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

[Osama Abdelkader]

On Thu, May 14, 2026 at 07:13:04PM +0530, Anup Patel wrote:
> 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

Thanks Anup for the review, I just did that.

Regards,
Osama

> 
> > ---
> >  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
> >