Messages in this thread | | | Subject | Re: [PATCH v5 11/17] arm64: docs: document pointer authentication | From | Jon Masters <> | Date | Fri, 2 Nov 2018 02:02:03 -0400 |
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On 10/19/18 1:45 PM, Will Deacon wrote:
>>> I think an alternative solution is to just disable trapping of pointer >>> auth instructions in KVM. This will mean that the instructions will >>> behave the same in the guest as they do in the host. HINT-space >>> instructions (including XPACLRI) will behave as NOPs (or perform their >>> function, if enabled by the guest), and will not trap. >> >> OK, so this means disabling the trap (during early EL2 setup) but still >> sanitizing the CPUID not to report the feature to EL1 unless fully >> supported on all CPUs. > > ... which is perfectly sensible, but not actually my main concern here. > I'm worried about the possibility of distributions shipping *now* with > userspace that's built with these instructions. That stuff is going to > break if/when it encounters v8.3 hardware, and I don't think we can do > much about it other than alert them to the potential issue.
FYI tracking this for RHEL. It's not a problem currently. I'll alert our tools teams to hold off on any PAC work until this is figured out.
Jon.
-- Computer Architect | Sent with my Fedora powered laptop
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