[PATCH v4 3/3] KVM: riscv: selftests: Split SBI FWFT into separate feature-specific sublists

[Yong-Xuan Wang]

Divide the monolithic SBI FWFT (Firmware Features) register list into
separate sublists, each testing a specific FWFT feature independently
with proper dependency checking.

Previously, all FWFT features were tested together in a single sublist.
This caused issues because:
1. Not all FWFT features are available on all platforms
2. Some features depend on specific ISA extensions (e.g., pointer_masking
requires Smnpm)
3. Tests would fail if any single feature was unavailable

Add the feature-specific SBI FWFT sublists with the following
improvements:
- Add check_fwft_feature() helper to verify FWFT feature availability
  at runtime
- Update filter_reg() to handle per-feature FWFT register filtering

Signed-off-by: Yong-Xuan Wang <yongxuan.wang at sifive.com>
---
 tools/testing/selftests/kvm/riscv/get-reg-list.c | 60 ++++++++++++++++++++++--
 1 file changed, 57 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/kvm/riscv/get-reg-list.c b/tools/testing/selftests/kvm/riscv/get-reg-list.c
index 5033c09201ef..cb86cb6b3635 100644
--- a/tools/testing/selftests/kvm/riscv/get-reg-list.c
+++ b/tools/testing/selftests/kvm/riscv/get-reg-list.c
@@ -27,6 +27,7 @@ enum {
 };
 
 static bool isa_ext_cant_disable[KVM_RISCV_ISA_EXT_MAX];
+static bool sbi_ext_enabled[KVM_RISCV_SBI_EXT_MAX];
 
 bool filter_reg(__u64 reg)
 {
@@ -149,6 +150,14 @@ bool filter_reg(__u64 reg)
 	case KVM_REG_RISCV_CSR | KVM_REG_RISCV_CSR_AIA | KVM_REG_RISCV_CSR_AIA_REG(iprio1h):
 	case KVM_REG_RISCV_CSR | KVM_REG_RISCV_CSR_AIA | KVM_REG_RISCV_CSR_AIA_REG(iprio2h):
 		return isa_ext_cant_disable[KVM_RISCV_ISA_EXT_SSAIA];
+	/*
+	 * FWFT misaligned delegation registers are always visible when the SBI FWFT
+	 * extension is enable and the host supports the misaligned delegation.
+	 */
+	case KVM_REG_RISCV_SBI_STATE | KVM_REG_RISCV_SBI_FWFT | KVM_REG_RISCV_SBI_FWFT_REG(misaligned_deleg.enable):
+	case KVM_REG_RISCV_SBI_STATE | KVM_REG_RISCV_SBI_FWFT | KVM_REG_RISCV_SBI_FWFT_REG(misaligned_deleg.flags):
+	case KVM_REG_RISCV_SBI_STATE | KVM_REG_RISCV_SBI_FWFT | KVM_REG_RISCV_SBI_FWFT_REG(misaligned_deleg.value):
+		return sbi_ext_enabled[KVM_RISCV_SBI_EXT_FWFT];
 	default:
 		break;
 	}
@@ -193,6 +202,27 @@ static int override_vector_reg_size(struct kvm_vcpu *vcpu, struct vcpu_reg_subli
 	return 0;
 }
 
+void check_fwft_feature(struct kvm_vcpu *vcpu, struct vcpu_reg_sublist *s, u64 feature)
+{
+	unsigned long value;
+	int rc;
+
+	/* Enable SBI FWFT extension so that we can check the supported register */
+	rc = __vcpu_set_reg(vcpu, feature, 1);
+	if (rc)
+		return;
+
+	for (int i = 0; i < s->regs_n; i++) {
+		if ((s->regs[i] & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_SBI_STATE) {
+			rc = __vcpu_get_reg(vcpu, s->regs[i], &value);
+			__TEST_REQUIRE(!rc, "%s not available, skipping tests", s->name);
+		}
+	}
+
+	/* We should assert if disabling failed here while enabling succeeded before */
+	vcpu_set_reg(vcpu, feature, 0);
+}
+
 void finalize_vcpu(struct kvm_vcpu *vcpu, struct vcpu_reg_list *c)
 {
 	unsigned long isa_ext_state[KVM_RISCV_ISA_EXT_MAX] = { 0 };
@@ -235,6 +265,9 @@ void finalize_vcpu(struct kvm_vcpu *vcpu, struct vcpu_reg_list *c)
 			break;
 		case VCPU_FEATURE_SBI_EXT:
 			feature = RISCV_SBI_EXT_REG(s->feature);
+			if (s->feature == KVM_RISCV_SBI_EXT_FWFT)
+				check_fwft_feature(vcpu, s, feature);
+			sbi_ext_enabled[s->feature] = true;
 			break;
 		default:
 			TEST_FAIL("Unknown feature type");
@@ -897,11 +930,15 @@ static __u64 sbi_sta_regs[] = {
 	KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_STATE | KVM_REG_RISCV_SBI_STA | KVM_REG_RISCV_SBI_STA_REG(shmem_hi),
 };
 
-static __u64 sbi_fwft_regs[] = {
+static __u64 sbi_fwft_misaligned_deleg_regs[] = {
 	KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_EXT | KVM_REG_RISCV_SBI_SINGLE | KVM_RISCV_SBI_EXT_FWFT,
 	KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_STATE | KVM_REG_RISCV_SBI_FWFT | KVM_REG_RISCV_SBI_FWFT_REG(misaligned_deleg.enable),
 	KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_STATE | KVM_REG_RISCV_SBI_FWFT | KVM_REG_RISCV_SBI_FWFT_REG(misaligned_deleg.flags),
 	KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_STATE | KVM_REG_RISCV_SBI_FWFT | KVM_REG_RISCV_SBI_FWFT_REG(misaligned_deleg.value),
+};
+
+static __u64 sbi_fwft_pointer_masking_regs[] = {
+	KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_EXT | KVM_REG_RISCV_SBI_SINGLE | KVM_RISCV_SBI_EXT_FWFT,
 	KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_STATE | KVM_REG_RISCV_SBI_FWFT | KVM_REG_RISCV_SBI_FWFT_REG(pointer_masking.enable),
 	KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_STATE | KVM_REG_RISCV_SBI_FWFT | KVM_REG_RISCV_SBI_FWFT_REG(pointer_masking.flags),
 	KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_STATE | KVM_REG_RISCV_SBI_FWFT | KVM_REG_RISCV_SBI_FWFT_REG(pointer_masking.value),
@@ -1129,7 +1166,6 @@ KVM_SBI_EXT_SIMPLE_CONFIG(pmu, PMU);
 KVM_SBI_EXT_SIMPLE_CONFIG(dbcn, DBCN);
 KVM_SBI_EXT_SIMPLE_CONFIG(susp, SUSP);
 KVM_SBI_EXT_SIMPLE_CONFIG(mpxy, MPXY);
-KVM_SBI_EXT_SUBLIST_CONFIG(fwft, FWFT);
 
 KVM_ISA_EXT_SUBLIST_CONFIG(aia, SSAIA);
 KVM_ISA_EXT_SUBLIST_CONFIG(fp_f, F);
@@ -1206,6 +1242,23 @@ KVM_ISA_EXT_SIMPLE_CONFIG(zvksed, ZVKSED);
 KVM_ISA_EXT_SIMPLE_CONFIG(zvksh, ZVKSH);
 KVM_ISA_EXT_SIMPLE_CONFIG(zvkt, ZVKT);
 
+static struct vcpu_reg_list config_sbi_fwft_misaligned_deleg = {
+	.sublists = {
+		SUBLIST_BASE,
+		SUBLIST_SBI(fwft_misaligned_deleg, FWFT),
+		{0},
+	},
+};
+
+static struct vcpu_reg_list config_sbi_fwft_pointer_masking = {
+	.sublists = {
+		SUBLIST_BASE,
+		SUBLIST_ISA(smnpm, SMNPM),
+		SUBLIST_SBI(fwft_pointer_masking, FWFT),
+		{0},
+	},
+};
+
 struct vcpu_reg_list *vcpu_configs[] = {
 	&config_sbi_base,
 	&config_sbi_sta,
@@ -1213,7 +1266,8 @@ struct vcpu_reg_list *vcpu_configs[] = {
 	&config_sbi_dbcn,
 	&config_sbi_susp,
 	&config_sbi_mpxy,
-	&config_sbi_fwft,
+	&config_sbi_fwft_misaligned_deleg,
+	&config_sbi_fwft_pointer_masking,
 	&config_aia,
 	&config_fp_f,
 	&config_fp_d,

-- 
2.43.7