linux-kernel - Re: [PATCH 04/16] KVM: x86/mmu: Add address conversion functions for TDX shared bit of GPA

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Date: Thu, 16 May 2024 01:20:11 +0000
From: "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
To: "kvm@...r.kernel.org" <kvm@...r.kernel.org>, "pbonzini@...hat.com"
	<pbonzini@...hat.com>, "seanjc@...gle.com" <seanjc@...gle.com>, "Huang, Kai"
	<kai.huang@...el.com>
CC: "Zhao, Yan Y" <yan.y.zhao@...el.com>, "sagis@...gle.com"
	<sagis@...gle.com>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "Aktas, Erdem" <erdemaktas@...gle.com>,
	"isaku.yamahata@...il.com" <isaku.yamahata@...il.com>, "dmatlack@...gle.com"
	<dmatlack@...gle.com>
Subject: Re: [PATCH 04/16] KVM: x86/mmu: Add address conversion functions for
 TDX shared bit of GPA

On Thu, 2024-05-16 at 13:04 +1200, Huang, Kai wrote:
> 
> I really don't see difference between ...
> 
>         is_private_mem(gpa)
> 
> ... and
> 
>         is_private_gpa(gpa)
> 
> If it confuses me, it can confuses other people.

Again, point taken. I'll try to think of a better name. Please share if you do.

> 
> The point is there's really no need to distinguish the two.  The GPA is 
> only meaningful when it refers to the memory that it points to.
> 
> So far I am not convinced we need this helper, because such info we can 
> already get from:
> 
>    1) fault->is_private;
>    2) Xarray which records memtype for given GFN.
> 
> So we should just get rid of it.

Kai, can you got look through the dev branch a bit more before making the same
point on every patch?

kvm_is_private_gpa() is used to set PFERR_PRIVATE_ACCESS, which in turn sets
fault->is_private. So you are saying we can use these other things that are
dependent on it. Look at the other callers too.