[PATCH v3 11/13] RISC-V: KVM: selftests: Add guest_sbi_probe_extension

[Atish Patra]

On Sun, Dec 17, 2023 at 12:40 PM Andrew Jones <ajones at ventanamicro.com> wrote:
>
> Add guest_sbi_probe_extension(), allowing guest code to probe for
> SBI extensions. As guest_sbi_probe_extension() needs
> SBI_ERR_NOT_SUPPORTED, take the opportunity to bring in all SBI
> error codes. We don't bring in all current extension IDs or base
> extension function IDs though, even though we need one of each,
> because we'd prefer to bring those in as necessary.
>
> Reviewed-by: Anup Patel <anup at brainfault.org>
> Signed-off-by: Andrew Jones <ajones at ventanamicro.com>
> ---
>  .../selftests/kvm/include/riscv/processor.h   | 21 +++++++++++++++++++
>  .../selftests/kvm/lib/riscv/processor.c       | 19 +++++++++++++++++
>  2 files changed, 40 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/include/riscv/processor.h b/tools/testing/selftests/kvm/include/riscv/processor.h
> index e70ccda2011b..dc50ad62e150 100644
> --- a/tools/testing/selftests/kvm/include/riscv/processor.h
> +++ b/tools/testing/selftests/kvm/include/riscv/processor.h
> @@ -108,6 +108,17 @@ static inline uint64_t __kvm_reg_id(uint64_t type, uint64_t subtype,
>  #define SATP_ASID_SHIFT                                44
>  #define SATP_ASID_MASK                         _AC(0xFFFF, UL)
>
> +/* SBI return error codes */
> +#define SBI_SUCCESS                            0
> +#define SBI_ERR_FAILURE                                -1
> +#define SBI_ERR_NOT_SUPPORTED                  -2
> +#define SBI_ERR_INVALID_PARAM                  -3
> +#define SBI_ERR_DENIED                         -4
> +#define SBI_ERR_INVALID_ADDRESS                        -5
> +#define SBI_ERR_ALREADY_AVAILABLE              -6
> +#define SBI_ERR_ALREADY_STARTED                        -7
> +#define SBI_ERR_ALREADY_STOPPED                        -8
> +

Add SBI_ERR_NO_SHMEM as well ?

>  #define SBI_EXT_EXPERIMENTAL_START             0x08000000
>  #define SBI_EXT_EXPERIMENTAL_END               0x08FFFFFF
>
> @@ -115,6 +126,14 @@ static inline uint64_t __kvm_reg_id(uint64_t type, uint64_t subtype,
>  #define KVM_RISCV_SELFTESTS_SBI_UCALL          0
>  #define KVM_RISCV_SELFTESTS_SBI_UNEXP          1
>
> +enum sbi_ext_id {
> +       SBI_EXT_BASE = 0x10,
> +};
> +
> +enum sbi_ext_base_fid {
> +       SBI_EXT_BASE_PROBE_EXT = 3,
> +};
> +
>  struct sbiret {
>         long error;
>         long value;
> @@ -125,4 +144,6 @@ struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
>                         unsigned long arg3, unsigned long arg4,
>                         unsigned long arg5);
>
> +bool guest_sbi_probe_extension(int extid, long *out_val);
> +
>  #endif /* SELFTEST_KVM_PROCESSOR_H */
> diff --git a/tools/testing/selftests/kvm/lib/riscv/processor.c b/tools/testing/selftests/kvm/lib/riscv/processor.c
> index 6905a4348380..7ca736fb4194 100644
> --- a/tools/testing/selftests/kvm/lib/riscv/processor.c
> +++ b/tools/testing/selftests/kvm/lib/riscv/processor.c
> @@ -393,3 +393,22 @@ struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
>
>         return ret;
>  }
> +
> +bool guest_sbi_probe_extension(int extid, long *out_val)
> +{
> +       struct sbiret ret;
> +
> +       ret = sbi_ecall(SBI_EXT_BASE, SBI_EXT_BASE_PROBE_EXT, extid,
> +                       0, 0, 0, 0, 0);
> +
> +       __GUEST_ASSERT(!ret.error || ret.error == SBI_ERR_NOT_SUPPORTED,
> +                      "ret.error=%ld, ret.value=%ld\n", ret.error, ret.value);
> +
> +       if (ret.error == SBI_ERR_NOT_SUPPORTED)
> +               return false;
> +
> +       if (out_val)
> +               *out_val = ret.value;
> +
> +       return true;
> +}
> --
> 2.43.0
>


Apart from that, LGTM.

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

-- 
Regards,
Atish