Messages in this thread | | | Date | Fri, 2 Mar 2018 10:07:37 +0100 | From | Joerg Roedel <> | Subject | Re: [PATCH 12/31] x86/entry/32: Add PTI cr3 switch to non-NMI entry/exit points |
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On Thu, Mar 01, 2018 at 01:24:39PM -0500, Brian Gerst wrote: > The IF flag only affects external maskable interrupts, not traps or > faults. You do need to check CR3 because SYSENTER does not clear TF > and will immediately cause a debug trap on kernel entry (with user > CR3) if set. That is why the code existed before to check for the > entry stack for debug/NMI.
Yeah, okay, thanks for the clarification. This also means the #DB handler needs to leave with the same cr3 as it entered. I'll work that into my patches.
Thanks,
Joerg
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