KVM: selftests: Convert xss_msr_test away from VCPU_ID

Convert xss_msr_test to use vm_create_with_one_vcpu() and pass around a
'struct kvm_vcpu' object instead of using a global VCPU_ID.  Note, this
is a "functional" change in the sense that the test now creates a vCPU
with vcpu_id==0 instead of vcpu_id==1.  The non-zero VCPU_ID was 100%
arbitrary and added little to no validation coverage.  If testing
non-zero vCPU IDs is desirable for generic tests, that can be done in the
future by tweaking the VM creation helpers.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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

@@ -12,7 +12,6 @@
 #include "kvm_util.h"
 #include "vmx.h"
 
-#define VCPU_ID	      1
 #define MSR_BITS      64
 
 #define X86_FEATURE_XSAVES	(1<<3)
@@ -23,11 +22,12 @@ int main(int argc, char *argv[])
 	bool xss_supported = false;
 	bool xss_in_msr_list;
 	struct kvm_vm *vm;
+	struct kvm_vcpu *vcpu;
 	uint64_t xss_val;
 	int i, r;
 
 	/* Create VM */
-	vm = vm_create_default(VCPU_ID, 0, 0);
+	vm = vm_create_with_one_vcpu(&vcpu, NULL);
 
 	if (kvm_get_cpuid_max_basic() >= 0xd) {
 		entry = kvm_get_supported_cpuid_index(0xd, 1);
@@ -38,11 +38,12 @@ int main(int argc, char *argv[])
 		exit(KSFT_SKIP);
 	}
 
-	xss_val = vcpu_get_msr(vm, VCPU_ID, MSR_IA32_XSS);
+	xss_val = vcpu_get_msr(vm, vcpu->id, MSR_IA32_XSS);
 	TEST_ASSERT(xss_val == 0,
 		    "MSR_IA32_XSS should be initialized to zero\n");
 
-	vcpu_set_msr(vm, VCPU_ID, MSR_IA32_XSS, xss_val);
+	vcpu_set_msr(vm, vcpu->id, MSR_IA32_XSS, xss_val);
+
 	/*
 	 * At present, KVM only supports a guest IA32_XSS value of 0. Verify
 	 * that trying to set the guest IA32_XSS to an unsupported value fails.
@@ -51,7 +52,7 @@ int main(int argc, char *argv[])
 	 */
 	xss_in_msr_list = kvm_msr_is_in_save_restore_list(MSR_IA32_XSS);
 	for (i = 0; i < MSR_BITS; ++i) {
-		r = _vcpu_set_msr(vm, VCPU_ID, MSR_IA32_XSS, 1ull << i);
+		r = _vcpu_set_msr(vm, vcpu->id, MSR_IA32_XSS, 1ull << i);
 
 		/*
 		 * Setting a list of MSRs returns the entry that "faulted", or