diff options
Diffstat (limited to 'arch/arm64/kvm/hyp/nvhe/sys_regs.c')
| -rw-r--r-- | arch/arm64/kvm/hyp/nvhe/sys_regs.c | 516 |
1 files changed, 516 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/nvhe/sys_regs.c b/arch/arm64/kvm/hyp/nvhe/sys_regs.c new file mode 100644 index 000000000000..edd969a1f36b --- /dev/null +++ b/arch/arm64/kvm/hyp/nvhe/sys_regs.c @@ -0,0 +1,516 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2021 Google LLC + * Author: Fuad Tabba <tabba@google.com> + */ + +#include <linux/irqchip/arm-gic-v3.h> + +#include <asm/kvm_asm.h> +#include <asm/kvm_mmu.h> + +#include <hyp/adjust_pc.h> + +#include <nvhe/fixed_config.h> + +#include "../../sys_regs.h" + +/* + * Copies of the host's CPU features registers holding sanitized values at hyp. + */ +u64 id_aa64pfr0_el1_sys_val; +u64 id_aa64pfr1_el1_sys_val; +u64 id_aa64isar0_el1_sys_val; +u64 id_aa64isar1_el1_sys_val; +u64 id_aa64isar2_el1_sys_val; +u64 id_aa64mmfr0_el1_sys_val; +u64 id_aa64mmfr1_el1_sys_val; +u64 id_aa64mmfr2_el1_sys_val; +u64 id_aa64smfr0_el1_sys_val; + +/* + * Inject an unknown/undefined exception to an AArch64 guest while most of its + * sysregs are live. + */ +static void inject_undef64(struct kvm_vcpu *vcpu) +{ + u64 esr = (ESR_ELx_EC_UNKNOWN << ESR_ELx_EC_SHIFT); + + *vcpu_pc(vcpu) = read_sysreg_el2(SYS_ELR); + *vcpu_cpsr(vcpu) = read_sysreg_el2(SYS_SPSR); + + kvm_pend_exception(vcpu, EXCEPT_AA64_EL1_SYNC); + + __kvm_adjust_pc(vcpu); + + write_sysreg_el1(esr, SYS_ESR); + write_sysreg_el1(read_sysreg_el2(SYS_ELR), SYS_ELR); + write_sysreg_el2(*vcpu_pc(vcpu), SYS_ELR); + write_sysreg_el2(*vcpu_cpsr(vcpu), SYS_SPSR); +} + +/* + * Returns the restricted features values of the feature register based on the + * limitations in restrict_fields. + * A feature id field value of 0b0000 does not impose any restrictions. + * Note: Use only for unsigned feature field values. + */ +static u64 get_restricted_features_unsigned(u64 sys_reg_val, + u64 restrict_fields) +{ + u64 value = 0UL; + u64 mask = GENMASK_ULL(ARM64_FEATURE_FIELD_BITS - 1, 0); + + /* + * According to the Arm Architecture Reference Manual, feature fields + * use increasing values to indicate increases in functionality. + * Iterate over the restricted feature fields and calculate the minimum + * unsigned value between the one supported by the system, and what the + * value is being restricted to. + */ + while (sys_reg_val && restrict_fields) { + value |= min(sys_reg_val & mask, restrict_fields & mask); + sys_reg_val &= ~mask; + restrict_fields &= ~mask; + mask <<= ARM64_FEATURE_FIELD_BITS; + } + + return value; +} + +/* + * Functions that return the value of feature id registers for protected VMs + * based on allowed features, system features, and KVM support. + */ + +static u64 get_pvm_id_aa64pfr0(const struct kvm_vcpu *vcpu) +{ + u64 set_mask = 0; + u64 allow_mask = PVM_ID_AA64PFR0_ALLOW; + + set_mask |= get_restricted_features_unsigned(id_aa64pfr0_el1_sys_val, + PVM_ID_AA64PFR0_RESTRICT_UNSIGNED); + + return (id_aa64pfr0_el1_sys_val & allow_mask) | set_mask; +} + +static u64 get_pvm_id_aa64pfr1(const struct kvm_vcpu *vcpu) +{ + const struct kvm *kvm = (const struct kvm *)kern_hyp_va(vcpu->kvm); + u64 allow_mask = PVM_ID_AA64PFR1_ALLOW; + + if (!kvm_has_mte(kvm)) + allow_mask &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_EL1_MTE); + + return id_aa64pfr1_el1_sys_val & allow_mask; +} + +static u64 get_pvm_id_aa64zfr0(const struct kvm_vcpu *vcpu) +{ + /* + * No support for Scalable Vectors, therefore, hyp has no sanitized + * copy of the feature id register. + */ + BUILD_BUG_ON(PVM_ID_AA64ZFR0_ALLOW != 0ULL); + return 0; +} + +static u64 get_pvm_id_aa64dfr0(const struct kvm_vcpu *vcpu) +{ + /* + * No support for debug, including breakpoints, and watchpoints, + * therefore, pKVM has no sanitized copy of the feature id register. + */ + BUILD_BUG_ON(PVM_ID_AA64DFR0_ALLOW != 0ULL); + return 0; +} + +static u64 get_pvm_id_aa64dfr1(const struct kvm_vcpu *vcpu) +{ + /* + * No support for debug, therefore, hyp has no sanitized copy of the + * feature id register. + */ + BUILD_BUG_ON(PVM_ID_AA64DFR1_ALLOW != 0ULL); + return 0; +} + +static u64 get_pvm_id_aa64afr0(const struct kvm_vcpu *vcpu) +{ + /* + * No support for implementation defined features, therefore, hyp has no + * sanitized copy of the feature id register. + */ + BUILD_BUG_ON(PVM_ID_AA64AFR0_ALLOW != 0ULL); + return 0; +} + +static u64 get_pvm_id_aa64afr1(const struct kvm_vcpu *vcpu) +{ + /* + * No support for implementation defined features, therefore, hyp has no + * sanitized copy of the feature id register. + */ + BUILD_BUG_ON(PVM_ID_AA64AFR1_ALLOW != 0ULL); + return 0; +} + +static u64 get_pvm_id_aa64isar0(const struct kvm_vcpu *vcpu) +{ + return id_aa64isar0_el1_sys_val & PVM_ID_AA64ISAR0_ALLOW; +} + +static u64 get_pvm_id_aa64isar1(const struct kvm_vcpu *vcpu) +{ + u64 allow_mask = PVM_ID_AA64ISAR1_ALLOW; + + if (!vcpu_has_ptrauth(vcpu)) + allow_mask &= ~(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_APA) | + ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_API) | + ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_GPA) | + ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_GPI)); + + return id_aa64isar1_el1_sys_val & allow_mask; +} + +static u64 get_pvm_id_aa64isar2(const struct kvm_vcpu *vcpu) +{ + u64 allow_mask = PVM_ID_AA64ISAR2_ALLOW; + + if (!vcpu_has_ptrauth(vcpu)) + allow_mask &= ~(ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_APA3) | + ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_GPA3)); + + return id_aa64isar2_el1_sys_val & allow_mask; +} + +static u64 get_pvm_id_aa64mmfr0(const struct kvm_vcpu *vcpu) +{ + u64 set_mask; + + set_mask = get_restricted_features_unsigned(id_aa64mmfr0_el1_sys_val, + PVM_ID_AA64MMFR0_RESTRICT_UNSIGNED); + + return (id_aa64mmfr0_el1_sys_val & PVM_ID_AA64MMFR0_ALLOW) | set_mask; +} + +static u64 get_pvm_id_aa64mmfr1(const struct kvm_vcpu *vcpu) +{ + return id_aa64mmfr1_el1_sys_val & PVM_ID_AA64MMFR1_ALLOW; +} + +static u64 get_pvm_id_aa64mmfr2(const struct kvm_vcpu *vcpu) +{ + return id_aa64mmfr2_el1_sys_val & PVM_ID_AA64MMFR2_ALLOW; +} + +/* Read a sanitized cpufeature ID register by its encoding */ +u64 pvm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id) +{ + switch (id) { + case SYS_ID_AA64PFR0_EL1: + return get_pvm_id_aa64pfr0(vcpu); + case SYS_ID_AA64PFR1_EL1: + return get_pvm_id_aa64pfr1(vcpu); + case SYS_ID_AA64ZFR0_EL1: + return get_pvm_id_aa64zfr0(vcpu); + case SYS_ID_AA64DFR0_EL1: + return get_pvm_id_aa64dfr0(vcpu); + case SYS_ID_AA64DFR1_EL1: + return get_pvm_id_aa64dfr1(vcpu); + case SYS_ID_AA64AFR0_EL1: + return get_pvm_id_aa64afr0(vcpu); + case SYS_ID_AA64AFR1_EL1: + return get_pvm_id_aa64afr1(vcpu); + case SYS_ID_AA64ISAR0_EL1: + return get_pvm_id_aa64isar0(vcpu); + case SYS_ID_AA64ISAR1_EL1: + return get_pvm_id_aa64isar1(vcpu); + case SYS_ID_AA64ISAR2_EL1: + return get_pvm_id_aa64isar2(vcpu); + case SYS_ID_AA64MMFR0_EL1: + return get_pvm_id_aa64mmfr0(vcpu); + case SYS_ID_AA64MMFR1_EL1: + return get_pvm_id_aa64mmfr1(vcpu); + case SYS_ID_AA64MMFR2_EL1: + return get_pvm_id_aa64mmfr2(vcpu); + default: + /* Unhandled ID register, RAZ */ + return 0; + } +} + +static u64 read_id_reg(const struct kvm_vcpu *vcpu, + struct sys_reg_desc const *r) +{ + return pvm_read_id_reg(vcpu, reg_to_encoding(r)); +} + +/* Handler to RAZ/WI sysregs */ +static bool pvm_access_raz_wi(struct kvm_vcpu *vcpu, struct sys_reg_params *p, + const struct sys_reg_desc *r) +{ + if (!p->is_write) + p->regval = 0; + + return true; +} + +/* + * Accessor for AArch32 feature id registers. + * + * The value of these registers is "unknown" according to the spec if AArch32 + * isn't supported. + */ +static bool pvm_access_id_aarch32(struct kvm_vcpu *vcpu, + struct sys_reg_params *p, + const struct sys_reg_desc *r) +{ + if (p->is_write) { + inject_undef64(vcpu); + return false; + } + + /* + * No support for AArch32 guests, therefore, pKVM has no sanitized copy + * of AArch32 feature id registers. + */ + BUILD_BUG_ON(FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_EL1), + PVM_ID_AA64PFR0_RESTRICT_UNSIGNED) > ID_AA64PFR0_EL1_ELx_64BIT_ONLY); + + return pvm_access_raz_wi(vcpu, p, r); +} + +/* + * Accessor for AArch64 feature id registers. + * + * If access is allowed, set the regval to the protected VM's view of the + * register and return true. + * Otherwise, inject an undefined exception and return false. + */ +static bool pvm_access_id_aarch64(struct kvm_vcpu *vcpu, + struct sys_reg_params *p, + const struct sys_reg_desc *r) +{ + if (p->is_write) { + inject_undef64(vcpu); + return false; + } + + p->regval = read_id_reg(vcpu, r); + return true; +} + +static bool pvm_gic_read_sre(struct kvm_vcpu *vcpu, + struct sys_reg_params *p, + const struct sys_reg_desc *r) +{ + /* pVMs only support GICv3. 'nuf said. */ + if (!p->is_write) + p->regval = ICC_SRE_EL1_DIB | ICC_SRE_EL1_DFB | ICC_SRE_EL1_SRE; + + return true; +} + +/* Mark the specified system register as an AArch32 feature id register. */ +#define AARCH32(REG) { SYS_DESC(REG), .access = pvm_access_id_aarch32 } + +/* Mark the specified system register as an AArch64 feature id register. */ +#define AARCH64(REG) { SYS_DESC(REG), .access = pvm_access_id_aarch64 } + +/* + * sys_reg_desc initialiser for architecturally unallocated cpufeature ID + * register with encoding Op0=3, Op1=0, CRn=0, CRm=crm, Op2=op2 + * (1 <= crm < 8, 0 <= Op2 < 8). + */ +#define ID_UNALLOCATED(crm, op2) { \ + Op0(3), Op1(0), CRn(0), CRm(crm), Op2(op2), \ + .access = pvm_access_id_aarch64, \ +} + +/* Mark the specified system register as Read-As-Zero/Write-Ignored */ +#define RAZ_WI(REG) { SYS_DESC(REG), .access = pvm_access_raz_wi } + +/* Mark the specified system register as not being handled in hyp. */ +#define HOST_HANDLED(REG) { SYS_DESC(REG), .access = NULL } + +/* + * Architected system registers. + * Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2 + * + * NOTE: Anything not explicitly listed here is *restricted by default*, i.e., + * it will lead to injecting an exception into the guest. + */ +static const struct sys_reg_desc pvm_sys_reg_descs[] = { + /* Cache maintenance by set/way operations are restricted. */ + + /* Debug and Trace Registers are restricted. */ + + /* AArch64 mappings of the AArch32 ID registers */ + /* CRm=1 */ + AARCH32(SYS_ID_PFR0_EL1), + AARCH32(SYS_ID_PFR1_EL1), + AARCH32(SYS_ID_DFR0_EL1), + AARCH32(SYS_ID_AFR0_EL1), + AARCH32(SYS_ID_MMFR0_EL1), + AARCH32(SYS_ID_MMFR1_EL1), + AARCH32(SYS_ID_MMFR2_EL1), + AARCH32(SYS_ID_MMFR3_EL1), + + /* CRm=2 */ + AARCH32(SYS_ID_ISAR0_EL1), + AARCH32(SYS_ID_ISAR1_EL1), + AARCH32(SYS_ID_ISAR2_EL1), + AARCH32(SYS_ID_ISAR3_EL1), + AARCH32(SYS_ID_ISAR4_EL1), + AARCH32(SYS_ID_ISAR5_EL1), + AARCH32(SYS_ID_MMFR4_EL1), + AARCH32(SYS_ID_ISAR6_EL1), + + /* CRm=3 */ + AARCH32(SYS_MVFR0_EL1), + AARCH32(SYS_MVFR1_EL1), + AARCH32(SYS_MVFR2_EL1), + ID_UNALLOCATED(3,3), + AARCH32(SYS_ID_PFR2_EL1), + AARCH32(SYS_ID_DFR1_EL1), + AARCH32(SYS_ID_MMFR5_EL1), + ID_UNALLOCATED(3,7), + + /* AArch64 ID registers */ + /* CRm=4 */ + AARCH64(SYS_ID_AA64PFR0_EL1), + AARCH64(SYS_ID_AA64PFR1_EL1), + ID_UNALLOCATED(4,2), + ID_UNALLOCATED(4,3), + AARCH64(SYS_ID_AA64ZFR0_EL1), + ID_UNALLOCATED(4,5), + ID_UNALLOCATED(4,6), + ID_UNALLOCATED(4,7), + AARCH64(SYS_ID_AA64DFR0_EL1), + AARCH64(SYS_ID_AA64DFR1_EL1), + ID_UNALLOCATED(5,2), + ID_UNALLOCATED(5,3), + AARCH64(SYS_ID_AA64AFR0_EL1), + AARCH64(SYS_ID_AA64AFR1_EL1), + ID_UNALLOCATED(5,6), + ID_UNALLOCATED(5,7), + AARCH64(SYS_ID_AA64ISAR0_EL1), + AARCH64(SYS_ID_AA64ISAR1_EL1), + AARCH64(SYS_ID_AA64ISAR2_EL1), + ID_UNALLOCATED(6,3), + ID_UNALLOCATED(6,4), + ID_UNALLOCATED(6,5), + ID_UNALLOCATED(6,6), + ID_UNALLOCATED(6,7), + AARCH64(SYS_ID_AA64MMFR0_EL1), + AARCH64(SYS_ID_AA64MMFR1_EL1), + AARCH64(SYS_ID_AA64MMFR2_EL1), + ID_UNALLOCATED(7,3), + ID_UNALLOCATED(7,4), + ID_UNALLOCATED(7,5), + ID_UNALLOCATED(7,6), + ID_UNALLOCATED(7,7), + + /* Scalable Vector Registers are restricted. */ + + RAZ_WI(SYS_ERRIDR_EL1), + RAZ_WI(SYS_ERRSELR_EL1), + RAZ_WI(SYS_ERXFR_EL1), + RAZ_WI(SYS_ERXCTLR_EL1), + RAZ_WI(SYS_ERXSTATUS_EL1), + RAZ_WI(SYS_ERXADDR_EL1), + RAZ_WI(SYS_ERXMISC0_EL1), + RAZ_WI(SYS_ERXMISC1_EL1), + + /* Performance Monitoring Registers are restricted. */ + + /* Limited Ordering Regions Registers are restricted. */ + + HOST_HANDLED(SYS_ICC_SGI1R_EL1), + HOST_HANDLED(SYS_ICC_ASGI1R_EL1), + HOST_HANDLED(SYS_ICC_SGI0R_EL1), + { SYS_DESC(SYS_ICC_SRE_EL1), .access = pvm_gic_read_sre, }, + + HOST_HANDLED(SYS_CCSIDR_EL1), + HOST_HANDLED(SYS_CLIDR_EL1), + HOST_HANDLED(SYS_CSSELR_EL1), + HOST_HANDLED(SYS_CTR_EL0), + + /* Performance Monitoring Registers are restricted. */ + + /* Activity Monitoring Registers are restricted. */ + + HOST_HANDLED(SYS_CNTP_TVAL_EL0), + HOST_HANDLED(SYS_CNTP_CTL_EL0), + HOST_HANDLED(SYS_CNTP_CVAL_EL0), + + /* Performance Monitoring Registers are restricted. */ +}; + +/* + * Checks that the sysreg table is unique and in-order. + * + * Returns 0 if the table is consistent, or 1 otherwise. + */ +int kvm_check_pvm_sysreg_table(void) +{ + unsigned int i; + + for (i = 1; i < ARRAY_SIZE(pvm_sys_reg_descs); i++) { + if (cmp_sys_reg(&pvm_sys_reg_descs[i-1], &pvm_sys_reg_descs[i]) >= 0) + return 1; + } + + return 0; +} + +/* + * Handler for protected VM MSR, MRS or System instruction execution. + * + * Returns true if the hypervisor has handled the exit, and control should go + * back to the guest, or false if it hasn't, to be handled by the host. + */ +bool kvm_handle_pvm_sysreg(struct kvm_vcpu *vcpu, u64 *exit_code) +{ + const struct sys_reg_desc *r; + struct sys_reg_params params; + unsigned long esr = kvm_vcpu_get_esr(vcpu); + int Rt = kvm_vcpu_sys_get_rt(vcpu); + + params = esr_sys64_to_params(esr); + params.regval = vcpu_get_reg(vcpu, Rt); + + r = find_reg(¶ms, pvm_sys_reg_descs, ARRAY_SIZE(pvm_sys_reg_descs)); + + /* Undefined (RESTRICTED). */ + if (r == NULL) { + inject_undef64(vcpu); + return true; + } + + /* Handled by the host (HOST_HANDLED) */ + if (r->access == NULL) + return false; + + /* Handled by hyp: skip instruction if instructed to do so. */ + if (r->access(vcpu, ¶ms, r)) + __kvm_skip_instr(vcpu); + + if (!params.is_write) + vcpu_set_reg(vcpu, Rt, params.regval); + + return true; +} + +/* + * Handler for protected VM restricted exceptions. + * + * Inject an undefined exception into the guest and return true to indicate that + * the hypervisor has handled the exit, and control should go back to the guest. + */ +bool kvm_handle_pvm_restricted(struct kvm_vcpu *vcpu, u64 *exit_code) +{ + inject_undef64(vcpu); + return true; +} |