[PATCH v8 19/20] KVM: selftests: Make number of vCPUs configurable in IRQ test

[Sean Christopherson <seanjc@google.com>]

From: David Matlack <dmatlack@google.com>

Extend the eventfd IRQ test with a '-v' flag to allow the user to
configure the number of vCPUs to create and run (versus only ever using a
single vCPU).

Update the routing logic to play nice with 32 bit IDs, enable x2APIC format
in KVM (to enable 32-bit ID routing), and disable KVM's x2APIC broadcast
quirk so that targeting vCPU 255 doesn't blast the interrupt to all vCPUs
when in x2APIC mode.

Signed-off-by: David Matlack <dmatlack@google.com>
Co-developed-by: Josh Hilke <jrhilke@google.com>
Signed-off-by: Josh Hilke <jrhilke@google.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 tools/testing/selftests/kvm/irq_test.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/kvm/irq_test.c b/tools/testing/selftests/kvm/irq_test.c
index c0ff6e60b167..d2c745c54960 100644
--- a/tools/testing/selftests/kvm/irq_test.c
+++ b/tools/testing/selftests/kvm/irq_test.c
@@ -124,7 +124,8 @@ static void kvm_route_msi(struct kvm_vm *vm, u32 gsi, struct kvm_vcpu *vcpu,
 		.entry = {
 			.gsi = gsi,
 			.type = KVM_IRQ_ROUTING_MSI,
-			.u.msi.address_lo = 0xFEE00000 | (vcpu->id << 12),
+			.u.msi.address_lo = 0xFEE00000 | (vcpu->id & GENMASK(7, 0)) << 12,
+			.u.msi.address_hi = vcpu->id & GENMASK(31, 8),
 			.u.msi.data = use_nmi ? NMI_VECTOR | (4 << 8) : vector,
 		},
 	};
@@ -157,7 +158,7 @@ static const char *probe_iommu_type(void)
 
 static void help(const char *name)
 {
-	printf("Usage: %s [-a] [-d <segment:bus:device.function>] [-e] [-h] [-i nr_irqs] [-m] [-n] [-t iommu_type]\n", name);
+	printf("Usage: %s [-a] [-d <segment:bus:device.function>] [-e] [-h] [-i nr_irqs] [-m] [-n] [-t iommu_type] [-v nr_vcpus]\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");
@@ -167,6 +168,7 @@ static void help(const char *name)
 	printf("-m	Pin target vCPU to random physical CPU before triggering interrupt\n");
 	printf("-n	Deliver 50 percent of IRQs as non-maskable interrupts\n");
 	printf("-t	Override the IOMMU type to use (vfio_type1_iommu or iommufd)\n");
+	printf("-v	Number of vCPUS to run\n");
 	printf("\n");
 	exit(KSFT_FAIL);
 }
@@ -203,7 +205,7 @@ int main(int argc, char **argv)
 	struct kvm_vm *vm;
 	int irq, irq_cpu;
 
-	while ((c = getopt(argc, argv, "ad:ehi:mnt:")) != -1) {
+	while ((c = getopt(argc, argv, "ad:ehi:mnt:v:")) != -1) {
 		switch (c) {
 		case 'a':
 			irq_affinity = true;
@@ -226,6 +228,11 @@ int main(int argc, char **argv)
 		case 't':
 			iommu_type = optarg;
 			break;
+		case 'v':
+			nr_vcpus = atoi_positive("Number of vCPUS", optarg);
+			TEST_ASSERT(nr_vcpus <= KVM_MAX_VCPUS,
+				    "KVM selftests support at most %u vCPUs", KVM_MAX_VCPUS);
+			break;
 		case 'h':
 		default:
 			help(argv[0]);
@@ -235,6 +242,9 @@ int main(int argc, char **argv)
 	TEST_REQUIRE(kvm_arch_has_default_irqchip());
 
 	vm = vm_create_with_vcpus(nr_vcpus, guest_code, vcpus);
+	vm_enable_cap(vm, KVM_CAP_X2APIC_API, KVM_X2APIC_API_USE_32BIT_IDS |
+					      KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK);
+
 	vm_install_exception_handler(vm, vector, guest_irq_handler);
 	vm_install_exception_handler(vm, NMI_VECTOR, guest_nmi_handler);
 
-- 
2.55.0.rc0.799.gd6f94ed593-goog