[PATCH v8 11/14] RISC-V: KVM: add SBI extension init()/deinit() functions

[Anup Patel]

On Fri, May 23, 2025 at 3:52 PM Clément Léger <cleger at rivosinc.com> wrote:
>
> The FWFT SBI extension will need to dynamically allocate memory and do
> init time specific initialization. Add an init/deinit callbacks that
> allows to do so.
>
> Signed-off-by: Clément Léger <cleger at rivosinc.com>
> Reviewed-by: Andrew Jones <ajones at ventanamicro.com>
> Reviewed-by: Atish Patra <atishp at rivosinc.com>

Queued this patch for Linux-6.17

Thanks,
Anup

> ---
>  arch/riscv/include/asm/kvm_vcpu_sbi.h |  9 +++++++++
>  arch/riscv/kvm/vcpu.c                 |  2 ++
>  arch/riscv/kvm/vcpu_sbi.c             | 26 ++++++++++++++++++++++++++
>  3 files changed, 37 insertions(+)
>
> diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h
> index 4ed6203cdd30..bcb90757b149 100644
> --- a/arch/riscv/include/asm/kvm_vcpu_sbi.h
> +++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h
> @@ -49,6 +49,14 @@ struct kvm_vcpu_sbi_extension {
>
>         /* Extension specific probe function */
>         unsigned long (*probe)(struct kvm_vcpu *vcpu);
> +
> +       /*
> +        * Init/deinit function called once during VCPU init/destroy. These
> +        * might be use if the SBI extensions need to allocate or do specific
> +        * init time only configuration.
> +        */
> +       int (*init)(struct kvm_vcpu *vcpu);
> +       void (*deinit)(struct kvm_vcpu *vcpu);
>  };
>
>  void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run);
> @@ -69,6 +77,7 @@ const struct kvm_vcpu_sbi_extension *kvm_vcpu_sbi_find_ext(
>  bool riscv_vcpu_supports_sbi_ext(struct kvm_vcpu *vcpu, int idx);
>  int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu, struct kvm_run *run);
>  void kvm_riscv_vcpu_sbi_init(struct kvm_vcpu *vcpu);
> +void kvm_riscv_vcpu_sbi_deinit(struct kvm_vcpu *vcpu);
>
>  int kvm_riscv_vcpu_get_reg_sbi_sta(struct kvm_vcpu *vcpu, unsigned long reg_num,
>                                    unsigned long *reg_val);
> diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> index 02635bac91f1..2259717e3b89 100644
> --- a/arch/riscv/kvm/vcpu.c
> +++ b/arch/riscv/kvm/vcpu.c
> @@ -187,6 +187,8 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
>
>  void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
>  {
> +       kvm_riscv_vcpu_sbi_deinit(vcpu);
> +
>         /* Cleanup VCPU AIA context */
>         kvm_riscv_vcpu_aia_deinit(vcpu);
>
> diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
> index d1c83a77735e..3139f171c20f 100644
> --- a/arch/riscv/kvm/vcpu_sbi.c
> +++ b/arch/riscv/kvm/vcpu_sbi.c
> @@ -508,5 +508,31 @@ void kvm_riscv_vcpu_sbi_init(struct kvm_vcpu *vcpu)
>                 scontext->ext_status[idx] = ext->default_disabled ?
>                                         KVM_RISCV_SBI_EXT_STATUS_DISABLED :
>                                         KVM_RISCV_SBI_EXT_STATUS_ENABLED;
> +
> +               if (ext->init && ext->init(vcpu) != 0)
> +                       scontext->ext_status[idx] = KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE;
> +       }
> +}
> +
> +void kvm_riscv_vcpu_sbi_deinit(struct kvm_vcpu *vcpu)
> +{
> +       struct kvm_vcpu_sbi_context *scontext = &vcpu->arch.sbi_context;
> +       const struct kvm_riscv_sbi_extension_entry *entry;
> +       const struct kvm_vcpu_sbi_extension *ext;
> +       int idx, i;
> +
> +       for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {
> +               entry = &sbi_ext[i];
> +               ext = entry->ext_ptr;
> +               idx = entry->ext_idx;
> +
> +               if (idx < 0 || idx >= ARRAY_SIZE(scontext->ext_status))
> +                       continue;
> +
> +               if (scontext->ext_status[idx] == KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE ||
> +                   !ext->deinit)
> +                       continue;
> +
> +               ext->deinit(vcpu);
>         }
>  }
> --
> 2.49.0
>