[PATCH v3 05/13] RISC-V: KVM: Add steal-update vcpu request

[Atish Patra]

On Sun, Dec 17, 2023 at 12:40 PM Andrew Jones <ajones at ventanamicro.com> wrote:
>
> Add a new vcpu request to inform a vcpu that it should record its
> steal-time information. The request is made each time it has been
> detected that the vcpu task was not assigned a cpu for some time,
> which is easy to do by making the request from vcpu-load. The record
> function is just a stub for now and will be filled in with the rest
> of the steal-time support functions in following patches.
>
> Reviewed-by: Anup Patel <anup at brainfault.org>
> Signed-off-by: Andrew Jones <ajones at ventanamicro.com>
> ---
>  arch/riscv/include/asm/kvm_host.h | 3 +++
>  arch/riscv/kvm/vcpu.c             | 5 +++++
>  arch/riscv/kvm/vcpu_sbi_sta.c     | 4 ++++
>  3 files changed, 12 insertions(+)
>
> diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
> index 0eefd9c991ae..230b82c3118d 100644
> --- a/arch/riscv/include/asm/kvm_host.h
> +++ b/arch/riscv/include/asm/kvm_host.h
> @@ -41,6 +41,7 @@
>         KVM_ARCH_REQ_FLAGS(4, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
>  #define KVM_REQ_HFENCE                 \
>         KVM_ARCH_REQ_FLAGS(5, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
> +#define KVM_REQ_STEAL_UPDATE           KVM_ARCH_REQ(6)
>
>  enum kvm_riscv_hfence_type {
>         KVM_RISCV_HFENCE_UNKNOWN = 0,
> @@ -372,4 +373,6 @@ bool kvm_riscv_vcpu_has_interrupts(struct kvm_vcpu *vcpu, u64 mask);
>  void kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu);
>  void kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu);
>
> +void kvm_riscv_vcpu_record_steal_time(struct kvm_vcpu *vcpu);
> +
>  #endif /* __RISCV_KVM_HOST_H__ */
> diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> index bf3952d1a621..6995b8b641e4 100644
> --- a/arch/riscv/kvm/vcpu.c
> +++ b/arch/riscv/kvm/vcpu.c
> @@ -541,6 +541,8 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
>
>         kvm_riscv_vcpu_aia_load(vcpu, cpu);
>
> +       kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu);
> +
>         vcpu->cpu = cpu;
>  }
>
> @@ -614,6 +616,9 @@ static void kvm_riscv_check_vcpu_requests(struct kvm_vcpu *vcpu)
>
>                 if (kvm_check_request(KVM_REQ_HFENCE, vcpu))
>                         kvm_riscv_hfence_process(vcpu);
> +
> +               if (kvm_check_request(KVM_REQ_STEAL_UPDATE, vcpu))
> +                       kvm_riscv_vcpu_record_steal_time(vcpu);
>         }
>  }
>
> diff --git a/arch/riscv/kvm/vcpu_sbi_sta.c b/arch/riscv/kvm/vcpu_sbi_sta.c
> index 839911dcd837..e28351c9488b 100644
> --- a/arch/riscv/kvm/vcpu_sbi_sta.c
> +++ b/arch/riscv/kvm/vcpu_sbi_sta.c
> @@ -8,6 +8,10 @@
>  #include <asm/kvm_vcpu_sbi.h>
>  #include <asm/sbi.h>
>
> +void kvm_riscv_vcpu_record_steal_time(struct kvm_vcpu *vcpu)
> +{
> +}
> +
>  static int kvm_sbi_sta_steal_time_set_shmem(struct kvm_vcpu *vcpu)
>  {
>         return SBI_ERR_FAILURE;
> --
> 2.43.0
>

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

-- 
Regards,
Atish