[RFC PATCH] riscv: kvm: return SBI_ERR_FAILURE for PMU shmem OOM

[Anup Patel]

On Thu, Apr 16, 2026 at 3:40 AM Osama Abdelkader
<osama.abdelkader at gmail.com> wrote:
>
> kvm_riscv_vcpu_pmu_snapshot_set_shmem() and kvm_riscv_vcpu_pmu_event_info()
> returned -ENOMEM from the SBI extension handler, which caused
> kvm_riscv_vcpu_sbi_ecall() to abort KVM_RUN and surface the error to
> userspace instead of completing the ECALL with a negative SBI error in a0.
> Use SBI_ERR_FAILURE and the normal retdata path, matching other PMU
> handlers and kvm_sbi_ext_pmu_handler comment.
>
> Signed-off-by: Osama Abdelkader <osama.abdelkader at gmail.com>

Split this into two patches where:

1) One patch fixing kvm_riscv_vcpu_pmu_snapshot_set_shmem()
2) Second patch fixing kvm_riscv_vcpu_pmu_event_info()

Make sure to add Fixes tag in both patches.

Regards,
Anup

> ---
>  arch/riscv/kvm/vcpu_pmu.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/arch/riscv/kvm/vcpu_pmu.c b/arch/riscv/kvm/vcpu_pmu.c
> index e873430e596b..f36b099f447c 100644
> --- a/arch/riscv/kvm/vcpu_pmu.c
> +++ b/arch/riscv/kvm/vcpu_pmu.c
> @@ -435,8 +435,10 @@ int kvm_riscv_vcpu_pmu_snapshot_set_shmem(struct kvm_vcpu *vcpu, unsigned long s
>         }
>
>         kvpmu->sdata = kzalloc(snapshot_area_size, GFP_ATOMIC);
> -       if (!kvpmu->sdata)
> -               return -ENOMEM;
> +       if (!kvpmu->sdata) {
> +               sbiret = SBI_ERR_FAILURE;
> +               goto out;
> +       }
>
>         /* No need to check writable slot explicitly as kvm_vcpu_write_guest does it internally */
>         if (kvm_vcpu_write_guest(vcpu, saddr, kvpmu->sdata, snapshot_area_size)) {
> @@ -480,8 +482,10 @@ int kvm_riscv_vcpu_pmu_event_info(struct kvm_vcpu *vcpu, unsigned long saddr_low
>         }
>
>         einfo = kzalloc(shmem_size, GFP_KERNEL);
> -       if (!einfo)
> -               return -ENOMEM;
> +       if (!einfo) {
> +               ret = SBI_ERR_FAILURE;
> +               goto out;
> +       }
>
>         ret = kvm_vcpu_read_guest(vcpu, shmem, einfo, shmem_size);
>         if (ret) {
> --
> 2.43.0
>