Re: [PATCH v19 043/130] KVM: TDX: create/free TDX vcpu structure

[Isaku Yamahata]

On Thu, Mar 21, 2024 at 09:30:12AM +0800,
Chao Gao <chao.gao@xxxxxxxxx> wrote:

> >+int tdx_vcpu_create(struct kvm_vcpu *vcpu)
> >+{
> >+	struct kvm_tdx *kvm_tdx = to_kvm_tdx(vcpu->kvm);
> >+
> >+	WARN_ON_ONCE(vcpu->arch.cpuid_entries);
> >+	WARN_ON_ONCE(vcpu->arch.cpuid_nent);
> >+
> >+	/* TDX only supports x2APIC, which requires an in-kernel local APIC. */
> 
> Cannot QEMU emulate x2APIC? In my understanding, the reason is TDX module always
> enables APICv for TDs. So, KVM cannot intercept every access to APIC and forward
> them to QEMU for emulation.

You're right. Let me update it as follows.

  /*
   * TDX module always enables APICv for TDs. So, KVM cannot intercept every
   * access to APIC and forward them to user space VMM.
   */



> >+	if (!vcpu->arch.apic)
> 
> will "if (!irqchip_in_kernel(vcpu->kvm))" work? looks this is the custome for such
> a check.


It should work because kvm_arch_vcpu_create().  Will update it.
-- 
Isaku Yamahata <isaku.yamahata@xxxxxxxxx>