Re: [RFC 3/9] RISC-V: KVM: Define a probe function for SBI extension data structures

Andrew Jones
2022-11-01T15:33:16Z

On Mon, Jul 18, 2022 at 10:01:59AM -0700, Atish Patra wrote:
> c,urrently the probe function just check if an SBI extension is
Currently checks

> registered or not. However, the extension may not want to advertise
> itself depending on some other condition.
> An additional extension specific probe function will allow
> extensions to decide if they want to be advertised to the caller or
> not. Any extension that do not require additional dependency check
does checks

> does not required to implement this function.

s/does/is/

>
> Signed-off-by: Atish Patra <atishp@rivosinc.com>
> ---
> arch/riscv/include/asm/kvm_vcpu_sbi.h | 3 +++
> arch/riscv/kvm/vcpu_sbi_base.c | 13 +++++++++++--
> 2 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h
> index 83d6d4d2b1df..5853a1ef71ea 100644
> --- a/arch/riscv/include/asm/kvm_vcpu_sbi.h
> +++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h
> @@ -25,6 +25,9 @@ struct kvm_vcpu_sbi_extension {
> int (*handler)(struct kvm_vcpu *vcpu, struct kvm_run *run,
> unsigned long *out_val, struct kvm_cpu_trap *utrap,
> bool *exit);
> +
> + /* Extension specific probe function */
> + unsigned long (*probe)(unsigned long extid);
> };
>
> void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run);
> diff --git a/arch/riscv/kvm/vcpu_sbi_base.c b/arch/riscv/kvm/vcpu_sbi_base.c
> index 48f431091cdb..14be1a819588 100644
> --- a/arch/riscv/kvm/vcpu_sbi_base.c
> +++ b/arch/riscv/kvm/vcpu_sbi_base.c
> @@ -22,6 +22,7 @@ static int kvm_sbi_ext_base_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
> int ret = 0;
> struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
> struct sbiret ecall_ret;
> + const struct kvm_vcpu_sbi_extension *sbi_ext;
>
> switch (cp->a6) {
> case SBI_EXT_BASE_GET_SPEC_VERSION:
> @@ -46,8 +47,16 @@ static int kvm_sbi_ext_base_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
> */
> kvm_riscv_vcpu_sbi_forward(vcpu, run);
> *exit = true;
> - } else
> - *out_val = kvm_vcpu_sbi_find_ext(cp->a0) ? 1 : 0;
> + } else {
> + sbi_ext = kvm_vcpu_sbi_find_ext(cp->a0);
> + if (sbi_ext) {
> + if (sbi_ext->probe)
> + *out_val = sbi_ext->probe(cp->a0);
> + else
> + *out_val = 1;
> + } else
> + *out_val = 0;
> + }
> break;
> case SBI_EXT_BASE_GET_MVENDORID:
> case SBI_EXT_BASE_GET_MARCHID:
> --
> 2.25.1
>

Other than the commit message fixes

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>