From: Marc Zyngier Date: Thu, 30 Jul 2020 15:13:04 +0000 (+0100) Subject: Merge branch 'kvm-arm64/misc-5.9' into kvmarm-master/next X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=16314874b12b451bd5a1df86bcb69745eb487502;p=linux.git Merge branch 'kvm-arm64/misc-5.9' into kvmarm-master/next Signed-off-by: Marc Zyngier --- 16314874b12b451bd5a1df86bcb69745eb487502 diff --cc arch/arm64/kvm/hyp/include/hyp/switch.h index 0511af14dc815,0000000000000..426ef65601dd9 mode 100644,000000..100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@@ -1,511 -1,0 +1,511 @@@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2015 - ARM Ltd + * Author: Marc Zyngier + */ + +#ifndef __ARM64_KVM_HYP_SWITCH_H__ +#define __ARM64_KVM_HYP_SWITCH_H__ + +#include +#include +#include +#include +#include + +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +extern const char __hyp_panic_string[]; + +/* 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.host_thread_info->flags & _TIF_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. + */ + write_sysreg(0, pmselr_el0); + write_sysreg(ARMV8_PMU_USERENR_MASK, pmuserenr_el0); + write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2); +} + +static inline void __deactivate_traps_common(void) +{ + write_sysreg(0, hstr_el2); + 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 void __activate_vm(struct kvm_s2_mmu *mmu) +{ + __load_guest_stage2(mmu); +} + +static inline bool __translate_far_to_hpfar(u64 far, u64 *hpfar) +{ + u64 par, tmp; + + /* + * Resolve the IPA the hard way using the guest VA. + * + * Stage-1 translation already validated the memory access + * rights. As such, we can use the EL1 translation regime, and + * don't have to distinguish between EL0 and EL1 access. + * + * We do need to save/restore PAR_EL1 though, as we haven't + * saved the guest context yet, and we may return early... + */ + par = read_sysreg(par_el1); + asm volatile("at s1e1r, %0" : : "r" (far)); + isb(); + + tmp = read_sysreg(par_el1); + write_sysreg(par, par_el1); + + if (unlikely(tmp & SYS_PAR_EL1_F)) + return false; /* Translation failed, back to guest */ + + /* Convert PAR to HPFAR format */ + *hpfar = PAR_TO_HPFAR(tmp); + return true; +} + +static inline bool __populate_fault_info(struct kvm_vcpu *vcpu) +{ + u8 ec; + u64 esr; + u64 hpfar, far; + + esr = vcpu->arch.fault.esr_el2; + ec = ESR_ELx_EC(esr); + + if (ec != ESR_ELx_EC_DABT_LOW && ec != ESR_ELx_EC_IABT_LOW) + return true; + + far = read_sysreg_el2(SYS_FAR); + + /* + * The HPFAR can be invalid if the stage 2 fault did not + * happen during a stage 1 page table walk (the ESR_EL2.S1PTW + * bit is clear) and one of the two following cases are true: + * 1. The fault was due to a permission fault + * 2. The processor carries errata 834220 + * + * Therefore, for all non S1PTW faults where we either have a + * permission fault or the errata workaround is enabled, we + * resolve the IPA using the AT instruction. + */ + if (!(esr & ESR_ELx_S1PTW) && + (cpus_have_final_cap(ARM64_WORKAROUND_834220) || + (esr & ESR_ELx_FSC_TYPE) == FSC_PERM)) { + if (!__translate_far_to_hpfar(far, &hpfar)) + return false; + } else { + hpfar = read_sysreg(hpfar_el2); + } + + vcpu->arch.fault.far_el2 = far; + vcpu->arch.fault.hpfar_el2 = hpfar; + return true; +} + +/* Check for an FPSIMD/SVE trap and handle as appropriate */ +static inline bool __hyp_handle_fpsimd(struct kvm_vcpu *vcpu) +{ + bool vhe, sve_guest, sve_host; + u8 esr_ec; + + if (!system_supports_fpsimd()) + return false; + + /* + * Currently system_supports_sve() currently implies has_vhe(), + * so the check is redundant. However, has_vhe() can be determined + * statically and helps the compiler remove dead code. + */ + if (has_vhe() && system_supports_sve()) { + sve_guest = vcpu_has_sve(vcpu); + sve_host = vcpu->arch.flags & KVM_ARM64_HOST_SVE_IN_USE; + vhe = true; + } else { + sve_guest = false; + sve_host = false; + vhe = has_vhe(); + } + + esr_ec = kvm_vcpu_trap_get_class(vcpu); + if (esr_ec != ESR_ELx_EC_FP_ASIMD && + esr_ec != ESR_ELx_EC_SVE) + return false; + + /* Don't handle SVE traps for non-SVE vcpus here: */ + if (!sve_guest) + if (esr_ec != ESR_ELx_EC_FP_ASIMD) + return false; + + /* Valid trap. Switch the context: */ + + if (vhe) { + u64 reg = read_sysreg(cpacr_el1) | CPACR_EL1_FPEN; + + if (sve_guest) + reg |= CPACR_EL1_ZEN; + + write_sysreg(reg, cpacr_el1); + } else { + write_sysreg(read_sysreg(cptr_el2) & ~(u64)CPTR_EL2_TFP, + cptr_el2); + } + + isb(); + + if (vcpu->arch.flags & KVM_ARM64_FP_HOST) { + /* + * In the SVE case, VHE is assumed: it is enforced by + * Kconfig and kvm_arch_init(). + */ + if (sve_host) { + struct thread_struct *thread = container_of( + vcpu->arch.host_fpsimd_state, + struct thread_struct, uw.fpsimd_state); + + sve_save_state(sve_pffr(thread), + &vcpu->arch.host_fpsimd_state->fpsr); + } else { + __fpsimd_save_state(vcpu->arch.host_fpsimd_state); + } + + vcpu->arch.flags &= ~KVM_ARM64_FP_HOST; + } + + if (sve_guest) { + sve_load_state(vcpu_sve_pffr(vcpu), + &vcpu->arch.ctxt.fp_regs.fpsr, + sve_vq_from_vl(vcpu->arch.sve_max_vl) - 1); + write_sysreg_s(__vcpu_sys_reg(vcpu, ZCR_EL1), SYS_ZCR_EL12); + } 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(u32 esr) +{ + u32 ec = ESR_ELx_EC(esr); + + if (ec == ESR_ELx_EC_PAC) + return true; + + if (ec != ESR_ELx_EC_SYS64) + return false; + + 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) + +static inline bool __hyp_handle_ptrauth(struct kvm_vcpu *vcpu) +{ + struct kvm_cpu_context *ctxt; + u64 val; + + if (!vcpu_has_ptrauth(vcpu) || + !esr_is_ptrauth_trap(kvm_vcpu_get_esr(vcpu))) + return false; + + ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_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; +} + +/* + * 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) +{ + if (ARM_EXCEPTION_CODE(*exit_code) != ARM_EXCEPTION_IRQ) + vcpu->arch.fault.esr_el2 = read_sysreg_el2(SYS_ESR); + + /* + * 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; + + if (cpus_have_final_cap(ARM64_WORKAROUND_CAVIUM_TX2_219_TVM) && + kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_SYS64 && + handle_tx2_tvm(vcpu)) + return true; + + /* + * 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. + */ + if (__hyp_handle_fpsimd(vcpu)) + return true; + + if (__hyp_handle_ptrauth(vcpu)) + return true; + + if (!__populate_fault_info(vcpu)) + return true; + + if (static_branch_unlikely(&vgic_v2_cpuif_trap)) { + bool valid; + + valid = kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_DABT_LOW && + kvm_vcpu_trap_get_fault_type(vcpu) == FSC_FAULT && + kvm_vcpu_dabt_isvalid(vcpu) && - !kvm_vcpu_dabt_isextabt(vcpu) && ++ !kvm_vcpu_abt_issea(vcpu) && + !kvm_vcpu_dabt_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; + + goto exit; + } + } + + if (static_branch_unlikely(&vgic_v3_cpuif_trap) && + (kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_SYS64 || + kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_CP15_32)) { + int ret = __vgic_v3_perform_cpuif_access(vcpu); + + if (ret == 1) + return true; + } + +exit: + /* Return to the host kernel and handle the exit */ + return false; +} + +static inline bool __needs_ssbd_off(struct kvm_vcpu *vcpu) +{ + if (!cpus_have_final_cap(ARM64_SSBD)) + return false; + + return !(vcpu->arch.workaround_flags & VCPU_WORKAROUND_2_FLAG); +} + +static inline void __set_guest_arch_workaround_state(struct kvm_vcpu *vcpu) +{ +#ifdef CONFIG_ARM64_SSBD + /* + * The host runs with the workaround always present. If the + * guest wants it disabled, so be it... + */ + if (__needs_ssbd_off(vcpu) && + __hyp_this_cpu_read(arm64_ssbd_callback_required)) + arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_2, 0, NULL); +#endif +} + +static inline void __set_host_arch_workaround_state(struct kvm_vcpu *vcpu) +{ +#ifdef CONFIG_ARM64_SSBD + /* + * If the guest has disabled the workaround, bring it back on. + */ + if (__needs_ssbd_off(vcpu) && + __hyp_this_cpu_read(arm64_ssbd_callback_required)) + arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_2, 1, NULL); +#endif +} + +#endif /* __ARM64_KVM_HYP_SWITCH_H__ */