Re: [RFC PATCH v5 092/104] KVM: TDX: Handle TDX PV HLT hypercall

[Paolo Bonzini]

On 4/8/22 06:58, Isaku Yamahata wrote:
> On Thu, Apr 07, 2022 at 05:56:05PM +0200,
> Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
>
> > You didn't answer the other question, which is "Where is R12 documented for
> > TDG.VP.VMCALL<Instruction.HLT>?" though...  Should I be worried? :)
>
> It's publicly documented.
>
> Guest-Host-Communication Interface(GHCI) spec, 344426-003US Feburary 2022.
> 3.8 TDG.VP.VMCALL<Instruction.HLT>
> R12 Interrupt Blocked Flag.
>      The TD is expected to clear this flag iff RFLAGS.IF == 1 or the TDCALL instruction
>      (that invoked TDG.VP.TDVMCALL(Instruction.HLT)) immediately follows an STI
>      instruction, otherwise this flag should be set.

Oh, Google doesn't know about this version of the spec...  It can be 
downloaded from 
https://www.intel.com/content/www/us/en/developer/articles/technical/intel-trust-domain-extensions.html 
though.

I also found VCPU_STATE_DETAILS in 
https://www.intel.com/content/dam/develop/external/us/en/documents/tdx-module-1.0-public-spec-v0.931.pdf:

  Bit 0: VMXIP, indicates that a virtual interrupt is pending
  delivery, i.e. VMCS.RVI[7:4] > TDVPS.VAPIC.VPPR[7:4]

It also documents how it has to be used.  So this looks more or less 
okay, just rename "vmxip" to "interrupt_pending_delivery".

The VCPU_STATE_DETAILS being "non-architectural" is still worrisome.

Paolo