[PATCH 0/2] KVM: arm64: Support FFA_FN64_MEM_RECLAIM2 in host handler

[Snehal Koukuntla <snehalreddy@google.com>]

The Arm Firmware Framework for Arm A-profile (FF-A) v1.3 ALP5
specification (DEN0140 rev J) [1] introduces the optional
FFA_MEM_RECLAIM2 (0xC4000091) ABI.

Reclaiming large memory regions with the existing FFA_MEM_RECLAIM ABI
can take significant time, or relies on a stateful time-slicing
mechanism in the Relayer. FFA_MEM_RECLAIM2 allows an Owner to reclaim
exclusive access to a subset of pages from a shared or lent memory
region by passing an array of constituent memory region descriptors in
its TX buffer along with a starting descriptor byte offset and initial
page index. The Relayer returns the number of 4K pages reclaimed in
that invocation without maintaining intermediate transaction state.

This series adds the FFA_FN64_MEM_RECLAIM2 function ID definition and
implements host proxy support in the pKVM nVHE FF-A handler, unsharing
the reclaimed pages in the host stage-2 page tables upon a successful
reclaim response from EL3/SPMD.

This series is based on kvmarm/next, as Patch 2 uses
ffa_check_unused_args_sbz() introduced in commit 3e9df0b0ebd5
("KVM: arm64: Enforce strict SBZ checks in the FF-A proxy").

[1] https://support.arm.com/documentation/den0140/j

Snehal Koukuntla (2):
  firmware: arm_ffa: Add FFA_FN64_MEM_RECLAIM2 function ID
  KVM: arm64: Support FFA_FN64_MEM_RECLAIM2 in host handler

 arch/arm64/kvm/hyp/nvhe/ffa.c | 117 ++++++++++++++++++++++++++++++++++
 include/linux/arm_ffa.h       |   1 +
 2 files changed, 118 insertions(+)


base-commit: 23ddf997ab16b5f4aa9f948f5a68f5b35e4e398f
-- 
2.55.0.1082.g2b9226bbc0-goog