[PATCH 01/13] RISC-V: KVM: Fix the size parameter check in SBI SFENCE calls

[Anup Patel]

On Thu, Jun 5, 2025 at 11:45 AM Anup Patel <apatel at ventanamicro.com> wrote:
>
> As-per the SBI specification, an SBI remote fence operation applies
> to the entire address space if either:
> 1) start_addr and size are both 0
> 2) size is equal to 2^XLEN-1
>
> From the above, only #1 is checked by SBI SFENCE calls so fix the
> size parameter check in SBI SFENCE calls to cover #2 as well.
>
> Fixes: 13acfec2dbcc ("RISC-V: KVM: Add remote HFENCE functions based on VCPU requests")
> Signed-off-by: Anup Patel <apatel at ventanamicro.com>

Queued as a fix for Linux-6.16

Regards,
Anup

> ---
>  arch/riscv/kvm/vcpu_sbi_replace.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/riscv/kvm/vcpu_sbi_replace.c b/arch/riscv/kvm/vcpu_sbi_replace.c
> index 5fbf3f94f1e8..9752d2ffff68 100644
> --- a/arch/riscv/kvm/vcpu_sbi_replace.c
> +++ b/arch/riscv/kvm/vcpu_sbi_replace.c
> @@ -103,7 +103,7 @@ static int kvm_sbi_ext_rfence_handler(struct kvm_vcpu *vcpu, struct kvm_run *run
>                 kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_FENCE_I_SENT);
>                 break;
>         case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA:
> -               if (cp->a2 == 0 && cp->a3 == 0)
> +               if ((cp->a2 == 0 && cp->a3 == 0) || cp->a3 == -1UL)
>                         kvm_riscv_hfence_vvma_all(vcpu->kvm, hbase, hmask);
>                 else
>                         kvm_riscv_hfence_vvma_gva(vcpu->kvm, hbase, hmask,
> @@ -111,7 +111,7 @@ static int kvm_sbi_ext_rfence_handler(struct kvm_vcpu *vcpu, struct kvm_run *run
>                 kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_HFENCE_VVMA_SENT);
>                 break;
>         case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID:
> -               if (cp->a2 == 0 && cp->a3 == 0)
> +               if ((cp->a2 == 0 && cp->a3 == 0) || cp->a3 == -1UL)
>                         kvm_riscv_hfence_vvma_asid_all(vcpu->kvm,
>                                                        hbase, hmask, cp->a4);
>                 else
> --
> 2.43.0
>