[PATCH v3 3/7] KVM: arm64: Support FFA_NOTIFICATION_BIND in host handler

[Vincent Donnefort]

On Tue, Jun 16, 2026 at 10:54:12AM +0000, Sebastian Ene wrote:
> Verify the arguments of the FF-A notification bind call and forward the
> message to Trustzone.
> 
> Signed-off-by: Sebastian Ene <sebastianene at google.com>
> ---
>  arch/arm64/kvm/hyp/nvhe/ffa.c | 32 +++++++++++++++++++++++++++++++-
>  1 file changed, 31 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c
> index dc7496ec295f..3d8ed829f558 100644
> --- a/arch/arm64/kvm/hyp/nvhe/ffa.c
> +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c
> @@ -42,6 +42,8 @@
>   */
>  #define HOST_FFA_ID	0
>  
> +#define FFA_NOTIF_SENDER_ENDP_MASK	GENMASK(31, 16)
> +
>  /*
>   * A buffer to hold the maximum descriptor size we can see from the host,
>   * which is required when the SPMD returns a fragmented FFA_MEM_RETRIEVE_RESP
> @@ -713,7 +715,6 @@ 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_BIND:
>  	case FFA_NOTIFICATION_UNBIND:
>  	case FFA_NOTIFICATION_SET:
>  	case FFA_NOTIFICATION_GET:
> @@ -929,6 +930,32 @@ static void do_ffa_notif_bitmap(struct arm_smccc_1_2_regs *res,
>  	hyp_smccc_1_2_smc(args, res);
>  }
>  
> +static void do_ffa_notif_bind(struct arm_smccc_1_2_regs *res,
> +			      struct kvm_cpu_context *ctxt)
> +{
> +	DECLARE_REG(u32, endp_id, ctxt, 1);
> +	DECLARE_REG(u32, flags, ctxt, 2);
> +	struct arm_smccc_1_2_regs *args;
> +
> +	if (ffa_check_unused_args_sbz(ctxt, 5)) {
> +		ffa_to_smccc_res(res, FFA_RET_INVALID_PARAMETERS);
> +		return;
> +	}
> +
> +	if (FIELD_GET(FFA_NOTIF_SENDER_ENDP_MASK, endp_id) != HOST_FFA_ID) {

"A Receiver uses the FFA_NOTIFICATION_BIND interface to bind one or more
notifications to the Sender"

Does that mean that if the host issues a FFA_NOTIFICATION_BIND it is the
"Receiver" and not the "Sender"? 

(Same for unbind)


> +		ffa_to_smccc_res(res, FFA_RET_INVALID_PARAMETERS);
> +		return;
> +	}
> +
> +	if (flags > 1) {
> +		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;
> @@ -991,6 +1018,9 @@ bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt, u32 func_id)
>  	case FFA_NOTIFICATION_BITMAP_DESTROY:
>  		do_ffa_notif_bitmap(&res, host_ctxt);
>  		goto out_handled;
> +	case FFA_NOTIFICATION_BIND:
> +		do_ffa_notif_bind(&res, host_ctxt);
> +		goto out_handled;
>  	}
>  
>  	if (ffa_call_supported(func_id))
> -- 
> 2.54.0.1136.gdb2ca164c4-goog
>