From: David Matlack Add the '-b' flag to tools/testing/selftests/kvm/irq_test.c to verify that interrupts successfully wake up vCPUs that are in a halted state. By default, the guest code spins using cpu_relax() while waiting for interrupts. With the '-b' flag, the guest executes the HLT instruction instead. At the end of the test, the host explicitly routes and triggers a final interrupt for each vCPU. If the interrupt fails to wake the halted vCPU, the guest will never exit its loop, and the host's call to pthread_join() will hang, causing the test to time out and fail. Co-developed-by: Josh Hilke Signed-off-by: Josh Hilke Signed-off-by: David Matlack --- tools/testing/selftests/kvm/irq_test.c | 32 ++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/kvm/irq_test.c b/tools/testing/selftests/kvm/irq_test.c index e76784e0a054..562b9ab187a4 100644 --- a/tools/testing/selftests/kvm/irq_test.c +++ b/tools/testing/selftests/kvm/irq_test.c @@ -18,6 +18,7 @@ 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 irq_affinity; +static bool block_vcpus; static bool done; #define GUEST_RECEIVED_IRQ(__vcpu) \ @@ -43,8 +44,12 @@ static void guest_code(void) WRITE_ONCE(guest_ready_for_irqs[guest_get_vcpu_id()], true); - while (!READ_ONCE(done)) - cpu_relax(); + while (!READ_ONCE(done)) { + if (block_vcpus) + hlt(); + else + cpu_relax(); + } GUEST_DONE(); } @@ -111,10 +116,11 @@ static void kvm_route_msi(struct kvm_vm *vm, u32 gsi, struct kvm_vcpu *vcpu, static void help(const char *name) { - printf("Usage: %s [-a] [-d ] [-h]\n", name); + printf("Usage: %s [-a] [-b] [-d ] [-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("-d Use a VFIO device to send MSI-X interrupts instead of using an emulated eventfd\n"); printf("\n"); exit(KSFT_FAIL); @@ -147,11 +153,14 @@ int main(int argc, char **argv) struct iommu *iommu; struct kvm_vm *vm; - while ((c = getopt(argc, argv, "ad:h")) != -1) { + while ((c = getopt(argc, argv, "abd:h")) != -1) { switch (c) { case 'a': irq_affinity = true; break; + case 'b': + block_vcpus = true; + break; case 'd': device_bdf = optarg; break; @@ -188,6 +197,8 @@ int main(int argc, char **argv) kvm_assign_irqfd(vm, gsi, eventfd); + sync_global_to_guest(vm, block_vcpus); + for (i = 0; i < nr_vcpus; i++) pthread_create(&vcpu_threads[i], NULL, vcpu_thread_main, vcpus[i]); @@ -237,8 +248,19 @@ int main(int argc, char **argv) WRITE_AND_SYNC_TO_GUEST(vm, done, true); - for (i = 0; i < nr_vcpus; i++) + for (i = 0; i < nr_vcpus; i++) { + /* + * Verify that sending an interrupt to a halted vCPU wakes it + * up. If the vCPU does not wake up, the call to pthread_join(), + * below, will hang. + */ + if (block_vcpus) { + kvm_route_msi(vm, gsi, vcpus[i], vector); + trigger_interrupt(device, eventfd); + } + pthread_join(vcpu_threads[i], NULL); + } if (irq_affinity) fclose(irq_affinity_fp); -- 2.54.0.929.g9b7fa37559-goog