On Thu, Feb 02, 2023 at 04:14:35PM +0100, Andrew Jones wrote:
> On Wed, Feb 01, 2023 at 03:12:40PM -0800, Atish Patra wrote:
> > Currently the probe function just checks if an SBI extension is
> > 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 does not require additional dependency checks
> > can avoid implementing this function.
> >
> > Reviewed-by: Anup Patel <anup@xxxxxxxxxxxxxx>
> > Signed-off-by: Atish Patra <atishp@xxxxxxxxxxxx>
> > ---
> > 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 f79478a..45ba341 100644
> > --- a/arch/riscv/include/asm/kvm_vcpu_sbi.h
> > +++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h
> > @@ -29,6 +29,9 @@ 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)(struct kvm_vcpu *vcpu);
> > };
> >
> > 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 5d65c63..846d518 100644
> > --- a/arch/riscv/kvm/vcpu_sbi_base.c
> > +++ b/arch/riscv/kvm/vcpu_sbi_base.c
> > @@ -19,6 +19,7 @@ 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;
> > + const struct kvm_vcpu_sbi_extension *sbi_ext;
> >
> > switch (cp->a6) {
> > case SBI_EXT_BASE_GET_SPEC_VERSION:
> > @@ -43,8 +44,16 @@ 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(vcpu);
> > + else
> > + *out_val = 1;
> > + } else
> > + *out_val = 0;
>
> Conor points out elsewhere that we need {} on both arms if one arm needs
> it. We actually don't need {} on either arm, though, or even the if, if
> we rewrite as
>
> *out_val = sbi_ext && sbi_ext->probe ? sbi_ext->probe(vcpu) : !!sbi_ext;
I sent too soon, I meant to add
In any case,
Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx>
Thanks,
drew
>
> Thanks,
> drew
>
> > + }
> > break;
> > case SBI_EXT_BASE_GET_MVENDORID:
> > *out_val = vcpu->arch.mvendorid;
> > --
> > 2.25.1
> >
