(vcpu)) { + vcpu_set_reg(vcpu, 0, ~0UL); + return 1; + } + + /* + * If imm is zero then it is likely an SMCCC call. + * + * Note that on ARMv8.3, even if EL3 is not implemented, SMC executed + * at Non-secure EL1 is trapped to EL2 if HCR_EL2.TSC==1, rather than + * being treated as UNDEFINED. + */ + return kvm_smccc_call_handler(vcpu); } /* - * Guest access to FP/ASIMD registers are routed to this handler only - * when the system doesn't support FP/ASIMD. + * This handles the cases where the system does not support FP/ASIMD or when + * we are running nested virtualization and the guest hypervisor is trapping + * FP/ASIMD accesses by its guest guest. + * + * All other handling of guest vs. host FP/ASIMD register state is handled in + * fixup_guest_exit(). */ -static int handle_no_fpsimd(struct kvm_vcpu *vcpu, struct kvm_run *run) +static int kvm_handle_fpasimd(struct kvm_vcpu *vcpu) { + if (guest_hyp_fpsimd_traps_enabled(vcpu)) + return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu)); + + /* This is the case when the system doesn't support FP/ASIMD. */ kvm_inject_undefined(vcpu); return 1; } @@ -81,26 +117,56 @@ static int handle_no_fpsimd(struct kvm_vcpu *vcpu, struct kvm_run *run) * * @vcpu: the vcpu pointer * - * WFE: Yield the CPU and come back to this vcpu when the scheduler + * WFE[T]: 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 + * WFI: Simply call kvm_vcpu_halt(), which will halt execution of * world-switches and schedule other host processes until there is an * incoming IRQ or FIQ to the VM. + * WFIT: Same as WFI, with a timed wakeup implemented as a background timer + * + * WF{I,E}T can immediately return if the deadline has already expired. */ -static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run) +static int kvm_handle_wfx(struct kvm_vcpu *vcpu) { - if (kvm_vcpu_get_hsr(vcpu) & ESR_ELx_WFx_ISS_WFE) { + u64 esr = kvm_vcpu_get_esr(vcpu); + bool is_wfe = !!(esr & ESR_ELx_WFx_ISS_WFE); + + if (guest_hyp_wfx_traps_enabled(vcpu)) + return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu)); + + if (is_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)); + if (esr & ESR_ELx_WFx_ISS_WFxT) { + if (esr & ESR_ELx_WFx_ISS_RV) { + u64 val, now; + + now = kvm_arm_timer_get_reg(vcpu, KVM_REG_ARM_TIMER_CNT); + val = vcpu_get_reg(vcpu, kvm_vcpu_sys_get_rt(vcpu)); + + if (now >= val) + goto out; + } else { + /* Treat WFxT as WFx if RN is invalid */ + esr &= ~ESR_ELx_WFx_ISS_WFxT; + } + } + + if (esr & ESR_ELx_WFx_ISS_WFE) { + kvm_vcpu_on_spin(vcpu, vcpu_mode_priv(vcpu)); + } else { + if (esr & ESR_ELx_WFx_ISS_WFxT) + vcpu_set_flag(vcpu, IN_WFIT); + + kvm_vcpu_wfi(vcpu); + } +out: + kvm_incr_pc(vcpu); return 1; } @@ -109,93 +175,126 @@ static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run) * 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 + * @return: 0 (while setting vcpu->run->exit_reason) */ -static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run) +static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu) { - u32 hsr = kvm_vcpu_get_hsr(vcpu); - int ret = 0; + struct kvm_run *run = vcpu->run; + u64 esr = kvm_vcpu_get_esr(vcpu); + + if (!vcpu->guest_debug && forward_debug_exception(vcpu)) + return 1; run->exit_reason = KVM_EXIT_DEBUG; - run->debug.arch.hsr = hsr; + run->debug.arch.hsr = lower_32_bits(esr); + run->debug.arch.hsr_high = upper_32_bits(esr); + run->flags = KVM_DEBUG_ARCH_HSR_HIGH_VALID; - switch (ESR_ELx_EC(hsr)) { + switch (ESR_ELx_EC(esr)) { 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; + case ESR_ELx_EC_SOFTSTP_LOW: + *vcpu_cpsr(vcpu) |= DBG_SPSR_SS; break; } - return ret; + return 0; } -static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu, struct kvm_run *run) +static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu) { - u32 hsr = kvm_vcpu_get_hsr(vcpu); + u64 esr = kvm_vcpu_get_esr(vcpu); - kvm_pr_unimpl("Unknown exception class: hsr: %#08x -- %s\n", - hsr, esr_get_class_string(hsr)); + kvm_pr_unimpl("Unknown exception class: esr: %#016llx -- %s\n", + esr, esr_get_class_string(esr)); kvm_inject_undefined(vcpu); return 1; } -static int handle_sve(struct kvm_vcpu *vcpu, struct kvm_run *run) +/* + * Guest access to SVE registers should be routed to this handler only + * when the system doesn't support SVE. + */ +static int handle_sve(struct kvm_vcpu *vcpu) { - /* Until SVE is supported for guests: */ + if (guest_hyp_sve_traps_enabled(vcpu)) + return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu)); + kvm_inject_undefined(vcpu); return 1; } -#define __ptrauth_save_key(regs, key) \ -({ \ - regs[key ## KEYLO_EL1] = read_sysreg_s(SYS_ ## key ## KEYLO_EL1); \ - regs[key ## KEYHI_EL1] = read_sysreg_s(SYS_ ## key ## KEYHI_EL1); \ -}) - /* - * Handle the guest trying to use a ptrauth instruction, or trying to access a - * ptrauth register. + * Two possibilities to handle a trapping ptrauth instruction: + * + * - Guest usage of a ptrauth instruction (which the guest EL1 did not + * turn into a NOP). If we get here, it is because we didn't enable + * ptrauth for the guest. This results in an UNDEF, as it isn't + * supposed to use ptrauth without being told it could. + * + * - Running an L2 NV guest while L1 has left HCR_EL2.API==0, and for + * which we reinject the exception into L1. + * + * Anything else is an emulation bug (hence the WARN_ON + UNDEF). */ -void kvm_arm_vcpu_ptrauth_trap(struct kvm_vcpu *vcpu) +static int kvm_handle_ptrauth(struct kvm_vcpu *vcpu) { - struct kvm_cpu_context *ctxt; - - if (vcpu_has_ptrauth(vcpu)) { - vcpu_ptrauth_enable(vcpu); - ctxt = vcpu->arch.host_cpu_context; - __ptrauth_save_key(ctxt->sys_regs, APIA); - __ptrauth_save_key(ctxt->sys_regs, APIB); - __ptrauth_save_key(ctxt->sys_regs, APDA); - __ptrauth_save_key(ctxt->sys_regs, APDB); - __ptrauth_save_key(ctxt->sys_regs, APGA); - } else { + if (!vcpu_has_ptrauth(vcpu)) { kvm_inject_undefined(vcpu); + return 1; + } + + if (vcpu_has_nv(vcpu) && !is_hyp_ctxt(vcpu)) { + kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu)); + return 1; } + + /* Really shouldn't be here! */ + WARN_ON_ONCE(1); + kvm_inject_undefined(vcpu); + return 1; } -/* - * Guest usage of a ptrauth instruction (which the guest EL1 did not turn into - * a NOP). - */ -static int kvm_handle_ptrauth(struct kvm_vcpu *vcpu, struct kvm_run *run) +static int kvm_handle_eret(struct kvm_vcpu *vcpu) { - kvm_arm_vcpu_ptrauth_trap(vcpu); + if (esr_iss_is_eretax(kvm_vcpu_get_esr(vcpu)) && + !vcpu_has_ptrauth(vcpu)) + return kvm_handle_ptrauth(vcpu); + + /* + * If we got here, two possibilities: + * + * - the guest is in EL2, and we need to fully emulate ERET + * + * - the guest is in EL1, and we need to reinject the + * exception into the L1 hypervisor. + * + * If KVM ever traps ERET for its own use, we'll have to + * revisit this. + */ + if (is_hyp_ctxt(vcpu)) + kvm_emulate_nested_eret(vcpu); + else + kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu)); + + return 1; +} + +static int handle_svc(struct kvm_vcpu *vcpu) +{ + /* + * So far, SVC traps only for NV via HFGITR_EL2. A SVC from a + * 32bit guest would be caught by vpcu_mode_is_bad_32bit(), so + * we should only have to deal with a 64 bit exception. + */ + kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu)); return 1; } @@ -206,13 +305,16 @@ static exit_handle_fn arm_exit_handlers[] = { [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_CP10_ID] = kvm_handle_cp10_id, [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_SVC64] = handle_svc, [ESR_ELx_EC_SYS64] = kvm_handle_sys_reg, [ESR_ELx_EC_SVE] = handle_sve, + [ESR_ELx_EC_ERET] = kvm_handle_eret, [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, @@ -220,16 +322,16 @@ static exit_handle_fn arm_exit_handlers[] = { [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_FP_ASIMD] = kvm_handle_fpasimd, [ESR_ELx_EC_PAC] = kvm_handle_ptrauth, }; 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); + u64 esr = kvm_vcpu_get_esr(vcpu); + u8 esr_ec = ESR_ELx_EC(esr); - return arm_exit_handlers[hsr_ec]; + return arm_exit_handlers[esr_ec]; } /* @@ -238,7 +340,7 @@ static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu) * KVM_EXIT_DEBUG, otherwise userspace needs to complete its * emulation first. */ -static int handle_trap_exceptions(struct kvm_vcpu *vcpu, struct kvm_run *run) +static int handle_trap_exceptions(struct kvm_vcpu *vcpu) { int handled; @@ -247,13 +349,13 @@ static int handle_trap_exceptions(struct kvm_vcpu *vcpu, struct kvm_run *run) * that fail their condition code check" */ if (!kvm_condition_valid(vcpu)) { - kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); + kvm_incr_pc(vcpu); handled = 1; } else { exit_handle_fn exit_handler; exit_handler = kvm_get_exit_handler(vcpu); - handled = exit_handler(vcpu, run); + handled = exit_handler(vcpu); } return handled; @@ -263,23 +365,15 @@ static int handle_trap_exceptions(struct kvm_vcpu *vcpu, struct kvm_run *run) * 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) +int handle_exit(struct kvm_vcpu *vcpu, int exception_index) { - if (ARM_SERROR_PENDING(exception_index)) { - u8 hsr_ec = ESR_ELx_EC(kvm_vcpu_get_hsr(vcpu)); + struct kvm_run *run = vcpu->run; + if (ARM_SERROR_PENDING(exception_index)) { /* - * HVC/SMC already have an adjusted PC, which we need - * to correct in order to return to after having - * injected the SError. + * The SError is handled by handle_exit_early(). If the guest + * survives it will re-execute the original instruction. */ - 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; } @@ -291,11 +385,11 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run, case ARM_EXCEPTION_EL1_SERROR: return 1; case ARM_EXCEPTION_TRAP: - return handle_trap_exceptions(vcpu, run); + 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. + * is pre-emptied by kvm_reboot()'s shutdown call. */ run->exit_reason = KVM_EXIT_FAIL_ENTRY; return 0; @@ -315,8 +409,7 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run, } /* 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) +void handle_exit_early(struct kvm_vcpu *vcpu, int exception_index) { if (ARM_SERROR_PENDING(exception_index)) { if (this_cpu_has_cap(ARM64_HAS_RAS_EXTN)) { @@ -333,5 +426,69 @@ void handle_exit_early(struct kvm_vcpu *vcpu, struct kvm_run *run, exception_index = ARM_EXCEPTION_CODE(exception_index); if (exception_index == ARM_EXCEPTION_EL1_SERROR) - kvm_handle_guest_serror(vcpu, kvm_vcpu_get_hsr(vcpu)); + kvm_handle_guest_serror(vcpu, kvm_vcpu_get_esr(vcpu)); +} + +static void print_nvhe_hyp_panic(const char *name, u64 panic_addr) +{ + kvm_err("nVHE hyp %s at: [<%016llx>] %pB!\n", name, panic_addr, + (void *)(panic_addr + kaslr_offset())); +} + +static void kvm_nvhe_report_cfi_failure(u64 panic_addr) +{ + print_nvhe_hyp_panic("CFI failure", panic_addr); + + if (IS_ENABLED(CONFIG_CFI_PERMISSIVE)) + kvm_err(" (CONFIG_CFI_PERMISSIVE ignored for hyp failures)\n"); +} + +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; + u64 panic_addr = elr_virt + hyp_offset; + + 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_brk_comment(esr) == 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 + print_nvhe_hyp_panic("BUG", panic_addr); + } else if (IS_ENABLED(CONFIG_CFI_CLANG) && esr_is_cfi_brk(esr)) { + kvm_nvhe_report_cfi_failure(panic_addr); + } else { + print_nvhe_hyp_panic("panic", panic_addr); + } + + /* Dump the nVHE hypervisor backtrace */ + kvm_nvhe_dump_backtrace(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:%016llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%016lx\n", + spsr, elr_virt, esr, far, hpfar, par, vcpu); } |