linux-kernel - Re: [PATCH v4 08/12] KVM: arm64: selftests: Move reject

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Message-ID: <CAJve8ony9nj9LyCAJjtvthR+ABLvSPHvpeE5e5=wr_z44i20qw@mail.gmail.com>
Date:   Wed, 28 Jun 2023 13:58:21 +0800
From:   Haibo Xu <xiaobo55x@...il.com>
To:     Andrew Jones <ajones@...tanamicro.com>
Cc:     Haibo Xu <haibo1.xu@...el.com>, maz@...nel.org,
        oliver.upton@...ux.dev, seanjc@...gle.com,
        Paolo Bonzini <pbonzini@...hat.com>,
        Jonathan Corbet <corbet@....net>,
        Anup Patel <anup@...infault.org>,
        Atish Patra <atishp@...shpatra.org>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Shuah Khan <shuah@...nel.org>,
        James Morse <james.morse@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Zenghui Yu <yuzenghui@...wei.com>,
        David Matlack <dmatlack@...gle.com>,
        Ben Gardon <bgardon@...gle.com>,
        Ricardo Koller <ricarkol@...gle.com>,
        Vishal Annapurve <vannapurve@...gle.com>,
        Vipin Sharma <vipinsh@...gle.com>,
        Colton Lewis <coltonlewis@...gle.com>, kvm@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        kvm-riscv@...ts.infradead.org, linux-riscv@...ts.infradead.org,
        linux-kselftest@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev
Subject: Re: [PATCH v4 08/12] KVM: arm64: selftests: Move reject_set check
 logic to a function

On Tue, Jun 27, 2023 at 5:09 PM Andrew Jones <ajones@...tanamicro.com> wrote:
>
> On Fri, Jun 23, 2023 at 06:40:10PM +0800, Haibo Xu wrote:
> > No functional changes. Just move the reject_set check logic to a
> > function so we can check for specific errno for specific register.
> > This is a preparation for support reject_set in riscv.
> >
> > Suggested-by: Andrew Jones <ajones@...tanamicro.com>
> > Signed-off-by: Haibo Xu <haibo1.xu@...el.com>
> > ---
> >  tools/testing/selftests/kvm/aarch64/get-reg-list.c | 8 ++++++++
> >  tools/testing/selftests/kvm/get-reg-list.c         | 7 ++++++-
> >  2 files changed, 14 insertions(+), 1 deletion(-)
> >
> > diff --git a/tools/testing/selftests/kvm/aarch64/get-reg-list.c b/tools/testing/selftests/kvm/aarch64/get-reg-list.c
> > index aaf035c969ec..4e2e1fe833eb 100644
> > --- a/tools/testing/selftests/kvm/aarch64/get-reg-list.c
> > +++ b/tools/testing/selftests/kvm/aarch64/get-reg-list.c
> > @@ -27,6 +27,14 @@ bool filter_reg(__u64 reg)
> >       return false;
> >  }
> >
> > +bool reject_set_fail(__u64 reg)
> > +{
> > +     if (reg == KVM_REG_ARM64_SVE_VLS)
> > +             return (errno != EPERM);
> > +
> > +     return false;
> > +}
>
> I think we should pass errno in as a parameter and I prefer positive
> predicate functions, so I'd name this check_reject_set() and reverse
> the logic. Also, we don't want to check for KVM_REG_ARM64_SVE_VLS,
> because that duplicates the rejects set. I see in a later patch
> that riscv needs to check reg because different errors are used
> for different registers, but that's because KVM_REG_RISCV_TIMER_REG(state)
> was erroneously added to the rejects set. KVM_REG_RISCV_TIMER_REG(state)
> doesn't belong there. That register can be set, but it only supports
> certain input, otherwise, it correctly, results in EINVAL. We'll need
> the concept of a "skip set" to avoid tripping over that one.
>
> So, I think arm's function should be
>
>  bool check_reject_set(int errno)
>  {
>      return errno == EPERM;
>  }
>
> and riscv's should be
>
>  bool check_reject_set(int errno)
>  {
>      return errno == EOPNOTSUPP;
>  }
>

Sure, will add a new 'skips_set' member to 'struct vcpu_reg_sublist' and
move KVM_REG_RISCV_TIMER_REG(state) reg to it.

> > +
> >  #define REG_MASK (KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK | KVM_REG_ARM_COPROC_MASK)
> >
> >  #define CORE_REGS_XX_NR_WORDS        2
> > diff --git a/tools/testing/selftests/kvm/get-reg-list.c b/tools/testing/selftests/kvm/get-reg-list.c
> > index f6ad7991a812..b956ee410996 100644
> > --- a/tools/testing/selftests/kvm/get-reg-list.c
> > +++ b/tools/testing/selftests/kvm/get-reg-list.c
> > @@ -98,6 +98,11 @@ void __weak print_reg(const char *prefix, __u64 id)
> >       printf("\t0x%llx,\n", id);
> >  }
> >
> > +bool __weak reject_set_fail(__u64 reg)
> > +{
> > +     return false;
> > +}
> > +
> >  #ifdef __aarch64__
> >  static void prepare_vcpu_init(struct vcpu_reg_list *c, struct kvm_vcpu_init *init)
> >  {
> > @@ -216,7 +221,7 @@ static void run_test(struct vcpu_reg_list *c)
> >                       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) {
> > +                             if (ret != -1 || reject_set_fail(reg.id)) {
> >                                       printf("%s: Failed to reject (ret=%d, errno=%d) ", config_name(c), ret, errno);
> >                                       print_reg(config_name(c), reg.id);
> >                                       putchar('\n');
> > --
> > 2.34.1
> >
>
> Thanks,
> drew