Re: [PATCH v3 2/7] KVM: arm64: Forward FFA_NOTIFICATION_BITMAP calls to Trustzone

[Sebastian Ene <sebastianene@google.com>]

On Tue, Jun 16, 2026 at 01:42:35PM +0100, Vincent Donnefort wrote:
> On Tue, Jun 16, 2026 at 10:54:10AM +0000, Sebastian Ene wrote:
> > Allow FF-A notification bitmap messages to be forwarded to
> > Trustzone from the host kernel driver enforce checking for
> > SBZ fields.
> > 
> > Signed-off-by: Sebastian Ene <sebastianene@google.com>
> > ---
> >  arch/arm64/kvm/hyp/nvhe/ffa.c | 28 ++++++++++++++++++++++++++--
> >  1 file changed, 26 insertions(+), 2 deletions(-)
> > 
> > diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c
> > index c723a21006aa..dc7496ec295f 100644
> > --- a/arch/arm64/kvm/hyp/nvhe/ffa.c
> > +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c
> > @@ -713,8 +713,6 @@ static bool ffa_call_supported(u64 func_id)
> >  	case FFA_MEM_DONATE:
> >  	case FFA_MEM_RETRIEVE_REQ:
> >         /* Optional notification interfaces added in FF-A 1.1 */
> > -	case FFA_NOTIFICATION_BITMAP_CREATE:
> > -	case FFA_NOTIFICATION_BITMAP_DESTROY:
> >  	case FFA_NOTIFICATION_BIND:
> >  	case FFA_NOTIFICATION_UNBIND:
> >  	case FFA_NOTIFICATION_SET:
> > @@ -909,6 +907,28 @@ static void do_ffa_part_get(struct arm_smccc_1_2_regs *res,
> >  	hyp_spin_unlock(&host_buffers.lock);
> >  }
> >  
> > +static void do_ffa_notif_bitmap(struct arm_smccc_1_2_regs *res,
> > +				struct kvm_cpu_context *ctxt)
> > +{
> > +	DECLARE_REG(u32, func_id, ctxt, 0);
> > +	DECLARE_REG(u32, vmid, ctxt, 1);
> > +	struct arm_smccc_1_2_regs *args;
> > +	u32 idx_unused_args = func_id == FFA_NOTIFICATION_BITMAP_CREATE ? 3 : 2;
> 
> nit: should probably better expressed as a int as this is the type in the
> ffa_check_unused_args_sbz proto.
> 
> Perhaps you can even fold that directly into the ffa_check_unused_args_sbz()
> call?
> 

Yes, let me try this.

> > +
> > +	if (ffa_check_unused_args_sbz(ctxt, idx_unused_args)) {
> > +		ffa_to_smccc_res(res, FFA_RET_INVALID_PARAMETERS);
> > +		return;
> > +	}
> > +
> > +	if (vmid != HOST_FFA_ID) {
> > +		ffa_to_smccc_res(res, FFA_RET_INVALID_PARAMETERS);
> > +		return;
> > +	}
> > +
> > +	args = (void *)&ctxt->regs.regs[0];
> > +	hyp_smccc_1_2_smc(args, res);
> > +}
> > +
> >  bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt, u32 func_id)
> >  {
> >  	struct arm_smccc_1_2_regs res;
> > @@ -967,6 +987,10 @@ bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt, u32 func_id)
> >  	case FFA_PARTITION_INFO_GET:
> >  		do_ffa_part_get(&res, host_ctxt);
> >  		goto out_handled;
> > +	case FFA_NOTIFICATION_BITMAP_CREATE:
> > +	case FFA_NOTIFICATION_BITMAP_DESTROY:
> > +		do_ffa_notif_bitmap(&res, host_ctxt);
> > +		goto out_handled;
> >  	}
> >  
> >  	if (ffa_call_supported(func_id))
> > -- 
> > 2.54.0.1136.gdb2ca164c4-goog
> > 

Thanks,
Sebastian