Re: [PATCH v5 5/5] KVM: riscv: selftests: Split SBI FWFT into separate feature-specific sublists

From: Anup Patel

Date: Fri Jun 05 2026 - 12:38:17 EST

On Mon, Jun 1, 2026 at 3:56 PM Yong-Xuan Wang <yongxuan.wang@xxxxxxxxxx> wrote:
>
> 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@xxxxxxxxxx>

LGTM.

Reviewed-by: Anup Patel <anup@xxxxxxxxxxxxxx>

Thanks,
Anup

> ---
> 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
>