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Mon, 01 Jun 2026 01:44:14 -0700 (PDT) From: Inochi Amaoto To: Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Anup Patel , Atish Patra , Paolo Bonzini , Shuah Khan , Deepak Gupta , Thomas Huth , Charlie Jenkins , Sergey Matyukevich , Inochi Amaoto Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-kselftest@vger.kernel.org, Yixun Lan , Longbin Li , Quan Zhou Subject: [PATCH v2 6/7] RISC-V: KVM: Add support for control-flow integrity FWFT features Date: Mon, 1 Jun 2026 16:43:34 +0800 Message-ID: <20260601084336.2601675-7-inochiama@gmail.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260601084336.2601675-1-inochiama@gmail.com> References: <20260601084336.2601675-1-inochiama@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Control-flow integrity is controlled through a WARL field in henvcfg. Expose the feature only if the Zicfilp/Zicfiss is supported for VS-mode. Allow the VMM to block access to the feature by disabling the ISA extension in the guest. Assisted-by: YuanSheng:claude-4.7-opus Co-developed-by: Quan Zhou Signed-off-by: Quan Zhou Signed-off-by: Inochi Amaoto --- arch/riscv/kvm/vcpu_sbi_fwft.c | 70 ++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) diff --git a/arch/riscv/kvm/vcpu_sbi_fwft.c b/arch/riscv/kvm/vcpu_sbi_fwft.c index 375269e43c13..278eb95b97de 100644 --- a/arch/riscv/kvm/vcpu_sbi_fwft.c +++ b/arch/riscv/kvm/vcpu_sbi_fwft.c @@ -163,6 +163,58 @@ static long kvm_sbi_fwft_get_misaligned_delegation(struct kvm_vcpu *vcpu, return SBI_SUCCESS; } +static bool kvm_sbi_fwft_landing_pad_supported(struct kvm_vcpu *vcpu) +{ + return riscv_isa_extension_available(vcpu->arch.isa, ZICFILP); +} + +static void kvm_sbi_fwft_reset_landing_pad(struct kvm_vcpu *vcpu) +{ + kvm_sbi_fwft_env_flag_reset_helper(vcpu, ENVCFG_LPE); +} + +static long kvm_sbi_fwft_set_landing_pad(struct kvm_vcpu *vcpu, + struct kvm_sbi_fwft_config *conf, + bool one_reg_access, unsigned long value) +{ + return kvm_sbi_fwft_env_flag_set_helper(vcpu, conf, one_reg_access, + value, ENVCFG_LPE); +} + +static long kvm_sbi_fwft_get_landing_pad(struct kvm_vcpu *vcpu, + struct kvm_sbi_fwft_config *conf, + bool one_reg_access, unsigned long *value) +{ + return kvm_sbi_fwft_env_flag_get_helper(vcpu, conf, one_reg_access, + value, ENVCFG_LPE); +} + +static bool kvm_sbi_fwft_shadow_stack_supported(struct kvm_vcpu *vcpu) +{ + return riscv_isa_extension_available(vcpu->arch.isa, ZICFISS); +} + +static void kvm_sbi_fwft_reset_shadow_stack(struct kvm_vcpu *vcpu) +{ + kvm_sbi_fwft_env_flag_reset_helper(vcpu, ENVCFG_SSE); +} + +static long kvm_sbi_fwft_set_shadow_stack(struct kvm_vcpu *vcpu, + struct kvm_sbi_fwft_config *conf, + bool one_reg_access, unsigned long value) +{ + return kvm_sbi_fwft_env_flag_set_helper(vcpu, conf, one_reg_access, + value, ENVCFG_SSE); +} + +static long kvm_sbi_fwft_get_shadow_stack(struct kvm_vcpu *vcpu, + struct kvm_sbi_fwft_config *conf, + bool one_reg_access, unsigned long *value) +{ + return kvm_sbi_fwft_env_flag_get_helper(vcpu, conf, one_reg_access, + value, ENVCFG_SSE); +} + static bool kvm_sbi_fwft_pte_ad_hw_updating_supported(struct kvm_vcpu *vcpu) { return riscv_isa_extension_available(vcpu->arch.isa, SVADU) && @@ -288,6 +340,24 @@ static const struct kvm_sbi_fwft_feature features[] = { .set = kvm_sbi_fwft_set_misaligned_delegation, .get = kvm_sbi_fwft_get_misaligned_delegation, }, + { + .id = SBI_FWFT_LANDING_PAD, + .first_reg_num = offsetof(struct kvm_riscv_sbi_fwft, landing_pad.enable) / + sizeof(unsigned long), + .supported = kvm_sbi_fwft_landing_pad_supported, + .reset = kvm_sbi_fwft_reset_landing_pad, + .set = kvm_sbi_fwft_set_landing_pad, + .get = kvm_sbi_fwft_get_landing_pad, + }, + { + .id = SBI_FWFT_SHADOW_STACK, + .first_reg_num = offsetof(struct kvm_riscv_sbi_fwft, shadow_stack.enable) / + sizeof(unsigned long), + .supported = kvm_sbi_fwft_shadow_stack_supported, + .reset = kvm_sbi_fwft_reset_shadow_stack, + .set = kvm_sbi_fwft_set_shadow_stack, + .get = kvm_sbi_fwft_get_shadow_stack, + }, { .id = SBI_FWFT_PTE_AD_HW_UPDATING, .first_reg_num = offsetof(struct kvm_riscv_sbi_fwft, pte_ad_hw_updating.enable) / -- 2.54.0