From: David Matlack Add the -n flag to tools/testing/selftests/kvm/irq_test.c to route a portion of device interrupts as NMIs (Non-Maskable Interrupts) into the guest using an alternating pattern of 4 NMIs followed by 4 regular interrupts. While this adds coverage for NMI injection, the primary goal is to validate KVM's handling of non-postable interrupt delivery—specifically the transitions between posted and remapped modes. NMIs are used for this purpose because they are a reliable, architectural way to force these code paths. Co-developed-by: Josh Hilke Signed-off-by: Josh Hilke Signed-off-by: David Matlack --- tools/testing/selftests/kvm/irq_test.c | 44 ++++++++++++++++++++------ 1 file changed, 34 insertions(+), 10 deletions(-) diff --git a/tools/testing/selftests/kvm/irq_test.c b/tools/testing/selftests/kvm/irq_test.c index 9efb7e655623..03b88b7585b3 100644 --- a/tools/testing/selftests/kvm/irq_test.c +++ b/tools/testing/selftests/kvm/irq_test.c @@ -17,6 +17,7 @@ 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 guest_received_nmi[KVM_MAX_VCPUS]; static bool irq_affinity; static bool block_vcpus; static bool done; @@ -33,6 +34,11 @@ static void guest_irq_handler(struct ex_regs *regs) x2apic_write_reg(APIC_EOI, 0); } +static void guest_nmi_handler(struct ex_regs *regs) +{ + WRITE_ONCE(guest_received_nmi[guest_get_vcpu_id()], true); +} + static void guest_code(void) { x2apic_enable(); @@ -93,7 +99,7 @@ static void trigger_interrupt(struct vfio_pci_device *device, int eventfd) static void kvm_route_msi(struct kvm_vm *vm, u32 gsi, struct kvm_vcpu *vcpu, - u8 vector) + u8 vector, bool use_nmi) { struct { struct kvm_irq_routing head; @@ -106,7 +112,7 @@ static void kvm_route_msi(struct kvm_vm *vm, u32 gsi, struct kvm_vcpu *vcpu, routes->entries[0].gsi = gsi; routes->entries[0].type = KVM_IRQ_ROUTING_MSI; routes->entries[0].u.msi.address_lo = 0xFEE00000 | (vcpu->id << 12); - routes->entries[0].u.msi.data = vector; + routes->entries[0].u.msi.data = use_nmi ? NMI_VECTOR | (4 << 8) : vector; vm_ioctl(vm, KVM_SET_GSI_ROUTING, routes); } @@ -120,7 +126,7 @@ static void kvm_clear_gsi_routes(struct kvm_vm *vm) static void help(const char *name) { - printf("Usage: %s [-a] [-b] [-c] [-d ] [-h] [-i nr_irqs]\n", name); + printf("Usage: %s [-a] [-b] [-c] [-d ] [-h] [-i nr_irqs] [-n]\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"); @@ -128,6 +134,7 @@ static void help(const char *name) 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("-i The number of IRQs to generate during the test\n"); + printf("-n Deliver 50 percent of IRQs as non-maskable interrupts\n"); printf("\n"); exit(KSFT_FAIL); } @@ -149,6 +156,7 @@ int main(int argc, char **argv) u32 gsi = kvm_random_u64_in_range(&kvm_rng, 24, KVM_MAX_IRQ_ROUTES - 1); u8 vector = kvm_random_u64_in_range(&kvm_rng, 32, UINT8_MAX); + bool clear_routes = false, use_nmi = false; int i, j, c, msi, irq, eventfd, irq_cpu; struct kvm_vcpu *vcpus[KVM_MAX_VCPUS]; pthread_t vcpu_threads[KVM_MAX_VCPUS]; @@ -156,11 +164,10 @@ 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, "abcd:hi:")) != -1) { + while ((c = getopt(argc, argv, "abcd:hi:n")) != -1) { switch (c) { case 'a': irq_affinity = true; @@ -177,6 +184,9 @@ int main(int argc, char **argv) case 'i': nr_irqs = atoi_positive("Number of IRQs", optarg); break; + case 'n': + use_nmi = true; + break; case 'h': default: help(argv[0]); @@ -187,6 +197,7 @@ int main(int argc, char **argv) vm = vm_create_with_vcpus(nr_vcpus, guest_code, vcpus); vm_install_exception_handler(vm, vector, guest_irq_handler); + vm_install_exception_handler(vm, NMI_VECTOR, guest_nmi_handler); if (device_bdf) { iommu = iommu_init(default_iommu_mode); @@ -224,35 +235,45 @@ int main(int argc, char **argv) for (i = 0; i < nr_irqs; i++) { const bool do_clear_routes = clear_routes && (i & BIT(3)); + const bool do_use_nmi = use_nmi && (i & BIT(2)); 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); + kvm_route_msi(vm, gsi, vcpu, vector, do_use_nmi); if (irq_affinity && vcpu->id == 0) { irq_cpu = kvm_random_u64(&kvm_rng) % get_nprocs(); write_proc_irq_affinity(irq_affinity_fp, irq, irq_cpu); } - for (j = 0; j < nr_vcpus; j++) + for (j = 0; j < nr_vcpus; j++) { TEST_ASSERT( !SYNC_FROM_GUEST_AND_READ(vm, guest_received_irq[vcpus[j]->id]), "IRQ flag for vCPU %d not clear prior to test", vcpus[j]->id); + TEST_ASSERT( + !SYNC_FROM_GUEST_AND_READ(vm, guest_received_nmi[vcpus[j]->id]), + "NMI flag for vCPU %d not clear prior to test", + vcpus[j]->id); + } trigger_interrupt(device, eventfd); clock_gettime(CLOCK_MONOTONIC, &start); for (;;) { - if (SYNC_FROM_GUEST_AND_READ(vm, guest_received_irq[vcpu->id])) + if (!do_use_nmi && SYNC_FROM_GUEST_AND_READ(vm, guest_received_irq[vcpu->id])) + break; + + if (do_use_nmi && SYNC_FROM_GUEST_AND_READ(vm, guest_received_nmi[vcpu->id])) break; if (timespec_to_ns(timespec_elapsed(start)) > timeout_ns) { printf("Timeout waiting for interrupt!\n"); printf(" vCPU: %d\n", vcpu->id); + printf(" is interrupt NMI: %s\n", do_use_nmi ? "true" : "false"); if (irq_affinity) printf(" irq_cpu: %d\n", irq_cpu); @@ -261,7 +282,10 @@ int main(int argc, char **argv) } } - WRITE_AND_SYNC_TO_GUEST(vm, guest_received_irq[vcpu->id], false); + if (do_use_nmi) + WRITE_AND_SYNC_TO_GUEST(vm, guest_received_nmi[vcpu->id], false); + else + WRITE_AND_SYNC_TO_GUEST(vm, guest_received_irq[vcpu->id], false); } WRITE_AND_SYNC_TO_GUEST(vm, done, true); @@ -273,7 +297,7 @@ int main(int argc, char **argv) * below, will hang. */ if (block_vcpus) { - kvm_route_msi(vm, gsi, vcpus[i], vector); + kvm_route_msi(vm, gsi, vcpus[i], vector, false); trigger_interrupt(device, eventfd); } -- 2.54.0.rc2.533.g4f5dca5207-goog