[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v1 3/6] x86: Enable Supervisor Mode Execution Prevention (SMAP) for Xen
On 15/04/14 15:16, Jan Beulich wrote: >>>> On 15.04.14 at 16:09, <andrew.cooper3@xxxxxxxxxx> wrote: >> And having just sent this email, I further realise that functions like >> show_page_walk() need protection against SMAP otherwise we will take a >> recursive fault when trying to dump the error information from the first >> fault. I don't recall any of your other patches dealing with this. > I don't follow: page table walks are done using map_domain_page(), > which ought to not produce user mode accessible mappings. Or did > you mean to say "may" instead of "will", and meant to do this just to > be on the safe side? > > Jan > Hmm yes - in retrospect we shouldn't actually take faults from domain mapped pages. However for the safe side of things, we don't want to be taking recursive faults in a panic scenario, so it might be a good idea to preemptively stac() on terminal error paths. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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