linux-kernel - Re: [PATCH v19 011/130] KVM: Add new members to struct kvm_gfn

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Date: Fri, 26 Apr 2024 13:50:46 +0000
From: "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
To: "tabba@...gle.com" <tabba@...gle.com>, "Yamahata, Isaku"
	<isaku.yamahata@...el.com>
CC: "Zhang, Tina" <tina.zhang@...el.com>, "seanjc@...gle.com"
	<seanjc@...gle.com>, "Huang, Kai" <kai.huang@...el.com>,
	"binbin.wu@...ux.intel.com" <binbin.wu@...ux.intel.com>, "Chen, Bo2"
	<chen.bo@...el.com>, "sagis@...gle.com" <sagis@...gle.com>,
	"isaku.yamahata@...ux.intel.com" <isaku.yamahata@...ux.intel.com>,
	"isaku.yamahata@...il.com" <isaku.yamahata@...il.com>, "Aktas, Erdem"
	<erdemaktas@...gle.com>, "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
	"pbonzini@...hat.com" <pbonzini@...hat.com>, "Yuan, Hang"
	<hang.yuan@...el.com>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v19 011/130] KVM: Add new members to struct kvm_gfn_range
 to operate on

On Fri, 2024-04-26 at 08:39 +0100, Fuad Tabba wrote:
> > I'm fine with those names. Anyway, I'm fine with wither way, two bools or
> > enum.
> 
> I don't have a strong opinion, but I'd brought it up in a previous
> patch series. I think that having two bools to encode three states is
> less intuitive and potentially more bug prone, more so than the naming
> itself (i.e., _only):
> https://lore.kernel.org/all/ZUO1Giju0GkUdF0o@google.com/

Currently in our internal branch we switched to:
exclude_private
exclude_shared

It came together bettter in the code that uses it.

But I started to wonder if we actually really need exclude_shared. For TDX
zapping private memory has to be done with more care, because it cannot be re-
populated without guest coordination. But for shared memory if we are zapping a
range that includes both private and shared memory, I don't think it should hurt
to zap the shared memory.