// SPDX-License-Identifier: GPL-2.0-only /* * Test edge cases and race conditions in kvm_recalculate_apic_map(). */ #include <sys/ioctl.h> #include <pthread.h> #include <time.h> #include "processor.h" #include "test_util.h" #include "kvm_util.h" #include "apic.h" #define TIMEOUT 5 /* seconds */ #define LAPIC_DISABLED 0 #define LAPIC_X2APIC (MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE) #define MAX_XAPIC_ID 0xff static void *race(void *arg) { struct kvm_lapic_state lapic = {}; struct kvm_vcpu *vcpu = arg; while (1) { /* Trigger kvm_recalculate_apic_map(). */ vcpu_ioctl(vcpu, KVM_SET_LAPIC, &lapic); pthread_testcancel(); } return NULL; } int main(void) { struct kvm_vcpu *vcpus[KVM_MAX_VCPUS]; struct kvm_vcpu *vcpuN; struct kvm_vm *vm; pthread_t thread; time_t t; int i; kvm_static_assert(KVM_MAX_VCPUS > MAX_XAPIC_ID); /* * Create the max number of vCPUs supported by selftests so that KVM * has decent amount of work to do when recalculating the map, i.e. to * make the problematic window large enough to hit. */ vm = vm_create_with_vcpus(KVM_MAX_VCPUS, NULL, vcpus); /* * Enable x2APIC on all vCPUs so that KVM doesn't bail from the recalc * due to vCPUs having aliased xAPIC IDs (truncated to 8 bits). */ for (i = 0; i < KVM_MAX_VCPUS; i++) vcpu_set_msr(vcpus[i], MSR_IA32_APICBASE, LAPIC_X2APIC); TEST_ASSERT_EQ(pthread_create(&thread, NULL, race, vcpus[0]), 0); vcpuN = vcpus[KVM_MAX_VCPUS - 1]; for (t = time(NULL) + TIMEOUT; time(NULL) < t;) { vcpu_set_msr(vcpuN, MSR_IA32_APICBASE, LAPIC_X2APIC); vcpu_set_msr(vcpuN, MSR_IA32_APICBASE, LAPIC_DISABLED); } TEST_ASSERT_EQ(pthread_cancel(thread), 0); TEST_ASSERT_EQ(pthread_join(thread, NULL), 0); kvm_vm_free(vm); return 0; }