KVM: selftests: Convert userspace_io_test away from VCPU_ID

Convert userspace_io_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.

Opportunistically use vcpu_run() instead of _vcpu_run() with an open
coded assert that KVM_RUN succeeded.
Signed-off-by: NSean Christopherson <seanjc@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

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

@@ -10,8 +10,6 @@
 #include "kvm_util.h"
 #include "processor.h"
 
-#define VCPU_ID			1
-
 static void guest_ins_port80(uint8_t *buffer, unsigned int count)
 {
 	unsigned long end;
@@ -52,31 +50,29 @@ static void guest_code(void)
 
 int main(int argc, char *argv[])
 {
+	struct kvm_vcpu *vcpu;
 	struct kvm_regs regs;
 	struct kvm_run *run;
 	struct kvm_vm *vm;
 	struct ucall uc;
-	int rc;
 
 	/* Tell stdout not to buffer its content */
 	setbuf(stdout, NULL);
 
-	/* Create VM */
-	vm = vm_create_default(VCPU_ID, 0, guest_code);
-	run = vcpu_state(vm, VCPU_ID);
+	vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+	run = vcpu->run;
 
 	memset(&regs, 0, sizeof(regs));
 
 	while (1) {
-		rc = _vcpu_run(vm, VCPU_ID);
+		vcpu_run(vm, vcpu->id);
 
-		TEST_ASSERT(rc == 0, "vcpu_run failed: %d\n", rc);
 		TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
 			    "Unexpected exit reason: %u (%s),\n",
 			    run->exit_reason,
 			    exit_reason_str(run->exit_reason));
 
-		if (get_ucall(vm, VCPU_ID, &uc))
+		if (get_ucall(vm, vcpu->id, &uc))
 			break;
 
 		TEST_ASSERT(run->io.port == 0x80,
@@ -89,13 +85,13 @@ int main(int argc, char *argv[])
 		 * scope from a testing perspective as it's not ABI in any way,
 		 * i.e. it really is abusing internal KVM knowledge.
 		 */
-		vcpu_regs_get(vm, VCPU_ID, &regs);
+		vcpu_regs_get(vm, vcpu->id, &regs);
 		if (regs.rcx == 2)
 			regs.rcx = 1;
 		if (regs.rcx == 3)
 			regs.rcx = 8192;
 		memset((void *)run + run->io.data_offset, 0xaa, 4096);
-		vcpu_regs_set(vm, VCPU_ID, &regs);
+		vcpu_regs_set(vm, vcpu->id, &regs);
 	}
 
 	switch (uc.cmd) {