1 files changed, 325 insertions, 94 deletions

diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c
index 58dcd92bf346..f731cc4c3f28 100644
--- a/arch/arm64/kvm/hyp/nvhe/ffa.c
+++ b/arch/arm64/kvm/hyp/nvhe/ffa.c
@@ -67,37 +67,72 @@ struct kvm_ffa_buffers {
  */
 static struct kvm_ffa_buffers hyp_buffers;
 static struct kvm_ffa_buffers host_buffers;
+static u32 hyp_ffa_version;
+static bool has_version_negotiated;
+static hyp_spinlock_t version_lock;
 
-static void ffa_to_smccc_error(struct arm_smccc_res *res, u64 ffa_errno)
+static void ffa_to_smccc_error(struct arm_smccc_1_2_regs *res, u64 ffa_errno)
 {
-	*res = (struct arm_smccc_res) {
+	*res = (struct arm_smccc_1_2_regs) {
 		.a0	= FFA_ERROR,
 		.a2	= ffa_errno,
 	};
 }
 
-static void ffa_to_smccc_res_prop(struct arm_smccc_res *res, int ret, u64 prop)
+static void ffa_to_smccc_res_prop(struct arm_smccc_1_2_regs *res, int ret, u64 prop)
 {
 	if (ret == FFA_RET_SUCCESS) {
-		*res = (struct arm_smccc_res) { .a0 = FFA_SUCCESS,
-						.a2 = prop };
+		*res = (struct arm_smccc_1_2_regs) { .a0 = FFA_SUCCESS,
+						      .a2 = prop };
 	} else {
 		ffa_to_smccc_error(res, ret);
 	}
 }
 
-static void ffa_to_smccc_res(struct arm_smccc_res *res, int ret)
+static void ffa_to_smccc_res(struct arm_smccc_1_2_regs *res, int ret)
 {
 	ffa_to_smccc_res_prop(res, ret, 0);
 }
 
 static void ffa_set_retval(struct kvm_cpu_context *ctxt,
-			   struct arm_smccc_res *res)
+			   struct arm_smccc_1_2_regs *res)
 {
 	cpu_reg(ctxt, 0) = res->a0;
 	cpu_reg(ctxt, 1) = res->a1;
 	cpu_reg(ctxt, 2) = res->a2;
 	cpu_reg(ctxt, 3) = res->a3;
+	cpu_reg(ctxt, 4) = res->a4;
+	cpu_reg(ctxt, 5) = res->a5;
+	cpu_reg(ctxt, 6) = res->a6;
+	cpu_reg(ctxt, 7) = res->a7;
+
+	/*
+	 * DEN0028C 2.6: SMC32/HVC32 call from aarch64 must preserve x8-x30.
+	 *
+	 * In FF-A 1.2, we cannot rely on the function ID sent by the caller to
+	 * detect 32-bit calls because the CPU cycle management interfaces (e.g.
+	 * FFA_MSG_WAIT, FFA_RUN) are 32-bit only but can have 64-bit responses.
+	 *
+	 * FFA-1.3 introduces 64-bit variants of the CPU cycle management
+	 * interfaces. Moreover, FF-A 1.3 clarifies that SMC32 direct requests
+	 * complete with SMC32 direct responses which *should* allow us use the
+	 * function ID sent by the caller to determine whether to return x8-x17.
+	 *
+	 * Note that we also cannot rely on function IDs in the response.
+	 *
+	 * Given the above, assume SMC64 and send back x0-x17 unconditionally
+	 * as the passthrough code (__kvm_hyp_host_forward_smc) does the same.
+	 */
+	cpu_reg(ctxt, 8) = res->a8;
+	cpu_reg(ctxt, 9) = res->a9;
+	cpu_reg(ctxt, 10) = res->a10;
+	cpu_reg(ctxt, 11) = res->a11;
+	cpu_reg(ctxt, 12) = res->a12;
+	cpu_reg(ctxt, 13) = res->a13;
+	cpu_reg(ctxt, 14) = res->a14;
+	cpu_reg(ctxt, 15) = res->a15;
+	cpu_reg(ctxt, 16) = res->a16;
+	cpu_reg(ctxt, 17) = res->a17;
 }
 
 static bool is_ffa_call(u64 func_id)
@@ -110,74 +145,92 @@ static bool is_ffa_call(u64 func_id)
 
 static int ffa_map_hyp_buffers(u64 ffa_page_count)
 {
-	struct arm_smccc_res res;
+	struct arm_smccc_1_2_regs res;
 
-	arm_smccc_1_1_smc(FFA_FN64_RXTX_MAP,
-			  hyp_virt_to_phys(hyp_buffers.tx),
-			  hyp_virt_to_phys(hyp_buffers.rx),
-			  ffa_page_count,
-			  0, 0, 0, 0,
-			  &res);
+	arm_smccc_1_2_smc(&(struct arm_smccc_1_2_regs) {
+		.a0 = FFA_FN64_RXTX_MAP,
+		.a1 = hyp_virt_to_phys(hyp_buffers.tx),
+		.a2 = hyp_virt_to_phys(hyp_buffers.rx),
+		.a3 = ffa_page_count,
+	}, &res);
 
 	return res.a0 == FFA_SUCCESS ? FFA_RET_SUCCESS : res.a2;
 }
 
 static int ffa_unmap_hyp_buffers(void)
 {
-	struct arm_smccc_res res;
+	struct arm_smccc_1_2_regs res;
 
-	arm_smccc_1_1_smc(FFA_RXTX_UNMAP,
-			  HOST_FFA_ID,
-			  0, 0, 0, 0, 0, 0,
-			  &res);
+	arm_smccc_1_2_smc(&(struct arm_smccc_1_2_regs) {
+		.a0 = FFA_RXTX_UNMAP,
+		.a1 = HOST_FFA_ID,
+	}, &res);
 
 	return res.a0 == FFA_SUCCESS ? FFA_RET_SUCCESS : res.a2;
 }
 
-static void ffa_mem_frag_tx(struct arm_smccc_res *res, u32 handle_lo,
+static void ffa_mem_frag_tx(struct arm_smccc_1_2_regs *res, u32 handle_lo,
 			     u32 handle_hi, u32 fraglen, u32 endpoint_id)
 {
-	arm_smccc_1_1_smc(FFA_MEM_FRAG_TX,
-			  handle_lo, handle_hi, fraglen, endpoint_id,
-			  0, 0, 0,
-			  res);
+	arm_smccc_1_2_smc(&(struct arm_smccc_1_2_regs) {
+		.a0 = FFA_MEM_FRAG_TX,
+		.a1 = handle_lo,
+		.a2 = handle_hi,
+		.a3 = fraglen,
+		.a4 = endpoint_id,
+	}, res);
 }
 
-static void ffa_mem_frag_rx(struct arm_smccc_res *res, u32 handle_lo,
+static void ffa_mem_frag_rx(struct arm_smccc_1_2_regs *res, u32 handle_lo,
 			     u32 handle_hi, u32 fragoff)
 {
-	arm_smccc_1_1_smc(FFA_MEM_FRAG_RX,
-			  handle_lo, handle_hi, fragoff, HOST_FFA_ID,
-			  0, 0, 0,
-			  res);
+	arm_smccc_1_2_smc(&(struct arm_smccc_1_2_regs) {
+		.a0 = FFA_MEM_FRAG_RX,
+		.a1 = handle_lo,
+		.a2 = handle_hi,
+		.a3 = fragoff,
+		.a4 = HOST_FFA_ID,
+	}, res);
 }
 
-static void ffa_mem_xfer(struct arm_smccc_res *res, u64 func_id, u32 len,
+static void ffa_mem_xfer(struct arm_smccc_1_2_regs *res, u64 func_id, u32 len,
 			  u32 fraglen)
 {
-	arm_smccc_1_1_smc(func_id, len, fraglen,
-			  0, 0, 0, 0, 0,
-			  res);
+	arm_smccc_1_2_smc(&(struct arm_smccc_1_2_regs) {
+		.a0 = func_id,
+		.a1 = len,
+		.a2 = fraglen,
+	}, res);
 }
 
-static void ffa_mem_reclaim(struct arm_smccc_res *res, u32 handle_lo,
+static void ffa_mem_reclaim(struct arm_smccc_1_2_regs *res, u32 handle_lo,
 			     u32 handle_hi, u32 flags)
 {
-	arm_smccc_1_1_smc(FFA_MEM_RECLAIM,
-			  handle_lo, handle_hi, flags,
-			  0, 0, 0, 0,
-			  res);
+	arm_smccc_1_2_smc(&(struct arm_smccc_1_2_regs) {
+		.a0 = FFA_MEM_RECLAIM,
+		.a1 = handle_lo,
+		.a2 = handle_hi,
+		.a3 = flags,
+	}, res);
+}
+
+static void ffa_retrieve_req(struct arm_smccc_1_2_regs *res, u32 len)
+{
+	arm_smccc_1_2_smc(&(struct arm_smccc_1_2_regs) {
+		.a0 = FFA_FN64_MEM_RETRIEVE_REQ,
+		.a1 = len,
+		.a2 = len,
+	}, res);
 }
 
-static void ffa_retrieve_req(struct arm_smccc_res *res, u32 len)
+static void ffa_rx_release(struct arm_smccc_1_2_regs *res)
 {
-	arm_smccc_1_1_smc(FFA_FN64_MEM_RETRIEVE_REQ,
-			  len, len,
-			  0, 0, 0, 0, 0,
-			  res);
+	arm_smccc_1_2_smc(&(struct arm_smccc_1_2_regs) {
+		.a0 = FFA_RX_RELEASE,
+	}, res);
 }
 
-static void do_ffa_rxtx_map(struct arm_smccc_res *res,
+static void do_ffa_rxtx_map(struct arm_smccc_1_2_regs *res,
 			    struct kvm_cpu_context *ctxt)
 {
 	DECLARE_REG(phys_addr_t, tx, ctxt, 1);
@@ -256,7 +309,7 @@ err_unmap:
 	goto out_unlock;
 }
 
-static void do_ffa_rxtx_unmap(struct arm_smccc_res *res,
+static void do_ffa_rxtx_unmap(struct arm_smccc_1_2_regs *res,
 			      struct kvm_cpu_context *ctxt)
 {
 	DECLARE_REG(u32, id, ctxt, 1);
@@ -357,7 +410,7 @@ static int ffa_host_unshare_ranges(struct ffa_mem_region_addr_range *ranges,
 	return ret;
 }
 
-static void do_ffa_mem_frag_tx(struct arm_smccc_res *res,
+static void do_ffa_mem_frag_tx(struct arm_smccc_1_2_regs *res,
 			       struct kvm_cpu_context *ctxt)
 {
 	DECLARE_REG(u32, handle_lo, ctxt, 1);
@@ -415,22 +468,20 @@ out:
 	return;
 }
 
-static __always_inline void do_ffa_mem_xfer(const u64 func_id,
-					    struct arm_smccc_res *res,
-					    struct kvm_cpu_context *ctxt)
+static void __do_ffa_mem_xfer(const u64 func_id,
+			      struct arm_smccc_1_2_regs *res,
+			      struct kvm_cpu_context *ctxt)
 {
 	DECLARE_REG(u32, len, ctxt, 1);
 	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;
+	u32 offset, nr_ranges, checked_offset;
 	int ret = 0;
 
-	BUILD_BUG_ON(func_id != FFA_FN64_MEM_SHARE &&
-		     func_id != FFA_FN64_MEM_LEND);
-
 	if (addr_mbz || npages_mbz || fraglen > len ||
 	    fraglen > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE) {
 		ret = FFA_RET_INVALID_PARAMETERS;
@@ -449,16 +500,28 @@ static __always_inline void do_ffa_mem_xfer(const u64 func_id,
 		goto out_unlock;
 	}
 
+	if (len > ffa_desc_buf.len) {
+		ret = FFA_RET_NO_MEMORY;
+		goto out_unlock;
+	}
+
 	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, hyp_ffa_version);
+	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;
 	}
 
-	if (fraglen < offset + sizeof(struct ffa_composite_mem_region)) {
+	if (check_add_overflow(offset, sizeof(struct ffa_composite_mem_region), &checked_offset)) {
+		ret = FFA_RET_INVALID_PARAMETERS;
+		goto out_unlock;
+	}
+
+	if (fraglen < checked_offset) {
 		ret = FFA_RET_INVALID_PARAMETERS;
 		goto out_unlock;
 	}
@@ -498,12 +561,20 @@ err_unshare:
 	goto out_unlock;
 }
 
-static void do_ffa_mem_reclaim(struct arm_smccc_res *res,
+#define do_ffa_mem_xfer(fid, res, ctxt)				\
+	do {							\
+		BUILD_BUG_ON((fid) != FFA_FN64_MEM_SHARE &&	\
+			     (fid) != FFA_FN64_MEM_LEND);	\
+		__do_ffa_mem_xfer((fid), (res), (ctxt));	\
+	} while (0);
+
+static void do_ffa_mem_reclaim(struct arm_smccc_1_2_regs *res,
 			       struct kvm_cpu_context *ctxt)
 {
 	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 +599,9 @@ 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, hyp_ffa_version);
+	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_
@@ -537,16 +610,19 @@ static void do_ffa_mem_reclaim(struct arm_smccc_res *res,
 	if (WARN_ON(offset > len ||
 		    fraglen > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE)) {
 		ret = FFA_RET_ABORTED;
+		ffa_rx_release(res);
 		goto out_unlock;
 	}
 
 	if (len > ffa_desc_buf.len) {
 		ret = FFA_RET_NO_MEMORY;
+		ffa_rx_release(res);
 		goto out_unlock;
 	}
 
 	buf = ffa_desc_buf.buf;
 	memcpy(buf, hyp_buffers.rx, fraglen);
+	ffa_rx_release(res);
 
 	for (fragoff = fraglen; fragoff < len; fragoff += fraglen) {
 		ffa_mem_frag_rx(res, handle_lo, handle_hi, fragoff);
@@ -557,6 +633,7 @@ static void do_ffa_mem_reclaim(struct arm_smccc_res *res,
 
 		fraglen = res->a3;
 		memcpy((void *)buf + fragoff, hyp_buffers.rx, fraglen);
+		ffa_rx_release(res);
 	}
 
 	ffa_mem_reclaim(res, handle_lo, handle_hi, flags);
@@ -594,18 +671,30 @@ static bool ffa_call_supported(u64 func_id)
 	case FFA_MSG_POLL:
 	case FFA_MSG_WAIT:
 	/* 32-bit variants of 64-bit calls */
-	case FFA_MSG_SEND_DIRECT_REQ:
 	case FFA_MSG_SEND_DIRECT_RESP:
 	case FFA_RXTX_MAP:
 	case FFA_MEM_DONATE:
 	case FFA_MEM_RETRIEVE_REQ:
+       /* Optional notification interfaces added in FF-A 1.1 */
+	case FFA_NOTIFICATION_BITMAP_CREATE:
+	case FFA_NOTIFICATION_BITMAP_DESTROY:
+	case FFA_NOTIFICATION_BIND:
+	case FFA_NOTIFICATION_UNBIND:
+	case FFA_NOTIFICATION_SET:
+	case FFA_NOTIFICATION_GET:
+	case FFA_NOTIFICATION_INFO_GET:
+	/* Optional interfaces added in FF-A 1.2 */
+	case FFA_MSG_SEND_DIRECT_REQ2:		/* Optional per 7.5.1 */
+	case FFA_MSG_SEND_DIRECT_RESP2:		/* Optional per 7.5.1 */
+	case FFA_CONSOLE_LOG:			/* Optional per 13.1: not in Table 13.1 */
+	case FFA_PARTITION_INFO_GET_REGS:	/* Optional for virtual instances per 13.1 */
 		return false;
 	}
 
 	return true;
 }
 
-static bool do_ffa_features(struct arm_smccc_res *res,
+static bool do_ffa_features(struct arm_smccc_1_2_regs *res,
 			    struct kvm_cpu_context *ctxt)
 {
 	DECLARE_REG(u32, id, ctxt, 1);
@@ -634,10 +723,148 @@ out_handled:
 	return true;
 }
 
-bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt)
+static int hyp_ffa_post_init(void)
 {
-	DECLARE_REG(u64, func_id, host_ctxt, 0);
-	struct arm_smccc_res res;
+	size_t min_rxtx_sz;
+	struct arm_smccc_1_2_regs res;
+
+	arm_smccc_1_2_smc(&(struct arm_smccc_1_2_regs){
+		.a0 = FFA_ID_GET,
+	}, &res);
+	if (res.a0 != FFA_SUCCESS)
+		return -EOPNOTSUPP;
+
+	if (res.a2 != HOST_FFA_ID)
+		return -EINVAL;
+
+	arm_smccc_1_2_smc(&(struct arm_smccc_1_2_regs){
+		.a0 = FFA_FEATURES,
+		.a1 = FFA_FN64_RXTX_MAP,
+	}, &res);
+	if (res.a0 != FFA_SUCCESS)
+		return -EOPNOTSUPP;
+
+	switch (res.a2 & FFA_FEAT_RXTX_MIN_SZ_MASK) {
+	case FFA_FEAT_RXTX_MIN_SZ_4K:
+		min_rxtx_sz = SZ_4K;
+		break;
+	case FFA_FEAT_RXTX_MIN_SZ_16K:
+		min_rxtx_sz = SZ_16K;
+		break;
+	case FFA_FEAT_RXTX_MIN_SZ_64K:
+		min_rxtx_sz = SZ_64K;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (min_rxtx_sz > PAGE_SIZE)
+		return -EOPNOTSUPP;
+
+	return 0;
+}
+
+static void do_ffa_version(struct arm_smccc_1_2_regs *res,
+			   struct kvm_cpu_context *ctxt)
+{
+	DECLARE_REG(u32, ffa_req_version, ctxt, 1);
+
+	if (FFA_MAJOR_VERSION(ffa_req_version) != 1) {
+		res->a0 = FFA_RET_NOT_SUPPORTED;
+		return;
+	}
+
+	hyp_spin_lock(&version_lock);
+	if (has_version_negotiated) {
+		if (FFA_MINOR_VERSION(ffa_req_version) < FFA_MINOR_VERSION(hyp_ffa_version))
+			res->a0 = FFA_RET_NOT_SUPPORTED;
+		else
+			res->a0 = hyp_ffa_version;
+		goto unlock;
+	}
+
+	/*
+	 * If the client driver tries to downgrade the version, we need to ask
+	 * first if TEE supports it.
+	 */
+	if (FFA_MINOR_VERSION(ffa_req_version) < FFA_MINOR_VERSION(hyp_ffa_version)) {
+		arm_smccc_1_2_smc(&(struct arm_smccc_1_2_regs) {
+			.a0 = FFA_VERSION,
+			.a1 = ffa_req_version,
+		}, res);
+		if (res->a0 == FFA_RET_NOT_SUPPORTED)
+			goto unlock;
+
+		hyp_ffa_version = ffa_req_version;
+	}
+
+	if (hyp_ffa_post_init()) {
+		res->a0 = FFA_RET_NOT_SUPPORTED;
+	} else {
+		smp_store_release(&has_version_negotiated, true);
+		res->a0 = hyp_ffa_version;
+	}
+unlock:
+	hyp_spin_unlock(&version_lock);
+}
+
+static void do_ffa_part_get(struct arm_smccc_1_2_regs *res,
+			    struct kvm_cpu_context *ctxt)
+{
+	DECLARE_REG(u32, uuid0, ctxt, 1);
+	DECLARE_REG(u32, uuid1, ctxt, 2);
+	DECLARE_REG(u32, uuid2, ctxt, 3);
+	DECLARE_REG(u32, uuid3, ctxt, 4);
+	DECLARE_REG(u32, flags, ctxt, 5);
+	u32 count, partition_sz, copy_sz;
+
+	hyp_spin_lock(&host_buffers.lock);
+	if (!host_buffers.rx) {
+		ffa_to_smccc_res(res, FFA_RET_BUSY);
+		goto out_unlock;
+	}
+
+	arm_smccc_1_2_smc(&(struct arm_smccc_1_2_regs) {
+		.a0 = FFA_PARTITION_INFO_GET,
+		.a1 = uuid0,
+		.a2 = uuid1,
+		.a3 = uuid2,
+		.a4 = uuid3,
+		.a5 = flags,
+	}, res);
+
+	if (res->a0 != FFA_SUCCESS)
+		goto out_unlock;
+
+	count = res->a2;
+	if (!count)
+		goto out_unlock;
+
+	if (hyp_ffa_version > FFA_VERSION_1_0) {
+		/* Get the number of partitions deployed in the system */
+		if (flags & 0x1)
+			goto out_unlock;
+
+		partition_sz  = res->a3;
+	} else {
+		/* FFA_VERSION_1_0 lacks the size in the response */
+		partition_sz = FFA_1_0_PARTITON_INFO_SZ;
+	}
+
+	copy_sz = partition_sz * count;
+	if (copy_sz > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE) {
+		ffa_to_smccc_res(res, FFA_RET_ABORTED);
+		goto out_unlock;
+	}
+
+	memcpy(host_buffers.rx, hyp_buffers.rx, copy_sz);
+out_unlock:
+	hyp_spin_unlock(&host_buffers.lock);
+}
+
+bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt, u32 func_id)
+{
+	struct arm_smccc_1_2_regs res;
 
 	/*
 	 * There's no way we can tell what a non-standard SMC call might
@@ -655,6 +882,12 @@ bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt)
 	if (!is_ffa_call(func_id))
 		return false;
 
+	if (func_id != FFA_VERSION &&
+	    !smp_load_acquire(&has_version_negotiated)) {
+		ffa_to_smccc_error(&res, FFA_RET_INVALID_PARAMETERS);
+		goto out_handled;
+	}
+
 	switch (func_id) {
 	case FFA_FEATURES:
 		if (!do_ffa_features(&res, host_ctxt))
@@ -681,6 +914,12 @@ bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt)
 	case FFA_MEM_FRAG_TX:
 		do_ffa_mem_frag_tx(&res, host_ctxt);
 		goto out_handled;
+	case FFA_VERSION:
+		do_ffa_version(&res, host_ctxt);
+		goto out_handled;
+	case FFA_PARTITION_INFO_GET:
+		do_ffa_part_get(&res, host_ctxt);
+		goto out_handled;
 	}
 
 	if (ffa_call_supported(func_id))
@@ -694,48 +933,39 @@ out_handled:
 
 int hyp_ffa_init(void *pages)
 {
-	struct arm_smccc_res res;
-	size_t min_rxtx_sz;
+	struct arm_smccc_1_2_regs res;
 	void *tx, *rx;
 
 	if (kvm_host_psci_config.smccc_version < ARM_SMCCC_VERSION_1_2)
 		return 0;
 
-	arm_smccc_1_1_smc(FFA_VERSION, FFA_VERSION_1_0, 0, 0, 0, 0, 0, 0, &res);
+	arm_smccc_1_2_smc(&(struct arm_smccc_1_2_regs) {
+		.a0 = FFA_VERSION,
+		.a1 = FFA_VERSION_1_2,
+	}, &res);
 	if (res.a0 == FFA_RET_NOT_SUPPORTED)
 		return 0;
 
-	if (res.a0 != FFA_VERSION_1_0)
-		return -EOPNOTSUPP;
-
-	arm_smccc_1_1_smc(FFA_ID_GET, 0, 0, 0, 0, 0, 0, 0, &res);
-	if (res.a0 != FFA_SUCCESS)
-		return -EOPNOTSUPP;
-
-	if (res.a2 != HOST_FFA_ID)
-		return -EINVAL;
-
-	arm_smccc_1_1_smc(FFA_FEATURES, FFA_FN64_RXTX_MAP,
-			  0, 0, 0, 0, 0, 0, &res);
-	if (res.a0 != FFA_SUCCESS)
+	/*
+	 * Firmware returns the maximum supported version of the FF-A
+	 * implementation. Check that the returned version is
+	 * backwards-compatible with the hyp according to the rules in DEN0077A
+	 * v1.1 REL0 13.2.1.
+	 *
+	 * Of course, things are never simple when dealing with firmware. v1.1
+	 * broke ABI with v1.0 on several structures, which is itself
+	 * incompatible with the aforementioned versioning scheme. The
+	 * expectation is that v1.x implementations that do not support the v1.0
+	 * ABI return NOT_SUPPORTED rather than a version number, according to
+	 * DEN0077A v1.1 REL0 18.6.4.
+	 */
+	if (FFA_MAJOR_VERSION(res.a0) != 1)
 		return -EOPNOTSUPP;
 
-	switch (res.a2) {
-	case FFA_FEAT_RXTX_MIN_SZ_4K:
-		min_rxtx_sz = SZ_4K;
-		break;
-	case FFA_FEAT_RXTX_MIN_SZ_16K:
-		min_rxtx_sz = SZ_16K;
-		break;
-	case FFA_FEAT_RXTX_MIN_SZ_64K:
-		min_rxtx_sz = SZ_64K;
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	if (min_rxtx_sz > PAGE_SIZE)
-		return -EOPNOTSUPP;
+	if (FFA_MINOR_VERSION(res.a0) < FFA_MINOR_VERSION(FFA_VERSION_1_2))
+		hyp_ffa_version = res.a0;
+	else
+		hyp_ffa_version = FFA_VERSION_1_2;
 
 	tx = pages;
 	pages += KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE;
@@ -758,5 +988,6 @@ int hyp_ffa_init(void *pages)
 		.lock	= __HYP_SPIN_LOCK_UNLOCKED,
 	};
 
+	version_lock = __HYP_SPIN_LOCK_UNLOCKED;
 	return 0;
 }