[PATCH v2 04/13] RISC-V: KVM: Add SBI STA extension skeleton

[Anup Patel]

On Thu, Dec 14, 2023 at 3:46 PM Andrew Jones <ajones at ventanamicro.com> wrote:
>
> Add the files and functions needed to support the SBI STA
> (steal-time accounting) extension. In the next patches we'll
> complete the functions to fully enable SBI STA support.
>
> Signed-off-by: Andrew Jones <ajones at ventanamicro.com>

LGTM.

Reviewed-by: Anup Patel <anup at brainfault.org>

Regards,
Anup

> ---
>  arch/riscv/include/asm/kvm_vcpu_sbi.h |  1 +
>  arch/riscv/include/uapi/asm/kvm.h     |  1 +
>  arch/riscv/kvm/Makefile               |  1 +
>  arch/riscv/kvm/vcpu_sbi.c             |  4 +++
>  arch/riscv/kvm/vcpu_sbi_sta.c         | 47 +++++++++++++++++++++++++++
>  5 files changed, 54 insertions(+)
>  create mode 100644 arch/riscv/kvm/vcpu_sbi_sta.c
>
> diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h
> index bffda0ac59b6..99c23bb37a37 100644
> --- a/arch/riscv/include/asm/kvm_vcpu_sbi.h
> +++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h
> @@ -76,6 +76,7 @@ extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_rfence;
>  extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_srst;
>  extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_hsm;
>  extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_dbcn;
> +extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_sta;
>  extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_experimental;
>  extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_vendor;
>
> diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
> index 60d3b21dead7..e961d79622fb 100644
> --- a/arch/riscv/include/uapi/asm/kvm.h
> +++ b/arch/riscv/include/uapi/asm/kvm.h
> @@ -157,6 +157,7 @@ enum KVM_RISCV_SBI_EXT_ID {
>         KVM_RISCV_SBI_EXT_EXPERIMENTAL,
>         KVM_RISCV_SBI_EXT_VENDOR,
>         KVM_RISCV_SBI_EXT_DBCN,
> +       KVM_RISCV_SBI_EXT_STA,
>         KVM_RISCV_SBI_EXT_MAX,
>  };
>
> diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
> index 4c2067fc59fc..c9646521f113 100644
> --- a/arch/riscv/kvm/Makefile
> +++ b/arch/riscv/kvm/Makefile
> @@ -26,6 +26,7 @@ kvm-$(CONFIG_RISCV_SBI_V01) += vcpu_sbi_v01.o
>  kvm-y += vcpu_sbi_base.o
>  kvm-y += vcpu_sbi_replace.o
>  kvm-y += vcpu_sbi_hsm.o
> +kvm-y += vcpu_sbi_sta.o
>  kvm-y += vcpu_timer.o
>  kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o vcpu_sbi_pmu.o
>  kvm-y += aia.o
> diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
> index dcdff4458190..088daaa23dd8 100644
> --- a/arch/riscv/kvm/vcpu_sbi.c
> +++ b/arch/riscv/kvm/vcpu_sbi.c
> @@ -70,6 +70,10 @@ static const struct kvm_riscv_sbi_extension_entry sbi_ext[] = {
>                 .ext_idx = KVM_RISCV_SBI_EXT_DBCN,
>                 .ext_ptr = &vcpu_sbi_ext_dbcn,
>         },
> +       {
> +               .ext_idx = KVM_RISCV_SBI_EXT_STA,
> +               .ext_ptr = &vcpu_sbi_ext_sta,
> +       },
>         {
>                 .ext_idx = KVM_RISCV_SBI_EXT_EXPERIMENTAL,
>                 .ext_ptr = &vcpu_sbi_ext_experimental,
> diff --git a/arch/riscv/kvm/vcpu_sbi_sta.c b/arch/riscv/kvm/vcpu_sbi_sta.c
> new file mode 100644
> index 000000000000..839911dcd837
> --- /dev/null
> +++ b/arch/riscv/kvm/vcpu_sbi_sta.c
> @@ -0,0 +1,47 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2023 Ventana Micro Systems Inc.
> + */
> +
> +#include <linux/kvm_host.h>
> +
> +#include <asm/kvm_vcpu_sbi.h>
> +#include <asm/sbi.h>
> +
> +static int kvm_sbi_sta_steal_time_set_shmem(struct kvm_vcpu *vcpu)
> +{
> +       return SBI_ERR_FAILURE;
> +}
> +
> +static int kvm_sbi_ext_sta_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
> +                                  struct kvm_vcpu_sbi_return *retdata)
> +{
> +       struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
> +       unsigned long funcid = cp->a6;
> +       int ret;
> +
> +       switch (funcid) {
> +       case SBI_EXT_STA_STEAL_TIME_SET_SHMEM:
> +               ret = kvm_sbi_sta_steal_time_set_shmem(vcpu);
> +               break;
> +       default:
> +               ret = SBI_ERR_NOT_SUPPORTED;
> +               break;
> +       }
> +
> +       retdata->err_val = ret;
> +
> +       return 0;
> +}
> +
> +static unsigned long kvm_sbi_ext_sta_probe(struct kvm_vcpu *vcpu)
> +{
> +       return 0;
> +}
> +
> +const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_sta = {
> +       .extid_start = SBI_EXT_STA,
> +       .extid_end = SBI_EXT_STA,
> +       .handler = kvm_sbi_ext_sta_handler,
> +       .probe = kvm_sbi_ext_sta_probe,
> +};
> --
> 2.43.0
>