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From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: luto@kernel.org, linux-sgx@vger.kernel.org
Subject: Re: sgx_encl_may_map()
Date: Fri, 23 Aug 2019 13:37:09 -0700	[thread overview]
Message-ID: <20190823203709.GA24772@linux.intel.com> (raw)
In-Reply-To: <20190823150248.kuxgdxyd4z5wlsz5@linux.intel.com>

On Fri, Aug 23, 2019 at 06:02:48PM +0300, Jarkko Sakkinen wrote:
> Hi
> 
> Couple of remarks that are not reasoned in the code too well:
> 
> 1. Why to allow to mmap() to a range where pages have differing
>    permissions? I think it would be better just to require all
>    pages in a range to have the same permissions.

You mean different vm_max_prot_bits?  I don't think we should deny
mapping a mix of R and RW pages with PROT_READ, e.g. map read-only but
have the option to make select pages writable in the future.

> 2. Why not require exact match with the PROT bits?

Toggling W in particular in the PTEs likely has value, e.g. initialize
data with runtime info and then lock the range in the PTEs.

  parent reply	other threads:[~2019-08-23 20:37 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-23 15:02 sgx_encl_may_map() Jarkko Sakkinen
2019-08-23 16:04 ` sgx_encl_may_map() Jarkko Sakkinen
2019-08-23 16:27   ` sgx_encl_may_map() Jarkko Sakkinen
2019-08-23 20:37 ` Sean Christopherson [this message]
2019-08-26  2:56   ` sgx_encl_may_map() Jarkko Sakkinen

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