linux-kernel - Re: [PATCH v19 117/130] KVM: TDX: Silently ignore INIT/SIPI

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Date: Fri, 19 Apr 2024 11:06:53 -0700
From: Isaku Yamahata <isaku.yamahata@...el.com>
To: Binbin Wu <binbin.wu@...ux.intel.com>
Cc: isaku.yamahata@...el.com, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org, isaku.yamahata@...il.com,
	Paolo Bonzini <pbonzini@...hat.com>, erdemaktas@...gle.com,
	Sean Christopherson <seanjc@...gle.com>,
	Sagi Shahar <sagis@...gle.com>, Kai Huang <kai.huang@...el.com>,
	chen.bo@...el.com, hang.yuan@...el.com, tina.zhang@...el.com,
	isaku.yamahata@...ux.intel.com
Subject: Re: [PATCH v19 117/130] KVM: TDX: Silently ignore INIT/SIPI

On Fri, Apr 19, 2024 at 04:31:54PM +0800,
Binbin Wu <binbin.wu@...ux.intel.com> wrote:

> 
> 
> On 2/26/2024 4:26 PM, isaku.yamahata@...el.com wrote:
> > From: Isaku Yamahata <isaku.yamahata@...el.com>
> > 
> > The TDX module API doesn't provide API for VMM to inject INIT IPI and SIPI.
> > Instead it defines the different protocols to boot application processors.
> > Ignore INIT and SIPI events for the TDX guest.
> > 
> > There are two options. 1) (silently) ignore INIT/SIPI request or 2) return
> > error to guest TDs somehow.  Given that TDX guest is paravirtualized to
> > boot AP, the option 1 is chosen for simplicity.
> > 
> > Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
> > ---
> [...]
> > +
> > +static void vt_vcpu_deliver_init(struct kvm_vcpu *vcpu)
> > +{
> > +	if (is_td_vcpu(vcpu)) {
> > +		/* TDX doesn't support INIT.  Ignore INIT event */
> > +		vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
> Why change the mp_state to KVM_MP_STATE_RUNNABLE here?
> 
> And I am not sure whether we can say the INIT event is ignored since
> mp_state could be modified.

We should drop the line.  Now it's not necessary and KVM_TDX_INIT_VCPU change
it.
-- 
Isaku Yamahata <isaku.yamahata@...el.com>