[PATCH v2 5/7] RISC-V: KVM: Handle software-check exits for VCPU

[Inochi Amaoto]

The extension Zicfiss/Zicfilp introduces a software-check exception
to the privilege architecture. Delegate this exception to VS mode so
the CFI violations in VU/VS could be reported.

Assisted-by: YuanSheng:claude-4.7-opus
Co-developed-by: Quan Zhou <zhouquan at iscas.ac.cn>
Signed-off-by: Quan Zhou <zhouquan at iscas.ac.cn>
Signed-off-by: Inochi Amaoto <inochiama at gmail.com>
---
 arch/riscv/include/asm/csr.h | 1 +
 arch/riscv/kvm/vcpu_config.c | 4 ++++
 arch/riscv/kvm/vcpu_exit.c   | 3 +++
 3 files changed, 8 insertions(+)

diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index 31b8988f4488..224af9facf1f 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -117,6 +117,7 @@
 #define EXC_INST_PAGE_FAULT	12
 #define EXC_LOAD_PAGE_FAULT	13
 #define EXC_STORE_PAGE_FAULT	15
+#define EXC_SOFTWARE_CHECK		18
 #define EXC_INST_GUEST_PAGE_FAULT	20
 #define EXC_LOAD_GUEST_PAGE_FAULT	21
 #define EXC_VIRTUAL_INST_FAULT		22
diff --git a/arch/riscv/kvm/vcpu_config.c b/arch/riscv/kvm/vcpu_config.c
index b2a1028106d5..dbe4167ac4f1 100644
--- a/arch/riscv/kvm/vcpu_config.c
+++ b/arch/riscv/kvm/vcpu_config.c
@@ -65,6 +65,10 @@ void kvm_riscv_vcpu_config_ran_once(struct kvm_vcpu *vcpu)
 
 	if (vcpu->guest_debug)
 		cfg->hedeleg &= ~BIT(EXC_BREAKPOINT);
+
+	if (riscv_isa_extension_available(isa, ZICFILP) ||
+	    riscv_isa_extension_available(isa, ZICFISS))
+		cfg->hedeleg |= BIT(EXC_SOFTWARE_CHECK);
 }
 
 void kvm_riscv_vcpu_config_load(struct kvm_vcpu *vcpu)
diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
index 0bb0c51e3c89..5ab8e87ed248 100644
--- a/arch/riscv/kvm/vcpu_exit.c
+++ b/arch/riscv/kvm/vcpu_exit.c
@@ -243,6 +243,9 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 		run->exit_reason = KVM_EXIT_DEBUG;
 		ret = 0;
 		break;
+	case EXC_SOFTWARE_CHECK:
+		ret = vcpu_redirect(vcpu, trap);
+		break;
 	default:
 		break;
 	}
-- 
2.54.0