From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: linux-sgx@vger.kernel.org, Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCH] x86/sgx: Pass userspace source address directly to EADD
Date: Mon, 26 Aug 2019 09:32:06 +0300 [thread overview]
Message-ID: <20190826063206.hx3gk7ma5f2qa6uc@linux.intel.com> (raw)
In-Reply-To: <20190823021009.3880-1-sean.j.christopherson@intel.com>
On Thu, Aug 22, 2019 at 07:10:09PM -0700, Sean Christopherson wrote:
> Invoke EADD with the userspace source address instead of first copying
> the data to a kernel page to avoid the overhead of alloc_page() and
> copy_from_user().
>
> Remove all pre-validation of TCS pages. The source page is no longer
> readily available since it's not copied into the kernel, and validating
> the TCS essentially requires accessing the entire page since the vast
> majority of the TCS is reserved bytes. Given that userspace can now
> cause EADD to fault simply by passing a bad pointer, validating the TCS
> to avoid faults on EADD provides little to no value.
>
> Suggested-by: Andy Lutomirski <luto@kernel.org>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
I already merged this to my tree but just realized that the commit
message does not address why get_user_pages() is no option.
/Jarkko
next prev parent reply other threads:[~2019-08-26 6:32 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-23 2:10 [PATCH] x86/sgx: Pass userspace source address directly to EADD Sean Christopherson
2019-08-23 13:44 ` Jarkko Sakkinen
2019-08-26 6:32 ` Jarkko Sakkinen [this message]
2019-08-27 1:20 ` Sean Christopherson
2019-08-27 12:30 ` Jarkko Sakkinen
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