KVM: VMX: Move caching of MSR_IA32_XSS to hardware_setup()

MSR_IA32_XSS has no relation to the VMCS whatsoever, it doesn't belong
in setup_vmcs_config() and its reference to host_xss prevents moving
setup_vmcs_config() to a dedicated file.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/vmx.c

@@ -4740,9 +4740,6 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
 		}
 	}
 
-	if (boot_cpu_has(X86_FEATURE_XSAVES))
-		rdmsrl(MSR_IA32_XSS, host_xss);
-
 	return 0;
 }
 
@@ -7917,6 +7914,9 @@ static __init int hardware_setup(void)
 		WARN_ONCE(host_bndcfgs, "KVM: BNDCFGS in host will be lost");
 	}
 
+	if (boot_cpu_has(X86_FEATURE_XSAVES))
+		rdmsrl(MSR_IA32_XSS, host_xss);
+
 	if (!cpu_has_vmx_vpid() || !cpu_has_vmx_invvpid() ||
 		!(cpu_has_vmx_invvpid_single() || cpu_has_vmx_invvpid_global()))
 		enable_vpid = 0;