[PATCH v6 2/2] KVM: arm64: Support FFA_MSG_SEND_DIRECT_REQ2 in host handler

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

From: Per Larsen <perlarsen@google.com>

FF-A 1.2 adds the DIRECT_REQ2 messaging interface which is similar to
the existing FFA_MSG_SEND_DIRECT_{REQ,RESP} functions and can use the
existing handler function. Add support for FFA_MSG_SEND_DIRECT_REQ2 in
the host ffa handler.

Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Per Larsen <perlarsen@google.com>
---
 arch/arm64/kvm/hyp/nvhe/ffa.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c
index 3a58e01d255f..e5718c0f1c31 100644
--- a/arch/arm64/kvm/hyp/nvhe/ffa.c
+++ b/arch/arm64/kvm/hyp/nvhe/ffa.c
@@ -684,11 +684,12 @@ static bool ffa_call_supported(u64 func_id)
 	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;
+	case FFA_MSG_SEND_DIRECT_REQ2:		/* Optional per 7.5.1 */
+		return hyp_ffa_version >= FFA_VERSION_1_2;
 	}
 
 	return true;
@@ -865,6 +866,7 @@ static void do_ffa_part_get(struct arm_smccc_1_2_regs *res,
 static void do_ffa_direct_msg(struct arm_smccc_1_2_regs *res,
 			      struct kvm_cpu_context *ctxt)
 {
+	DECLARE_REG(u64, func_id, ctxt, 0);
 	DECLARE_REG(u32, endp, ctxt, 1);
 	DECLARE_REG(u32, flags, ctxt, 2);
 
@@ -875,8 +877,12 @@ static void do_ffa_direct_msg(struct arm_smccc_1_2_regs *res,
 		return;
 	}
 
-	/* filter out framework messages and validate SBZ/MBZ bits */
-	if (flags) {
+	/*
+	 * filter out framework messages and validate SBZ/MBZ flag bits.
+	 * FFA_MSG_SEND_DIRECT_REQ2 implies flag-less partition message.
+	 */
+	if ((func_id == FFA_MSG_SEND_DIRECT_REQ ||
+	     func_id == FFA_FN64_MSG_SEND_DIRECT_REQ) && flags) {
 		ffa_to_smccc_error(res, FFA_RET_INVALID_PARAMETERS);
 		return;
 	}
@@ -942,6 +948,10 @@ bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt, u32 func_id)
 	case FFA_PARTITION_INFO_GET:
 		do_ffa_part_get(&res, host_ctxt);
 		goto out_handled;
+	case FFA_MSG_SEND_DIRECT_REQ2:
+		if (!ffa_call_supported(func_id))
+			goto out_not_supported;
+		fallthrough;
 	case FFA_MSG_SEND_DIRECT_REQ:
 	case FFA_FN64_MSG_SEND_DIRECT_REQ:
 		do_ffa_direct_msg(&res, host_ctxt);
@@ -951,6 +961,7 @@ bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt, u32 func_id)
 	if (ffa_call_supported(func_id))
 		return false; /* Pass through */
 
+out_not_supported:
 	ffa_to_smccc_error(&res, FFA_RET_NOT_SUPPORTED);
 out_handled:
 	ffa_set_retval(host_ctxt, &res);

-- 
2.54.0.545.g6539524ca2-goog