Re: [PATCH v2 16/25] KVM: TDX: Get system-wide info about TDX module on initialization

[Huang, Kai]

On Wed, 2025-01-08 at 10:34 +0800, Gao, Chao wrote:
> > @@ -147,11 +278,17 @@ static int __init __tdx_bringup(void)
> > 		goto get_sysinfo_err;
> > 	}
> > 
> > +	/* Check TDX module and KVM capabilities */
> > +	if (!tdx_get_supported_attrs(&tdx_sysinfo->td_conf) ||
> > +	    !tdx_get_supported_xfam(&tdx_sysinfo->td_conf))
> > +		goto get_sysinfo_err;
> 
> The return value should be set to -EINVAL before the goto.
> 

Yeah.  Sean actually pointed this out before.  I proposed internally to do below
change to the patch "[PATCH v2 02/25] KVM: TDX: Get TDX global information":

--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -3274,12 +3274,11 @@ static int __init __tdx_bringup(void)
        if (r)
                goto tdx_bringup_err;
 
+       r = -EINVAL;
        /* Get TDX global information for later use */
        tdx_sysinfo = tdx_get_sysinfo();
-       if (WARN_ON_ONCE(!tdx_sysinfo)) {
-               r = -EINVAL;
+       if (WARN_ON_ONCE(!tdx_sysinfo))
                goto get_sysinfo_err;
-       }

.. so that further failures can just 'goto <err_label>'.  I.e., below should be
done to the patch "[PATCH v2 18/25] KVM: TDX: Support per-VM KVM_CAP_MAX_VCPUS
extension check":

        /* Check TDX module and KVM capabilities */
        if (!tdx_get_supported_attrs(&tdx_sysinfo->td_conf) ||
@@ -3319,7 +3318,6 @@ static int __init __tdx_bringup(void)
        if (td_conf->max_vcpus_per_td < num_present_cpus()) {
                pr_err("Disable TDX: MAX_VCPU_PER_TD (%u) smaller than number of
logical CPUs (%u).\n",
                                td_conf->max_vcpus_per_td, num_present_cpus());
-               r = -EINVAL;
                goto get_sysinfo_err;
        }

Alternatively, we can just set ret to -EINVAL before the goto which is a simple
fix to this patch, which probably is easier for Paolo to do.