diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 22a4b687ea5b..73588fcaff8c 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1553,6 +1553,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			nosid	disable Source ID checking
 			no_x2apic_optout
 				BIOS x2APIC opt-out request will be ignored
+			nopost	disable Interrupt Posting
 
 	iomem=		Disable strict checking of access to MMIO memory
 		strict	regions from userspace.
diff --git a/drivers/iommu/irq_remapping.c b/drivers/iommu/irq_remapping.c
index 913455a5fd40..8adaaeae3268 100644
--- a/drivers/iommu/irq_remapping.c
+++ b/drivers/iommu/irq_remapping.c
@@ -22,7 +22,7 @@ int irq_remap_broken;
 int disable_sourceid_checking;
 int no_x2apic_optout;
 
-int disable_irq_post = 1;
+int disable_irq_post = 0;
 
 static int disable_irq_remap;
 static struct irq_remap_ops *remap_ops;
@@ -58,14 +58,18 @@ static __init int setup_irqremap(char *str)
 		return -EINVAL;
 
 	while (*str) {
-		if (!strncmp(str, "on", 2))
+		if (!strncmp(str, "on", 2)) {
 			disable_irq_remap = 0;
-		else if (!strncmp(str, "off", 3))
+			disable_irq_post = 0;
+		} else if (!strncmp(str, "off", 3)) {
 			disable_irq_remap = 1;
-		else if (!strncmp(str, "nosid", 5))
+			disable_irq_post = 1;
+		} else if (!strncmp(str, "nosid", 5))
 			disable_sourceid_checking = 1;
 		else if (!strncmp(str, "no_x2apic_optout", 16))
 			no_x2apic_optout = 1;
+		else if (!strncmp(str, "nopost", 6))
+			disable_irq_post = 1;
 
 		str += strcspn(str, ",");
 		while (*str == ',')