diff options
Diffstat (limited to 'arch/arm64/kvm/hyp/include/hyp/switch.h')
| -rw-r--r-- | arch/arm64/kvm/hyp/include/hyp/switch.h | 781 |
1 files changed, 781 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h new file mode 100644 index 000000000000..e3fcf8c4d5b4 --- /dev/null +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -0,0 +1,781 @@ +// 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/kvm_nested.h> +#include <asm/fpsimd.h> +#include <asm/debug-monitors.h> +#include <asm/processor.h> +#include <asm/traps.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 are owned by the guest */ +static inline bool guest_owns_fp_regs(struct kvm_vcpu *vcpu) +{ + return vcpu->arch.fp_state == FP_STATE_GUEST_OWNED; +} + +/* 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(); + } +} + +#define compute_clr_set(vcpu, reg, clr, set) \ + do { \ + u64 hfg; \ + hfg = __vcpu_sys_reg(vcpu, reg) & ~__ ## reg ## _RES0; \ + set |= hfg & __ ## reg ## _MASK; \ + clr |= ~hfg & __ ## reg ## _nMASK; \ + } while(0) + +#define reg_to_fgt_group_id(reg) \ + ({ \ + enum fgt_group_id id; \ + switch(reg) { \ + case HFGRTR_EL2: \ + case HFGWTR_EL2: \ + id = HFGxTR_GROUP; \ + break; \ + case HFGITR_EL2: \ + id = HFGITR_GROUP; \ + break; \ + case HDFGRTR_EL2: \ + case HDFGWTR_EL2: \ + id = HDFGRTR_GROUP; \ + break; \ + case HAFGRTR_EL2: \ + id = HAFGRTR_GROUP; \ + break; \ + default: \ + BUILD_BUG_ON(1); \ + } \ + \ + id; \ + }) + +#define compute_undef_clr_set(vcpu, kvm, reg, clr, set) \ + do { \ + u64 hfg = kvm->arch.fgu[reg_to_fgt_group_id(reg)]; \ + set |= hfg & __ ## reg ## _MASK; \ + clr |= hfg & __ ## reg ## _nMASK; \ + } while(0) + +#define update_fgt_traps_cs(hctxt, vcpu, kvm, reg, clr, set) \ + do { \ + u64 c = 0, s = 0; \ + \ + ctxt_sys_reg(hctxt, reg) = read_sysreg_s(SYS_ ## reg); \ + if (vcpu_has_nv(vcpu) && !is_hyp_ctxt(vcpu)) \ + compute_clr_set(vcpu, reg, c, s); \ + \ + compute_undef_clr_set(vcpu, kvm, reg, c, s); \ + \ + s |= set; \ + c |= clr; \ + if (c || s) { \ + u64 val = __ ## reg ## _nMASK; \ + val |= s; \ + val &= ~c; \ + write_sysreg_s(val, SYS_ ## reg); \ + } \ + } while(0) + +#define update_fgt_traps(hctxt, vcpu, kvm, reg) \ + update_fgt_traps_cs(hctxt, vcpu, kvm, reg, 0, 0) + +/* + * Validate the fine grain trap masks. + * Check that the masks do not overlap and that all bits are accounted for. + */ +#define CHECK_FGT_MASKS(reg) \ + do { \ + BUILD_BUG_ON((__ ## reg ## _MASK) & (__ ## reg ## _nMASK)); \ + BUILD_BUG_ON(~((__ ## reg ## _RES0) ^ (__ ## reg ## _MASK) ^ \ + (__ ## reg ## _nMASK))); \ + } while(0) + +static inline bool cpu_has_amu(void) +{ + u64 pfr0 = read_sysreg_s(SYS_ID_AA64PFR0_EL1); + + return cpuid_feature_extract_unsigned_field(pfr0, + ID_AA64PFR0_EL1_AMU_SHIFT); +} + +static inline void __activate_traps_hfgxtr(struct kvm_vcpu *vcpu) +{ + struct kvm_cpu_context *hctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt; + struct kvm *kvm = kern_hyp_va(vcpu->kvm); + + CHECK_FGT_MASKS(HFGRTR_EL2); + CHECK_FGT_MASKS(HFGWTR_EL2); + CHECK_FGT_MASKS(HFGITR_EL2); + CHECK_FGT_MASKS(HDFGRTR_EL2); + CHECK_FGT_MASKS(HDFGWTR_EL2); + CHECK_FGT_MASKS(HAFGRTR_EL2); + CHECK_FGT_MASKS(HCRX_EL2); + + if (!cpus_have_final_cap(ARM64_HAS_FGT)) + return; + + update_fgt_traps(hctxt, vcpu, kvm, HFGRTR_EL2); + update_fgt_traps_cs(hctxt, vcpu, kvm, HFGWTR_EL2, 0, + cpus_have_final_cap(ARM64_WORKAROUND_AMPERE_AC03_CPU_38) ? + HFGxTR_EL2_TCR_EL1_MASK : 0); + update_fgt_traps(hctxt, vcpu, kvm, HFGITR_EL2); + update_fgt_traps(hctxt, vcpu, kvm, HDFGRTR_EL2); + update_fgt_traps(hctxt, vcpu, kvm, HDFGWTR_EL2); + + if (cpu_has_amu()) + update_fgt_traps(hctxt, vcpu, kvm, HAFGRTR_EL2); +} + +#define __deactivate_fgt(htcxt, vcpu, kvm, reg) \ + do { \ + if ((vcpu_has_nv(vcpu) && !is_hyp_ctxt(vcpu)) || \ + kvm->arch.fgu[reg_to_fgt_group_id(reg)]) \ + write_sysreg_s(ctxt_sys_reg(hctxt, reg), \ + SYS_ ## reg); \ + } while(0) + +static inline void __deactivate_traps_hfgxtr(struct kvm_vcpu *vcpu) +{ + struct kvm_cpu_context *hctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt; + struct kvm *kvm = kern_hyp_va(vcpu->kvm); + + if (!cpus_have_final_cap(ARM64_HAS_FGT)) + return; + + __deactivate_fgt(hctxt, vcpu, kvm, HFGRTR_EL2); + if (cpus_have_final_cap(ARM64_WORKAROUND_AMPERE_AC03_CPU_38)) + write_sysreg_s(ctxt_sys_reg(hctxt, HFGWTR_EL2), SYS_HFGWTR_EL2); + else + __deactivate_fgt(hctxt, vcpu, kvm, HFGWTR_EL2); + __deactivate_fgt(hctxt, vcpu, kvm, HFGITR_EL2); + __deactivate_fgt(hctxt, vcpu, kvm, HDFGRTR_EL2); + __deactivate_fgt(hctxt, vcpu, kvm, HDFGWTR_EL2); + + if (cpu_has_amu()) + __deactivate_fgt(hctxt, vcpu, kvm, HAFGRTR_EL2); +} + +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()) { + struct kvm_cpu_context *hctxt; + + write_sysreg(0, pmselr_el0); + + hctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt; + ctxt_sys_reg(hctxt, PMUSERENR_EL0) = read_sysreg(pmuserenr_el0); + write_sysreg(ARMV8_PMU_USERENR_MASK, pmuserenr_el0); + vcpu_set_flag(vcpu, PMUSERENR_ON_CPU); + } + + vcpu->arch.mdcr_el2_host = read_sysreg(mdcr_el2); + write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2); + + if (cpus_have_final_cap(ARM64_HAS_HCX)) { + u64 hcrx = vcpu->arch.hcrx_el2; + if (vcpu_has_nv(vcpu) && !is_hyp_ctxt(vcpu)) { + u64 clr = 0, set = 0; + + compute_clr_set(vcpu, HCRX_EL2, clr, set); + + hcrx |= set; + hcrx &= ~clr; + } + + write_sysreg_s(hcrx, SYS_HCRX_EL2); + } + + __activate_traps_hfgxtr(vcpu); +} + +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()) { + struct kvm_cpu_context *hctxt; + + hctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt; + write_sysreg(ctxt_sys_reg(hctxt, PMUSERENR_EL0), pmuserenr_el0); + vcpu_clear_flag(vcpu, PMUSERENR_ON_CPU); + } + + if (cpus_have_final_cap(ARM64_HAS_HCX)) + write_sysreg_s(HCRX_HOST_FLAGS, SYS_HCRX_EL2); + + __deactivate_traps_hfgxtr(vcpu); +} + +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 bool kvm_hyp_handle_mops(struct kvm_vcpu *vcpu, u64 *exit_code) +{ + *vcpu_pc(vcpu) = read_sysreg_el2(SYS_ELR); + arm64_mops_reset_regs(vcpu_gp_regs(vcpu), vcpu->arch.fault.esr_el2); + write_sysreg_el2(*vcpu_pc(vcpu), SYS_ELR); + + /* + * Finish potential single step before executing the prologue + * instruction. + */ + *vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS; + write_sysreg_el2(*vcpu_cpsr(vcpu), SYS_SPSR); + + return true; +} + +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); + + /* Only handle traps the vCPU can support here: */ + switch (esr_ec) { + case ESR_ELx_EC_FP_ASIMD: + break; + case ESR_ELx_EC_SVE: + if (!sve_guest) + return false; + break; + default: + return false; + } + + /* Valid trap. Switch the context: */ + + /* First disable enough traps to allow us to update the registers */ + if (has_vhe() || has_hvhe()) { + 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.fp_state == FP_STATE_HOST_OWNED) + __fpsimd_save_state(vcpu->arch.host_fpsimd_state); + + /* 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.fp_state = FP_STATE_GUEST_OWNED; + + 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_cntpct(struct kvm_vcpu *vcpu) +{ + struct arch_timer_context *ctxt; + u32 sysreg; + u64 val; + + /* + * We only get here for 64bit guests, 32bit guests will hit + * the long and winding road all the way to the standard + * handling. Yes, it sucks to be irrelevant. + */ + sysreg = esr_sys64_to_sysreg(kvm_vcpu_get_esr(vcpu)); + + switch (sysreg) { + case SYS_CNTPCT_EL0: + case SYS_CNTPCTSS_EL0: + if (vcpu_has_nv(vcpu)) { + if (is_hyp_ctxt(vcpu)) { + ctxt = vcpu_hptimer(vcpu); + break; + } + + /* Check for guest hypervisor trapping */ + val = __vcpu_sys_reg(vcpu, CNTHCTL_EL2); + if (!vcpu_el2_e2h_is_set(vcpu)) + val = (val & CNTHCTL_EL1PCTEN) << 10; + + if (!(val & (CNTHCTL_EL1PCTEN << 10))) + return false; + } + + ctxt = vcpu_ptimer(vcpu); + break; + default: + return false; + } + + val = arch_timer_read_cntpct_el0(); + + if (ctxt->offset.vm_offset) + val -= *kern_hyp_va(ctxt->offset.vm_offset); + if (ctxt->offset.vcpu_offset) + val -= *kern_hyp_va(ctxt->offset.vcpu_offset); + + vcpu_set_reg(vcpu, kvm_vcpu_sys_get_rt(vcpu), val); + __kvm_skip_instr(vcpu); + return true; +} + +static bool handle_ampere1_tcr(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); + + if (sysreg != SYS_TCR_EL1) + return false; + + /* + * Affected parts do not advertise support for hardware Access Flag / + * Dirty state management in ID_AA64MMFR1_EL1.HAFDBS, but the underlying + * control bits are still functional. The architecture requires these be + * RES0 on systems that do not implement FEAT_HAFDBS. + * + * Uphold the requirements of the architecture by masking guest writes + * to TCR_EL1.{HA,HD} here. + */ + val &= ~(TCR_HD | TCR_HA); + write_sysreg_el1(val, SYS_TCR); + __kvm_skip_instr(vcpu); + 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 (cpus_have_final_cap(ARM64_WORKAROUND_AMPERE_AC03_CPU_38) && + handle_ampere1_tcr(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); + + if (kvm_hyp_handle_cntpct(vcpu)) + return true; + + 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_memory_fault(struct kvm_vcpu *vcpu, u64 *exit_code) +{ + if (!__populate_fault_info(vcpu)) + return true; + + return false; +} +static bool kvm_hyp_handle_iabt_low(struct kvm_vcpu *vcpu, u64 *exit_code) + __alias(kvm_hyp_handle_memory_fault); +static bool kvm_hyp_handle_watchpt_low(struct kvm_vcpu *vcpu, u64 *exit_code) + __alias(kvm_hyp_handle_memory_fault); + +static bool kvm_hyp_handle_dabt_low(struct kvm_vcpu *vcpu, u64 *exit_code) +{ + if (kvm_hyp_handle_memory_fault(vcpu, exit_code)) + return true; + + if (static_branch_unlikely(&vgic_v2_cpuif_trap)) { + bool valid; + + valid = kvm_vcpu_trap_is_translation_fault(vcpu) && + 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__ */ |