diff options
Diffstat (limited to 'arch/riscv/kvm/vcpu_sbi_fwft.c')
| -rw-r--r-- | arch/riscv/kvm/vcpu_sbi_fwft.c | 544 |
1 files changed, 544 insertions, 0 deletions
diff --git a/arch/riscv/kvm/vcpu_sbi_fwft.c b/arch/riscv/kvm/vcpu_sbi_fwft.c new file mode 100644 index 000000000000..62cc9c3d5759 --- /dev/null +++ b/arch/riscv/kvm/vcpu_sbi_fwft.c @@ -0,0 +1,544 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2025 Rivos Inc. + * + * Authors: + * Clément Léger <cleger@rivosinc.com> + */ + +#include <linux/errno.h> +#include <linux/err.h> +#include <linux/kvm_host.h> +#include <asm/cpufeature.h> +#include <asm/sbi.h> +#include <asm/kvm_vcpu_sbi.h> +#include <asm/kvm_vcpu_sbi_fwft.h> + +#define MIS_DELEG (BIT_ULL(EXC_LOAD_MISALIGNED) | BIT_ULL(EXC_STORE_MISALIGNED)) + +struct kvm_sbi_fwft_feature { + /** + * @id: Feature ID + */ + enum sbi_fwft_feature_t id; + + /** + * @first_reg_num: ONE_REG index of the first ONE_REG register + */ + unsigned long first_reg_num; + + /** + * @supported: Check if the feature is supported on the vcpu + * + * This callback is optional, if not provided the feature is assumed to + * be supported + */ + bool (*supported)(struct kvm_vcpu *vcpu); + + /** + * @reset: Reset the feature value irrespective whether feature is supported or not + * + * This callback is mandatory + */ + void (*reset)(struct kvm_vcpu *vcpu); + + /** + * @set: Set the feature value + * + * Return SBI_SUCCESS on success or an SBI error (SBI_ERR_*) + * + * This callback is mandatory + */ + long (*set)(struct kvm_vcpu *vcpu, struct kvm_sbi_fwft_config *conf, + bool one_reg_access, unsigned long value); + + /** + * @get: Get the feature current value + * + * Return SBI_SUCCESS on success or an SBI error (SBI_ERR_*) + * + * This callback is mandatory + */ + long (*get)(struct kvm_vcpu *vcpu, struct kvm_sbi_fwft_config *conf, + bool one_reg_access, unsigned long *value); +}; + +static const enum sbi_fwft_feature_t kvm_fwft_defined_features[] = { + SBI_FWFT_MISALIGNED_EXC_DELEG, + SBI_FWFT_LANDING_PAD, + SBI_FWFT_SHADOW_STACK, + SBI_FWFT_DOUBLE_TRAP, + SBI_FWFT_PTE_AD_HW_UPDATING, + SBI_FWFT_POINTER_MASKING_PMLEN, +}; + +static bool kvm_fwft_is_defined_feature(enum sbi_fwft_feature_t feature) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(kvm_fwft_defined_features); i++) { + if (kvm_fwft_defined_features[i] == feature) + return true; + } + + return false; +} + +static bool kvm_sbi_fwft_misaligned_delegation_supported(struct kvm_vcpu *vcpu) +{ + return misaligned_traps_can_delegate(); +} + +static void kvm_sbi_fwft_reset_misaligned_delegation(struct kvm_vcpu *vcpu) +{ + struct kvm_vcpu_config *cfg = &vcpu->arch.cfg; + + cfg->hedeleg &= ~MIS_DELEG; +} + +static long kvm_sbi_fwft_set_misaligned_delegation(struct kvm_vcpu *vcpu, + struct kvm_sbi_fwft_config *conf, + bool one_reg_access, unsigned long value) +{ + struct kvm_vcpu_config *cfg = &vcpu->arch.cfg; + + if (value == 1) { + cfg->hedeleg |= MIS_DELEG; + if (!one_reg_access) + csr_set(CSR_HEDELEG, MIS_DELEG); + } else if (value == 0) { + cfg->hedeleg &= ~MIS_DELEG; + if (!one_reg_access) + csr_clear(CSR_HEDELEG, MIS_DELEG); + } else { + return SBI_ERR_INVALID_PARAM; + } + + return SBI_SUCCESS; +} + +static long kvm_sbi_fwft_get_misaligned_delegation(struct kvm_vcpu *vcpu, + struct kvm_sbi_fwft_config *conf, + bool one_reg_access, unsigned long *value) +{ + struct kvm_vcpu_config *cfg = &vcpu->arch.cfg; + + *value = (cfg->hedeleg & MIS_DELEG) == MIS_DELEG; + return SBI_SUCCESS; +} + +#ifndef CONFIG_32BIT + +static bool try_to_set_pmm(unsigned long value) +{ + csr_set(CSR_HENVCFG, value); + return (csr_read_clear(CSR_HENVCFG, ENVCFG_PMM) & ENVCFG_PMM) == value; +} + +static bool kvm_sbi_fwft_pointer_masking_pmlen_supported(struct kvm_vcpu *vcpu) +{ + struct kvm_sbi_fwft *fwft = vcpu_to_fwft(vcpu); + + if (!riscv_isa_extension_available(vcpu->arch.isa, SMNPM)) + return false; + + fwft->have_vs_pmlen_7 = try_to_set_pmm(ENVCFG_PMM_PMLEN_7); + fwft->have_vs_pmlen_16 = try_to_set_pmm(ENVCFG_PMM_PMLEN_16); + + return fwft->have_vs_pmlen_7 || fwft->have_vs_pmlen_16; +} + +static void kvm_sbi_fwft_reset_pointer_masking_pmlen(struct kvm_vcpu *vcpu) +{ + vcpu->arch.cfg.henvcfg &= ~ENVCFG_PMM; +} + +static long kvm_sbi_fwft_set_pointer_masking_pmlen(struct kvm_vcpu *vcpu, + struct kvm_sbi_fwft_config *conf, + bool one_reg_access, unsigned long value) +{ + struct kvm_sbi_fwft *fwft = vcpu_to_fwft(vcpu); + unsigned long pmm; + + switch (value) { + case 0: + pmm = ENVCFG_PMM_PMLEN_0; + break; + case 7: + if (!fwft->have_vs_pmlen_7) + return SBI_ERR_INVALID_PARAM; + pmm = ENVCFG_PMM_PMLEN_7; + break; + case 16: + if (!fwft->have_vs_pmlen_16) + return SBI_ERR_INVALID_PARAM; + pmm = ENVCFG_PMM_PMLEN_16; + break; + default: + return SBI_ERR_INVALID_PARAM; + } + + vcpu->arch.cfg.henvcfg &= ~ENVCFG_PMM; + vcpu->arch.cfg.henvcfg |= pmm; + + /* + * Instead of waiting for vcpu_load/put() to update HENVCFG CSR, + * update here so that VCPU see's pointer masking mode change + * immediately. + */ + if (!one_reg_access) + csr_write(CSR_HENVCFG, vcpu->arch.cfg.henvcfg); + + return SBI_SUCCESS; +} + +static long kvm_sbi_fwft_get_pointer_masking_pmlen(struct kvm_vcpu *vcpu, + struct kvm_sbi_fwft_config *conf, + bool one_reg_access, unsigned long *value) +{ + switch (vcpu->arch.cfg.henvcfg & ENVCFG_PMM) { + case ENVCFG_PMM_PMLEN_0: + *value = 0; + break; + case ENVCFG_PMM_PMLEN_7: + *value = 7; + break; + case ENVCFG_PMM_PMLEN_16: + *value = 16; + break; + default: + return SBI_ERR_FAILURE; + } + + return SBI_SUCCESS; +} + +#endif + +static const struct kvm_sbi_fwft_feature features[] = { + { + .id = SBI_FWFT_MISALIGNED_EXC_DELEG, + .first_reg_num = offsetof(struct kvm_riscv_sbi_fwft, misaligned_deleg.enable) / + sizeof(unsigned long), + .supported = kvm_sbi_fwft_misaligned_delegation_supported, + .reset = kvm_sbi_fwft_reset_misaligned_delegation, + .set = kvm_sbi_fwft_set_misaligned_delegation, + .get = kvm_sbi_fwft_get_misaligned_delegation, + }, +#ifndef CONFIG_32BIT + { + .id = SBI_FWFT_POINTER_MASKING_PMLEN, + .first_reg_num = offsetof(struct kvm_riscv_sbi_fwft, pointer_masking.enable) / + sizeof(unsigned long), + .supported = kvm_sbi_fwft_pointer_masking_pmlen_supported, + .reset = kvm_sbi_fwft_reset_pointer_masking_pmlen, + .set = kvm_sbi_fwft_set_pointer_masking_pmlen, + .get = kvm_sbi_fwft_get_pointer_masking_pmlen, + }, +#endif +}; + +static const struct kvm_sbi_fwft_feature *kvm_sbi_fwft_regnum_to_feature(unsigned long reg_num) +{ + const struct kvm_sbi_fwft_feature *feature; + int i; + + for (i = 0; i < ARRAY_SIZE(features); i++) { + feature = &features[i]; + if (feature->first_reg_num <= reg_num && reg_num < (feature->first_reg_num + 3)) + return feature; + } + + return NULL; +} + +static struct kvm_sbi_fwft_config * +kvm_sbi_fwft_get_config(struct kvm_vcpu *vcpu, enum sbi_fwft_feature_t feature) +{ + int i; + struct kvm_sbi_fwft *fwft = vcpu_to_fwft(vcpu); + + for (i = 0; i < ARRAY_SIZE(features); i++) { + if (fwft->configs[i].feature->id == feature) + return &fwft->configs[i]; + } + + return NULL; +} + +static int kvm_fwft_get_feature(struct kvm_vcpu *vcpu, u32 feature, + struct kvm_sbi_fwft_config **conf) +{ + struct kvm_sbi_fwft_config *tconf; + + tconf = kvm_sbi_fwft_get_config(vcpu, feature); + if (!tconf) { + if (kvm_fwft_is_defined_feature(feature)) + return SBI_ERR_NOT_SUPPORTED; + + return SBI_ERR_DENIED; + } + + if (!tconf->supported || !tconf->enabled) + return SBI_ERR_NOT_SUPPORTED; + + *conf = tconf; + + return SBI_SUCCESS; +} + +static int kvm_sbi_fwft_set(struct kvm_vcpu *vcpu, u32 feature, + unsigned long value, unsigned long flags) +{ + int ret; + struct kvm_sbi_fwft_config *conf; + + ret = kvm_fwft_get_feature(vcpu, feature, &conf); + if (ret) + return ret; + + if ((flags & ~SBI_FWFT_SET_FLAG_LOCK) != 0) + return SBI_ERR_INVALID_PARAM; + + if (conf->flags & SBI_FWFT_SET_FLAG_LOCK) + return SBI_ERR_DENIED_LOCKED; + + conf->flags = flags; + + return conf->feature->set(vcpu, conf, false, value); +} + +static int kvm_sbi_fwft_get(struct kvm_vcpu *vcpu, unsigned long feature, + unsigned long *value) +{ + int ret; + struct kvm_sbi_fwft_config *conf; + + ret = kvm_fwft_get_feature(vcpu, feature, &conf); + if (ret) + return ret; + + return conf->feature->get(vcpu, conf, false, value); +} + +static int kvm_sbi_ext_fwft_handler(struct kvm_vcpu *vcpu, struct kvm_run *run, + struct kvm_vcpu_sbi_return *retdata) +{ + int ret; + struct kvm_cpu_context *cp = &vcpu->arch.guest_context; + unsigned long funcid = cp->a6; + + switch (funcid) { + case SBI_EXT_FWFT_SET: + ret = kvm_sbi_fwft_set(vcpu, cp->a0, cp->a1, cp->a2); + break; + case SBI_EXT_FWFT_GET: + ret = kvm_sbi_fwft_get(vcpu, cp->a0, &retdata->out_val); + break; + default: + ret = SBI_ERR_NOT_SUPPORTED; + break; + } + + retdata->err_val = ret; + + return 0; +} + +static int kvm_sbi_ext_fwft_init(struct kvm_vcpu *vcpu) +{ + struct kvm_sbi_fwft *fwft = vcpu_to_fwft(vcpu); + const struct kvm_sbi_fwft_feature *feature; + struct kvm_sbi_fwft_config *conf; + int i; + + fwft->configs = kcalloc(ARRAY_SIZE(features), sizeof(struct kvm_sbi_fwft_config), + GFP_KERNEL); + if (!fwft->configs) + return -ENOMEM; + + for (i = 0; i < ARRAY_SIZE(features); i++) { + feature = &features[i]; + conf = &fwft->configs[i]; + if (feature->supported) + conf->supported = feature->supported(vcpu); + else + conf->supported = true; + + conf->enabled = conf->supported; + conf->feature = feature; + } + + return 0; +} + +static void kvm_sbi_ext_fwft_deinit(struct kvm_vcpu *vcpu) +{ + struct kvm_sbi_fwft *fwft = vcpu_to_fwft(vcpu); + + kfree(fwft->configs); +} + +static void kvm_sbi_ext_fwft_reset(struct kvm_vcpu *vcpu) +{ + struct kvm_sbi_fwft *fwft = vcpu_to_fwft(vcpu); + const struct kvm_sbi_fwft_feature *feature; + int i; + + for (i = 0; i < ARRAY_SIZE(features); i++) { + fwft->configs[i].flags = 0; + feature = &features[i]; + if (feature->reset) + feature->reset(vcpu); + } +} + +static unsigned long kvm_sbi_ext_fwft_get_reg_count(struct kvm_vcpu *vcpu) +{ + unsigned long max_reg_count = sizeof(struct kvm_riscv_sbi_fwft) / sizeof(unsigned long); + const struct kvm_sbi_fwft_feature *feature; + struct kvm_sbi_fwft_config *conf; + unsigned long reg, ret = 0; + + for (reg = 0; reg < max_reg_count; reg++) { + feature = kvm_sbi_fwft_regnum_to_feature(reg); + if (!feature) + continue; + + conf = kvm_sbi_fwft_get_config(vcpu, feature->id); + if (!conf || !conf->supported) + continue; + + ret++; + } + + return ret; +} + +static int kvm_sbi_ext_fwft_get_reg_id(struct kvm_vcpu *vcpu, int index, u64 *reg_id) +{ + int reg, max_reg_count = sizeof(struct kvm_riscv_sbi_fwft) / sizeof(unsigned long); + const struct kvm_sbi_fwft_feature *feature; + struct kvm_sbi_fwft_config *conf; + int idx = 0; + + for (reg = 0; reg < max_reg_count; reg++) { + feature = kvm_sbi_fwft_regnum_to_feature(reg); + if (!feature) + continue; + + conf = kvm_sbi_fwft_get_config(vcpu, feature->id); + if (!conf || !conf->supported) + continue; + + if (index == idx) { + *reg_id = KVM_REG_RISCV | + (IS_ENABLED(CONFIG_32BIT) ? + KVM_REG_SIZE_U32 : KVM_REG_SIZE_U64) | + KVM_REG_RISCV_SBI_STATE | + KVM_REG_RISCV_SBI_FWFT | reg; + return 0; + } + + idx++; + } + + return -ENOENT; +} + +static int kvm_sbi_ext_fwft_get_reg(struct kvm_vcpu *vcpu, unsigned long reg_num, + unsigned long reg_size, void *reg_val) +{ + const struct kvm_sbi_fwft_feature *feature; + struct kvm_sbi_fwft_config *conf; + unsigned long *value; + int ret = 0; + + if (reg_size != sizeof(unsigned long)) + return -EINVAL; + value = reg_val; + + feature = kvm_sbi_fwft_regnum_to_feature(reg_num); + if (!feature) + return -ENOENT; + + conf = kvm_sbi_fwft_get_config(vcpu, feature->id); + if (!conf || !conf->supported) + return -ENOENT; + + switch (reg_num - feature->first_reg_num) { + case 0: + *value = conf->enabled; + break; + case 1: + *value = conf->flags; + break; + case 2: + ret = conf->feature->get(vcpu, conf, true, value); + break; + default: + return -ENOENT; + } + + return sbi_err_map_linux_errno(ret); +} + +static int kvm_sbi_ext_fwft_set_reg(struct kvm_vcpu *vcpu, unsigned long reg_num, + unsigned long reg_size, const void *reg_val) +{ + const struct kvm_sbi_fwft_feature *feature; + struct kvm_sbi_fwft_config *conf; + unsigned long value; + int ret = 0; + + if (reg_size != sizeof(unsigned long)) + return -EINVAL; + value = *(const unsigned long *)reg_val; + + feature = kvm_sbi_fwft_regnum_to_feature(reg_num); + if (!feature) + return -ENOENT; + + conf = kvm_sbi_fwft_get_config(vcpu, feature->id); + if (!conf || !conf->supported) + return -ENOENT; + + switch (reg_num - feature->first_reg_num) { + case 0: + switch (value) { + case 0: + conf->enabled = false; + break; + case 1: + conf->enabled = true; + break; + default: + return -EINVAL; + } + break; + case 1: + conf->flags = value & SBI_FWFT_SET_FLAG_LOCK; + break; + case 2: + ret = conf->feature->set(vcpu, conf, true, value); + break; + default: + return -ENOENT; + } + + return sbi_err_map_linux_errno(ret); +} + +const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_fwft = { + .extid_start = SBI_EXT_FWFT, + .extid_end = SBI_EXT_FWFT, + .handler = kvm_sbi_ext_fwft_handler, + .init = kvm_sbi_ext_fwft_init, + .deinit = kvm_sbi_ext_fwft_deinit, + .reset = kvm_sbi_ext_fwft_reset, + .state_reg_subtype = KVM_REG_RISCV_SBI_FWFT, + .get_state_reg_count = kvm_sbi_ext_fwft_get_reg_count, + .get_state_reg_id = kvm_sbi_ext_fwft_get_reg_id, + .get_state_reg = kvm_sbi_ext_fwft_get_reg, + .set_state_reg = kvm_sbi_ext_fwft_set_reg, +}; |