Re: [PATCH 3/3] KVM: riscv: selftests: Add vector extension tests

[Andrew Jones <ajones@ventanamicro.com>]

On Mon, Apr 28, 2025 at 05:32:09PM -0700, Atish Patra wrote:
> 
> On 4/25/25 7:20 AM, Andrew Jones wrote:
> > On Mon, Mar 24, 2025 at 05:40:31PM -0700, Atish Patra wrote:
> > > Add vector related tests with the ISA extension standard template.
> > > However, the vector registers are bit tricky as the register length is
> > > variable based on vlenb value of the system. That's why the macros are
> > > defined with a default and overidden with actual value at runtime.
> > > 
> > > Signed-off-by: Atish Patra <atishp@rivosinc.com>
> > > ---
> > >   tools/testing/selftests/kvm/riscv/get-reg-list.c | 111 ++++++++++++++++++++++-
> > >   1 file changed, 110 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/tools/testing/selftests/kvm/riscv/get-reg-list.c b/tools/testing/selftests/kvm/riscv/get-reg-list.c
> > > index 8515921dfdbf..576ab8eb7368 100644
> > > --- a/tools/testing/selftests/kvm/riscv/get-reg-list.c
> > > +++ b/tools/testing/selftests/kvm/riscv/get-reg-list.c
> > > @@ -145,7 +145,9 @@ void finalize_vcpu(struct kvm_vcpu *vcpu, struct vcpu_reg_list *c)
> > >   {
> > >   	unsigned long isa_ext_state[KVM_RISCV_ISA_EXT_MAX] = { 0 };
> > >   	struct vcpu_reg_sublist *s;
> > > -	uint64_t feature;
> > > +	uint64_t feature = 0;
> > > +	u64 reg, size;
> > > +	unsigned long vlenb_reg;
> > >   	int rc;
> > >   	for (int i = 0; i < KVM_RISCV_ISA_EXT_MAX; i++)
> > > @@ -173,6 +175,23 @@ void finalize_vcpu(struct kvm_vcpu *vcpu, struct vcpu_reg_list *c)
> > >   		switch (s->feature_type) {
> > >   		case VCPU_FEATURE_ISA_EXT:
> > >   			feature = RISCV_ISA_EXT_REG(s->feature);
> > > +			if (s->feature == KVM_RISCV_ISA_EXT_V) {
> > > +				/* Enable V extension so that we can get the vlenb register */
> > > +				__vcpu_set_reg(vcpu, feature, 1);
> > We probably want to bail here if __vcpu_set_reg returns an error.
> > 
> Sure. What do you mean by bail here ?
> Continue to the next reg or just assert if it returns error.

Continue to the next sublist, but now that I think of it, let's keep
this line as it is and either add a

 __TEST_REQUIRE(__vcpu_has_ext(vcpu, feature),
                "%s not available, skipping tests", s->name);
 continue;

after it. Or, add a label to the __TEST_REQUIRE already at the bottom of
the loop and then goto that.

Thanks,
drew