Re: [PATCH v7 1/3] KVM: arm64: Block host-initiated FF-A direct responses

[Fuad Tabba]

Hi Per,

On Mon, 31 Aug 2026 at 00:08, Per Larsen via B4 Relay
<devnull+perlarsen.google.com@xxxxxxxxxx> wrote:
...
> @@ -686,8 +686,10 @@ static bool ffa_call_supported(u64 func_id)
>   case FFA_MSG_SEND:
>   case FFA_MSG_POLL:
>   case FFA_MSG_WAIT:
> - /* 32-bit variants of 64-bit calls */
> + /* The host is never the target of a direct request */
>   case FFA_MSG_SEND_DIRECT_RESP:
> + case FFA_FN64_MSG_SEND_DIRECT_RESP:
> + /* 32-bit variants of 64-bit calls */
>   case FFA_RXTX_MAP:
>   case FFA_MEM_DONATE:
>   case FFA_MEM_RETRIEVE_REQ:

Sashiko asked whether the interfaces it listed should be added to the
blocklist too. For FFA_FN64_NOTIFICATION_INFO_GET the answer looks
like yes: FFA_FN_NATIVE() is FFA_FN64_##name on arm64, and
ffa_notification_info_get() is the only in-tree caller, so the 32-bit
entry a few lines below never matches what the host sends. Could you
add it here?

The other three aren't the same case. FFA_RX_RELEASE has to keep going
through, since the host's release is what frees the hypervisor's RX
buffer after do_ffa_part_get().

Cheers,
/fuad