linux-kernel - Re: [PATCH 07/25] x86/sgx: Move PTE zap code to separate function

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Message-ID: <917c53ff755d9a20e1f4bcb48c70add8364d1065.camel@kernel.org>
Date:   Sat, 11 Dec 2021 09:52:11 +0200
From:   Jarkko Sakkinen <jarkko@...nel.org>
To:     Reinette Chatre <reinette.chatre@...el.com>
Cc:     dave.hansen@...ux.intel.com, tglx@...utronix.de, bp@...en8.de,
        luto@...nel.org, mingo@...hat.com, linux-sgx@...r.kernel.org,
        x86@...nel.org, seanjc@...gle.com, kai.huang@...el.com,
        cathy.zhang@...el.com, cedric.xing@...el.com,
        haitao.huang@...el.com, mark.shanahan@...el.com, hpa@...or.com,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 07/25] x86/sgx: Move PTE zap code to separate function

On Mon, 2021-12-06 at 13:30 -0800, Reinette Chatre wrote:
> Hi Jarkko,
> 
> On 12/4/2021 2:59 PM, Jarkko Sakkinen wrote:
> > On Wed, Dec 01, 2021 at 11:23:05AM -0800, Reinette Chatre wrote:
> > > The SGX reclaimer removes page table entries pointing to pages that are
> > > moved to swap. SGX2 enables changes to pages belonging to an initialized
> > > enclave, for example changing page permissions. Supporting SGX2 requires
> > > this ability to remove page table entries that is available in the
> > > SGX reclaimer code.
> > 
> > Missing: why SGX2 requirest this?
> 
> The above paragraph states that SGX2 needs to remove page table entries 
> because it modifies page permissions. Could you please elaborate what is 
> missing?

It does not say why SGX2 requires an ability to remove page table entries.

/Jarkko