Re: [PATCH v2 1/2] KVM: arm64: Support FFA_MSG_SEND_DIRECT_REQ in host handler

[Will Deacon <will@kernel.org>]

On Thu, Oct 30, 2025 at 03:49:16PM +0000, Per Larsen via B4 Relay wrote:
> From: Sebastian Ene <sebastianene@google.com>
> 
> Allow direct messages to be forwarded from the host.
> 
> Signed-off-by: Sebastian Ene <sebastianene@google.com>
> Signed-off-by: Per Larsen <perlarsen@google.com>
> ---
>  arch/arm64/kvm/hyp/nvhe/ffa.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c
> index 4e16f9b96f637599873b16148c6e40cf1210aa3e..bb38ee7c86bad1646c16c562127eb3bef6297a84 100644
> --- a/arch/arm64/kvm/hyp/nvhe/ffa.c
> +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c
> @@ -857,6 +857,15 @@ static void do_ffa_part_get(struct arm_smccc_1_2_regs *res,
>  	hyp_spin_unlock(&host_buffers.lock);
>  }
>  
> +static void do_ffa_direct_msg(struct arm_smccc_1_2_regs *res,
> +			      struct kvm_cpu_context *ctxt,
> +			      u64 vm_handle)
> +{
> +	struct arm_smccc_1_2_regs *args = (void *)&ctxt->regs.regs[0];
> +
> +	arm_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;
> @@ -915,6 +924,10 @@ 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_MSG_SEND_DIRECT_REQ:
> +	case FFA_FN64_MSG_SEND_DIRECT_REQ:
> +		do_ffa_direct_msg(&res, host_ctxt, HOST_FFA_ID);
> +		goto out_handled;

Should we filter out framework messages so that this is limited to partition
messages instead?

Will