Re: [PATCH v2 1/4] RISC-V: KVM: Forward SBI experimental and vendor extensions

From: Atish Patra <atishp@atishpatra.org>
To: Anup Patel <anup.patel@wdc.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Shuah Khan <shuah@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alistair Francis <Alistair.Francis@wdc.com>,
	Anup Patel <anup@brainfault.org>,
	KVM General <kvm@vger.kernel.org>,
	kvm-riscv@lists.infradead.org,
	linux-riscv <linux-riscv@lists.infradead.org>,
	"linux-kernel@vger.kernel.org List"
	<linux-kernel@vger.kernel.org>,
	linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v2 1/4] RISC-V: KVM: Forward SBI experimental and vendor extensions
Date: Thu, 16 Dec 2021 21:42:35 -0800	[thread overview]
Message-ID: <CAOnJCU+=SfN0e-prQsrR8BHfcs7hP9Ab61cnD-yOEZZQ2Gh9cA@mail.gmail.com> (raw)
In-Reply-To: <20211129075451.418122-2-anup.patel@wdc.com>

On Mon, Nov 29, 2021 at 12:10 AM Anup Patel <anup.patel@wdc.com> wrote:
>
> The SBI experimental extension space is for temporary (or experimental)
> stuff whereas SBI vendor extension space is for hardware vendor specific
> stuff. Both these SBI extension spaces won't be standardized by the SBI
> specification so let's blindly forward such SBI calls to the userspace.
>
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> ---
>  arch/riscv/kvm/vcpu_sbi.c      |  4 ++++
>  arch/riscv/kvm/vcpu_sbi_base.c | 27 +++++++++++++++++++++++++++
>  2 files changed, 31 insertions(+)
>
> diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
> index f62d25bc9733..78aa3db76225 100644
> --- a/arch/riscv/kvm/vcpu_sbi.c
> +++ b/arch/riscv/kvm/vcpu_sbi.c
> @@ -46,6 +46,8 @@ extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_time;
>  extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_ipi;
>  extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_rfence;
>  extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_hsm;
> +extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_experimental;
> +extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_vendor;
>
>  static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
>         &vcpu_sbi_ext_v01,
> @@ -54,6 +56,8 @@ static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
>         &vcpu_sbi_ext_ipi,
>         &vcpu_sbi_ext_rfence,
>         &vcpu_sbi_ext_hsm,
> +       &vcpu_sbi_ext_experimental,
> +       &vcpu_sbi_ext_vendor,
>  };
>
>  void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run)
> diff --git a/arch/riscv/kvm/vcpu_sbi_base.c b/arch/riscv/kvm/vcpu_sbi_base.c
> index 641015549d12..ac0537d479d8 100644
> --- a/arch/riscv/kvm/vcpu_sbi_base.c
> +++ b/arch/riscv/kvm/vcpu_sbi_base.c
> @@ -68,3 +68,30 @@ const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_base = {
>         .extid_end = SBI_EXT_BASE,
>         .handler = kvm_sbi_ext_base_handler,
>  };
> +
> +static int kvm_sbi_ext_forward_handler(struct kvm_vcpu *vcpu,
> +                                       struct kvm_run *run,
> +                                       unsigned long *out_val,
> +                                       struct kvm_cpu_trap *utrap,
> +                                       bool *exit)
> +{
> +       /*
> +        * Both SBI experimental and vendor extensions are
> +        * unconditionally forwarded to userspace.
> +        */
> +       kvm_riscv_vcpu_sbi_forward(vcpu, run);
> +       *exit = true;
> +       return 0;
> +}
> +
> +const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_experimental = {
> +       .extid_start = SBI_EXT_EXPERIMENTAL_START,
> +       .extid_end = SBI_EXT_EXPERIMENTAL_END,
> +       .handler = kvm_sbi_ext_forward_handler,
> +};
> +
> +const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_vendor = {
> +       .extid_start = SBI_EXT_VENDOR_START,
> +       .extid_end = SBI_EXT_VENDOR_END,
> +       .handler = kvm_sbi_ext_forward_handler,
> +};
> --
> 2.25.1
>

Reviewed-by: Atish Patra <atishp@rivosinc.com>

--
Regards,
Atish

-- 
Regards,
Atish