linux-kernel - Re: [PATCH v2 7/8] KVM: riscv: selftest: Change vcpu_has

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Message-ID: <20230907-bde62d037a3aaeedfe31f964@orel>
Date:   Thu, 7 Sep 2023 11:01:42 +0200
From:   Andrew Jones <ajones@...tanamicro.com>
To:     Haibo Xu <xiaobo55x@...il.com>
Cc:     Haibo Xu <haibo1.xu@...el.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Shuah Khan <shuah@...nel.org>, Marc Zyngier <maz@...nel.org>,
        Oliver Upton <oliver.upton@...ux.dev>,
        James Morse <james.morse@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Zenghui Yu <yuzenghui@...wei.com>,
        Anup Patel <anup@...infault.org>,
        Atish Patra <atishp@...shpatra.org>,
        Guo Ren <guoren@...nel.org>,
        Daniel Henrique Barboza <dbarboza@...tanamicro.com>,
        wchen <waylingii@...il.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Ricardo Koller <ricarkol@...gle.com>,
        Vishal Annapurve <vannapurve@...gle.com>,
        David Matlack <dmatlack@...gle.com>,
        Aaron Lewis <aaronlewis@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Ackerley Tng <ackerleytng@...gle.com>,
        Mingwei Zhang <mizhang@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        Lei Wang <lei4.wang@...el.com>,
        Vipin Sharma <vipinsh@...gle.com>,
        Maxim Levitsky <mlevitsk@...hat.com>,
        Like Xu <likexu@...cent.com>, Peter Gonda <pgonda@...gle.com>,
        Thomas Huth <thuth@...hat.com>,
        Philippe Mathieu-Daudé <philmd@...aro.org>,
        David Woodhouse <dwmw@...zon.co.uk>,
        Michal Luczaj <mhal@...x.co>, Paul Durrant <paul@....org>,
        linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org,
        kvm@...r.kernel.org, linux-kselftest@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
        kvm-riscv@...ts.infradead.org
Subject: Re: [PATCH v2 7/8] KVM: riscv: selftest: Change vcpu_has_ext to a
 common function

On Thu, Sep 07, 2023 at 11:57:00AM +0800, Haibo Xu wrote:
> On Wed, Sep 6, 2023 at 6:10 PM Haibo Xu <xiaobo55x@...il.com> wrote:
> >
> > On Mon, Sep 4, 2023 at 10:04 PM Andrew Jones <ajones@...tanamicro.com> wrote:
> > >
> > > On Sat, Sep 02, 2023 at 08:59:29PM +0800, Haibo Xu wrote:
> > > > diff --git a/tools/testing/selftests/kvm/riscv/get-reg-list.c b/tools/testing/selftests/kvm/riscv/get-reg-list.c
> > > > index d8ecacd03ecf..c4028bf32e3f 100644
> > > > --- a/tools/testing/selftests/kvm/riscv/get-reg-list.c
> > > > +++ b/tools/testing/selftests/kvm/riscv/get-reg-list.c
> > > > @@ -44,20 +44,6 @@ bool check_reject_set(int err)
> > > >       return err == EINVAL;
> > > >  }
> > > >
> > > > -static inline bool vcpu_has_ext(struct kvm_vcpu *vcpu, int ext)
> > > > -{
> > > > -     int ret;
> > > > -     unsigned long value;
> > > > -
> > > > -     ret = __vcpu_get_reg(vcpu, RISCV_ISA_EXT_REG(ext), &value);
> > > > -     if (ret) {
> > > > -             printf("Failed to get ext %d", ext);
> > > > -             return false;
> > > > -     }
> > > > -
> > > > -     return !!value;
> > >
> > > get-reg-list will now assert on get-reg when an extension isn't present,
> > > rather than failing the __TEST_REQUIRE(), which would do a skip instead.
> > > We need both the return false version and the assert version.
> > >
> >
> > Ok, Will keep this one for get-reg-list and add another one for
> > arch-timer specific usage.
> >
> 
> Just thought about it again, maybe we only need the "return false"
> version for both get-reg-list
> and arch-timer tests since if an extension was not available, the test
> can be skipped with a message.
> 
> bool vcpu_has_ext(struct kvm_vcpu *vcpu, int ext)
> {
>        unsigned long value = 0;
> 
>        __vcpu_get_reg(vcpu, RISCV_ISA_EXT_REG(ext), &value);
> 
>        return !!value;
> }

Yup, I had actually seen that when reviewing a later patch in this series,
but I wasn't concerned if we added the assert type anyway, since we
frequently end up with the two function types for KVM queries. If we don't
have a need for an assert type yet, then we don't need to introduce it.
However, we should introduce the non-assert type as __vcpu_has_ext(),
reserving the vcpu_has_ext() name for the assert type, per the kvm
selftests naming convention.

Thanks,
drew