Add basic infrastructure to support the FWFT extension in KVM.
Signed-off-by: Clément Léger cleger@rivosinc.com Reviewed-by: Andrew Jones ajones@ventanamicro.com --- arch/riscv/include/asm/kvm_host.h | 4 + arch/riscv/include/asm/kvm_vcpu_sbi.h | 1 + arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h | 29 +++ arch/riscv/include/uapi/asm/kvm.h | 1 + arch/riscv/kvm/Makefile | 1 + arch/riscv/kvm/vcpu_sbi.c | 4 + arch/riscv/kvm/vcpu_sbi_fwft.c | 216 +++++++++++++++++++++ 7 files changed, 256 insertions(+) create mode 100644 arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h create mode 100644 arch/riscv/kvm/vcpu_sbi_fwft.c
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h index bb93d2995ea2..c0db61ba691a 100644 --- a/arch/riscv/include/asm/kvm_host.h +++ b/arch/riscv/include/asm/kvm_host.h @@ -19,6 +19,7 @@ #include <asm/kvm_vcpu_fp.h> #include <asm/kvm_vcpu_insn.h> #include <asm/kvm_vcpu_sbi.h> +#include <asm/kvm_vcpu_sbi_fwft.h> #include <asm/kvm_vcpu_timer.h> #include <asm/kvm_vcpu_pmu.h>
@@ -281,6 +282,9 @@ struct kvm_vcpu_arch { /* Performance monitoring context */ struct kvm_pmu pmu_context;
+ /* Firmware feature SBI extension context */ + struct kvm_sbi_fwft fwft_context; + /* 'static' configurations which are set only once */ struct kvm_vcpu_config cfg;
diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h index cb68b3a57c8f..ffd03fed0c06 100644 --- a/arch/riscv/include/asm/kvm_vcpu_sbi.h +++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h @@ -98,6 +98,7 @@ extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_hsm; extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_dbcn; extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_susp; extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_sta; +extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_fwft; extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_experimental; extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_vendor;
diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h b/arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h new file mode 100644 index 000000000000..9ba841355758 --- /dev/null +++ b/arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h @@ -0,0 +1,29 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (c) 2025 Rivos Inc. + * + * Authors: + * Clément Léger cleger@rivosinc.com + */ + +#ifndef __KVM_VCPU_RISCV_FWFT_H +#define __KVM_VCPU_RISCV_FWFT_H + +#include <asm/sbi.h> + +struct kvm_sbi_fwft_feature; + +struct kvm_sbi_fwft_config { + const struct kvm_sbi_fwft_feature *feature; + bool supported; + unsigned long flags; +}; + +/* FWFT data structure per vcpu */ +struct kvm_sbi_fwft { + struct kvm_sbi_fwft_config *configs; +}; + +#define vcpu_to_fwft(vcpu) (&(vcpu)->arch.fwft_context) + +#endif /* !__KVM_VCPU_RISCV_FWFT_H */ diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h index f06bc5efcd79..fa6eee1caf41 100644 --- a/arch/riscv/include/uapi/asm/kvm.h +++ b/arch/riscv/include/uapi/asm/kvm.h @@ -202,6 +202,7 @@ enum KVM_RISCV_SBI_EXT_ID { KVM_RISCV_SBI_EXT_DBCN, KVM_RISCV_SBI_EXT_STA, KVM_RISCV_SBI_EXT_SUSP, + KVM_RISCV_SBI_EXT_FWFT, KVM_RISCV_SBI_EXT_MAX, };
diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile index 4e0bba91d284..06e2d52a9b88 100644 --- a/arch/riscv/kvm/Makefile +++ b/arch/riscv/kvm/Makefile @@ -26,6 +26,7 @@ kvm-y += vcpu_onereg.o kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o kvm-y += vcpu_sbi.o kvm-y += vcpu_sbi_base.o +kvm-y += vcpu_sbi_fwft.o kvm-y += vcpu_sbi_hsm.o kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_sbi_pmu.o kvm-y += vcpu_sbi_replace.o diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c index 50be079b5528..0748810c0252 100644 --- a/arch/riscv/kvm/vcpu_sbi.c +++ b/arch/riscv/kvm/vcpu_sbi.c @@ -78,6 +78,10 @@ static const struct kvm_riscv_sbi_extension_entry sbi_ext[] = { .ext_idx = KVM_RISCV_SBI_EXT_STA, .ext_ptr = &vcpu_sbi_ext_sta, }, + { + .ext_idx = KVM_RISCV_SBI_EXT_FWFT, + .ext_ptr = &vcpu_sbi_ext_fwft, + }, { .ext_idx = KVM_RISCV_SBI_EXT_EXPERIMENTAL, .ext_ptr = &vcpu_sbi_ext_experimental, diff --git a/arch/riscv/kvm/vcpu_sbi_fwft.c b/arch/riscv/kvm/vcpu_sbi_fwft.c new file mode 100644 index 000000000000..8a7cfe1fe7a7 --- /dev/null +++ b/arch/riscv/kvm/vcpu_sbi_fwft.c @@ -0,0 +1,216 @@ +// 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> + +struct kvm_sbi_fwft_feature { + /** + * @id: Feature ID + */ + enum sbi_fwft_feature_t id; + + /** + * @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); + + /** + * @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, 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, 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 const struct kvm_sbi_fwft_feature features[] = { +}; + +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) + 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, 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, 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->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) +{ + int i; + struct kvm_sbi_fwft *fwft = vcpu_to_fwft(vcpu); + + for (i = 0; i < ARRAY_SIZE(features); i++) + fwft->configs[i].flags = 0; +} + +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, +};