[PATCH 2/3] RISC-V: KVM: Update firmware counters for various events

[Anup Patel]

On Fri, Dec 13, 2024 at 2:27 AM Atish Patra <atishp at rivosinc.com> wrote:
>
> SBI PMU specification defines few firmware counters which can be
> used by the guests to collect the statstics about various traps
> occurred in the host.
>
> Update these counters whenever a corresponding trap is taken
>
> Signed-off-by: Atish Patra <atishp at rivosinc.com>

LGTM.

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

Regards,
Anup

> ---
>  arch/riscv/kvm/vcpu_exit.c | 31 +++++++++++++++++++++++++++----
>  1 file changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
> index c9f8b2094554..acdcd619797e 100644
> --- a/arch/riscv/kvm/vcpu_exit.c
> +++ b/arch/riscv/kvm/vcpu_exit.c
> @@ -165,6 +165,17 @@ void kvm_riscv_vcpu_trap_redirect(struct kvm_vcpu *vcpu,
>         vcpu->arch.guest_context.sstatus |= SR_SPP;
>  }
>
> +static inline int vcpu_redirect(struct kvm_vcpu *vcpu, struct kvm_cpu_trap *trap)
> +{
> +       int ret = -EFAULT;
> +
> +       if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV) {
> +               kvm_riscv_vcpu_trap_redirect(vcpu, trap);
> +               ret = 1;
> +       }
> +       return ret;
> +}
> +
>  /*
>   * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
>   * proper exit to userspace.
> @@ -183,15 +194,27 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
>         run->exit_reason = KVM_EXIT_UNKNOWN;
>         switch (trap->scause) {
>         case EXC_INST_ILLEGAL:
> +               kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_ILLEGAL_INSN);
> +               ret = vcpu_redirect(vcpu, trap);
> +               break;
>         case EXC_LOAD_MISALIGNED:
> +               kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_MISALIGNED_LOAD);
> +               ret = vcpu_redirect(vcpu, trap);
> +               break;
>         case EXC_STORE_MISALIGNED:
> +               kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_MISALIGNED_STORE);
> +               ret = vcpu_redirect(vcpu, trap);
> +               break;
>         case EXC_LOAD_ACCESS:
> +               kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_ACCESS_LOAD);
> +               ret = vcpu_redirect(vcpu, trap);
> +               break;
>         case EXC_STORE_ACCESS:
> +               kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_ACCESS_STORE);
> +               ret = vcpu_redirect(vcpu, trap);
> +               break;
>         case EXC_INST_ACCESS:
> -               if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV) {
> -                       kvm_riscv_vcpu_trap_redirect(vcpu, trap);
> -                       ret = 1;
> -               }
> +               ret = vcpu_redirect(vcpu, trap);
>                 break;
>         case EXC_VIRTUAL_INST_FAULT:
>                 if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV)
>
> --
> 2.34.1
>