[PATCH v4 10/19] KVM: selftests: Verify interrupts are received after modifying IRQ routes in IRQ test

[Josh Hilke <jrhilke@google.com>]

From: David Matlack <dmatlack@google.com>

Add the '-c' flag to tools/testing/selftests/kvm/irq_test.c to destroy
and recreate KVM's GSI routing table between interrupts. This ensures
that KVM correctly handles dynamic updates to the interrupt routing
table while interrupts are actively being signaled by assigned devices.

Co-developed-by: Josh Hilke <jrhilke@google.com>
Signed-off-by: Josh Hilke <jrhilke@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
---
 tools/testing/selftests/kvm/irq_test.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kvm/irq_test.c b/tools/testing/selftests/kvm/irq_test.c
index 562b9ab187a4..72b9106216ed 100644
--- a/tools/testing/selftests/kvm/irq_test.c
+++ b/tools/testing/selftests/kvm/irq_test.c
@@ -114,13 +114,21 @@ static void kvm_route_msi(struct kvm_vm *vm, u32 gsi, struct kvm_vcpu *vcpu,
 	vm_ioctl(vm, KVM_SET_GSI_ROUTING, routes);
 }
 
+static void kvm_clear_gsi_routes(struct kvm_vm *vm)
+{
+	struct kvm_irq_routing routes = {};
+
+	vm_ioctl(vm, KVM_SET_GSI_ROUTING, &routes);
+}
+
 static void help(const char *name)
 {
-	printf("Usage: %s [-a] [-b] [-d <segment:bus:device.function>] [-h]\n", name);
+	printf("Usage: %s [-a] [-b] [-c] [-d <segment:bus:device.function>] [-h]\n", name);
 	printf("\n");
 	printf("Tests KVM IRQ injection via irqfd using an emulated eventfd.\n");
 	printf("-a	Randomly affinitize the device's host IRQ to different physical CPUs throughout the test\n");
 	printf("-b	Block vCPUs (e.g. HLT) instead of spinning in guest-mode\n");
+	printf("-c	Destroy and recreate KVM's GSI routing table in between some interrupts\n");
 	printf("-d	Use a VFIO device to send MSI-X interrupts instead of using an emulated eventfd\n");
 	printf("\n");
 	exit(KSFT_FAIL);
@@ -150,10 +158,11 @@ int main(int argc, char **argv)
 	int nr_irqs = 1000, nr_vcpus = 1;
 	const char *device_bdf = NULL;
 	FILE *irq_affinity_fp = NULL;
+	bool clear_routes = false;
 	struct iommu *iommu;
 	struct kvm_vm *vm;
 
-	while ((c = getopt(argc, argv, "abd:h")) != -1) {
+	while ((c = getopt(argc, argv, "abcd:h")) != -1) {
 		switch (c) {
 		case 'a':
 			irq_affinity = true;
@@ -164,6 +173,9 @@ int main(int argc, char **argv)
 		case 'd':
 			device_bdf = optarg;
 			break;
+		case 'c':
+			clear_routes = true;
+			break;
 		case 'h':
 		default:
 			help(argv[0]);
@@ -210,9 +222,13 @@ int main(int argc, char **argv)
 	}
 
 	for (i = 0; i < nr_irqs; i++) {
+		const bool do_clear_routes = clear_routes && (i & BIT(3));
 		struct kvm_vcpu *vcpu = vcpus[i % nr_vcpus];
 		struct timespec start;
 
+		if (do_clear_routes)
+			kvm_clear_gsi_routes(vm);
+
 		kvm_route_msi(vm, gsi, vcpu, vector);
 
 		if (irq_affinity && vcpu->id == 0) {
-- 
2.54.0.929.g9b7fa37559-goog