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Signed-off-by: Jing Zhang --- arch/arm64/include/asm/cpufeature.h | 1 + arch/arm64/kernel/cpufeature.c | 2 +- arch/arm64/kvm/id_regs.c | 361 ++++++++++++++++++---------- 3 files changed, 242 insertions(+), 122 deletions(-) diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 6bf013fb110d..dc769c2eb7a4 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -915,6 +915,7 @@ static inline unsigned int get_vmid_bits(u64 mmfr1) return 8; } +s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new, s64 cur); struct arm64_ftr_reg *get_arm64_ftr_reg(u32 sys_id); extern struct arm64_ftr_override id_aa64mmfr1_override; diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 2e3e55139777..677ec4fe9f6b 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -791,7 +791,7 @@ static u64 arm64_ftr_set_value(const struct arm64_ftr_bits *ftrp, s64 reg, return reg; } -static s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new, +s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new, s64 cur) { s64 ret = 0; diff --git a/arch/arm64/kvm/id_regs.c b/arch/arm64/kvm/id_regs.c index 64d40aa395be..6cd56c9e6428 100644 --- a/arch/arm64/kvm/id_regs.c +++ b/arch/arm64/kvm/id_regs.c @@ -18,6 +18,86 @@ #include "sys_regs.h" +static s64 kvm_arm64_ftr_safe_value(u32 id, const struct arm64_ftr_bits *ftrp, + s64 new, s64 cur) +{ + struct arm64_ftr_bits kvm_ftr = *ftrp; + + /* Some features have different safe value type in KVM than host features */ + switch (id) { + case SYS_ID_AA64DFR0_EL1: + if (kvm_ftr.shift == ID_AA64DFR0_EL1_PMUVer_SHIFT) + kvm_ftr.type = FTR_LOWER_SAFE; + break; + case SYS_ID_DFR0_EL1: + if (kvm_ftr.shift == ID_DFR0_EL1_PerfMon_SHIFT) + kvm_ftr.type = FTR_LOWER_SAFE; + break; + } + + return arm64_ftr_safe_value(&kvm_ftr, new, cur); +} + +/** + * arm64_check_features() - Check if a feature register value constitutes + * a subset of features indicated by the idreg's KVM sanitised limit. + * + * This function will check if each feature field of @val is the "safe" value + * against idreg's KVM sanitised limit return from reset() callback. + * If a field value in @val is the same as the one in limit, it is always + * considered the safe value regardless For register fields that are not in + * writable, only the value in limit is considered the safe value. + * + * Return: 0 if all the fields are safe. Otherwise, return negative errno. + */ +static int arm64_check_features(struct kvm_vcpu *vcpu, + const struct sys_reg_desc *rd, + u64 val) +{ + const struct arm64_ftr_reg *ftr_reg; + const struct arm64_ftr_bits *ftrp = NULL; + u32 id = reg_to_encoding(rd); + u64 writable_mask = rd->val; + u64 limit = 0; + u64 mask = 0; + + /* For hidden and unallocated idregs without reset, only val = 0 is allowed. */ + if (rd->reset) { + limit = rd->reset(vcpu, rd); + ftr_reg = get_arm64_ftr_reg(id); + if (!ftr_reg) + return -EINVAL; + ftrp = ftr_reg->ftr_bits; + } + + for (; ftrp && ftrp->width; ftrp++) { + s64 f_val, f_lim, safe_val; + u64 ftr_mask; + + ftr_mask = arm64_ftr_mask(ftrp); + if ((ftr_mask & writable_mask) != ftr_mask) + continue; + + f_val = arm64_ftr_value(ftrp, val); + f_lim = arm64_ftr_value(ftrp, limit); + mask |= ftr_mask; + + if (f_val == f_lim) + safe_val = f_val; + else + safe_val = kvm_arm64_ftr_safe_value(id, ftrp, f_val, f_lim); + + if (safe_val != f_val) + return -E2BIG; + } + + /* For fields that are not writable, values in limit are the safe values. */ + if ((val & ~mask) != (limit & ~mask)) + return -E2BIG; + + return 0; +} + static u8 vcpu_pmuver(const struct kvm_vcpu *vcpu) { if (kvm_vcpu_has_pmu(vcpu)) @@ -68,7 +148,6 @@ u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id) case SYS_ID_AA64PFR0_EL1: if (!vcpu_has_sve(vcpu)) val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_SVE); - val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU); if (kvm_vgic_global_state.type == VGIC_V3) { val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC); val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC), 1); @@ -95,15 +174,10 @@ u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id) val &= ~ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_WFxT); break; case SYS_ID_AA64DFR0_EL1: - /* Limit debug to ARMv8.0 */ - val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer); - val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer), 6); /* Set PMUver to the required version */ val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer); val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), vcpu_pmuver(vcpu)); - /* Hide SPE from guests */ - val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMSVer); break; case SYS_ID_DFR0_EL1: val &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon); @@ -167,11 +241,23 @@ static int get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, u64 val) { - /* This is what we mean by invariant: you can't change it. */ - if (val != read_id_reg(vcpu, rd)) - return -EINVAL; + struct kvm_arch *arch = &vcpu->kvm->arch; + u32 id = reg_to_encoding(rd); + int ret = 0; - return 0; + mutex_lock(&arch->config_lock); + /* Only allow userspace to change the idregs before VM running */ + if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &vcpu->kvm->arch.flags)) { + if (val != read_id_reg(vcpu, rd)) + ret = -EBUSY; + } else { + ret = arm64_check_features(vcpu, rd, val); + if (!ret) + IDREG(vcpu->kvm, id) = val; + } + mutex_unlock(&arch->config_lock); + + return ret; } static unsigned int id_visibility(const struct kvm_vcpu *vcpu, @@ -203,14 +289,40 @@ static unsigned int aa32_id_visibility(const struct kvm_vcpu *vcpu, return id_visibility(vcpu, r); } +static u64 read_sanitised_id_aa64pfr0_el1(struct kvm_vcpu *vcpu, + const struct sys_reg_desc *rd) +{ + u64 val; + u32 id = reg_to_encoding(rd); + + val = read_sanitised_ftr_reg(id); + /* + * The default is to expose CSV2 == 1 if the HW isn't affected. + * Although this is a per-CPU feature, we make it global because + * asymmetric systems are just a nuisance. + * + * Userspace can override this as long as it doesn't promise + * the impossible. + */ + if (arm64_get_spectre_v2_state() == SPECTRE_UNAFFECTED) { + val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2); + val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2), 1); + } + if (arm64_get_meltdown_state() == SPECTRE_UNAFFECTED) { + val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3); + val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3), 1); + } + + val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU); + + return val; +} + static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, u64 val) { - struct kvm_arch *arch = &vcpu->kvm->arch; - u64 sval = val; u8 csv2, csv3; - int ret = 0; /* * Allow AA64PFR0_EL1.CSV2 to be set from userspace as long as @@ -226,26 +338,30 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu, if (csv3 > 1 || (csv3 && arm64_get_meltdown_state() != SPECTRE_UNAFFECTED)) return -EINVAL; - mutex_lock(&arch->config_lock); - /* We can only differ with CSV[23], and anything else is an error */ - val ^= read_id_reg(vcpu, rd); - val &= ~(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2) | - ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3)); - if (val) { - ret = -EINVAL; - goto out; - } + return set_id_reg(vcpu, rd, val); +} - /* Only allow userspace to change the idregs before VM running */ - if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &vcpu->kvm->arch.flags)) { - if (sval != read_id_reg(vcpu, rd)) - ret = -EBUSY; - } else { - IDREG(vcpu->kvm, reg_to_encoding(rd)) = sval; - } -out: - mutex_unlock(&arch->config_lock); - return ret; +static u64 read_sanitised_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, + const struct sys_reg_desc *rd) +{ + u64 val; + u32 id = reg_to_encoding(rd); + + val = read_sanitised_ftr_reg(id); + /* Limit debug to ARMv8.0 */ + val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer); + val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer), 6); + /* + * Initialise the default PMUver before there is a chance to + * create an actual PMU. + */ + val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer); + val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), + kvm_arm_pmu_get_pmuver_limit()); + /* Hide SPE from guests */ + val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMSVer); + + return val; } static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, @@ -255,7 +371,6 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, struct kvm_arch *arch = &vcpu->kvm->arch; u8 pmuver, host_pmuver; bool valid_pmu; - u64 sval = val; int ret = 0; host_pmuver = kvm_arm_pmu_get_pmuver_limit(); @@ -277,40 +392,61 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, return -EINVAL; mutex_lock(&arch->config_lock); - /* We can only differ with PMUver, and anything else is an error */ - val ^= read_id_reg(vcpu, rd); - val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer); - if (val) { - ret = -EINVAL; - goto out; - } - /* Only allow userspace to change the idregs before VM running */ if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &vcpu->kvm->arch.flags)) { - if (sval != read_id_reg(vcpu, rd)) + if (val != read_id_reg(vcpu, rd)) ret = -EBUSY; - } else { - if (valid_pmu) { - val = IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1); - val &= ~ID_AA64DFR0_EL1_PMUVer_MASK; - val |= FIELD_PREP(ID_AA64DFR0_EL1_PMUVer_MASK, pmuver); - IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) = val; - - val = IDREG(vcpu->kvm, SYS_ID_DFR0_EL1); - val &= ~ID_DFR0_EL1_PerfMon_MASK; - val |= FIELD_PREP(ID_DFR0_EL1_PerfMon_MASK, pmuver_to_perfmon(pmuver)); - IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) = val; - } else { - assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags, - pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF); - } + goto out; + } + + if (!valid_pmu) { + /* + * Ignore the PMUVer filed in @val. The PMUVer would be determined + * by arch flags bit KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, + */ + pmuver = FIELD_GET(ID_AA64DFR0_EL1_PMUVer_MASK, + IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1)); + val &= ~ID_AA64DFR0_EL1_PMUVer_MASK; + val |= FIELD_PREP(ID_AA64DFR0_EL1_PMUVer_MASK, pmuver); } + ret = arm64_check_features(vcpu, rd, val); + if (ret) + goto out; + + IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) = val; + + val = IDREG(vcpu->kvm, SYS_ID_DFR0_EL1); + val &= ~ID_DFR0_EL1_PerfMon_MASK; + val |= FIELD_PREP(ID_DFR0_EL1_PerfMon_MASK, pmuver_to_perfmon(pmuver)); + IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) = val; + + if (!valid_pmu) + assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags, + pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF); + out: mutex_unlock(&arch->config_lock); return ret; } +static u64 read_sanitised_id_dfr0_el1(struct kvm_vcpu *vcpu, + const struct sys_reg_desc *rd) +{ + u64 val; + u32 id = reg_to_encoding(rd); + + val = read_sanitised_ftr_reg(id); + /* + * Initialise the default PMUver before there is a chance to + * create an actual PMU. + */ + val &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon); + val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon), kvm_arm_pmu_get_pmuver_limit()); + + return val; +} + static int set_id_dfr0_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, u64 val) @@ -318,7 +454,6 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu, struct kvm_arch *arch = &vcpu->kvm->arch; u8 perfmon, host_perfmon; bool valid_pmu; - u64 sval = val; int ret = 0; host_perfmon = pmuver_to_perfmon(kvm_arm_pmu_get_pmuver_limit()); @@ -341,35 +476,39 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu, return -EINVAL; mutex_lock(&arch->config_lock); - /* We can only differ with PerfMon, and anything else is an error */ - val ^= read_id_reg(vcpu, rd); - val &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon); - if (val) { - ret = -EINVAL; - goto out; - } - /* Only allow userspace to change the idregs before VM running */ if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &vcpu->kvm->arch.flags)) { - if (sval != read_id_reg(vcpu, rd)) + if (val != read_id_reg(vcpu, rd)) ret = -EBUSY; - } else { - if (valid_pmu) { - val = IDREG(vcpu->kvm, SYS_ID_DFR0_EL1); - val &= ~ID_DFR0_EL1_PerfMon_MASK; - val |= FIELD_PREP(ID_DFR0_EL1_PerfMon_MASK, perfmon); - IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) = val; - - val = IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1); - val &= ~ID_AA64DFR0_EL1_PMUVer_MASK; - val |= FIELD_PREP(ID_AA64DFR0_EL1_PMUVer_MASK, perfmon_to_pmuver(perfmon)); - IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) = val; - } else { - assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags, - perfmon == ID_DFR0_EL1_PerfMon_IMPDEF); - } + goto out; + } + + if (!valid_pmu) { + /* + * Ignore the PerfMon filed in @val. The PerfMon would be determined + * by arch flags bit KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, + */ + perfmon = FIELD_GET(ID_DFR0_EL1_PerfMon_MASK, + IDREG(vcpu->kvm, SYS_ID_DFR0_EL1)); + val &= ~ID_DFR0_EL1_PerfMon_MASK; + val |= FIELD_PREP(ID_DFR0_EL1_PerfMon_MASK, perfmon); } + ret = arm64_check_features(vcpu, rd, val); + if (ret) + goto out; + + IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) = val; + + val = IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1); + val &= ~ID_AA64DFR0_EL1_PMUVer_MASK; + val |= FIELD_PREP(ID_AA64DFR0_EL1_PMUVer_MASK, perfmon_to_pmuver(perfmon)); + IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) = val; + + if (!valid_pmu) + assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags, + perfmon == ID_DFR0_EL1_PerfMon_IMPDEF); + out: mutex_unlock(&arch->config_lock); return ret; @@ -448,9 +587,13 @@ const struct sys_reg_desc id_reg_descs[KVM_ARM_ID_REG_NUM] = { /* CRm=1 */ AA32_ID_SANITISED(ID_PFR0_EL1), AA32_ID_SANITISED(ID_PFR1_EL1), - { SYS_DESC(SYS_ID_DFR0_EL1), .access = access_id_reg, - .get_user = get_id_reg, .set_user = set_id_dfr0_el1, - .visibility = aa32_id_visibility, }, + { SYS_DESC(SYS_ID_DFR0_EL1), + .access = access_id_reg, + .get_user = get_id_reg, + .set_user = set_id_dfr0_el1, + .visibility = aa32_id_visibility, + .reset = read_sanitised_id_dfr0_el1, + .val = ID_DFR0_EL1_PerfMon_MASK, }, ID_HIDDEN(ID_AFR0_EL1), AA32_ID_SANITISED(ID_MMFR0_EL1), AA32_ID_SANITISED(ID_MMFR1_EL1), @@ -479,8 +622,12 @@ const struct sys_reg_desc id_reg_descs[KVM_ARM_ID_REG_NUM] = { /* AArch64 ID registers */ /* CRm=4 */ - { SYS_DESC(SYS_ID_AA64PFR0_EL1), .access = access_id_reg, - .get_user = get_id_reg, .set_user = set_id_aa64pfr0_el1, }, + { SYS_DESC(SYS_ID_AA64PFR0_EL1), + .access = access_id_reg, + .get_user = get_id_reg, + .set_user = set_id_aa64pfr0_el1, + .reset = read_sanitised_id_aa64pfr0_el1, + .val = ID_AA64PFR0_EL1_CSV2_MASK | ID_AA64PFR0_EL1_CSV3_MASK, }, ID_SANITISED(ID_AA64PFR1_EL1), ID_UNALLOCATED(4, 2), ID_UNALLOCATED(4, 3), @@ -490,8 +637,12 @@ const struct sys_reg_desc id_reg_descs[KVM_ARM_ID_REG_NUM] = { ID_UNALLOCATED(4, 7), /* CRm=5 */ - { SYS_DESC(SYS_ID_AA64DFR0_EL1), .access = access_id_reg, - .get_user = get_id_reg, .set_user = set_id_aa64dfr0_el1, }, + { SYS_DESC(SYS_ID_AA64DFR0_EL1), + .access = access_id_reg, + .get_user = get_id_reg, + .set_user = set_id_aa64dfr0_el1, + .reset = read_sanitised_id_aa64dfr0_el1, + .val = ID_AA64DFR0_EL1_PMUVer_MASK, }, ID_SANITISED(ID_AA64DFR1_EL1), ID_UNALLOCATED(5, 2), ID_UNALLOCATED(5, 3), @@ -563,36 +714,4 @@ void kvm_arm_init_id_regs(struct kvm *kvm) IDREG(kvm, id) = val; } - - /* - * The default is to expose CSV2 == 1 if the HW isn't affected. - * Although this is a per-CPU feature, we make it global because - * asymmetric systems are just a nuisance. - * - * Userspace can override this as long as it doesn't promise - * the impossible. - */ - val = IDREG(kvm, SYS_ID_AA64PFR0_EL1); - - if (arm64_get_spectre_v2_state() == SPECTRE_UNAFFECTED) { - val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2); - val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2), 1); - } - if (arm64_get_meltdown_state() == SPECTRE_UNAFFECTED) { - val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3); - val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3), 1); - } - - IDREG(kvm, SYS_ID_AA64PFR0_EL1) = val; - /* - * Initialise the default PMUver before there is a chance to - * create an actual PMU. - */ - val = IDREG(kvm, SYS_ID_AA64DFR0_EL1); - - val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer); - val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), - kvm_arm_pmu_get_pmuver_limit()); - - IDREG(kvm, SYS_ID_AA64DFR0_EL1) = val; }