diff --git a/tools/testing/selftests/kvm/irq_test.c b/tools/testing/selftests/kvm/irq_test.c
index 70b2c9cac279..fd386e3e9ac3 100644
--- a/tools/testing/selftests/kvm/irq_test.c
+++ b/tools/testing/selftests/kvm/irq_test.c
@@ -12,10 +12,12 @@
 #include <unistd.h>
 #include <pthread.h>
 #include <sys/eventfd.h>
+#include <sys/sysinfo.h>
 
 static u64 timeout_ns = 2ULL * 1000 * 1000 * 1000;
 static bool guest_ready_for_irqs[KVM_MAX_VCPUS];
 static bool guest_received_irq[KVM_MAX_VCPUS];
+static bool irq_affinity;
 static bool done;
 
 #define GUEST_RECEIVED_IRQ(__vcpu)	\
@@ -137,9 +139,10 @@ static const char *probe_iommu_type(void)
 
 static void help(const char *name)
 {
-	printf("Usage: %s [-d <segment:bus:device.function>] [-h] [-t iommu_type]\n", name);
+	printf("Usage: %s [-a] [-d <segment:bus:device.function>] [-h] [-t iommu_type]\n", name);
 	printf("\n");
 	printf("Tests KVM interrupt routing and delivery via irqfd.\n");
+	printf("-a	Affine the device's host IRQ to a random physical CPU\n");
 	printf("-d	Use a VFIO device to send MSI-X interrupts instead of manually signaling the eventfd\n");
 	printf("-t	Override the IOMMU type to use (vfio_type1_iommu or iommufd)\n");
 	printf("\n");
@@ -172,10 +175,13 @@ int main(int argc, char **argv)
 	int i, j, c, msix, eventfd;
 	struct iommu *iommu;
 	struct kvm_vm *vm;
-	int irq;
+	int irq, irq_cpu;
 
-	while ((c = getopt(argc, argv, "d:ht:")) != -1) {
+	while ((c = getopt(argc, argv, "ad:ht:")) != -1) {
 		switch (c) {
+		case 'a':
+			irq_affinity = true;
+			break;
 		case 'd':
 			device_bdf = optarg;
 			break;
@@ -204,7 +210,12 @@ int main(int argc, char **argv)
 		printf("Using device %s MSI-X[%d] (IRQ-%u)\n", device_bdf, msix,
 		       irq);
 	} else {
+		TEST_ASSERT(!irq_affinity,
+			    "Setting IRQ affinity (-a) requires a backing device (-d)");
+
 		eventfd = kvm_new_eventfd();
+		irq = -1;
+		irq_cpu = -1;
 	}
 
 	pr_info("Injecting interrupts for GSI %d (guest vector 0x%x) %d times\n",
@@ -228,6 +239,11 @@ int main(int argc, char **argv)
 
 		kvm_route_msi(vm, gsi, vcpu, vector);
 
+		if (irq_affinity) {
+			irq_cpu = kvm_random_u64(&kvm_rng) % get_nprocs();
+			proc_irq_set_smp_affinity(irq, irq_cpu);
+		}
+
 		for (j = 0; j < nr_vcpus; j++)
 			TEST_ASSERT(!GUEST_RECEIVED_IRQ(vcpus[j]),
 				    "IRQ flag for vCPU %d not clear prior to test",
@@ -241,8 +257,8 @@ int main(int argc, char **argv)
 			cpu_relax();
 
 		TEST_ASSERT(GUEST_RECEIVED_IRQ(vcpu),
-			    "vCPU %d timed out waiting for IRQ (vector 0x%x) from GSI %d\n",
-			    vcpu->id, vector, gsi);
+			    "vCPU %d timed out waiting for IRQ (vector 0x%x) from GSI %d (via CPU %d)\n",
+			    vcpu->id, vector, gsi, irq_cpu);
 
 		WRITE_AND_SYNC_TO_GUEST(vm, guest_received_irq[vcpu->id], false);
 	}