Re: [PATCH 11/16] KVM: TDX: Always block INIT/SIPI

[Huang, Kai]

On Thu, 2025-01-09 at 10:26 +0800, Binbin Wu wrote:
> > > > I think we can just say TDX doesn't support vcpu reset no matter due to
> > > > INIT event or not.
> > That's not entirely accurate either though.  TDX does support KVM's version of
> > RESET, because KVM's RESET is "power-on", i.e. vCPU creation.  Emulation of
> > runtime RESET is userspace's responsibility.
> > 
> > The real reason why KVM doesn't do anything during KVM's RESET is that what
> > little setup KVM does/can do needs to be defered until after guest CPUID is
> > configured.
> > 
> > KVM should also WARN if a TDX vCPU gets INIT, no?
> 
> There was a KVM_BUG_ON() if a TDX vCPU gets INIT in v19, and later it was
> removed during the cleanup about removing WARN_ON_ONCE() and KVM_BUG_ON().
> 
> Since INIT/SIPI are always blocked for TDX guests, a delivery of INIT
> event is a KVM bug and a WARN_ON_ONCE() is appropriate for this case.

Can TDX guest issue INIT via IPI?  Perhaps KVM_BUG_ON() is safer?