[PATCH RFT v2 15/18] KVM: arm64: FFA: Remove access of endpoint memory access descriptor array

[Sudeep Holla]

FF-A v1.1 removes the fixed location of endpoint memory access descriptor
array within the memory transaction descriptor structure. In preparation
to remove the ep_mem_access member from the ffa_mem_region structure,
provide the accessor to fetch the offset and use the same in FF-A proxy
implementation.

The accessor take the boolean argument that indicates if the memory access
descriptor versions is v1(old format) or not. Currently it is set true as
FF-A proxy supports only v1.0

Cc: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Oliver Upton <oliver.upton@xxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Quentin Perret <qperret@xxxxxxxxxx>
Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
---
 arch/arm64/kvm/hyp/nvhe/ffa.c | 8 ++++++--
 include/linux/arm_ffa.h       | 6 ++++++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c
index ab4f5d160c58..45e78af76e25 100644
--- a/arch/arm64/kvm/hyp/nvhe/ffa.c
+++ b/arch/arm64/kvm/hyp/nvhe/ffa.c
@@ -423,6 +423,7 @@ static __always_inline void do_ffa_mem_xfer(const u64 func_id,
 	DECLARE_REG(u32, fraglen, ctxt, 2);
 	DECLARE_REG(u64, addr_mbz, ctxt, 3);
 	DECLARE_REG(u32, npages_mbz, ctxt, 4);
+	struct ffa_mem_region_attributes *ep_mem_access;
 	struct ffa_composite_mem_region *reg;
 	struct ffa_mem_region *buf;
 	u32 offset, nr_ranges;
@@ -452,7 +453,8 @@ static __always_inline void do_ffa_mem_xfer(const u64 func_id,
 	buf = hyp_buffers.tx;
 	memcpy(buf, host_buffers.tx, fraglen);
 
-	offset = buf->ep_mem_access[0].composite_off;
+	ep_mem_access = (void *)buf + ffa_mem_desc_offset(buf, 0, true);
+	offset = ep_mem_access->composite_off;
 	if (!offset || buf->ep_count != 1 || buf->sender_id != HOST_FFA_ID) {
 		ret = FFA_RET_INVALID_PARAMETERS;
 		goto out_unlock;
@@ -504,6 +506,7 @@ static void do_ffa_mem_reclaim(struct arm_smccc_res *res,
 	DECLARE_REG(u32, handle_lo, ctxt, 1);
 	DECLARE_REG(u32, handle_hi, ctxt, 2);
 	DECLARE_REG(u32, flags, ctxt, 3);
+	struct ffa_mem_region_attributes *ep_mem_access;
 	struct ffa_composite_mem_region *reg;
 	u32 offset, len, fraglen, fragoff;
 	struct ffa_mem_region *buf;
@@ -528,7 +531,8 @@ static void do_ffa_mem_reclaim(struct arm_smccc_res *res,
 	len = res->a1;
 	fraglen = res->a2;
 
-	offset = buf->ep_mem_access[0].composite_off;
+	ep_mem_access = (void *)buf + ffa_mem_desc_offset(buf, 0, true);
+	offset = ep_mem_access->composite_off;
 	/*
 	 * We can trust the SPMD to get this right, but let's at least
 	 * check that we end up with something that doesn't look _completely_
diff --git a/include/linux/arm_ffa.h b/include/linux/arm_ffa.h
index 748d0a83a4bc..7be240e37f36 100644
--- a/include/linux/arm_ffa.h
+++ b/include/linux/arm_ffa.h
@@ -357,6 +357,12 @@ struct ffa_mem_region {
 #define CONSTITUENTS_OFFSET(x)	\
 	(offsetof(struct ffa_composite_mem_region, constituents[x]))
 
+static inline u32
+ffa_mem_desc_offset(struct ffa_mem_region *buf, int count, bool mem_desc_v1)
+{
+	return COMPOSITE_OFFSET(0);
+}
+
 struct ffa_mem_ops_args {
 	bool use_txbuf;
 	u32 nattrs;

-- 
2.42.0