From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: linux-sgx@vger.kernel.org
Cc: luto@kernel.org, Haitao Huang <haitao.huang@linux.intel.com>,
Sean Christopherson <sean.j.christopherson@intel.com>
Subject: Re: [PATCH] x86/sgx: Remove PROT_NONE branch from sgx_encl_may_map().
Date: Tue, 31 Mar 2020 00:13:36 +0300 [thread overview]
Message-ID: <20200330211320.GA1389628@linux.intel.com> (raw)
In-Reply-To: <20200330185452.1382455-1-jarkko.sakkinen@linux.intel.com>
On Mon, Mar 30, 2020 at 09:54:52PM +0300, Jarkko Sakkinen wrote:
> sgx_encl_may_map() always succeeding when PROT_NONE is given is not that
> useful behaviour as one can just well as do an anonymous mapping as
> demonstrated by the change in this patch to the test program. As a
> consequence, remove the special case.
>
> Pratically any possible way to make sure that you don't overwrite anything
> useful in the memory, should be fine. MAP_FIXED does not care what's
> underneath (if you want't it to care you ought to use
> MAP_FIXED_NO_REPLACE).
>
> After this change, the selftest run called sgx_mmap() only three times
> (TCS, text, data) instead of four.
>
> test_sgx-1811 [002] .... 586.907585: sgx_mmap <-mmap_region
> test_sgx-1811 [002] .... 586.911752: sgx_mmap <-mmap_region
> test_sgx-1811 [002] .... 586.911756: sgx_mmap <-mmap_region
>
> This also gives more angles to segregate enclave building and mapping as
> the mmap()'s need to be applied only when the enclave is fully built:
>
> Cc: luto@kernel.org
> Cc: Haitao Huang <haitao.huang@linux.intel.com>
> Cc: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Sean, would be cool if you can try this out soonish because I'm
building on top of this.
I tried you vdso change on a GLK NUC and they seem to work.
/Jarkko
next prev parent reply other threads:[~2020-03-30 21:13 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-30 18:54 [PATCH] x86/sgx: Remove PROT_NONE branch from sgx_encl_may_map() Jarkko Sakkinen
2020-03-30 21:13 ` Jarkko Sakkinen [this message]
2020-04-18 4:37 ` Sean Christopherson
2020-04-20 21:51 ` Jarkko Sakkinen
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