linux-kernel - Re: [PATCH 3/4] KVM: riscv: selftests: Fix ISA

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Message-ID: <CAOnJCUJYDHtbYS4js7PSAeLqT4sL5zi7DT5xeSww+5Nvs2UhcA@mail.gmail.com>
Date:   Tue, 19 Sep 2023 12:54:32 -0700
From:   Atish Patra <atishp@...shpatra.org>
To:     Anup Patel <apatel@...tanamicro.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>, Shuah Khan <shuah@...nel.org>,
        Palmer Dabbelt <palmer@...belt.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Andrew Jones <ajones@...tanamicro.com>, kvm@...r.kernel.org,
        kvm-riscv@...ts.infradead.org, linux-riscv@...ts.infradead.org,
        linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH 3/4] KVM: riscv: selftests: Fix ISA_EXT register handling
 in get-reg-list

On Mon, Sep 18, 2023 at 11:07 AM Anup Patel <apatel@...tanamicro.com> wrote:
>
> Same set of ISA_EXT registers are not present on all host because
> ISA_EXT registers are visible to the KVM user space based on the
> ISA extensions available on the host. Also, disabling an ISA
> extension using corresponding ISA_EXT register does not affect
> the visibility of the ISA_EXT register itself.
>
> Based on the above, we should filter-out all ISA_EXT registers.
>

In that case, we don't need the switch case any more. Just a
conditional check with KVM_RISCV_ISA_EXT_MAX should be sufficient.

> Fixes: 477069398ed6 ("KVM: riscv: selftests: Add get-reg-list test")
> Signed-off-by: Anup Patel <apatel@...tanamicro.com>
> ---
>  .../selftests/kvm/riscv/get-reg-list.c        | 35 +++++++++++--------
>  1 file changed, 21 insertions(+), 14 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/riscv/get-reg-list.c b/tools/testing/selftests/kvm/riscv/get-reg-list.c
> index d8ecacd03ecf..76c0ad11e423 100644
> --- a/tools/testing/selftests/kvm/riscv/get-reg-list.c
> +++ b/tools/testing/selftests/kvm/riscv/get-reg-list.c
> @@ -14,17 +14,33 @@
>
>  bool filter_reg(__u64 reg)
>  {
> +       switch (reg & ~REG_MASK) {
>         /*
> -        * Some ISA extensions are optional and not present on all host,
> -        * but they can't be disabled through ISA_EXT registers when present.
> -        * So, to make life easy, just filtering out these kind of registers.
> +        * Same set of ISA_EXT registers are not present on all host because
> +        * ISA_EXT registers are visible to the KVM user space based on the
> +        * ISA extensions available on the host. Also, disabling an ISA
> +        * extension using corresponding ISA_EXT register does not affect
> +        * the visibility of the ISA_EXT register itself.
> +        *
> +        * Based on above, we should filter-out all ISA_EXT registers.
>          */
> -       switch (reg & ~REG_MASK) {
> +       case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_A:
> +       case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_C:
> +       case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_D:
> +       case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_F:
> +       case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_H:
> +       case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_I:
> +       case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_M:
> +       case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_SVPBMT:
>         case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_SSTC:
>         case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_SVINVAL:
>         case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_ZIHINTPAUSE:
> +       case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_ZICBOM:
> +       case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_ZICBOZ:
>         case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_ZBB:
>         case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_SSAIA:
> +       case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_V:
> +       case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_SVNAPOT:
>         case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_ZBA:
>         case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_ZBS:
>         case KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_ZICNTR:
> @@ -50,12 +66,7 @@ static inline bool vcpu_has_ext(struct kvm_vcpu *vcpu, int ext)
>         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;
> +       return (ret) ? false : !!value;
>  }
>
>  void finalize_vcpu(struct kvm_vcpu *vcpu, struct vcpu_reg_list *c)
> @@ -506,10 +517,6 @@ static __u64 base_regs[] = {
>         KVM_REG_RISCV | KVM_REG_SIZE_U64 | KVM_REG_RISCV_TIMER | KVM_REG_RISCV_TIMER_REG(time),
>         KVM_REG_RISCV | KVM_REG_SIZE_U64 | KVM_REG_RISCV_TIMER | KVM_REG_RISCV_TIMER_REG(compare),
>         KVM_REG_RISCV | KVM_REG_SIZE_U64 | KVM_REG_RISCV_TIMER | KVM_REG_RISCV_TIMER_REG(state),
> -       KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_A,
> -       KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_C,
> -       KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_I,
> -       KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_ISA_EXT | KVM_RISCV_ISA_EXT_M,
>         KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_EXT | KVM_REG_RISCV_SBI_SINGLE | KVM_RISCV_SBI_EXT_V01,
>         KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_EXT | KVM_REG_RISCV_SBI_SINGLE | KVM_RISCV_SBI_EXT_TIME,
>         KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_EXT | KVM_REG_RISCV_SBI_SINGLE | KVM_RISCV_SBI_EXT_IPI,
> --
> 2.34.1
>


-- 
Regards,
Atish