Re: [PATCH v19 091/130] KVM: TDX: remove use of struct vcpu_vmx from posted_interrupt.c

Isaku Yamahata
2024-03-28T21:10:37Z

On Thu, Mar 28, 2024 at 04:12:36PM +0800,
Chao Gao <chao.gao@intel.com> wrote:

> On Mon, Feb 26, 2024 at 12:26:33AM -0800, isaku.yamahata@intel.com wrote:
> >@@ -190,7 +211,8 @@ static bool vmx_needs_pi_wakeup(struct kvm_vcpu *vcpu)
> > * notification vector is switched to the one that calls
> > * back to the pi_wakeup_handler() function.
> > */
> >- return vmx_can_use_ipiv(vcpu) || vmx_can_use_vtd_pi(vcpu->kvm);
> >+ return (vmx_can_use_ipiv(vcpu) && !is_td_vcpu(vcpu)) ||
> >+ vmx_can_use_vtd_pi(vcpu->kvm);
>
> It is better to separate this functional change from the code refactoring.

Agreed. Let's split this patch.

> > }
> >
> > void vmx_vcpu_pi_put(struct kvm_vcpu *vcpu)
> >@@ -200,7 +222,8 @@ void vmx_vcpu_pi_put(struct kvm_vcpu *vcpu)
> > if (!vmx_needs_pi_wakeup(vcpu))
> > return;
> >
> >- if (kvm_vcpu_is_blocking(vcpu) && !vmx_interrupt_blocked(vcpu))
> >+ if (kvm_vcpu_is_blocking(vcpu) &&
> >+ (is_td_vcpu(vcpu) || !vmx_interrupt_blocked(vcpu)))
>
> Ditto.
>
> This looks incorrect to me. here we assume interrupt is always enabled for TD.
> But on TDVMCALL(HLT), the guest tells KVM if hlt is called with interrupt
> disabled. KVM can just check that interrupt status passed from the guest.

That's true. We can complicate this function and HLT emulation. But I don't
think it's worthwhile because HLT with interrupt masked is rare. Only for
CPU online.
--
Isaku Yamahata <isaku.yamahata@intel.com>