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Peter Anvin" , Ingo Molnar , James Bottomley , Jonathan Adams , Kees Cook , Paul Turner , Thomas Gleixner , linux-mm@kvack.org, linux-security-module@vger.kernel.org, x86@kernel.org Subject: Re: [RFC PATCH 5/7] x86/mm/fault: hook up SCI verification Message-ID: <20190426074223.GY4038@hirez.programming.kicks-ass.net> References: <1556228754-12996-1-git-send-email-rppt@linux.ibm.com> <1556228754-12996-6-git-send-email-rppt@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1556228754-12996-6-git-send-email-rppt@linux.ibm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Apr 26, 2019 at 12:45:52AM +0300, Mike Rapoport wrote: > If a system call runs in isolated context, it's accesses to kernel code and > data will be verified by SCI susbsytem. > > Signed-off-by: Mike Rapoport > --- > arch/x86/mm/fault.c | 28 ++++++++++++++++++++++++++++ > 1 file changed, 28 insertions(+) There's a distinct lack of touching do_double_fault(). It appears to me that you'll instantly trigger #DF when you #PF, because the #PF handler itself will not be able to run. And then obviously you have to be very careful to make sure #DF can, _at_all_times_ run, otherwise you'll tripple-fault and we all know what that does.