kvm: selftests: Add KVM_CAP_MAX_VCPU_ID cap test

mainline inclusion
from mainline-v6.0-rc1
commit 753dcf7a
category: feature
feature: IPI Virtualization
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I5ODSC
CVE: N/A
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=753dcf7a8686a750fa6aa4b4ca42c6945fc75ac1

Intel-SIG: commit 753dcf7a ("kvm: selftests: Add KVM_CAP_MAX_VCPU_ID cap test")

-------------------------------------

kvm: selftests: Add KVM_CAP_MAX_VCPU_ID cap test

Basic test coverage of KVM_CAP_MAX_VCPU_ID cap.

This capability can be enabled before vCPU creation and only allowed
to set once. if assigned vcpu id is beyond KVM_CAP_MAX_VCPU_ID
capability, vCPU creation will fail.
Signed-off-by: NZeng Guang <guang.zeng@intel.com>
Message-Id: <20220422134456.26655-1-guang.zeng@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJason Zeng <jason.zeng@intel.com>

tools/testing/selftests/kvm/.gitignore

@@ -9,6 +9,7 @@
 /x86_64/evmcs_test
 /x86_64/kvm_pv_test
 /x86_64/hyperv_cpuid
+/x86_64/max_vcpuid_cap_test
 /x86_64/mmio_warning_test
 /x86_64/platform_info_test
 /x86_64/set_sregs_test

tools/testing/selftests/kvm/Makefile

@@ -59,6 +59,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/xss_msr_test
 TEST_GEN_PROGS_x86_64 += x86_64/debug_regs
 TEST_GEN_PROGS_x86_64 += x86_64/tsc_msrs_test
 TEST_GEN_PROGS_x86_64 += x86_64/user_msr_test
+TEST_GEN_PROGS_x86_64 += x86_64/max_vcpuid_cap_test
 TEST_GEN_PROGS_x86_64 += demand_paging_test
 TEST_GEN_PROGS_x86_64 += dirty_log_test
 TEST_GEN_PROGS_x86_64 += dirty_log_perf_test

tools/testing/selftests/kvm/include/kvm_util.h

@@ -62,6 +62,7 @@ enum vm_mem_backing_src_type {
 };
 
 int kvm_check_cap(long cap);
+int vm_check_cap(struct kvm_vm *vm, long cap);
 int vm_enable_cap(struct kvm_vm *vm, struct kvm_enable_cap *cap);
 int vcpu_enable_cap(struct kvm_vm *vm, uint32_t vcpu_id,
 		    struct kvm_enable_cap *cap);

tools/testing/selftests/kvm/lib/kvm_util.c

@@ -63,6 +63,33 @@ int kvm_check_cap(long cap)
 	return ret;
 }
 
+/* VM Check Capability
+ *
+ * Input Args:
+ * vm - Virtual Machine
+ * cap - Capability
+ *
+ * Output Args: None
+ *
+ * Return:
+ * On success, the Value corresponding to the capability (KVM_CAP_*)
+ * specified by the value of cap. On failure a TEST_ASSERT failure
+ * is produced.
+ *
+ * Looks up and returns the value corresponding to the capability
+ * (KVM_CAP_*) given by cap.
+ */
+int vm_check_cap(struct kvm_vm *vm, long cap)
+{
+	int ret;
+
+	ret = ioctl(vm->fd, KVM_CHECK_EXTENSION, cap);
+	TEST_ASSERT(ret >= 0, "KVM_CHECK_EXTENSION VM IOCTL failed,\n"
+		    " rc: %i errno: %i", ret, errno);
+
+	return ret;
+}
+
 /* VM Enable Capability
  *
  * Input Args:

tools/testing/selftests/kvm/x86_64/max_vcpuid_cap_test.c

+// 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"
+#include "../lib/kvm_util_internal.h"
+
+#define MAX_VCPU_ID	2
+
+int main(int argc, char *argv[])
+{
+	struct kvm_vm *vm;
+	struct kvm_enable_cap cap = { 0 };
+	int ret;
+
+	vm = vm_create(VM_MODE_DEFAULT, 0, O_RDWR);
+
+	/* 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 */
+	cap.cap = KVM_CAP_MAX_VCPU_ID;
+	cap.args[0] = ret + 1;
+	ret = ioctl(vm->fd, KVM_ENABLE_CAP, &cap);
+	TEST_ASSERT(ret < 0,
+		    "Unexpected success to enable KVM_CAP_MAX_VCPU_ID"
+		    "beyond KVM cap!\n");
+
+	/* Set KVM_CAP_MAX_VCPU_ID */
+	cap.cap = KVM_CAP_MAX_VCPU_ID;
+	cap.args[0] = MAX_VCPU_ID;
+	ret = ioctl(vm->fd, KVM_ENABLE_CAP, &cap);
+	TEST_ASSERT(ret == 0,
+		    "Unexpected failure to enable KVM_CAP_MAX_VCPU_ID!\n");
+
+	/* Try to set KVM_CAP_MAX_VCPU_ID again */
+	cap.args[0] = MAX_VCPU_ID + 1;
+	ret = ioctl(vm->fd, KVM_ENABLE_CAP, &cap);
+	TEST_ASSERT(ret < 0,
+		    "Unexpected success to enable KVM_CAP_MAX_VCPU_ID again\n");
+
+	/* Create vCPU with id beyond KVM_CAP_MAX_VCPU_ID cap*/
+	ret = ioctl(vm->fd, KVM_CREATE_VCPU, MAX_VCPU_ID);
+	TEST_ASSERT(ret < 0,
+		    "Unexpected success in creating a vCPU with VCPU ID out of range\n");
+
+	kvm_vm_free(vm);
+	return 0;
+}