Re: [PATCH v3 09/10] KVM: riscv: selftests: Skip some registers set operation

[Haibo Xu]

On Fri, Jun 9, 2023 at 5:24 PM Andrew Jones <ajones@xxxxxxxxxxxxxxxx> wrote:
>
> On Fri, Jun 09, 2023 at 10:12:17AM +0800, Haibo Xu wrote:
> > Set operation on some riscv registers(mostly pesudo ones) was not
> > supported and should be skipped in the get-reg-list test. Just
> > reuse the rejects_set utilities to handle it in riscv.
> >
> > Signed-off-by: Haibo Xu <haibo1.xu@xxxxxxxxx>
> > Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx>
> > ---
> >  tools/testing/selftests/kvm/get-reg-list.c | 20 +++++++++++++-------
> >  1 file changed, 13 insertions(+), 7 deletions(-)
> >
> > diff --git a/tools/testing/selftests/kvm/get-reg-list.c b/tools/testing/selftests/kvm/get-reg-list.c
> > index c4bd5a5259da..abacb95c21c6 100644
> > --- a/tools/testing/selftests/kvm/get-reg-list.c
> > +++ b/tools/testing/selftests/kvm/get-reg-list.c
> > @@ -211,16 +211,22 @@ static void run_test(struct vcpu_reg_list *c)
> >                       ++failed_get;
> >               }
> >
> > -             /* rejects_set registers are rejected after KVM_ARM_VCPU_FINALIZE */
> > +             /*
> > +              * rejects_set registers are rejected after KVM_ARM_VCPU_FINALIZE on aarch64,
> > +              * or registers that should skip set operation on riscv.
> > +              */
> >               for_each_sublist(c, s) {
> >                       if (s->rejects_set && find_reg(s->rejects_set, s->rejects_set_n, reg.id)) {
> >                               reject_reg = true;
> > -                             ret = __vcpu_ioctl(vcpu, KVM_SET_ONE_REG, &reg);
> > -                             if (ret != -1 || errno != EPERM) {
> > -                                     printf("%s: Failed to reject (ret=%d, errno=%d) ", config_name(c), ret, errno);
> > -                                     print_reg(config_name(c), reg.id);
> > -                                     putchar('\n');
> > -                                     ++failed_reject;
> > +                             if ((reg.id & KVM_REG_ARCH_MASK) == KVM_REG_ARM64) {
> > +                                     ret = __vcpu_ioctl(vcpu, KVM_SET_ONE_REG, &reg);
> > +                                     if (ret != -1 || errno != EPERM) {
> > +                                             printf("%s: Failed to reject (ret=%d, errno=%d) ",
> > +                                                             config_name(c), ret, errno);
> > +                                             print_reg(config_name(c), reg.id);
> > +                                             putchar('\n');
> > +                                             ++failed_reject;
> > +                                     }
>
> Thinking about this some more, shouldn't we attempt the set ioctl for
> riscv reject registers as well, but look for different error numbers?
>

Yes, we can. Currently, 2 different errno(EOPNOTSUPP/EINVAL) would be
reported for the rejected registers in risc-v.
These 2 errnos can be handled specially like below:

diff --git a/tools/testing/selftests/kvm/get-reg-list.c
b/tools/testing/selftests/kvm/get-reg-list.c
index 73f40e0842b8..f3f2c4519318 100644
--- a/tools/testing/selftests/kvm/get-reg-list.c
+++ b/tools/testing/selftests/kvm/get-reg-list.c
@@ -255,6 +255,15 @@ static void run_test(struct vcpu_reg_list *c)
                                                putchar('\n');
                                                ++failed_reject;
                                        }
+                } else {
+                                       ret = __vcpu_ioctl(vcpu,
KVM_SET_ONE_REG, &reg);
+                                       if (ret != -1 || (errno !=
EINVAL && errno != EOPNOTSUPP)) {
+                                               printf("%s: Failed to
reject (ret=%d, errno=%d) ",
+
config_name(c), ret, errno);
+
print_reg(config_name(c), reg.id);
+                                               putchar('\n');
+                                               ++failed_reject;
+                                       }

One possible issue for the above change is that when new registers
that don't support sets were added, we need
to add them to the reject registers list, or the test would fail.

Initially, in the v1 patch, the design was to just skip the EOPNOTSUPP
errno in set operations for all registers
since it's a known errno for registers that don't support sets. This
change cover all the registers even for future
new ones.

What's your opinion?

Thanks,
Haibo
> Thanks,
> drew