Re: [PATCH v14 004/113] KVM: TDX: Initialize the TDX module when loading the KVM intel kernel module

[Sean Christopherson]

On Tue, May 30, 2023, Zhi Wang wrote:
> On Sun, 28 May 2023 21:18:46 -0700 isaku.yamahata@xxxxxxxxx wrote:
> > +	/* tdx_enable() in tdx_module_setup() requires cpus lock. */
> > +	cpus_read_lock();
> > +	on_each_cpu(vmx_tdx_on, &err, true);	/* TDX requires vmxon. */
> > +	r = atomic_read(&err);
> > +	if (!r)
> > +		r = tdx_module_setup();
> > +	on_each_cpu(vmx_off, NULL, true);
> 
> Out of curiosity, why VMX has to be turned off after tdx_module_setup()?

KVM has historically enabled VMX if and only if KVM has active VMs.  Whether or
not it still makes sense to do dynamic enabling is debatable, but that's a
discussion for another day.