diff --git a/src/arch/aarch64/hypervisor/handler.c b/src/arch/aarch64/hypervisor/handler.c
index 5e8221e..7b00158 100644
--- a/src/arch/aarch64/hypervisor/handler.c
+++ b/src/arch/aarch64/hypervisor/handler.c
@@ -952,6 +952,13 @@
 		vcpu->regs.r[0] = api_debug_log(args.arg1, vcpu);
 		break;
 
+#if SECURE_WORLD == 1
+	case HF_INTERRUPT_DEACTIVATE:
+		vcpu->regs.r[0] = plat_ffa_interrupt_deactivate(
+			args.arg1, args.arg2, vcpu);
+		break;
+#endif
+
 	default:
 		vcpu->regs.r[0] = SMCCC_ERROR_UNKNOWN;
 	}
diff --git a/src/arch/aarch64/plat/ffa/spmc.c b/src/arch/aarch64/plat/ffa/spmc.c
index c720fd9..3177dcb 100644
--- a/src/arch/aarch64/plat/ffa/spmc.c
+++ b/src/arch/aarch64/plat/ffa/spmc.c
@@ -13,6 +13,7 @@
 #include "hf/dlog.h"
 #include "hf/ffa.h"
 #include "hf/ffa_internal.h"
+#include "hf/plat/interrupts.h"
 #include "hf/std.h"
 #include "hf/vm.h"
 
@@ -602,3 +603,49 @@
 
 	return ret;
 }
+
+/**
+ * Drops the current interrupt priority and deactivate the given interrupt ID
+ * for the calling vCPU.
+ *
+ * Returns 0 on success, or -1 otherwise.
+ */
+int64_t plat_ffa_interrupt_deactivate(uint32_t pint_id, uint32_t vint_id,
+				      struct vcpu *current)
+{
+	if (vint_id >= HF_NUM_INTIDS) {
+		return -1;
+	}
+
+	/*
+	 * Current implementation maps virtual interrupt to physical interrupt.
+	 */
+	if (pint_id != vint_id) {
+		return -1;
+	}
+
+	/*
+	 * Deny the de-activation request if not currently processing a
+	 * secure interrupt. panic() is not appropriate as it could be
+	 * abused by a rogue SP to create Denial-of-service.
+	 */
+	if (!current->processing_secure_interrupt) {
+		dlog_error("Cannot deactivate secure interrupt: %d\n", pint_id);
+		return -1;
+	}
+
+	/*
+	 * A malicious SP could de-activate an interrupt that does not belong to
+	 * it. Return error to indicate failure.
+	 */
+	if (current->current_sec_interrupt_id != pint_id) {
+		return -1;
+	}
+
+	if (!current->secure_interrupt_deactivated) {
+		plat_interrupts_end_of_interrupt(pint_id);
+		current->secure_interrupt_deactivated = true;
+	}
+
+	return 0;
+}