1 files changed, 62 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/x86/max_vcpuid_cap_test.c b/tools/testing/selftests/kvm/x86/max_vcpuid_cap_test.c
new file mode 100644
index 000000000000..7e2bfb3c3f3b
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86/max_vcpuid_cap_test.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * maximum APIC ID capability tests
+ *
+ * Copyright (C) 2022, Intel, Inc.
+ *
+ * Tests for getting/setting maximum APIC ID capability
+ */
+
+#include "kvm_util.h"
+
+#define MAX_VCPU_ID	2
+
+int main(int argc, char *argv[])
+{
+	struct kvm_vm *vm;
+	int ret;
+
+	vm = vm_create_barebones();
+
+	/* Get KVM_CAP_MAX_VCPU_ID cap supported in KVM */
+	ret = vm_check_cap(vm, KVM_CAP_MAX_VCPU_ID);
+
+	/* Try to set KVM_CAP_MAX_VCPU_ID beyond KVM cap */
+	ret = __vm_enable_cap(vm, KVM_CAP_MAX_VCPU_ID, ret + 1);
+	TEST_ASSERT(ret < 0,
+		    "Setting KVM_CAP_MAX_VCPU_ID beyond KVM cap should fail");
+
+	/* Test BOOT_CPU_ID interaction (MAX_VCPU_ID cannot be lower) */
+	if (kvm_has_cap(KVM_CAP_SET_BOOT_CPU_ID)) {
+		vm_ioctl(vm, KVM_SET_BOOT_CPU_ID, (void *)MAX_VCPU_ID);
+
+		/* Try setting KVM_CAP_MAX_VCPU_ID below BOOT_CPU_ID */
+		ret = __vm_enable_cap(vm, KVM_CAP_MAX_VCPU_ID, MAX_VCPU_ID - 1);
+		TEST_ASSERT(ret < 0,
+			    "Setting KVM_CAP_MAX_VCPU_ID below BOOT_CPU_ID should fail");
+	}
+
+	/* Set KVM_CAP_MAX_VCPU_ID */
+	vm_enable_cap(vm, KVM_CAP_MAX_VCPU_ID, MAX_VCPU_ID);
+
+	/* Try to set KVM_CAP_MAX_VCPU_ID again */
+	ret = __vm_enable_cap(vm, KVM_CAP_MAX_VCPU_ID, MAX_VCPU_ID + 1);
+	TEST_ASSERT(ret < 0,
+		    "Setting KVM_CAP_MAX_VCPU_ID multiple times should fail");
+
+	/* Create vCPU with id beyond KVM_CAP_MAX_VCPU_ID cap */
+	ret = __vm_ioctl(vm, KVM_CREATE_VCPU, (void *)MAX_VCPU_ID);
+	TEST_ASSERT(ret < 0, "Creating vCPU with ID > MAX_VCPU_ID should fail");
+
+	/* Create vCPU with bits 63:32 != 0, but an otherwise valid id */
+	ret = __vm_ioctl(vm, KVM_CREATE_VCPU, (void *)(1L << 32));
+	TEST_ASSERT(ret < 0, "Creating vCPU with ID[63:32] != 0 should fail");
+
+	/* Create vCPU with id within bounds */
+	ret = __vm_ioctl(vm, KVM_CREATE_VCPU, (void *)0);
+	TEST_ASSERT(ret >= 0, "Creating vCPU with ID 0 should succeed");
+
+	close(ret);
+	kvm_vm_free(vm);
+	return 0;
+}