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Diffstat (limited to '')
| -rw-r--r-- | arch/arm64/kvm/hypercalls.c | 483 |
1 files changed, 483 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c new file mode 100644 index 000000000..1f5beebf6 --- /dev/null +++ b/arch/arm64/kvm/hypercalls.c @@ -0,0 +1,483 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2019 Arm Ltd. + +#include <linux/arm-smccc.h> +#include <linux/kvm_host.h> + +#include <asm/kvm_emulate.h> + +#include <kvm/arm_hypercalls.h> +#include <kvm/arm_psci.h> + +#define KVM_ARM_SMCCC_STD_FEATURES \ + GENMASK(KVM_REG_ARM_STD_BMAP_BIT_COUNT - 1, 0) +#define KVM_ARM_SMCCC_STD_HYP_FEATURES \ + GENMASK(KVM_REG_ARM_STD_HYP_BMAP_BIT_COUNT - 1, 0) +#define KVM_ARM_SMCCC_VENDOR_HYP_FEATURES \ + GENMASK(KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_COUNT - 1, 0) + +static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val) +{ + struct system_time_snapshot systime_snapshot; + u64 cycles = ~0UL; + u32 feature; + + /* + * system time and counter value must captured at the same + * time to keep consistency and precision. + */ + ktime_get_snapshot(&systime_snapshot); + + /* + * This is only valid if the current clocksource is the + * architected counter, as this is the only one the guest + * can see. + */ + if (systime_snapshot.cs_id != CSID_ARM_ARCH_COUNTER) + return; + + /* + * The guest selects one of the two reference counters + * (virtual or physical) with the first argument of the SMCCC + * call. In case the identifier is not supported, error out. + */ + feature = smccc_get_arg1(vcpu); + switch (feature) { + case KVM_PTP_VIRT_COUNTER: + cycles = systime_snapshot.cycles - vcpu_read_sys_reg(vcpu, CNTVOFF_EL2); + break; + case KVM_PTP_PHYS_COUNTER: + cycles = systime_snapshot.cycles; + break; + default: + return; + } + + /* + * This relies on the top bit of val[0] never being set for + * valid values of system time, because that is *really* far + * in the future (about 292 years from 1970, and at that stage + * nobody will give a damn about it). + */ + val[0] = upper_32_bits(systime_snapshot.real); + val[1] = lower_32_bits(systime_snapshot.real); + val[2] = upper_32_bits(cycles); + val[3] = lower_32_bits(cycles); +} + +static bool kvm_hvc_call_default_allowed(u32 func_id) +{ + switch (func_id) { + /* + * List of function-ids that are not gated with the bitmapped + * feature firmware registers, and are to be allowed for + * servicing the call by default. + */ + case ARM_SMCCC_VERSION_FUNC_ID: + case ARM_SMCCC_ARCH_FEATURES_FUNC_ID: + return true; + default: + /* PSCI 0.2 and up is in the 0:0x1f range */ + if (ARM_SMCCC_OWNER_NUM(func_id) == ARM_SMCCC_OWNER_STANDARD && + ARM_SMCCC_FUNC_NUM(func_id) <= 0x1f) + return true; + + /* + * KVM's PSCI 0.1 doesn't comply with SMCCC, and has + * its own function-id base and range + */ + if (func_id >= KVM_PSCI_FN(0) && func_id <= KVM_PSCI_FN(3)) + return true; + + return false; + } +} + +static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id) +{ + struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat; + + switch (func_id) { + case ARM_SMCCC_TRNG_VERSION: + case ARM_SMCCC_TRNG_FEATURES: + case ARM_SMCCC_TRNG_GET_UUID: + case ARM_SMCCC_TRNG_RND32: + case ARM_SMCCC_TRNG_RND64: + return test_bit(KVM_REG_ARM_STD_BIT_TRNG_V1_0, + &smccc_feat->std_bmap); + case ARM_SMCCC_HV_PV_TIME_FEATURES: + case ARM_SMCCC_HV_PV_TIME_ST: + return test_bit(KVM_REG_ARM_STD_HYP_BIT_PV_TIME, + &smccc_feat->std_hyp_bmap); + case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID: + case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID: + return test_bit(KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT, + &smccc_feat->vendor_hyp_bmap); + case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID: + return test_bit(KVM_REG_ARM_VENDOR_HYP_BIT_PTP, + &smccc_feat->vendor_hyp_bmap); + default: + return kvm_hvc_call_default_allowed(func_id); + } +} + +int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) +{ + struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat; + u32 func_id = smccc_get_function(vcpu); + u64 val[4] = {SMCCC_RET_NOT_SUPPORTED}; + u32 feature; + gpa_t gpa; + + if (!kvm_hvc_call_allowed(vcpu, func_id)) + goto out; + + switch (func_id) { + case ARM_SMCCC_VERSION_FUNC_ID: + val[0] = ARM_SMCCC_VERSION_1_1; + break; + case ARM_SMCCC_ARCH_FEATURES_FUNC_ID: + feature = smccc_get_arg1(vcpu); + switch (feature) { + case ARM_SMCCC_ARCH_WORKAROUND_1: + switch (arm64_get_spectre_v2_state()) { + case SPECTRE_VULNERABLE: + break; + case SPECTRE_MITIGATED: + val[0] = SMCCC_RET_SUCCESS; + break; + case SPECTRE_UNAFFECTED: + val[0] = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED; + break; + } + break; + case ARM_SMCCC_ARCH_WORKAROUND_2: + switch (arm64_get_spectre_v4_state()) { + case SPECTRE_VULNERABLE: + break; + case SPECTRE_MITIGATED: + /* + * SSBS everywhere: Indicate no firmware + * support, as the SSBS support will be + * indicated to the guest and the default is + * safe. + * + * Otherwise, expose a permanent mitigation + * to the guest, and hide SSBS so that the + * guest stays protected. + */ + if (cpus_have_final_cap(ARM64_SSBS)) + break; + fallthrough; + case SPECTRE_UNAFFECTED: + val[0] = SMCCC_RET_NOT_REQUIRED; + break; + } + break; + case ARM_SMCCC_ARCH_WORKAROUND_3: + switch (arm64_get_spectre_bhb_state()) { + case SPECTRE_VULNERABLE: + break; + case SPECTRE_MITIGATED: + val[0] = SMCCC_RET_SUCCESS; + break; + case SPECTRE_UNAFFECTED: + val[0] = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED; + break; + } + break; + case ARM_SMCCC_HV_PV_TIME_FEATURES: + if (test_bit(KVM_REG_ARM_STD_HYP_BIT_PV_TIME, + &smccc_feat->std_hyp_bmap)) + val[0] = SMCCC_RET_SUCCESS; + break; + } + break; + case ARM_SMCCC_HV_PV_TIME_FEATURES: + val[0] = kvm_hypercall_pv_features(vcpu); + break; + case ARM_SMCCC_HV_PV_TIME_ST: + gpa = kvm_init_stolen_time(vcpu); + if (gpa != GPA_INVALID) + val[0] = gpa; + break; + case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID: + val[0] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0; + val[1] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1; + val[2] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2; + val[3] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3; + break; + case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID: + val[0] = smccc_feat->vendor_hyp_bmap; + break; + case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID: + kvm_ptp_get_time(vcpu, val); + break; + case ARM_SMCCC_TRNG_VERSION: + case ARM_SMCCC_TRNG_FEATURES: + case ARM_SMCCC_TRNG_GET_UUID: + case ARM_SMCCC_TRNG_RND32: + case ARM_SMCCC_TRNG_RND64: + return kvm_trng_call(vcpu); + default: + return kvm_psci_call(vcpu); + } + +out: + smccc_set_retval(vcpu, val[0], val[1], val[2], val[3]); + return 1; +} + +static const u64 kvm_arm_fw_reg_ids[] = { + KVM_REG_ARM_PSCI_VERSION, + KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1, + KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2, + KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3, + KVM_REG_ARM_STD_BMAP, + KVM_REG_ARM_STD_HYP_BMAP, + KVM_REG_ARM_VENDOR_HYP_BMAP, +}; + +void kvm_arm_init_hypercalls(struct kvm *kvm) +{ + struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; + + smccc_feat->std_bmap = KVM_ARM_SMCCC_STD_FEATURES; + smccc_feat->std_hyp_bmap = KVM_ARM_SMCCC_STD_HYP_FEATURES; + smccc_feat->vendor_hyp_bmap = KVM_ARM_SMCCC_VENDOR_HYP_FEATURES; +} + +int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu) +{ + return ARRAY_SIZE(kvm_arm_fw_reg_ids); +} + +int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(kvm_arm_fw_reg_ids); i++) { + if (put_user(kvm_arm_fw_reg_ids[i], uindices++)) + return -EFAULT; + } + + return 0; +} + +#define KVM_REG_FEATURE_LEVEL_MASK GENMASK(3, 0) + +/* + * Convert the workaround level into an easy-to-compare number, where higher + * values mean better protection. + */ +static int get_kernel_wa_level(u64 regid) +{ + switch (regid) { + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1: + switch (arm64_get_spectre_v2_state()) { + case SPECTRE_VULNERABLE: + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL; + case SPECTRE_MITIGATED: + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_AVAIL; + case SPECTRE_UNAFFECTED: + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_REQUIRED; + } + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL; + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2: + switch (arm64_get_spectre_v4_state()) { + case SPECTRE_MITIGATED: + /* + * As for the hypercall discovery, we pretend we + * don't have any FW mitigation if SSBS is there at + * all times. + */ + if (cpus_have_final_cap(ARM64_SSBS)) + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL; + fallthrough; + case SPECTRE_UNAFFECTED: + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED; + case SPECTRE_VULNERABLE: + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL; + } + break; + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3: + switch (arm64_get_spectre_bhb_state()) { + case SPECTRE_VULNERABLE: + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL; + case SPECTRE_MITIGATED: + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_AVAIL; + case SPECTRE_UNAFFECTED: + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_REQUIRED; + } + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL; + } + + return -EINVAL; +} + +int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) +{ + struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat; + void __user *uaddr = (void __user *)(long)reg->addr; + u64 val; + + switch (reg->id) { + case KVM_REG_ARM_PSCI_VERSION: + val = kvm_psci_version(vcpu); + break; + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1: + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2: + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3: + val = get_kernel_wa_level(reg->id) & KVM_REG_FEATURE_LEVEL_MASK; + break; + case KVM_REG_ARM_STD_BMAP: + val = READ_ONCE(smccc_feat->std_bmap); + break; + case KVM_REG_ARM_STD_HYP_BMAP: + val = READ_ONCE(smccc_feat->std_hyp_bmap); + break; + case KVM_REG_ARM_VENDOR_HYP_BMAP: + val = READ_ONCE(smccc_feat->vendor_hyp_bmap); + break; + default: + return -ENOENT; + } + + if (copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id))) + return -EFAULT; + + return 0; +} + +static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val) +{ + int ret = 0; + struct kvm *kvm = vcpu->kvm; + struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; + unsigned long *fw_reg_bmap, fw_reg_features; + + switch (reg_id) { + case KVM_REG_ARM_STD_BMAP: + fw_reg_bmap = &smccc_feat->std_bmap; + fw_reg_features = KVM_ARM_SMCCC_STD_FEATURES; + break; + case KVM_REG_ARM_STD_HYP_BMAP: + fw_reg_bmap = &smccc_feat->std_hyp_bmap; + fw_reg_features = KVM_ARM_SMCCC_STD_HYP_FEATURES; + break; + case KVM_REG_ARM_VENDOR_HYP_BMAP: + fw_reg_bmap = &smccc_feat->vendor_hyp_bmap; + fw_reg_features = KVM_ARM_SMCCC_VENDOR_HYP_FEATURES; + break; + default: + return -ENOENT; + } + + /* Check for unsupported bit */ + if (val & ~fw_reg_features) + return -EINVAL; + + mutex_lock(&kvm->arch.config_lock); + + if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &kvm->arch.flags) && + val != *fw_reg_bmap) { + ret = -EBUSY; + goto out; + } + + WRITE_ONCE(*fw_reg_bmap, val); +out: + mutex_unlock(&kvm->arch.config_lock); + return ret; +} + +int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) +{ + void __user *uaddr = (void __user *)(long)reg->addr; + u64 val; + int wa_level; + + if (KVM_REG_SIZE(reg->id) != sizeof(val)) + return -ENOENT; + if (copy_from_user(&val, uaddr, KVM_REG_SIZE(reg->id))) + return -EFAULT; + + switch (reg->id) { + case KVM_REG_ARM_PSCI_VERSION: + { + bool wants_02; + + wants_02 = test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features); + + switch (val) { + case KVM_ARM_PSCI_0_1: + if (wants_02) + return -EINVAL; + vcpu->kvm->arch.psci_version = val; + return 0; + case KVM_ARM_PSCI_0_2: + case KVM_ARM_PSCI_1_0: + case KVM_ARM_PSCI_1_1: + if (!wants_02) + return -EINVAL; + vcpu->kvm->arch.psci_version = val; + return 0; + } + break; + } + + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1: + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3: + if (val & ~KVM_REG_FEATURE_LEVEL_MASK) + return -EINVAL; + + if (get_kernel_wa_level(reg->id) < val) + return -EINVAL; + + return 0; + + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2: + if (val & ~(KVM_REG_FEATURE_LEVEL_MASK | + KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED)) + return -EINVAL; + + /* The enabled bit must not be set unless the level is AVAIL. */ + if ((val & KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED) && + (val & KVM_REG_FEATURE_LEVEL_MASK) != KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL) + return -EINVAL; + + /* + * Map all the possible incoming states to the only two we + * really want to deal with. + */ + switch (val & KVM_REG_FEATURE_LEVEL_MASK) { + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL: + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNKNOWN: + wa_level = KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL; + break; + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL: + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED: + wa_level = KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED; + break; + default: + return -EINVAL; + } + + /* + * We can deal with NOT_AVAIL on NOT_REQUIRED, but not the + * other way around. + */ + if (get_kernel_wa_level(reg->id) < wa_level) + return -EINVAL; + + return 0; + case KVM_REG_ARM_STD_BMAP: + case KVM_REG_ARM_STD_HYP_BMAP: + case KVM_REG_ARM_VENDOR_HYP_BMAP: + return kvm_arm_set_fw_reg_bmap(vcpu, reg->id, val); + default: + return -ENOENT; + } + + return -EINVAL; +} |