KVM: VMX: Allocate VPID after initializing VCPU

Do VPID allocation after calling the common kvm_vcpu_init() as a step
towards doing vCPU allocation (via kmem_cache_zalloc()) and calling
kvm_vcpu_init() back-to-back.  Squishing allocation and initialization
together will eventually allow the sequence to be moved to arch-agnostic
creation code.

Note, the VPID is not consumed until KVM_RUN, slightly delaying its
allocation should have no real function impact.  VPID allocation was
arbitrarily placed in the original patch, commit 2384d2b3 ("KVM:
VMX: Enable Virtual Processor Identification (VPID)").
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/vmx.c

@@ -6717,14 +6717,14 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
 		goto free_user_fpu;
 	}
 
-	vmx->vpid = allocate_vpid();
-
 	err = kvm_vcpu_init(&vmx->vcpu, kvm, id);
 	if (err)
 		goto free_vcpu;
 
 	err = -ENOMEM;
 
+	vmx->vpid = allocate_vpid();
+
 	/*
 	 * If PML is turned on, failure on enabling PML just results in failure
 	 * of creating the vcpu, therefore we can simplify PML logic (by
@@ -6835,8 +6835,8 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
 	vmx_destroy_pml_buffer(vmx);
 uninit_vcpu:
 	kvm_vcpu_uninit(&vmx->vcpu);
-free_vcpu:
 	free_vpid(vmx->vpid);
+free_vcpu:
 	kmem_cache_free(x86_fpu_cache, vmx->vcpu.arch.guest_fpu);
 free_user_fpu:
 	kmem_cache_free(x86_fpu_cache, vmx->vcpu.arch.user_fpu);