| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright (C) 2015 - ARM Ltd |
| * Author: Marc Zyngier <marc.zyngier@arm.com> |
| */ |
| |
| #ifndef __ARM64_KVM_HYP_SWITCH_H__ |
| #define __ARM64_KVM_HYP_SWITCH_H__ |
| |
| #include <hyp/adjust_pc.h> |
| #include <hyp/fault.h> |
| |
| #include <linux/arm-smccc.h> |
| #include <linux/kvm_host.h> |
| #include <linux/types.h> |
| #include <linux/jump_label.h> |
| #include <uapi/linux/psci.h> |
| |
| #include <kvm/arm_psci.h> |
| |
| #include <asm/barrier.h> |
| #include <asm/cpufeature.h> |
| #include <asm/extable.h> |
| #include <asm/kprobes.h> |
| #include <asm/kvm_asm.h> |
| #include <asm/kvm_emulate.h> |
| #include <asm/kvm_hyp.h> |
| #include <asm/kvm_mmu.h> |
| #include <asm/fpsimd.h> |
| #include <asm/debug-monitors.h> |
| #include <asm/processor.h> |
| |
| struct kvm_exception_table_entry { |
| int insn, fixup; |
| }; |
| |
| extern struct kvm_exception_table_entry __start___kvm_ex_table; |
| extern struct kvm_exception_table_entry __stop___kvm_ex_table; |
| |
| /* Check whether the FP regs were dirtied while in the host-side run loop: */ |
| static inline bool update_fp_enabled(struct kvm_vcpu *vcpu) |
| { |
| /* |
| * When the system doesn't support FP/SIMD, we cannot rely on |
| * the _TIF_FOREIGN_FPSTATE flag. However, we always inject an |
| * abort on the very first access to FP and thus we should never |
| * see KVM_ARM64_FP_ENABLED. For added safety, make sure we always |
| * trap the accesses. |
| */ |
| if (!system_supports_fpsimd() || |
| vcpu->arch.flags & KVM_ARM64_FP_FOREIGN_FPSTATE) |
| vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED | |
| KVM_ARM64_FP_HOST); |
| |
| return !!(vcpu->arch.flags & KVM_ARM64_FP_ENABLED); |
| } |
| |
| /* Save the 32-bit only FPSIMD system register state */ |
| static inline void __fpsimd_save_fpexc32(struct kvm_vcpu *vcpu) |
| { |
| if (!vcpu_el1_is_32bit(vcpu)) |
| return; |
| |
| __vcpu_sys_reg(vcpu, FPEXC32_EL2) = read_sysreg(fpexc32_el2); |
| } |
| |
| static inline void __activate_traps_fpsimd32(struct kvm_vcpu *vcpu) |
| { |
| /* |
| * We are about to set CPTR_EL2.TFP to trap all floating point |
| * register accesses to EL2, however, the ARM ARM clearly states that |
| * traps are only taken to EL2 if the operation would not otherwise |
| * trap to EL1. Therefore, always make sure that for 32-bit guests, |
| * we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit. |
| * If FP/ASIMD is not implemented, FPEXC is UNDEFINED and any access to |
| * it will cause an exception. |
| */ |
| if (vcpu_el1_is_32bit(vcpu) && system_supports_fpsimd()) { |
| write_sysreg(1 << 30, fpexc32_el2); |
| isb(); |
| } |
| } |
| |
| static inline void __activate_traps_common(struct kvm_vcpu *vcpu) |
| { |
| /* Trap on AArch32 cp15 c15 (impdef sysregs) accesses (EL1 or EL0) */ |
| write_sysreg(1 << 15, hstr_el2); |
| |
| /* |
| * Make sure we trap PMU access from EL0 to EL2. Also sanitize |
| * PMSELR_EL0 to make sure it never contains the cycle |
| * counter, which could make a PMXEVCNTR_EL0 access UNDEF at |
| * EL1 instead of being trapped to EL2. |
| */ |
| if (kvm_arm_support_pmu_v3()) { |
| write_sysreg(0, pmselr_el0); |
| write_sysreg(ARMV8_PMU_USERENR_MASK, pmuserenr_el0); |
| } |
| |
| vcpu->arch.mdcr_el2_host = read_sysreg(mdcr_el2); |
| write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2); |
| } |
| |
| static inline void __deactivate_traps_common(struct kvm_vcpu *vcpu) |
| { |
| write_sysreg(vcpu->arch.mdcr_el2_host, mdcr_el2); |
| |
| write_sysreg(0, hstr_el2); |
| if (kvm_arm_support_pmu_v3()) |
| write_sysreg(0, pmuserenr_el0); |
| } |
| |
| static inline void ___activate_traps(struct kvm_vcpu *vcpu) |
| { |
| u64 hcr = vcpu->arch.hcr_el2; |
| |
| if (cpus_have_final_cap(ARM64_WORKAROUND_CAVIUM_TX2_219_TVM)) |
| hcr |= HCR_TVM; |
| |
| write_sysreg(hcr, hcr_el2); |
| |
| if (cpus_have_final_cap(ARM64_HAS_RAS_EXTN) && (hcr & HCR_VSE)) |
| write_sysreg_s(vcpu->arch.vsesr_el2, SYS_VSESR_EL2); |
| } |
| |
| static inline void ___deactivate_traps(struct kvm_vcpu *vcpu) |
| { |
| /* |
| * If we pended a virtual abort, preserve it until it gets |
| * cleared. See D1.14.3 (Virtual Interrupts) for details, but |
| * the crucial bit is "On taking a vSError interrupt, |
| * HCR_EL2.VSE is cleared to 0." |
| */ |
| if (vcpu->arch.hcr_el2 & HCR_VSE) { |
| vcpu->arch.hcr_el2 &= ~HCR_VSE; |
| vcpu->arch.hcr_el2 |= read_sysreg(hcr_el2) & HCR_VSE; |
| } |
| } |
| |
| static inline bool __populate_fault_info(struct kvm_vcpu *vcpu) |
| { |
| return __get_fault_info(vcpu->arch.fault.esr_el2, &vcpu->arch.fault); |
| } |
| |
| static inline void __hyp_sve_restore_guest(struct kvm_vcpu *vcpu) |
| { |
| sve_cond_update_zcr_vq(vcpu_sve_max_vq(vcpu) - 1, SYS_ZCR_EL2); |
| __sve_restore_state(vcpu_sve_pffr(vcpu), |
| &vcpu->arch.ctxt.fp_regs.fpsr); |
| write_sysreg_el1(__vcpu_sys_reg(vcpu, ZCR_EL1), SYS_ZCR); |
| } |
| |
| /* |
| * We trap the first access to the FP/SIMD to save the host context and |
| * restore the guest context lazily. |
| * If FP/SIMD is not implemented, handle the trap and inject an undefined |
| * instruction exception to the guest. Similarly for trapped SVE accesses. |
| */ |
| static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code) |
| { |
| bool sve_guest; |
| u8 esr_ec; |
| u64 reg; |
| |
| if (!system_supports_fpsimd()) |
| return false; |
| |
| sve_guest = vcpu_has_sve(vcpu); |
| esr_ec = kvm_vcpu_trap_get_class(vcpu); |
| |
| /* Don't handle SVE traps for non-SVE vcpus here: */ |
| if (!sve_guest && esr_ec != ESR_ELx_EC_FP_ASIMD) |
| return false; |
| |
| /* Valid trap. Switch the context: */ |
| |
| /* First disable enough traps to allow us to update the registers */ |
| if (has_vhe()) { |
| reg = CPACR_EL1_FPEN_EL0EN | CPACR_EL1_FPEN_EL1EN; |
| if (sve_guest) |
| reg |= CPACR_EL1_ZEN_EL0EN | CPACR_EL1_ZEN_EL1EN; |
| |
| sysreg_clear_set(cpacr_el1, 0, reg); |
| } else { |
| reg = CPTR_EL2_TFP; |
| if (sve_guest) |
| reg |= CPTR_EL2_TZ; |
| |
| sysreg_clear_set(cptr_el2, reg, 0); |
| } |
| isb(); |
| |
| /* Write out the host state if it's in the registers */ |
| if (vcpu->arch.flags & KVM_ARM64_FP_HOST) { |
| __fpsimd_save_state(vcpu->arch.host_fpsimd_state); |
| vcpu->arch.flags &= ~KVM_ARM64_FP_HOST; |
| } |
| |
| /* Restore the guest state */ |
| if (sve_guest) |
| __hyp_sve_restore_guest(vcpu); |
| else |
| __fpsimd_restore_state(&vcpu->arch.ctxt.fp_regs); |
| |
| /* Skip restoring fpexc32 for AArch64 guests */ |
| if (!(read_sysreg(hcr_el2) & HCR_RW)) |
| write_sysreg(__vcpu_sys_reg(vcpu, FPEXC32_EL2), fpexc32_el2); |
| |
| vcpu->arch.flags |= KVM_ARM64_FP_ENABLED; |
| |
| return true; |
| } |
| |
| static inline bool handle_tx2_tvm(struct kvm_vcpu *vcpu) |
| { |
| u32 sysreg = esr_sys64_to_sysreg(kvm_vcpu_get_esr(vcpu)); |
| int rt = kvm_vcpu_sys_get_rt(vcpu); |
| u64 val = vcpu_get_reg(vcpu, rt); |
| |
| /* |
| * The normal sysreg handling code expects to see the traps, |
| * let's not do anything here. |
| */ |
| if (vcpu->arch.hcr_el2 & HCR_TVM) |
| return false; |
| |
| switch (sysreg) { |
| case SYS_SCTLR_EL1: |
| write_sysreg_el1(val, SYS_SCTLR); |
| break; |
| case SYS_TTBR0_EL1: |
| write_sysreg_el1(val, SYS_TTBR0); |
| break; |
| case SYS_TTBR1_EL1: |
| write_sysreg_el1(val, SYS_TTBR1); |
| break; |
| case SYS_TCR_EL1: |
| write_sysreg_el1(val, SYS_TCR); |
| break; |
| case SYS_ESR_EL1: |
| write_sysreg_el1(val, SYS_ESR); |
| break; |
| case SYS_FAR_EL1: |
| write_sysreg_el1(val, SYS_FAR); |
| break; |
| case SYS_AFSR0_EL1: |
| write_sysreg_el1(val, SYS_AFSR0); |
| break; |
| case SYS_AFSR1_EL1: |
| write_sysreg_el1(val, SYS_AFSR1); |
| break; |
| case SYS_MAIR_EL1: |
| write_sysreg_el1(val, SYS_MAIR); |
| break; |
| case SYS_AMAIR_EL1: |
| write_sysreg_el1(val, SYS_AMAIR); |
| break; |
| case SYS_CONTEXTIDR_EL1: |
| write_sysreg_el1(val, SYS_CONTEXTIDR); |
| break; |
| default: |
| return false; |
| } |
| |
| __kvm_skip_instr(vcpu); |
| return true; |
| } |
| |
| static inline bool esr_is_ptrauth_trap(u64 esr) |
| { |
| switch (esr_sys64_to_sysreg(esr)) { |
| case SYS_APIAKEYLO_EL1: |
| case SYS_APIAKEYHI_EL1: |
| case SYS_APIBKEYLO_EL1: |
| case SYS_APIBKEYHI_EL1: |
| case SYS_APDAKEYLO_EL1: |
| case SYS_APDAKEYHI_EL1: |
| case SYS_APDBKEYLO_EL1: |
| case SYS_APDBKEYHI_EL1: |
| case SYS_APGAKEYLO_EL1: |
| case SYS_APGAKEYHI_EL1: |
| return true; |
| } |
| |
| return false; |
| } |
| |
| #define __ptrauth_save_key(ctxt, key) \ |
| do { \ |
| u64 __val; \ |
| __val = read_sysreg_s(SYS_ ## key ## KEYLO_EL1); \ |
| ctxt_sys_reg(ctxt, key ## KEYLO_EL1) = __val; \ |
| __val = read_sysreg_s(SYS_ ## key ## KEYHI_EL1); \ |
| ctxt_sys_reg(ctxt, key ## KEYHI_EL1) = __val; \ |
| } while(0) |
| |
| DECLARE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt); |
| |
| static bool kvm_hyp_handle_ptrauth(struct kvm_vcpu *vcpu, u64 *exit_code) |
| { |
| struct kvm_cpu_context *ctxt; |
| u64 val; |
| |
| if (!vcpu_has_ptrauth(vcpu)) |
| return false; |
| |
| ctxt = this_cpu_ptr(&kvm_hyp_ctxt); |
| __ptrauth_save_key(ctxt, APIA); |
| __ptrauth_save_key(ctxt, APIB); |
| __ptrauth_save_key(ctxt, APDA); |
| __ptrauth_save_key(ctxt, APDB); |
| __ptrauth_save_key(ctxt, APGA); |
| |
| vcpu_ptrauth_enable(vcpu); |
| |
| val = read_sysreg(hcr_el2); |
| val |= (HCR_API | HCR_APK); |
| write_sysreg(val, hcr_el2); |
| |
| return true; |
| } |
| |
| static bool kvm_hyp_handle_sysreg(struct kvm_vcpu *vcpu, u64 *exit_code) |
| { |
| if (cpus_have_final_cap(ARM64_WORKAROUND_CAVIUM_TX2_219_TVM) && |
| handle_tx2_tvm(vcpu)) |
| return true; |
| |
| if (static_branch_unlikely(&vgic_v3_cpuif_trap) && |
| __vgic_v3_perform_cpuif_access(vcpu) == 1) |
| return true; |
| |
| if (esr_is_ptrauth_trap(kvm_vcpu_get_esr(vcpu))) |
| return kvm_hyp_handle_ptrauth(vcpu, exit_code); |
| |
| return false; |
| } |
| |
| static bool kvm_hyp_handle_cp15_32(struct kvm_vcpu *vcpu, u64 *exit_code) |
| { |
| if (static_branch_unlikely(&vgic_v3_cpuif_trap) && |
| __vgic_v3_perform_cpuif_access(vcpu) == 1) |
| return true; |
| |
| return false; |
| } |
| |
| static bool kvm_hyp_handle_iabt_low(struct kvm_vcpu *vcpu, u64 *exit_code) |
| { |
| if (!__populate_fault_info(vcpu)) |
| return true; |
| |
| return false; |
| } |
| |
| static bool kvm_hyp_handle_dabt_low(struct kvm_vcpu *vcpu, u64 *exit_code) |
| { |
| if (!__populate_fault_info(vcpu)) |
| return true; |
| |
| if (static_branch_unlikely(&vgic_v2_cpuif_trap)) { |
| bool valid; |
| |
| valid = kvm_vcpu_trap_get_fault_type(vcpu) == FSC_FAULT && |
| kvm_vcpu_dabt_isvalid(vcpu) && |
| !kvm_vcpu_abt_issea(vcpu) && |
| !kvm_vcpu_abt_iss1tw(vcpu); |
| |
| if (valid) { |
| int ret = __vgic_v2_perform_cpuif_access(vcpu); |
| |
| if (ret == 1) |
| return true; |
| |
| /* Promote an illegal access to an SError.*/ |
| if (ret == -1) |
| *exit_code = ARM_EXCEPTION_EL1_SERROR; |
| } |
| } |
| |
| return false; |
| } |
| |
| typedef bool (*exit_handler_fn)(struct kvm_vcpu *, u64 *); |
| |
| static const exit_handler_fn *kvm_get_exit_handler_array(struct kvm_vcpu *vcpu); |
| |
| static void early_exit_filter(struct kvm_vcpu *vcpu, u64 *exit_code); |
| |
| /* |
| * Allow the hypervisor to handle the exit with an exit handler if it has one. |
| * |
| * Returns true if the hypervisor handled the exit, and control should go back |
| * to the guest, or false if it hasn't. |
| */ |
| static inline bool kvm_hyp_handle_exit(struct kvm_vcpu *vcpu, u64 *exit_code) |
| { |
| const exit_handler_fn *handlers = kvm_get_exit_handler_array(vcpu); |
| exit_handler_fn fn; |
| |
| fn = handlers[kvm_vcpu_trap_get_class(vcpu)]; |
| |
| if (fn) |
| return fn(vcpu, exit_code); |
| |
| return false; |
| } |
| |
| static inline void synchronize_vcpu_pstate(struct kvm_vcpu *vcpu, u64 *exit_code) |
| { |
| /* |
| * Check for the conditions of Cortex-A510's #2077057. When these occur |
| * SPSR_EL2 can't be trusted, but isn't needed either as it is |
| * unchanged from the value in vcpu_gp_regs(vcpu)->pstate. |
| * Are we single-stepping the guest, and took a PAC exception from the |
| * active-not-pending state? |
| */ |
| if (cpus_have_final_cap(ARM64_WORKAROUND_2077057) && |
| vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP && |
| *vcpu_cpsr(vcpu) & DBG_SPSR_SS && |
| ESR_ELx_EC(read_sysreg_el2(SYS_ESR)) == ESR_ELx_EC_PAC) |
| write_sysreg_el2(*vcpu_cpsr(vcpu), SYS_SPSR); |
| |
| vcpu->arch.ctxt.regs.pstate = read_sysreg_el2(SYS_SPSR); |
| } |
| |
| /* |
| * Return true when we were able to fixup the guest exit and should return to |
| * the guest, false when we should restore the host state and return to the |
| * main run loop. |
| */ |
| static inline bool fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code) |
| { |
| /* |
| * Save PSTATE early so that we can evaluate the vcpu mode |
| * early on. |
| */ |
| synchronize_vcpu_pstate(vcpu, exit_code); |
| |
| /* |
| * Check whether we want to repaint the state one way or |
| * another. |
| */ |
| early_exit_filter(vcpu, exit_code); |
| |
| if (ARM_EXCEPTION_CODE(*exit_code) != ARM_EXCEPTION_IRQ) |
| vcpu->arch.fault.esr_el2 = read_sysreg_el2(SYS_ESR); |
| |
| if (ARM_SERROR_PENDING(*exit_code) && |
| ARM_EXCEPTION_CODE(*exit_code) != ARM_EXCEPTION_IRQ) { |
| u8 esr_ec = kvm_vcpu_trap_get_class(vcpu); |
| |
| /* |
| * HVC already have an adjusted PC, which we need to |
| * correct in order to return to after having injected |
| * the SError. |
| * |
| * SMC, on the other hand, is *trapped*, meaning its |
| * preferred return address is the SMC itself. |
| */ |
| if (esr_ec == ESR_ELx_EC_HVC32 || esr_ec == ESR_ELx_EC_HVC64) |
| write_sysreg_el2(read_sysreg_el2(SYS_ELR) - 4, SYS_ELR); |
| } |
| |
| /* |
| * We're using the raw exception code in order to only process |
| * the trap if no SError is pending. We will come back to the |
| * same PC once the SError has been injected, and replay the |
| * trapping instruction. |
| */ |
| if (*exit_code != ARM_EXCEPTION_TRAP) |
| goto exit; |
| |
| /* Check if there's an exit handler and allow it to handle the exit. */ |
| if (kvm_hyp_handle_exit(vcpu, exit_code)) |
| goto guest; |
| exit: |
| /* Return to the host kernel and handle the exit */ |
| return false; |
| |
| guest: |
| /* Re-enter the guest */ |
| asm(ALTERNATIVE("nop", "dmb sy", ARM64_WORKAROUND_1508412)); |
| return true; |
| } |
| |
| static inline void __kvm_unexpected_el2_exception(void) |
| { |
| extern char __guest_exit_panic[]; |
| unsigned long addr, fixup; |
| struct kvm_exception_table_entry *entry, *end; |
| unsigned long elr_el2 = read_sysreg(elr_el2); |
| |
| entry = &__start___kvm_ex_table; |
| end = &__stop___kvm_ex_table; |
| |
| while (entry < end) { |
| addr = (unsigned long)&entry->insn + entry->insn; |
| fixup = (unsigned long)&entry->fixup + entry->fixup; |
| |
| if (addr != elr_el2) { |
| entry++; |
| continue; |
| } |
| |
| write_sysreg(fixup, elr_el2); |
| return; |
| } |
| |
| /* Trigger a panic after restoring the hyp context. */ |
| write_sysreg(__guest_exit_panic, elr_el2); |
| } |
| |
| #endif /* __ARM64_KVM_HYP_SWITCH_H__ */ |