On Wed, Aug 20, 2025 at 01:10:04AM +0000, Per Larsen via B4 Relay wrote:

Hi,

The FF-A 1.2 specification introduces a new SEND_DIRECT2 ABI which
allows registers x4-x17 to be used for the message payload. This patch
set prevents the host from using a lower FF-A version than what has
already been negotiated with the hypervisor. This is necessary because
the hypervisor does not have the necessary compatibility paths to
translate from the hypervisor FF-A version to a previous version.

Support for FF-A 1.2 in the hypervisor is added as a precursor to the
addition of the FFA_MSG_SEND_DIRECT_REQ2 messaging interface. Notably,
this patch updates all smc calls to use SMCCC 1.2 as it makes it simpler
to support interfaces that need to accept more than 8 arguments and/or
return more than 4 values. The list of optional/unsupported interfaces
was updated to reflect additions in FF-A 1.2.

Tested by booting Android under QEMU and loading Trusty as the guest
VM and observing the SEND_DIRECT2 ABI being used successfully during
guest boot.

Changes in v11:
- 2/6:         ffa_set_retval: Add more details about anticipated FF-A 1.3 update. Fix typo.
- Link to v10: https://lore.kernel.org/r/20250809-virtio-msg-ffa-v10-0-189eeecf8ae8@google.com (local)

Thanks, this all looks good to me now.

Assuming Marc's happy, this should go via the kvmarm tree.

Will