linux-kernel - Re: [PATCH 13/21] KVM: TDX: Handle TLB tracking for TDX

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Message-ID: <6b9671bfdc7f1e8dab0ede65fa7c7e76f0358a06.camel@intel.com>
Date: Wed, 11 Sep 2024 17:28:18 +0000
From: "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
To: "yilun.xu@...ux.intel.com" <yilun.xu@...ux.intel.com>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"seanjc@...gle.com" <seanjc@...gle.com>, "Huang, Kai" <kai.huang@...el.com>,
	"isaku.yamahata@...il.com" <isaku.yamahata@...il.com>, "Zhao, Yan Y"
	<yan.y.zhao@...el.com>, "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
	"pbonzini@...hat.com" <pbonzini@...hat.com>, "nik.borisov@...e.com"
	<nik.borisov@...e.com>, "dmatlack@...gle.com" <dmatlack@...gle.com>
Subject: Re: [PATCH 13/21] KVM: TDX: Handle TLB tracking for TDX

On Wed, 2024-09-11 at 14:25 +0800, Xu Yilun wrote:
> > +static void vt_flush_tlb_all(struct kvm_vcpu *vcpu)
> > +{
> > +       /*
> > +        * TDX calls tdx_track() in tdx_sept_remove_private_spte() to ensure
> > +        * private EPT will be flushed on the next TD enter.
> > +        * No need to call tdx_track() here again even when this callback is
> > as
> > +        * a result of zapping private EPT.
> > +        * Just invoke invept() directly here to work for both shared EPT
> > and
> > +        * private EPT.
> 
> IIUC, private EPT is already flushed in .remove_private_spte(), so in
> theory we don't have to invept() for private EPT?

I think you are talking about the comment, and not an optimization. So changing:
"Just invoke invept() directly here to work for both shared EPT and private EPT"
to just "Just invoke invept() directly here to work for shared EPT".

Seems good to me.