Message-ID: <1d1eea17-6279-878a-e52a-2a9e9c8452f8@intel.com>
Date:   Fri, 3 Dec 2021 10:49:44 -0800
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Subject: Re: [PATCH 10/25] x86/sgx: Support enclave page permission changes
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To:     Dave Hansen <dave.hansen@intel.com>, <dave.hansen@linux.intel.com>,
        <jarkko@kernel.org>, <tglx@linutronix.de>, <bp@alien8.de>,
        <luto@kernel.org>, <mingo@redhat.com>, <linux-sgx@vger.kernel.org>,
        <x86@kernel.org>
CC:     <seanjc@google.com>, <kai.huang@intel.com>,
        <cathy.zhang@intel.com>, <cedric.xing@intel.com>,
        <haitao.huang@intel.com>, <mark.shanahan@intel.com>,
        <hpa@zytor.com>, <linux-kernel@vger.kernel.org>
References: <cover.1638381245.git.reinette.chatre@intel.com>
 <44fe170cfd855760857660b9f56cae8c4747cc15.1638381245.git.reinette.chatre@intel.com>
 <8087c21c-195b-3ffa-a3ca-542752db6462@intel.com>
From:   Reinette Chatre <reinette.chatre@intel.com>
In-Reply-To: <8087c21c-195b-3ffa-a3ca-542752db6462@intel.com>
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Hi Dave,

On 12/3/2021 10:14 AM, Dave Hansen wrote:
> On 12/1/21 11:23 AM, Reinette Chatre wrote:
>> Enclave page permission changes need to be approached with care and
>> for this reason this initial support is to allow enclave page
>> permission changes _only_ if the new permissions are the same or
>> more restrictive that the permissions originally vetted at the time the
>> pages were added to the enclave. Support for extending enclave page
>> permissions beyond what was originally vetted is deferred.
> 
> It's probably worth adding a few examples here:
> 
>   * RWX => RW => RX => RW => R => RWX
>   * RW => R => RW
>   * RX => R => RX
> 

Indeed - that would make the implications of this change clear.

Will do. Thank you very much.

Reinette