[PATCH v4 0/5] KVM: arm64: Support FF-A 1.2 and SEND_DIRECT2 ABI

[Per Larsen via B4 Relay <devnull+perlarsen.google.com@kernel.org>]

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. The bulk
of this change has to do with the upgrade to SMCCC 1.2 required by
FF-A 1.2. Additionally, unimplemented FF-A 1.2 interfaces are added to
the list of unsupported functions.

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 since v3:
- all:        Remove Signed-off-by: Per Larsen <perl@immunant.com>
- 2/5:        Split out from 2/3, zero x4-x7 in set_ffa_retval
- 3/5:        Split out from 2/3, Mark FFA_NOTIFICATION_* calls as
              unsupported
- 2/3 -> 4/5: Drop ffa_get_hypervisor_version, access hyp_ffa_version
              directly when version negotiation is complete.
- 3/3 -> 5/5: Call ffa_to_smccc_1_2_error directly in
              do_do_ffa_direct_msg2
              Push call to ffa_call_needs_smccc_1_2 lower down by adding
              ffa_get_func_id and ffa_set_retval_smccc_1_x.
              Drop ffa_to_smccc_1_2_regs and ffa_to_smccc_1_2_regs_prop
              as they are no longer used.
- Link to v3: https://lore.kernel.org/r/20250513-virtio-msg-ffa-v3-0-d66c76ff1b2c@google.com 

Changes since v2:
- 2/3: Removed files added by mistake.
       Add and use ffa_get_hypervisor_version to access hyp_ffa_version
- 3/3: Use ffa_get_hypervisor_version to access hyp_ffa_version safely
- Link to v2: https://lore.kernel.org/r/20250508-virtio-msg-ffa-v2-0-ed84f8053965@google.com

Changes since v1:
- 1/3: Simplify commit message; drop long comment in do_ffa_version
- 2/3: Correct use of Co-developed-by: footer
       s/arm_smccc_1_2_smc_fallback/arm_smccc_1_x_smc/
       Always access hyp_ffa_version w/lock held
       Remove superfluous comments in ffa_call_supported
       Add and use FFA_FEAT_RXTX_MIN_SZ_MASK instead of constant
       Add FFA_PARTITION_INFO_GET_REGS to calls that require SMCCC 1.2
- 3/3: Always access hyp_ffa_version w/lock held
       Correct formatting

Thanks,
Per Larsen

--
2.49.0

---
To: Marc Zyngier <maz@kernel.org>
To: Oliver Upton <oliver.upton@linux.dev>
To: Joey Gouly <joey.gouly@arm.com>
To: Suzuki K Poulose <suzuki.poulose@arm.com>
To: Zenghui Yu <yuzenghui@huawei.com>
To: Catalin Marinas <catalin.marinas@arm.com>
To: Will Deacon <will@kernel.org>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: kvmarm@lists.linux.dev
Cc: linux-kernel@vger.kernel.org

---

---
Per Larsen (5):
      KVM: arm64: Restrict FF-A host version renegotiation
      KVM: arm64: Zero x4-x7 in ffa_set_retval
      KVM: arm64: Mark FFA_NOTIFICATION_* calls as unsupported
      KVM: arm64: Bump the supported version of FF-A to 1.2
      KVM: arm64: Support FFA_MSG_SEND_DIRECT_REQ2 in host handler

 arch/arm64/kvm/hyp/nvhe/Makefile |   1 +
 arch/arm64/kvm/hyp/nvhe/ffa.c    | 186 +++++++++++++++++++++++++++++++++++++--
 include/linux/arm_ffa.h          |   3 +
 3 files changed, 182 insertions(+), 8 deletions(-)
---
base-commit: fee3e843b309444f48157e2188efa6818bae85cf
change-id: 20250506-virtio-msg-ffa-22af72c92150

Best regards,
-- 
Per Larsen <perlarsen@google.com>